Ide v ATB Sales Ltd

This is a single issue case. The claimant suffered very serious head injuries when he fell from his Marin Rift Zone bike as he rode along a bridleway in the South Downs on 21^st April 2002. It is common ground that the left handlebar of the bike fractured. The question which I have to decide is whether the fracture occurred because the handlebar was defective or whether the handlebar fractured as a result of the claimant falling from his bike.

The case for the claimant is that the handlebar was defective in that it suddenly snapped causing him to lose control and fall off the bike, hitting his head on the ground. The case for the defendant is that the claimant somehow lost control of the bike and fell off it with the result that the handlebar fractured during the fall. The defendant denies that the handlebar was defective and accordingly denies there was any defect to cause the damage suffered by the claimant.

This is a trial of liability only.

The claimant Mr Alan Ide was aged 43 at the time of his accident. After being made redundant, Mr Ide started working as a freelance bookkeeper in 1990. Some years later Mr Ide and his wife, together with two friends, formed a company whose business was to provide accountancy services to small businesses. The business flourished.

The business of the defendant, ATB Sales Limited (“ATB”), includes the importation and distribution within the UK of bikes designed and manufactured by other companies. One such company is Marin Mountain Bike Inc, a company incorporated in the US, which designs bikes and sub-contracts their manufacture to other companies. At the material times the Marin bikes were assembled by a sub-contractor in Taiwan.

On 30^th March 1999 Mr Ide purchased from a specialist Marin dealer trading as Freedom Bikes the Marin Rift Zone bike which he was riding at the time of his accident. The model is called a “Full Suspension Mountain Bike”. It is aluminium framed and has full suspension on both wheels. Mr Ide paid £1,295 for it.

The bike had been imported by ATB and distributed to Freedom Bikes. Included in the papers is a Marin Owner’s Manual, the first page of which contains the following warning:

The handlebars are straight rather than dropped. At both ends of the handlebars there are “bar ends” which are attached to the end of the handlebars and project forwards and upwards at about 45%.

Mr Ide’s evidence (which I accept) is that he ensured that the Marin was well-maintained and regularly serviced. He did own another off-road bike but the Marin was the one which he used for off-road riding.

By the time of his accident Mr Ide had been riding the Marin for just over 3 years. Mr Ide had been biking off-road almost every weekend for about a year before he acquired the Marin. He was in the habit of going out riding on a Sunday morning with three regular companions. They would ride for about two hours covering about 20 miles. Mr Ide usually went out on another similar ride each week. He would wear a helmet, cycling shorts and special cycling shoes, which clipped into the pedals.

Before I come to the events of 21^st April 2002, I will set out the legal basis on which the claim is founded. The Particulars of Claim include a claim in negligence. That claim has not been pursued. The reason is that the Consumer Protection Act, 1987 imposes strict liability on the importer of goods. This claim is based on that Act.

The material provisions of the 1987 Act are these:

Accordingly the central issue in this case is whether the claimant can establish that it is more probable than not that he fell from his bike because there was a defect in the bike within the meaning of section 3(1) of the Act which led to the handlebar fracturing, thereby causing the claimant to fall from the bike.

ATB’s answer to the claim under the 1987 Act is to be found at paragraph 3(iii) of the Amended Defence:

It is also pleaded that the bike was manufactured in accordance with the relevant British and Japanese Standards.

The accident happened on 21^st April 2002, which was a Sunday. Mr Ide has no recollection of the events of that day because he has post-traumatic amnesia of almost four weeks.

Accompanying him on the bike ride that day were two of Mr Ide’s regular biking companions, namely Paul Davis and Antony Martin, both of whom gave evidence. They are also experienced off-road bikers.

According to their evidence, the three of them met at 8am that day. The route which they took ran along the South Downs Way. They went westwards and decided to follow the South Downs Way halfway down towards the A24. Their plan was to return home along the foot of the scarp slope of the Downs. It was a route which they had all three cycled many times before.

Mr Martin’s evidence was that the conditions were clear; the tracks on top of the Downs had puddles in places but the tyres were gripping well on the tracks and the chalk was not greasy. He described the conditions as “pretty mild”. Mr Davis’s evidence was to a similar effect.

The part of the track where the accident happened was said by Mr Ide to run downhill but not very steeply. He estimated the gradient to be about 1:7. Mr Martin’s evidence was that the track drops about 450 feet over a quarter of a mile. Mr Davis described the surface of the track at the point where the accident happened as being quite wide, consisting of chalk with a small number of small stones. According to Mr Martin, there was normally a rut to the left hand side of a descending rider but he said that the rut was “not difficult”.

Mr Ide led the way down, followed by Mr Martin with Mr Davis (who is less experienced than the other two) bringing up the rear. The gaps between them were thought by Mr Martin to be about 20 seconds. Mr Martin estimated his speed as having been about 18 mph. Mr Ide’s evidence was that he would have been out of his saddle, holding the handlebars and standing on the pedals.

Neither Mr Martin nor Mr Davis saw the accident because it happened when Mr Ide was out of their sight round a bend. As he came round that bend, Mr Martin saw Mr Ide lying motionless slightly to the right hand side of the track. He was not moving or breathing because his airways were constricted by his tongue. Mr Martin pulled his tongue free. Mr Martin’s recollection is that the bike was lying across Mr Ide’s legs. Both Mr Ide and his bike were facing the same way. It seemed to Mr Martin that Mr Ide had fallen “with the bike”. Mr Martin’s abiding impression is that something catastrophic had occurred to make Mr Ide crash in that manner. He thought that Mr Ide had just stopped where he hit the ground rather than rolled down the hill. Both Mr Martin and Mr Davis noticed immediately that the left hand end of Mr Ide’s handlebar had snapped off.

