Trek 4300 disk brake crash

CliveW

On Saturday my son was riding his Trek 4300 downhill on the road. For some inexplicable reason his front wheel detached from the frame resulting in nasty crash and a trip to casualty.

From eyewitness reports he was cycling safely, no other vehicles were involved.

The bike is less than a year old and in good condition. As far as I can tell the quick release was securely fastened and I had in fact checked it a few days previously on a trip to Dartmoor and it had not been removed since then. I have a Trek 6000 series bike which I ride quite often and also has disk brakes and has never caused problems.

The disk warped severely during the crash.

Has anyone else had experience of disk brake problems causing a similar accident?

Anonymous

The QR lever must not have been done up tight enough. I'm sorry, but there is no other way.

nicklouse

the Qr had to be lose.
he had to be riding with a lose wheel.
forks have Lawyer tabs on them for a reason.

Anonymous

Sorry to hear about your lads crash, hope he's okay.

CliveW wrote:

The bike is less than a year old and in good condition. As far as I can tell the quick release was securely fastened and I had in fact checked it a few days previously on a trip to Dartmoor and it had not been removed since then.

Need to check QR every ride, and maybe a couple of times during the ride if it's a long one, definitely after any crash even if small ones, and it's easy to think they're tight when they're not tight enough. It's also possible for the release to get knocked out from branches, rocks, and the like.

Still, there was a thread recently on the topic of disc breaks and QRs.

http://www.bikeradar.com/forums/viewtop ... t=12792976

CliveW

deadkenny wrote:

Sorry to hear about your lads crash, hope he's okay.

Thanks - he's feeling pretty sorry for himself - lots of road rash and cuts and bruises but fortunately no breaks. He was wearing a helmet at the time which broke with the impact!

Strange - if the QR had come loose I'd have thought he'd have noticed it. I tested my bike afterwards with my wheel loose and it slopped around in the forks and was obviously loose.

Having experienced this I think I will replace all the QRs on my children's bikes with nuts!

benpinnick

Which way do you point the QR levers when tightening. Lots of people point them forwards, which is very foolish indeed.

CliveW

benpinnick wrote:

Which way do you point the QR levers when tightening. Lots of people point them forwards, which is very foolish indeed.

All front ones point upwards - parallel with the front forks for the front wheel. For the back wheel pointing upwards at about 45 degrees between the chain stays - but having said that my son's bike was set up by the bike shop with the back wheel lever pointing slightly down and forwards.

Anonymous

CliveW wrote:

Strange - if the QR had come loose I'd have thought he'd have noticed it. I tested my bike afterwards with my wheel loose and it slopped around in the forks and was obviously loose.

Not necessarily so easy to spot. When you're riding your bike, your weight will be helping to hold the wheel in the dropout, which can often appear as though the wheel is secure.
Also, the QR does not have to be so loose the wheel is flapping about. The most common indication is the wheel pulling slightly to the brake side under braking.
QR levers need to be done up pretty tight, much tighter, it seems, than many people realise.

benpinnick

For future reference, always best to have the levers pointing backwards, parallel to the ground. It's surprisingly easy to catch them on undergrowth or wire etc. and wrench them loose without noticing, even pointing upwards. By pointing them backwards you pretty much guarantee you won't catch them. not saying that's what's happened here, just helping avoid bothering A&E!

hannahoneill

I know that you posted this ages ago, did you find anything out? The exact same thing happened to my partner a couple of months ago on a trek 4300. She had not been off road on it and had only had it about a week....

nicklouse

hannahoneill wrote:

I know that you posted this ages ago, did you find anything out? The exact same thing happened to my partner a couple of months ago on a trek 4300. She had not been off road on it and had only had it about a week....

foe a wheel to come out the Qr must be loose (very loose) as there are lips on the fork to stop the wheel coming out. or the Qr is broken.

As per the manual Qrs should be checked before each ride and tightened correctly.

CliveW

Hi Hannah,
I sent the forks off to Trek for them to check, but the company did not accept that there was any fault with the bike. They did however replace the forks FOC. I am still very surprised that this happened and now make sure that the lever on the wheel clamp is tightened as much as possible.

hannahoneill

Seriously I know how to check a qr, as does my partner. There was no way it was loose... I'm paranoid about these things and always double check.
CliveW - did you report the accident to trek?

hannahoneill

Ok. Just got your message. I will also report, I wonder how many other people have had the same accident but not posted it online?

cat_with_no_tail

Your wheel can't come off unless the QR is loose. This isn't an opinion, it's a fact. It's physically impossible for a wheel to just fall off a bike unless the QR comes undone.

So with all due respect, you're wrong.

Not saying you hadn't checked it, but something has clearly happened *since* checking it, which caused the QR to come undone.

Are the lawyer lips still present on the fork?

Honestly, some people :roll:

hannahoneill

Lawyer lips are there... In poor condition as something ie. the wheel was ripped out of them at speed.
The qr may have come loose during that ride but when she set off it was fine. (I mean obviously because I'm a girl I must know nothing about bikes, but that would suggest there was a fault... Maybe a reason the qr came loose whilst on a routine ride).
Also I find your tone offensive, my girlfriends face was slammed into a pavement at about 15 miles an hour, I do not need your comments about how I was wrong about a loose qr.
I was looking for some help and advice which I kindly got from the person I asked.

cooldad

Just a point - Trek do not make the forks, the brakes, the QR, or most likely the hub etc. These parts will be common to millions of bikes.

cat_with_no_tail

No, what you were after was someone to AGREE with you.

