Expert advice required. I bought an allegedly new Kona Mahuna bike from Hart's Cyclery in Edinburgh, which I was shown on the shop pc before they went to pick it up from their other premises. When I was first shown the bike I immediately noticed there was dirt in the depths of the tyre treads and one side of the handlebar end grommets was damaged, the manager Mr Hart claimed it was just dust from their storeroom and that it had not been dropped! He replaced the grommet and convinced me to go ahead with the sale. Upon cycling from the back of the shop though a close to the front I realised the seat was set too high for me, so I got off to adjust it down, I took a few photographs of the bike there and noticed the bike was dirty on closer inspection, at which point two of the shop mechanics appeared and hearing my complaint they offered to wash it and took it back for a quick sponge wash. I left and after cycling for about 2 miles I noticed a repeating metallic catching sound from the front, I dismounted and whilst fully applying the front brake I pushed down hard on the handlebars and to my shock I could see the whole wheel move from its central position between the forks to the left by about a centimetre then spring back to central position when I took my weight pressure back off, I repeated this movement a couple of times in disbelief. About then one of the shop mechanics cycled passed me and asked if I was enjoying my new bike, I told him I was not, its broken and I'm returning it tomorrow, he stopped and asked what the problem was, after I told him he said he could fix it and he then tightened up the QR mechanism and went on his way. I cycled for about another 2 miles, then when descending a hill I crossed over a speed hump, which made a clunk sound from the front, I pulled the brake levers as gently as I could, however the front wheel totally locked up, which violently flipped me and the bike 180 degrees end over, severely breaking my collar bone due to the impact of my shoulder blade hitting the tarmac. The accident was filmed by a cars dashcam which shows the rear wheel had crossed the hump and travelled at least 50 cm before it flipped. I took photographs of the bike where it landed on a grass verge to the left of the road, in which there can be seen 2 lateral scores on the front rotor, can anyone explain how these marks were made? Could these marks indicate the accident was caused by a slightly warped rotor? Thankyou in advance for any light you can shed on this unfortunate incident. PS, I'm having a second surgery in August 2024 to remove and replace an ORIF titanium clavicle plate due to the first operation being unsuccessful as can be seen in the 4 months post op' x-ray.
What caused these lateral marks on the front rotor during a locked up wheel, end over accident on a new bike?
- Thread starter stieve
- Start date
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Bristolian
Senior Member
- Location
- Bristol, UK
Hi and welcome to CC. Sorry to hear about your crash and I hope you recover fully in good time 
. Can't help with your question though 
. Can't help with your question though 
Drago
Legendary Member
- Location
- Suburban Poshshire
I doubt a warped rotor is behind your spill, but from the description you've given it wouldn't surprise me at all if there was indeed some kind of mechanical issue or failure.
Your only means of reasonably establishing the cause is to have the bike properly examined by a properly qualified person.
Best of luck with your recovery.
Your only means of reasonably establishing the cause is to have the bike properly examined by a properly qualified person.
Best of luck with your recovery.
All uphill
Still rolling along
- Location
- Somerset
I am not an expert or a lawyer, just a random who rides bikes.
I suppose theoretically a problem with a loose QR could result in the brake disc moving and jamming in the caliper. I've never heard of that and can't quite see it happening.
As above you need an expert opinion if you are going to pursue this through the courts - if that is the case it may not be a good idea to make named allegations/implications on a public website.
I suppose theoretically a problem with a loose QR could result in the brake disc moving and jamming in the caliper. I've never heard of that and can't quite see it happening.
As above you need an expert opinion if you are going to pursue this through the courts - if that is the case it may not be a good idea to make named allegations/implications on a public website.
cyberknight
As long as I breathe, I attack.
- Location
- Land of confusion
ouch ! i hope you heal well .
In itself a slightly warped rotor would not stop the wheel turning suddenly but you would have found it hard to ride as it caught on the brake pad as it turned but it does sound like something caused the brakes to jam suddenly so i would be looking at the hub as the culprit but obviously it very hard to tell from a couple of pictures. Your best best is too take the bike to another bike shop and see if they can diagnose the issue .
This bike has clearly been been mis-sold as fit for purpose and it clearly is not new or safe so i would be contacting a solicitor for a claim for replacement of the bike , out of pocket expenses and loss of earning .If your a member of british cycling and cycling uk they have their own preferred company which is Leigh Day which you can contact yourself.