Although he was wearing a cycling helmet, Mr Ide sustained a very severe closed head injury with significant brain damage. He has suffered permanent neurological and neuropsychological damage with impairment of cognitive function. There was another minor injury to the inside of the left thigh about six inches above the knee.

The evidence in the case comes predominantly from experts on either side. Before I come to that body of evidence, however, I will summarise the evidence of Mr Joe Higgins who was called as a witness of fact by the defence. The significance of Mr Higgins’s evidence is, as it appears to me, that Dr Chinn one of ATB’s experts, places reliance on data obtained by Mr Higgins.

Mr Higgins has recently completed a Masters degree in mechanical engineering at Exeter University. He is also an experienced biker. Whilst a student he did some load measuring work for ATB. In late 2005, at which time he was studying for his Masters degree, Mr Higgins was asked to ride a Marin FRS Mountain Bike, fitted with Marin Lite handlebars measuring 530 millimetres in width and manufactured from 6061 aluminium alloy by a firm named Sameness. The rides were to take place along the bridleway in the South Downs where the accident happened. The object of the exercise was to measure on behalf of ATB the force applied to the handlebars in conditions similar to those encountered by Mr Ide on 21^st April 2002.

Mr Higgins told me that ATB bought some of the equipment necessary for the testing and that he had borrowed other equipment. The device used to measure the force supplied to the handlebars is a logger the trade name of which is “DataTaker” which is manufactured by an Australian company called Datataker Pty Limited. Mr Higgins said that he received advice over the phone from Datataker how to set up and use the logger. Having taken that advice, Mr Higgins set the logger at 90 Hz per second, which enabled 90 readings to be taken per second of the force applied to the handlebars.

Mr Higgins recorded a total of 6 runs at 2 locations. He travelled at speeds ranging from 18 to 28 mph. He rode standing on the pedals and holding the grips of the handlebars. The recorded loadings measured by Mr Higgins indicated that the maximum force measured was 32.6kg. Mr Higgins then loaded the measurement data on to a disc and provided it to ATB’s solicitors.

In the course of cross-examination, Mr Higgins agreed that he could have tested at a higher frequency, namely 110 Hz, which would have enabled 110 readings to be taken per second. He conceded that, having used the lower frequency, it was possible that he missed peak loadings which might have occurred for example where a rapid increase in the load occurred. Asked whether there was data from additional runs which had been discarded, Mr Higgins agreed that this might have happened, for instance when he had not kept the logger switched on for an entire length of run. Mr Higgins also agreed that he would have discarded data in cases where the memory of the logger had run out during a run. He accepted that there would have been data which he obtained but which was not transmitted to Dr Chinn.

Mr Higgins was also asked in cross-examination whether he had recorded higher readings in relation to the Marin bike than those which he provided to ATB’s solicitors. At first Mr Higgins seemed uncertain whether or not this had occurred. However, he did recall recording force measurements made in a car park on the Isle of Wight. These measurements were substantially higher than those recorded on the South Downs bridleway, possibly as high as 700 Newtons (70 kilograms). In re-examination Mr Higgins explained that the reading of 700 Newtons was taken when he lifted the front wheel of the bike and slammed it down on one side of the handlebars. He was asked in cross-examination about an email which he sent (for reasons which for present purposes do not matter) to Dr Morgan, who is one of the claimant’s experts, on 12^th June 2006. In the email Mr Higgins told Dr Morgan that his test had revealed forces on the handlebars ranging between 200 and 700 Newtons.

Each side called two experts: Mr Robert Bachelard, a materials engineer with Burgoynes and Dr John Morgan, Senior Lecturer in Material Science at the Department of Mechanical Engineering at Bristol University, who has some metallurgical experience, gave evidence for Mr Ide. Mr David Price, a Traffic Accident Investigator whose degree in Materials Science and Technology, covered metallurgy and Dr Bryan Chinn, also an experienced Traffic Accident Investigator, gave evidence for ATB. I will summarise their evidence in the order in which they entered the witness box, that is, Mr Bachelard first and then Mr Price, Dr Morgan and Dr Chinn.

In his report Mr Bachelard described the handlebars of Mr Ide’s bike thus: it was a straight handlebar with a large diameter, thick-walled central section that connected to the centre stem. The handlebar then tapered downwards, in both diameter and wall thickness, reaching a minimum diameter of 22.2mm and minimum wall thickness of 1.3mm at approximately 87.5mm from the centre of the handlebars. The handlebar then remained the same diameter and wall thickness along its length to the left and right hand side ends. He noted that fracture of the left hand side and bending of the right hand side of the handlebar had both occurred at 87.5mm from the centre of the handlebar. That indicates that this was the weakest point on each side of the handlebars.

Mr Bachelard’s examination of the handlebar revealed that the left hand side failed due to ductile fracture. The evidence indicated in his opinion that failure was due to a single overload. He found no evidence of fatigue crack growth and no evidence of any pre-existing mechanical defects or gross metallurgical defects that might have weakened the handlebar prior to the incident.

The evidence indicated to Mr Bachelard that overload failure was caused by a single vertical bending load applied through the left hand side grip around the centre of the handlebar with the top surface of the handlebar in tension. In Mr Bachelard’s opinion, whilst it is possible that the downward direction of loading through the handlebar grips could have resulted as the bike impacted the ground (i.e. as a result of the incident), Mr Bachelard found no physical evidence, such as damage to the left hand side handlebar end, to support such an event. His view is that the direction of the bending of the right hand side of the handlebar was consistent with having been caused by the right hand end of the handlebar impacting the ground.