The fact you are a woman is completely irrelevant, and I'm not quite sure why you'd feel the need to bring it up.

You stated that the QR was tight, I was merely pointing out that you are wrong. It can't possibly have been tight, or the wheel wouldn't have fallen off the bIoody bike.

If she's hit something with enough force for the QR to tear strips off the dropouts, I'd suggest that a loose QR is not at fault, but rather whatever she hit with such force.

And frankly, I don't give a toss how you find my tone. Shall I tell you what I find offensive? How about people who fail to check and maintain their bikes properly, then try and blame the manufacturers.

hannahoneill

I do check my bikes, that is my point. I know my way around a bike, and I'm not trying to blame a manufacturer, I'm trying to find out what went wrong, and as I found someone else who had the same problem I wanted some more information. I'm not looking to make money, I will get the bike fixed its no big deal. I want to make sure that the company is aware in case of a fault. You are a really horrible person, I hope that whatever it is that makes you so angry gets sorted out... Maybe seek counselling?

cat_with_no_tail

I am quite a horrible person you're right there.

I have also never forgotten to check a QR, resulting in me kissing the pavement at 15mph.

Just goes to show you everyone is different.

As previously stated, it's categorically user error. Feel free to let Trek know though (although letting the fork manufacturer or the QR manufacturer know might be a better bet).

hannahoneill

Will do that, thanks
Hope you get that counselling, don't be an anger ball your whole life.

The Rookie

Do up the QR as you normally do, then open it, now see if you can pull the front wheel out...no you can't, so even if it just flipped open it wouldn't come out, an external cam QR should require enough force that it leaves a white mark on your hand when doing it up, it should be that hard, anything else isn't tight despite what you may think - and the cheaper ones (not brass or delrin bush) need even more.

That said I only run Shimnano QR's as they are internal, cam, less friction and also a better leverage rate, or Halo bolt hrough (at £7.99 the bank is hardly marked let alone broken!)

gt-arrowhead

The beginner beat me to recommending these.

I guess it would help with the paranoia of the wheel sliding out of the fork as a result of the QR coming loose, because you can tighten them up tighter obbisouly They cant get caught either as, they need allen keys to be undone.

But if the area where the QR makes contact with the fork has been worn away, it will still be a bit risky, and i reckon a new fork/fork lower would be the safest bet.

Link to Halo Skewers http://www.ebay.co.uk/itm/Halo-Hex-Key- ... 53e130bec3

njee20

Never sure about allen key skewers - the average allen key isn't that long, and without a cam I'm not convinced they're as tight as a decent skewer.

Shimano FTW, although I must say I've been very impressed with the latest Bontrager offerings.

The Rookie

The torque of the allen key is multiplied many times by the fine thread pitch.....a 75mm long key moves it's tip through about 450mm to tighten the bolt through 1 turn, 0.75mm (maybe even finer pitch, not checked) so that is about 600:1, a QR lever is shorter with a ratio of much less.

declan1

njee20 wrote:

Never sure about allen key skewers - the average allen key isn't that long, and without a cam I'm not convinced they're as tight as a decent skewer.

Shimano FTW, although I must say I've been very impressed with the latest Bontrager offerings.

They're brilliant. You can do them up to 10Nm. The reason I got them is my front skewer kept slipping no matter how tight I did it up. With the allen key skewers they are rock solid!

Also, to the people who didn't do their QRs up tight enough - people on this thread are trying to help you. They all say the same thing; your QR skewer(s) were loose. If you're going to ask for advice, listen to it rather than just arguing with everyone!

JBA

Were the QR's done up the right way?
I see a surprising amount of bikes with the QR's flipped backwards.
I used to point it out to riders but gave up when some knuckle dragger told me it was none of my flippin'* business.

*Other swear words are available.

swod1

On my trek 4500 2012 model the wheels are shimano hubs and so shimano qr skewers.

Are trek using there own bontrager versions on some models of trek bikes i wonder ?

I've not had a problem with mine, the bike is a year old and just recently serviced.

Once i do change the front forks I'm thinking of going 15mm bolt through over qr.

arthur_scrimshaw

I think there's another (albeit remote) possibility, one that I think I read on Sheldon Brown. If the axle tube is not central, one end could stick out past the drop out so when the qr is closed it tightens up against the axle tube rather than the drop out?
SB also links this article about braking forces and qr wheels

http://www.ne.jp/asahi/julesandjames/ho ... index.html

97th choice

I've snapped a QR whilst tensioning it, but if it hasn't failed I can't see any reason why the wheel would come loose unless the QR wasn't tight or the wheel wasn't in the drop outs correctly.

Northwind

I use those Halo hex skewers but I suspect they're no more secure than QR- I just use 'em because they're light and I'm a tart. The cam action of a quality QR is very effective for resisting loosening, whereas a nut/bolt can be vulnerable to vibration.