Im sorry your collar bone did not heal although it does look like the bones were not set properly in the 1st place ? when i broke mine the bones were misaligned like yours but the surgeon realigned and pinned them after roughing up edges so they would bond together .
Before and after ....
In itself a slightly warped rotor would not stop the wheel turning suddenly but you would have found it hard to ride as it caught on the brake pad as it turned but it does sound like something caused the brakes to jam suddenly so i would be looking at the hub as the culprit but obviously it very hard to tell from a couple of pictures. Your best best is too take the bike to another bike shop and see if they can diagnose the issue .
This bike has clearly been been mis-sold as fit for purpose and it clearly is not new or safe so i would be contacting a solicitor for a claim for replacement of the bike , out of pocket expenses and loss of earning .If your a member of british cycling and cycling uk they have their own preferred company which is Leigh Day which you can contact yourself.
Im sorry your collar bone did not heal although it does look like the bones were not set properly in the 1st place ? when i broke mine the bones were misaligned like yours but the surgeon realigned and pinned them after roughing up edges so they would bond together .
Before and after ....
Attachments
Yellow Saddle
Guru
- Location
- Loch side.
Can't glean much from your photos. Does your camera have a focus feature?
The showed bike has received some unrespectful handling from potential customers in the shop, I'd say.
Damaging the anti slip surfaces on the quickrelease, allowing a sudden movement when receiving a hit from a road bump.
The rest consequence.
That guy that tightened back up the QR, should have inspected the ribbles on the nuts, and at least warned, ride careful, just further home, and replace the QR. He didn't, just tensioned it up again and then it slipped again, with less luck than the first time.
Damaging the anti slip surfaces on the quickrelease, allowing a sudden movement when receiving a hit from a road bump.
The rest consequence.
That guy that tightened back up the QR, should have inspected the ribbles on the nuts, and at least warned, ride careful, just further home, and replace the QR. He didn't, just tensioned it up again and then it slipped again, with less luck than the first time.
Hacienda71
Mancunian in self imposed exile in leafy Cheshire
- Location
- Wilmslow, Cheshire
Get a good solicitor on the case who will appoint a competent expert to examine the bike. You are likely to get a firm who will take it on at no upfront cost to you. They will take out insurance for you (at no cost to you) to cover their fees if they are unsuccessful after the initial review of the case.
PaulSB
Squire
- Location
- Chorley, Lancashire
If you want a "no win, no fee" company that has specialisation in bikes you could try CAMS
They will take 25% of a successful claim.
Disclaimer. My LBS speaks highly of them. I have 20+ year relationship with this LBS and I always value their opinion. However, I'm currently pursuing a personal injury claim and after speaking to CAMS elected to use British Cycling's solicitors.
Two reasons; I was very impressed by BC's professional approach and I felt 25% was simply too high. I recognise it's probably an industry standard.
They will take 25% of a successful claim.
Disclaimer. My LBS speaks highly of them. I have 20+ year relationship with this LBS and I always value their opinion. However, I'm currently pursuing a personal injury claim and after speaking to CAMS elected to use British Cycling's solicitors.
Two reasons; I was very impressed by BC's professional approach and I felt 25% was simply too high. I recognise it's probably an industry standard.
Mr Celine
Discordian
- Location
- Waxing my moustache
If you're in Edinburgh it would be better using a Scottish firm, eg cyclelawscotland based in Peebles. I have no personal experience of them, but do hear the occasional snippet on local radio news where they have won compo for injured cyclists.
cyberknight
As long as I breathe, I attack.
- Location
- Land of confusion
Another one post never to be seen again member ?
Rusty Nails
We remember
- Location
- Living in the slow lane
Nothing wrong with that. Even if you are just looking for answers to one question there is no way of asking it without joining...on this or any other forum.
Hi everyone and thanks for all of your replies ~
In hindsight I should have taken the bike to an independent bicycle expert to investigate
if there was a fault which caused the rotor to jam, however I returned the bike to the shop
for a full refund because it was faulty! The shop has since disposed of the bike, leaving only
the photographs and dashcam footage as visual evidence. I had hoped that the two score marks
on the rotor would be sufficient evidence to indicate that there was some fault which had caused
them, however the bicycle expert consulted by my lawyer Digby Brown was of the opinion it would
be difficult to prove that there was a fault with the bicycle, but did not mention nor explain the cause
of these rotor scores....This is why I have sought out your experiential knowledge on this forum.