Mr Bachelard’s calculations indicated that a load of 75kg at the grip area was required to cause yielding or bending of the handlebars outer surface and a load of 100kg at the same point to cause fracture of the handlebars. These loadings appeared to him to be low for handlebars designed specifically for the rough terrain of mountains.

Mr Bachelard’s conclusions were that the fracture of the aluminium handlebar was caused by a single overload. Although the physical evidence was consistent with an overload caused during “normal” riding of the bike, the possibility that overload could have occurred as the bike impacted the ground could not be ruled out.

Turning to the evidence of Mr Price, called on behalf of ATB, in his first report he expressed the opinion, based on what he had been told by Mr Bachelard about the failed handlebar, that the failure was by ductile rupture, characteristic of overload, and bore no signs of fatigue cracking or other defects. Mr Price examined an identical bar Marin provided to him by ATB and two other handlebars of similar design but of different origin. He reported that the handlebar that failed showed no “remarkable deformation” until the force applied had reached about 135kg. He found that the Marin handlebar which he tested performed in a similar manner to the two competitors’ handlebars with which he had been supplied. His conclusion was the handlebar of Mr Ide’s bike must have been loaded excessively to have failed.

Mr Price prepared a second report after he had examined the main section of the handlebar of Mr Ide’s bike. He did not, however, see the area to the left of the break because it had been sent to another expert, Dr Bulpett (who was not called to give evidence). In this report he described the impact test carried out at the suggestion of Dr Morgan in order to determine if the CNC machining of the handlebars caused them to be “notch sensitive”. The machining in question resulted in shallow circular grooves being present at regular intervals along the width of the handlebars. Their function was decorative. Optical microscopic investigation revealed some dirt on the surface at the failed left hand side. Basing himself on photographs produced by SEM investigation, taken by Dr Bulpett, Mr Price confirmed that they showed signs of plastic deformation and failure by ductile tearing but that none showed signs of fatigue cracking or signs of the handlebar being partially torn on an earlier occasion. On examination of the right hand side of the handlebar, Mr Price found failure by ductile tearing over almost all areas. At about the mid point from where it had torn, he found evidence of crushing and smearing of the surface. In that area he found what appeared to him to be faint fatigue striation marks.

Mr Price’s conclusions at the time of his second report were that the grooves resulting from the CNC machining of the handlebar were not likely to cause a handlebar to tear in an impact, as it would normally bend rather than tear. He found that the right hand side of the handlebar, where it tore in the slow bend test, showed evidence of having been cracked prior to testing probably by fatigue. The depth of the cracking was very small. As to the left side of Mr Ide’s handlebar, Mr Price found no signs of previous cracking apparent in the photographs but, since he had not had the opportunity to examine that area in detail, he could not confirm or deny the presence of previous cracking. Mr Price added that swaging of the handlebar does not in itself cause the handlebar to tear, although it is the weakest point and is where the handlebar will bend if a large amount of force is applied to it.

In the statement made jointly by Mr Bachelard and Mr Price after discussing the case, both agreed that the direction of fracture is likely to have been downwards and forwards; that the fracture in the left hand side was associated with some plastic deformation in the tube material adjacent to the line of fracture; and that the external surfaces of the handlebars showed no evidence of any pre-existing damage, either as a result of normal service conditions or abuse that may have weakened the handlebars prior to the incident. They agreed that the mode of failure was ductile overload failure, that is the single application of a load or force that exceeded the strength of the component and was therefore sufficient to cause failure.

According to their joint statement the SEM photographs showed no evidence of other features, such as pre-existing cracks or gross metallurgical defects on the fracture surfaces. Mr Bachelard and Mr Price were agreed that the fracture would have been sudden and complete resulting in “catastrophic failure”. They agreed that the small amount of red staining on the fracture surfaces was most likely due to post-incident contamination and so not indicative of a pre-existing crack in the handlebar. They further agreed that the bending and sudden partial fracture of the right hand side of Mr Ide’s handlebars (which happened on testing after the accident) occurred at a force of about 110kg.

Mr Price had reported that he had observed a small region on the SEM photographs which exhibited fine ripples which he considered might be indicative of a pre-existing crack possibly caused by fatigue. However, following discussion with Mr Bachelard, Mr Price accepted that those features are not indicative of a pre-existing crack in the handlebars prior to testing. Mr Bachelard and Mr Price therefore agreed that, when tested, the right hand side of Mr Ide’s handlebars had failed by ductile fracture at a load in the order of 110kg and that fracture was not associated with, or precipitated by, a pre-existing crack in the handlebars. This clearly represented a significant shift from the opinion which Mr Price had expressed in his second report.

In summary Mr Bachelard and Mr Price agreed that Mr Ide’s handlebars, at the time of the incident and during testing respectively, initially bent and then failed by sudden ductile overload fracture. By comparison, new Marin handlebars of the same design as Mr Ide’s, when overloaded in testing, failed by bending only with no evidence of fracture. Accordingly Mr Ide’s handlebars behaved differently when compared to the behaviour of the new handlebars tested. Notwithstanding this, Mr Bachelard and Mr Price agreed that this did not appear to be associated with, or precipitated by, pre-existing cracks or other service-induced defects in the handlebars. They agreed that Mr Ide’s handlebar was of a lower strength and more brittle than new handlebars of the same design. The physical evidence indicated that Mr Ide’s handlebar was likely to have been manufactured in that condition. It was possible, according to the two experts, that slight differences in the swaging, CNC machining, heat treatment and/or material properties could have resulted in Mr Ide’s handlebars having a slightly reduced strength and a greater propensity to fracture when compared to new handlebars.

In his oral evidence Mr Price said that there was a tiny machining defect on Mr Ide’s left hand handlebar. He agreed it was unfortunate that both ends of the handlebar had not been tested jointly. He said that a three year old bar would be in the same condition as a new one. However, depending on the use to which the bike had been put, there could be fatigue damage. He said that the damage to the extension bar of the right handlebar appeared to be damage which had occurred as a result of a severe levering effect.

Asked about the differing loads at which the various bars had begun to bend, Mr Price said he had expected Mr Ide’s bar to be the same as the other bars. (The Halford bar had been loaded to 160kg before bending; the comparator Marin bar was loaded to 130kg before bending and Mr Ide’s bar was loaded to no more than 110kg at the time when it fractured). Mr Price expressed surprise: he had not seen a fracture occur before and he considered that there was something different about Mr Ide’s bar. However the amount of the force or load was still considerable and he did not accept that there was a major defect in the bar, although he agreed that of all the bars tested Mr Ide’s bar was the only one which fractured.

Asked about the tear which had been revealed by Dr Bulpett’s SEM photos, Mr Price agreed that he had originally accepted that there was a very small depth of cracking at the point where the bar split but said that he had subsequently accepted that the damage in the stained area occurred after the accident. Whilst at the time of his written report he had thought that there might be fatigue which had induced ductile fracture, he had changed his view after discussing the matter with Mr Bachelard. He was not prepared to agree that fatigue striations are the only reliable indicators of fatigue failure. The absence of fatigue striations is not evidence that there was no fatigue. He was unable to explain what the striations found by Dr Bulpett were. Their position was in an area of unequivocal ductile rupture. According to Mr Price, one cannot have the two phenomena at the same location.

In re-examination Mr Price confirmed that, on the basis of the information provided by the SEM photographs, he was able to say that there was no sign of any pre-existing crack or fatigue. The machining did not in his opinion cause sensitivity such as would lead to a fracture.

I start with the evidence of Dr Morgan. He said that theoretically a load of about 82kg on the relevant part of the handlebar would cause a fracture. He said that repetitive cycle loads greater than 25kg would eventually cause a fatigue failure. In his opinion it was clear that the bar was under-designed for the loads that might be applied to it. He relied in that connection on information provided to him on a confidential basis by a Mr D Wright, who had suggested that forces in the range 78 to 93kg can typically occur when riding over rough ground. Dr Morgan later obtained a copy of the report (“the Murray report”) setting out this information. Dr Morgan pointed out that, when a Marin bar identical to Mr Ide’s was tested, it bent (but did not fracture) when a load of about 140kg was applied to it.

Dr Morgan examined the fracture surface of Mr Ide’s broken handlebar and noted that around the fracture line there appeared to be a small piece of metal missing. Microscopic examination showed that one side of the hole was stained light brown and the staining runs through the whole wall thickness. This suggested a stain that had developed over time by moisture leaching into a crack. In Dr Morgan’s opinion this staining strongly suggested that final catastrophic failure occurred after a fatigue crack had been developed in the handlebar.

Dr Morgan considered it to be extremely unlikely that (as Dr Chinn believed to have been the case) an impact by Mr Ide’s falling body upon the left hand handlebar could have generated a force sufficient to cause the handlebar to fracture. Dr Morgan pointed out that bodies are relatively soft objects and have a relatively large frontal area. Moreover the handlebars are free to rotate about the steering column of the bike. Dr Morgan found it hard to imagine how Mr Ide had subsequently ended up lying on the ground on his right hand side, still more or less on the bike, if the mechanism of the accident was as suggested by Dr Chinn. Dr Morgan saw no basis for the supposition that Mr Ide had been thrown over the handlebars.

Dr Morgan’s opinion was that a fatigue crack existed at the time of the accident and that the handlebar had snapped in a classic fast-fracture fatigue failure, causing Mr Ide to lose control of his bike and fall off. Dr Morgan also challenged Dr Chinn’s conclusions, firstly, that the handlebar fractured as a result of a single overload and, secondly, that the right side of the handlebar revealed significant levels of bending. (Dr Chinn subsequently admitted that he had not realised that the handlebars were designed with a bend in them).

Dr Morgan reported that fatigue failures result when a component has been cyclically loaded, usually at relatively low levels of stress, for a prolonged period of time. According to Dr Morgan, a fatigue crack is normally impossible to see by visual examination, especially if the crack has propagated from the bottom of a machined groove such as the one on Mr Ide’s handlebar. Dr Morgan relied on a publication entitled “Metals Handbook”, published by the American Society for Metals, which stated that the absence of beachmarks, cracking and striations is not evidence that the fracture of a bar is not due to fatigue.

In a further report Dr Morgan commented on slow loading tests referred to at paragraph (44) above. In the tests both the Halford bar and an identical Marin bar failed by bending but neither exhibited any evidence of fracture. The maximum loads applied were 158kg for the Halford bar and 130kg for the Marin bar. A further test was performed on the right hand side of Mr Ide’s bar. In this case the bar failed, not by bending, but by fracture at a maximum load of 110kg. This suggested to Dr Morgan that Mr Ide’s bar was weaker and more brittle than it should have been. He considered that the possible causes of such weakening were a defect in original manufacture or progressive weakening developed during normal use of the bike. Dr Morgan expressed the view that the damage to the right hand end bar of Mr Ide’s bike did not have any bearing on the slow loading tests which had been carried out.