There is another similar case discussed online explaining how a QR mechanism can loosen
due to the braking force on the rotor (acting as the new fulcrum point) which pushes the axle down
and potentially out of the dop outs, (hence the lawyers lips) and when hitting a pot hole or speed hump
it pushes the axle back up in the drop outs, which also moves the rotor position up and down within the
brake calliper. This action bends the rotor as the axle becomes askew in the drop outs, which then jams
when forced up into the calliper when knocked up by a speed hump. It is really a manufacturing faux pas
which is now solved with a through axle which fully encloses the axle to stop it from moving up or down.
Thank you for all the legal advice, but I fear I am at a loss as to what can be done next!
Unless the photographic evidence of those two very unusual lateral scores on the rotor indicate that a
mechanical fault had created them and in turn this caused the accident, then the case is closed.
Perhaps a different expert bicycle mechanics opinion other than the one that advised Digby Brown
lawyers could have a different opinion and explain their cause.
Attached photo is a zoom in on the the bikes front rotor from outside their shop when I bought it, which
shows no score marks on the rotor.
Yeah Cyberknight, your collar bone Open Reduction Internal Fixation looked good, I hope it no longer ales you.
The first time I seen my first post op' x-ray I said the same as you, and facing it all again is daunting to say the least.
This time they are going to take a bone graft from my femur to pack into the join.
For sure Silva, I agree, it was maybe even ridden hard and dropped/crashed on a gravel track by someone before they flogged
it off to me, which as you suggest might have worn out the anti slip surfaces and the nut ribbles.
I could kick myself for being such a mug to have bought this obviously imperfect bike in the first place, Ce la vie!
And, so the mystery continues ~
In hindsight I should have taken the bike to an independent bicycle expert to investigate
if there was a fault which caused the rotor to jam, however I returned the bike to the shop
for a full refund because it was faulty! The shop has since disposed of the bike, leaving only
the photographs and dashcam footage as visual evidence. I had hoped that the two score marks
on the rotor would be sufficient evidence to indicate that there was some fault which had caused
them, however the bicycle expert consulted by my lawyer Digby Brown was of the opinion it would
be difficult to prove that there was a fault with the bicycle, but did not mention nor explain the cause
of these rotor scores....This is why I have sought out your experiential knowledge on this forum.
There is another similar case discussed online explaining how a QR mechanism can loosen
due to the braking force on the rotor (acting as the new fulcrum point) which pushes the axle down
and potentially out of the dop outs, (hence the lawyers lips) and when hitting a pot hole or speed hump
it pushes the axle back up in the drop outs, which also moves the rotor position up and down within the
brake calliper. This action bends the rotor as the axle becomes askew in the drop outs, which then jams
when forced up into the calliper when knocked up by a speed hump. It is really a manufacturing faux pas
which is now solved with a through axle which fully encloses the axle to stop it from moving up or down.
Thank you for all the legal advice, but I fear I am at a loss as to what can be done next!
Unless the photographic evidence of those two very unusual lateral scores on the rotor indicate that a
mechanical fault had created them and in turn this caused the accident, then the case is closed.
Perhaps a different expert bicycle mechanics opinion other than the one that advised Digby Brown
lawyers could have a different opinion and explain their cause.
Attached photo is a zoom in on the the bikes front rotor from outside their shop when I bought it, which
shows no score marks on the rotor.
Yeah Cyberknight, your collar bone Open Reduction Internal Fixation looked good, I hope it no longer ales you.
The first time I seen my first post op' x-ray I said the same as you, and facing it all again is daunting to say the least.
This time they are going to take a bone graft from my femur to pack into the join.
For sure Silva, I agree, it was maybe even ridden hard and dropped/crashed on a gravel track by someone before they flogged
it off to me, which as you suggest might have worn out the anti slip surfaces and the nut ribbles.
I could kick myself for being such a mug to have bought this obviously imperfect bike in the first place, Ce la vie!
And, so the mystery continues ~
Attachments
cyberknight
As long as I breathe, I attack.
- Location
- Land of confusion
Im glad you at least got your money back , my post about you not replying was said in haste as we do tend to get a lot of people join CC , ask one question and never reply or update which although not against any rules can be a bit frustrating .As far as legal advice if you do decide to take further action sending the information you have to the solicitor and asking them what if anything they can proceed with as a claim would be up to them to decide .
Your x ray does look like they didnt join the ends up properly in the 1st place ? i would have thought packing a bit in is kind of like using filler rather than doing the job properly from scratch but then again im not a doctor