Dr Morgan’s conclusion was that with use during the three year life of Mr Ide’s bike, the handlebar had become progressively weaker as a result of the formation of micro-cracks forming and growing at the bottom of the CNC grooves that were initially machined along the handlebar as part of the manufacturing process. Failure by fracture, rather than bending, was in Dr Morgan’s opinion a strong indicator of the probability of fatigue cracks existing in the handlebar at the time of failure.

Dr Morgan also commented on so-called “pendulum tests” carried out in order to investigate the effect of fast impact loading and to identify the real energy required to bend or fracture Mr Ide’s handlebars. For the purposes of these tests rotation of the handlebars was prevented. Again a Halford bar and virtually identical Marin bar were tested. In these tests none of the handlebars fractured but rather all bent at the point where Mr Ide’s bar had fractured.

Dr Morgan’s overall conclusion was that Mr Ide’s handlebar was in a defective state, as evidenced by the different failure mode it demonstrated when tested by slow loading. As to the question what caused the defect to exist, Dr Morgan remained of the opinion that, as a result of time-dependent micro-crack growth in the handlebar, it had weakened and subsequently failed catastrophically. He pointed out that evidence of fatigue is often eliminated as a result of pre-failure damage occurring at the crack initiation sites, which effectively destroys the evidence of fatigue as it occurs. Dr Morgan expressed the opinion that Mr Ide’s handlebar would not have failed as it did if the handlebar had not been finished by radial CNC machining.

When he came to give evidence, Dr Morgan was vigorously and, if I may say so, skilfully cross-examined by Mr Neil Block QC for ABT. Dr Morgan refused to accept the opinion of Mr Bachelard and Mr Price as to the reason for the fracture. He said Mr Price had been right the first time. Dr Morgan declined to change his opinion in the light of Mr Bachelard’s SEM photographs which revealed no evidence of cracking. Dr Morgan’s explanation was that the surface damage had obliterated the cracks which he considered had been present. He maintained his opinion that the discolouration around the fracture site was caused by moisture leaching into a crack. He disagreed with the view expressed by Dr Bulpett that the staining indicated that it took place after Mr Ide met with his accident.

Dr Morgan maintained that loading up to 164kg was possible in the course of off-road mountain biking. Dr Morgan admitted that he had omitted to mention the Murray paper in his first report, although he did have a copy of it at that time. He accepted that the tests referred to in the Murray article related to a bike very different from Mr Ide’s. Dr Morgan did not accept that it was inappropriate for him to have placed reliance on an article in “Bike Magazine”. Asked about an article by DeLorenzo and Hull, Dr Morgan disputed its relevance to what happened to Mr Ide. He expressed the view that the tests reported in that article were wholly unrepresentative.

Dr Morgan rejected criticisms made of the methodology employed in the pendulum test. He agreed that, if the bar in fact had no cracks within it, a load of at least 110kg would be necessary to cause the bar to fracture. He conceded that it was difficult to imagine that one could ever put a load of 110kg on a handlebar in the course of riding a bike. He did not accept that the pendulum test had shown that a grooved bar was no different from one which had no grooves in terms of the effect of loading. Dr Morgan maintained that grooves are relevant to the extent that they are stress enhancers and have the potential to produce cracks. Asked how it is possible to know that there are fatigue type cracks in circumstances where such cracks are not apparent on SEM examination, Dr Morgan accepted that one could not know that the cracks were there. But he adhered to the opinion that there was a small or minute crack present in Mr Ide’s bar.

Dr Chinn is a Consultant to the Vehicle Safety Department at the Transport Research Laboratory, which specialises in vehicle safety topics. He has very wide experience of investigating accidents, albeit mostly accidents involving cars or motorbikes rather than bicycles. In his report Dr Chinn dealt at some length with the requirements of Japanese Standard D9412, which he at that time believed were applicable to Mr Ide’s bike. He frankly accepted during his oral evidence that he was wrong about the applicability of that Standard or indeed any other standard to a mountain bike of the type Mr Ide was riding.

Dr Chinn, in reliance on the tests carried out by Mr Higgins (see paragraphs 24 and following above), concluded that the maximum force on the handlebars generated on any of the test runs carried out by Mr Higgins was 32.6kg. He noted that this figure is only about 30% of the loading at which, according to the calculations of both Mr Bachelard and Mr Bagley, the handlebar would fail (by bending rather than through fracture). This figure was accepted by Mr Richard Lynagh QC on behalf of Mr Ide.

Reconstructing the accident, Dr Chinn concluded that, for the handlebar to have broken and caused the accident, it would have necessarily been subject to an extraordinarily high load on one side. He considered this to be highly improbable, if not impossible. In Dr Chinn’s opinion Mr Ide rode too close to the rut on the trail and the front and back wheels went into the rut, simultaneously moving to the right. This caused him to lose control; the bike began to fall to the right and to tip forward. During this phase of the accident Mr Ide lost his grip of the left side and he fell on the left side of the handlebars. What happened when the bicycle began to fall to the right was, according to Dr Chinn, that Mr Ide fell onto the left side of the handlebar which caused it to break. Mr Ide then fell forward and to his right on to his head and then his shoulder. Dr Chinn considered it to be highly unlikely that a very large vertical load to the left handlebar would have occurred during normal riding. It is apparent from paragraph 8.7 of his report that Dr Chinn at that time believed, wrongly, that the right hand side of Mr Ide’s handlebar had bent horizontally and rearward in the course of the accident.

In a third report Dr Chinn dealt with the pendulum test carried out at Bristol University. He concluded from the fact that all three bars tested had bent through the same distance that the CNC machined grooves did not cause the bar to fail by fracture as Dr Morgan believed to have been the case. Dr Chinn criticised the methodology employed by Dr Morgan in carrying out the pendulum tests; he considered that the data collected by Dr Morgan at 1000Hz during a pendulum impact is irrelevant to the case.

Dr Chinn referred in this report to a paper by Lorenzo and Hull. In summary the paper reported the results of test rides on a trail with a 8% slope which is described as having been rutted and to have had exposed rocks. The speeds range around 30mph; riders were in a standing position. The authors found that the maximum loading on the handlebar was about 10kg.

In paragraph 4.5 of his third report Dr Chinn reiterated his belief that Mr Ide lost control of his bicycle and fell on to the left side of the handlebar causing it to break. He added that the deformation at the right hand end of the bar confirmed his views and that the right hand side was in contact with the ground when the maximum force from the fall acted. This was something which Dr Chinn had not mentioned in his earlier reports.

Much of Dr Chinn’s oral evidence concerned the validity or otherwise of the test carried out by Mr Higgins which ultimately ceased to be a live issue in the case. As to Mr Ide’s accident, Dr Chinn said that it was irrelevant to determine what had caused Mr Ide to lose his balance. Dr Chinn relied on the damage to the end of the right handlebar as providing support for his reconstruction of the mechanism of the accident. He expressed the view that such damage was unlikely to have been caused by that end of the handlebar simply falling to the ground without any downward pressure. The fact that the end bar bent inwards, crushing the end of the right handlebar, provided further support for Dr Chinn’s thesis. Dr Chinn thought that the cleats which secured Mr Ide’s feet to the pedals would have caused the bike to stay with the rider to some extent at least. Dr Chinn was confident that Mr Ide would not have suffered so severe a head injury if he had not fallen head first to the ground. Dr Chinn regarded the injury to Mr Ide’s inner thigh as being consistent with his reconstruction. As to the angle of the fracture, Dr Chinn postulated 45% as being the likely forward and downward pressure or direction of force.

Asked in cross-examination about the damage to the right hand handlebar, Dr Chinn described it as having sustained major damage and more severe damage than he would expect from ordinary wear and tear. He thought it extremely unlikely that Mr Ide’s shoulder and head struck the ground at the same time. He did, however, accept that the bike did not travel far after it hit the ground. He thought the bar had started to break when Mr Ide fell on to the left side of the handlebar and completed when the right hand side of the handlebar impacted in the ground. He denied that this was a new theory on his part but agreed that he had not mentioned it in his first report.

Dr Chinn denied that the pendulum test demonstrated that his theory of the mechanism of the accident was untenable. He agreed that, if the right hand side handlebar had not impacted in the ground, it would have rotated away. He agreed that when he wrote his first report he had assumed that the pressure of Mr Ide’s body would have been directly downwards in direction. He subsequently accepted that Mr Ide’s body would also have been moving forward, which meant that it was far more likely that the handlebars would have turned.

One of the reasons why Dr Chinn rejected Dr Morgan’s theory about the accident, was that, if the left hand side handlebar broke in use, Mr Ide would (as Dr Morgan accepted) have fallen to the left, especially if the loading was as high as 110kg. Dr Chinn agreed, however, that this was not a point made in any of his written reports. Dr Morgan expressed the opinion that a load of 110 Kg could not have been placed on one side of the handlebar.

As it appears to me, the appropriate starting point is to consider the viability of Dr Chinn’s reconstruction of the mechanism of the accident.

When considering that question, I first take into account the evidence of Mr Ide himself and his fellow riders. I have summarised their evidence at paragraphs 16-23.

They were agreed that the part of the trail where the accident happened was neither particularly steep (a gradient of about 1 in 7); nor was it particularly difficult. There was evidence of a rut on the left hand side of the track and of the presence of some loose material, including stones, on the trail there was no evidence of any hidden trap or other lurking danger which might have caused Mr Ide to fall because he lost his balance, which is what Dr Chinn invites me to accept he did.

Also relevant to that question is the evidence as to Mr Ide’s skill and experience as a rider. His evidence was that the South Downs Trail was a route which he regularly followed, riding it as often as once a week. Mr Ide mentioned a previous accident which happened when a pedestrian stepped into the road in front of him, causing a collision. There was no evidence of any other accident, although I accept of course that that does not mean that this accident was the first or the only time when Mr Ide fell from his bike.

According to the evidence, Mr Ide was clearly by 2002 an experienced off-road biker. He had become interested in off-road biking in about 1995. Since that time he has owned three mountain bikes. He bought the Marin in 1999, so he was well used to it by the time of the accident. Mr Ide’s evidence was that he usually went riding twice a week for two hours on each occasion. That suggests that he would have ridden the Marin for several hundreds of hours before 21^st April 2002, even allowing for his six months off the road after colliding with a pedestrian.

Moreover there was evidence from one of Mr Ide’s companions, namely Mr Davis, that Mr Ide was the most skilled of any of them. Of course even the most skilled riders do have accidents. However, Mr Ide’s skill and experience, coupled with the nature of the trail, have to be taken into account when deciding whether Dr Chinn is correct in his thesis that Mr Ide rode his bike too close to a rut and allowed one or both wheels to go into the rut, causing him to lose control. Although it is not altogether clear from the evidence whether there was a rut in the track on the day in question, I accept that there probably was a rut present. However, it appears from photographs, albeit taken long afterwards, that the rut was to one side of the trail and so was easily avoidable. It was a straight section of track and so there was no reason for Mr Ide to brake sharply.

It is unfortunate that there is no direct evidence how the accident came about. However, there is evidence of the position in which Mr Ide and his bike ended up. According to Mr Martin, when he arrived at the scene seconds after the accident, Mr Ide was lying prone on the ground on his right side and the back bike was across his legs facing the same way. The significance of the fact that, at least according to the evidence of Mr Martin, Mr Ide and his bike did not part company or become separated in the accident is, as it appears to me, that if, as Dr Chinn maintains, Mr Ide was thrown over the handlebars, it is difficult to see how he and the bike were so close together when Mr Martin came upon the scene very soon after the accident. I note that it was Mr Martin’s impression that Mr Ide had fallen “with the bike”.

Crucial to Dr Chinn’s reconstruction is his opinion that the left hand handlebar of Mr Ide’s bike fractured when it came into contact with his body. In the drawing which he annexed to his first report, Dr Chinn indicated that the point of contact was in the lower stomach area. In the body of his report he says simply that Mr Ide “fell on the left side of the handlebars”. In his oral evidence Dr Chinn thought it would have been Mr Ide’s upper leg which came into contact with the bar. There is evidence that Mr Ide suffered a four centimeter laceration in that area.

Whatever part of Mr Ide’s body it was, I have to consider whether it is likely, or even possible, that the load of the body on the bar would have been sufficient to break it. It is pertinent to note that Dr Chinn gave evidence that he thought it might have been the case that Mr Ide was in mid-air at the time when, according to Dr Chinn, his body collided with the bike. I also have to bear in mind that (as Dr Chinn accepted) the load of Mr Ide’s body would have spread along the bar.

A final consideration which is in my opinion material is that it is another integral part of Dr Chinn’s reconstruction that in the course of the accident the end of the right hand end bar impacted in the ground. It strikes me as significant that Dr Chinn made no mention of this factor in his initial report. He mentioned it for the first time after Dr Morgan had pointed out that the handlebars of the bike would have rotated about the steering column, thus reducing the impact of the collision between Mr Ide’s body and the handlebar of the bike which Dr Chinn postulates. I have to say that I think that the inference is irresistible that Dr Chinn introduced his theory that the bar impacted in the ground in order to meet Dr Morgan’s point about the handlebars rotating. As to the extent of the damage to the end of the right hand handlebar, there is scuffing and it is true that the right end-bar was bent backwards. However, it appears to me that the nature and extent of the damage is such that it may well have been attributable to the right hand handlebar hitting the ground without impacting. That was Mr Bachelard’s opinion.

Weighing all the factors which I have enumerated above, I have come to the conclusion that Dr Chinn’s theory as to the mechanism of the accident is most unlikely to be right. Those factors include the following: the relatively straightforward nature of the terrain where the accident occurred; Mr Ide’s skill as a rider (as to which Mr Davis attested) as well as his experience (including his knowledge of the trail in question); his familiarity with the Marin bike; the circumstances of the accident itself (it is accepted that Mr Ide’s speed was 18 to 20mph, which is not excessive, and no other cyclist or pedestrian was involved); the unlikelihood as I see it, of the handlebar fracturing on impact with Mr Ide’s body, particularly if he was in mid-air; Dr Chinn’s belated reliance on the fact that (as he claimed) the right hand handlebar impacted in the ground; and, finally, the fact that, according to Mr Martin, Mr Ide was close to and virtually astride his bike when Mr Martin came on the scene. For these cumulative reasons I do not accept as being a likely explanation of the accident that Mr Ide lost his balance and that the handlebar fractured on impact with Mr Ide’s body.

It is of course important to note that the fact that I have rejected Dr Chinn’s theory as to how the accident happened does not of itself mean that Mr Ide succeeds on the issue of liability. He has to satisfy me on the balance of probability that there was a defect in the handlebar and that the defect caused him to fall and suffer the injuries which I have described.

That said, I think Mr Lynagh is correct in his submission that it is not necessary, in order for Mr Ide to succeed on the issue of liability, for him to establish how the accident happened, that is, what was the cause of the weakness which lead to the fracture of the handlebar of the accident. What I have to determine is whether it is more likely than not that the handlebar fractured because it was defective within the meaning of the 1987 Act.

As to that, the evidence in my judgment clearly suggests that Mr Ide fell on his bike because of some dramatic event. There is no evidential basis for supposing that Mr Ide lost his balance and continued to travel downhill as he struggled to regain control of the bike. In all the circumstances, I think it more likely than not that, however it came about, Mr Ide did lose control of the bike instantaneously. One possible explanation is that the front wheel of Mr Ide’s bike struck an immovable object so that he was literally thrown off the bike; another possibility is that there was a catastrophic fracture of the handlebar. In examining these possibilities, I will first consider whether Dr Morgan is justified in his conclusion that the cause of the fracture was that fatigue micro-cracking had developed over the two and half years during which Mr Ide had been riding the Marin bike off-road for perhaps several hundred hours. According to Dr Morgan, such cracking could have been propagated from one of the CNC-machined grooves on the handlebar. In Dr Morgan’s opinion this caused catastrophic, classic fast-fracture fatigue failure.

Mr Block was severely critical of both Dr Morgan’s methodology and of his approach to the discharge of his duty as an expert witness in this case. I recognise that there is some validity in these criticisms, although I have no doubt that Dr Morgan was doing his honest best to assist me in determining how the accident occurred.

Dr Morgan’s theory is contradicted by Mr Bachelard and (eventually, following his discussion with Mr Bachelard) by Mr Price, after he had carried out an SEM examination of the handlebars. Dr Chinn supports their opinions, relying on the high loading which he considers would have been necessary to bend the handlebar on the Marin bike assuming it to have been in good condition.

The fact that Dr Morgan is outnumbered by other experts who disagree with him is of course no reason to reject his explanation. The fact is, however, that, as Dr Morgan conceded, SEM photography revealed no evidence of any cracking or fatigue. That is not of course of itself fatal to Dr Morgan’s explanation because, as is stated in the textbook “Metals Handbook”, the absence of beachmarks cracking and striation does not mean that the fracture of the bar was not due to fatigue. I remind myself that Mr Price did find fatigue striation marks in the failed handlebar and that there was evidence of staining, which may or may not represent pre-accident leaching of moisture into what Dr Morgan considered to be a crack. I also bear in mind Dr Morgan’s claim in his evidence that the accident surface damage may well have obliterated evidence of cracking which was present before the accident.

Doing my best to make allowance for all these various considerations, my conclusion is that fatigue cracking is at least a possible cause of the fracture of the handlebar. However, as I have said, I do not consider it to be necessary for me to determine the precise mechanism which led to the handlebar fracturing but rather whether the evidence supports the conclusion that, as a matter of probability, the handlebar was defective in a way which caused it to fracture. That question falls to be determined in circumstances where (a) I have accepted that the fracture was both instantaneous and catastrophic and (b) I have rejected Dr Chinn’s theory as to the mechanism of the accident.

In my judgment the conclusion to be drawn from the totality of the evidence is that the left hand handlebar of Mr Ide’s bike was defective and that it was that defect which caused the handlebar to fracture with the result that Mr Ide fell off the bike and suffered serious injuries.

I arrive at that conclusion for the following reasons: it is common ground that the handlebar snapped. I ask myself how that can have come about given the evidence that the loading on the handlebars of a bike such as the Marin, when ridden on the kind of terrain which obtained here, falls well below the loading normally required even to bend the bar, let alone to fracture it. I have already referred to the possibility that Mr Ide’s front wheel did strike some obstacle. Mr Ide was travelling at a speed of 18 to 20mph at the time and the collision between the front wheel and the obstacle would have increased the loading on the handlebar to some significant, albeit indeterminate extent. Even so, a standard non-defective handlebar would not have failed in such circumstances.

Because the left hand handlebar broke at its weakest point, it has not been possible to test that handlebar at that point. It is consequently necessary to go by the evidence of what happened when the right hand handlebar was tested. It seems to me to be clear on the evidence of the testing of that handlebar that there was something wrong with it (or as Mr Price put it), there was something “different about” the right hand handlebar. So much is clear from the slow-loading tests which were carried out on Mr Ide’s right hand handlebar and on another virtually identical Marin bar as well as a comparable Halford bar. What these tests showed was that all the bars except Mr Ide’s bent but did not fracture, even at loadings as high as 158kg for the Halford bar and 130kg for the Marin bar. By contrast Mr Ide’s bar fractured, without prior bending, at the materially lower loading of 110kg. In the pendulum loading tests none of the bars tested fractured; they all bent. It is noteworthy that Mr Bachelard and Mr Price both agreed that Mr Ide’s handlebars behaved differently from the comparators.

In the light of these tests results I accept Dr Morgan’s conclusion that Mr Ide’s handlebar was weaker and more brittle than it should have been, especially in the light of the fact that the Marin bike is specifically designed for off-road riding.

I ask myself what is the likely cause of the materially different performance of Mr Ide’s right hand handlebar on testing. There is no reason to suppose that the left hand handlebar of Mr Ide’s bike would have performed any differently on testing. I find myself driven to conclude that the answer to that question is that the left hand handlebar was defective. The defect may have been an inherent manufacturing defect; alternatively the defect may have resulted from the handlebar degenerating over its two and half year period of user by Mr Ide to the point that it finally fractured during “normal” off-road riding of the bike. As Dr Morgan pointed out in his third report, the magnitude of the forces generated by the normal riding of a mountain bike would have been sufficient to fracture the handlebar in its weakened and defective condition. I accept that conclusion. I accept further that such a sudden fracture would have caused immediate loss of control of the bike. The configuration of Mr Ide and his bike immediately after the accident are consistent with this scenario. I accept that the defective condition of the handlebar and the occurrence of the accident are unlikely to have been purely coincidental.

Accordingly I accept that at the time when Mr Ide met with his accident on the 21^st April 2002 there was a defect in his Marin bike within the meaning of Section 3(1) of the 1987 Act. I further accept that, as a matter of probability, it was that defect affecting the left hand handlebar which caused it to fracture. Mr Bachelard accepted that the physical evidence was consistent with an overload caused during normal riding of the bike. The loadings calculations carried out by Mr Bachelard appeared to him to be low for handlebars specifically designed for rough terrain. Mr Bachelard and Mr Price agreed in their joint statement that the mode of fracture was ductile fracture overload failure, that is the single application of a load or force that was sufficient to cause fracture. Dr Morgan’s opinion is also that the bar failed catastrophically.

I have rejected Dr Chinn’s reconstruction of the accident which explained the fracture by reference to the right hand handlebar having impacted the ground. No other explanation for the mechanism by which the handlebar fractured was offered. In these circumstances my conclusion on the totality of the evidence is that the probability is that the bar fractured as Mr Ide rode along. The result was that he instantaneously fell without becoming separated from his bike, whereby he suffered serious head injuries.

For the above reasons I determine the issue of liability in favour of Mr Ide.