Back wheel fell off!

Anonymous

^^That seems like a complete cock and bull case, when you consider that "lawyer's lips" have been on forks for a long long time, BECAUSE it is known that a fastening can be foced open by a torque reaction with the wheel.
What precisely was the final aim, to force all manufacturers to go beyond common sense and put bolt thru axles on every fork?

Oh, and settling could either be down to bizzarre technicalities, or, I suspect, because Fox didn't want to be seen battling a cripple in court. Whether they win or lose, they would have looked like the "bad guy".

diy

What were the details of the claim? It seemed to imply that it was a combination of the angle of the drop out and the size and location of the brake. I'm struggling to get my head round how this could happen.

I doubt the sentiments expressed came into it. It will be purely business The cost of rectifying a fault and compensating the long queue of claimants vs. a 1-1.5M total bill.

The reasons both parties went public is probably because there were offers on the table that were near where they needed to be and both litigators were looking to apply pressure to the other side. Its pretty standard tactics.

Anonymous

Dude, I still barely understand a word you're saying, you must be a nightmare when ordering food.
Like I said, the opening of wheel fixings is a known, and from an engineering perspective, quite well understood phenomenon.
However, if it was a fault in fox's dropout design, it would happen all the time, not just a one off incident.

andrewjoseph

I don't know all the details or technical aspects.

I do know that part of Fox defence was that the QR was loose at the start of the descent and Russ was negligent in not ensuring it was tight enough.

For those not familiar with the Gap route, the descent is a few kilometres long, the first few hundred meters is steep, rocky and very technical, there are water bars on the flatter sections where you really have to lift the front wheel and several steps and small drops. The place Russ fell is the easiest, though fastest, final section.

If the QR was loose at the top, or at any time before the final section, he would have known it then.

Several of my friends have had the front wheel coming out of the forks, though none have had a serious result. Russ's incident, though rare, is by no means isolated.

From what I understand of the mechanics, having the brake caliper behind the fork leg causes forces on the rotor that try to pull the axle down and out of the fork drop out. This has been confirmed to me by other engineers.

I think Russ was claiming that this design, along with the QR and fork dropout design at the time, were contributery to his accident.

It is interesting that Fox, in my limited knowledge of the case, settled out of court only after Russ's defence team presented his arguments. I believe that Fox insisted that the case be sealed for perpetuity, so the technical arguments used cannot be made public.

Talking to Russ, sitting in his wheelchair, was enough to convince me that QR skewers are not for me. I don't race so I don't need them.

Anonymous

andrewjoseph wrote:

From what I understand of the mechanics, having the brake caliper behind the fork leg causes forces on the rotor that try to pull the axle down and out of the fork drop out. This has been confirmed to me by other engineers.

Definitely, LIKE I SAID, it's a fairly well understood phenomenon. So well understood in fact that all forks have had measures in place to pevent it for quite some time. Much further back than 2003.
There is nothing else you CAN do to eliminate it, short of making all forks thru-axle designs.

Several of my friends have had the front wheel coming out of the forks, though none have had a serious result. Russ's incident, though rare, is by no means isolated.

Really though? Hand on your heart in all honesty? I ask, because I've been riding for over 20 years, and the only time I have ever seen a front wheel come out of the forks is when it was either a prank, or a failed QR - quite commonly titanium ones.

blablablacksheep

Funny enough i saw bizzare ER and they had a MTB rider whos front wheel came off and his face got "gloved" :shock:

Gloved means face coming off head/skull :oops:

But tbh these cases are very rare and most of the time its near impossible to prove it was the fualt of the person or the bike/parts.

Most people settle out of court just for the simple reson that it costs too much to go to court and most of the time you will win or lose over technicalities like wording or phases rather than the issue at the centre of the action.

unlucky guy that all i can say.

andrewjoseph

yeehaamcgee wrote:

..
Really though? Hand on your heart in all honesty? I ask, because I've been riding for over 20 years, and the only time I have ever seen a front wheel come out of the forks is when it was either a prank, or a failed QR - quite commonly titanium ones.

I am not in the habit of lying and take offence at your suggestion that I am.

Several years ago, on the mtb-wales.com website, Russ Pinder asked for rider experiences of this happening. Some of my friends said it had. I have talke to them personally.

Just because it doesn't fit into your experience, doesn't fit with what you want, it doesn't mean it won't/doesn't/did not happen.

Despite your arrogant attitude and nasty, spitefull remarks on many threads, you are not the world expert in all things mountain biking.

You seem to delight in knocking down and refuting other peoples views and experiences, with little or no respect for facts and the experiences of others.

I have no respect for you at all.

Anonymous

andrewjoseph wrote:

yeehaamcgee wrote:

..
Really though? Hand on your heart in all honesty? I ask, because I've been riding for over 20 years, and the only time I have ever seen a front wheel come out of the forks is when it was either a prank, or a failed QR - quite commonly titanium ones.

I am not in the habit of lying and take offence at your suggestion that I am.

Several years ago, on the mtb-wales.com website, Russ Pinder asked for rider experiences of this happening. Some of my friends said it had. I have talke to them personally.

Just because it doesn't fit into your experience, doesn't fit with what you want, it doesn't mean it won't/doesn't/did not happen.

Despite your arrogant attitude and nasty, spitefull remarks on many threads, you are not the world expert in all things mountain biking.

You seem to delight in knocking down and refuting other peoples views and experiences, with little or no respect for facts and the experiences of others.

I have no respect for you at all.

Wow, you really have some issues. I find it hard to trust someone like that.

whitestar1

jeremyrundle wrote:

Doesn't everyone who buys a bike from any retailer check thge obvious before riding, sorry :!:

I didnt. I trust that they build the bike to the best standard otherwise I am going else where with my money :!:

whitestar1

Stokie wrote:

I agree with you that i should have checked it but do you use the same theory after you buy anything? If someone tells you that the job is done i tend to take the word for it otherwise id of done it myself really

Not your fault mate! If this was the US they would be sued

Anonymous

andrewjoseph wrote:

You seem to delight in knocking down and refuting other peoples views and experiences, with little or no respect for facts and the experiences of others.

I have no respect for you at all.

You realise your sentence here applies to you as well, right?
So far, you have told us that you were part of the case against Fox. You then told us the outcome, which I believe was previously unknown, but of course, it's under a secrecy agreement, so we can't be told the whole story.
And you expect us to just believe you, without question? Despite having a great many years of experience that seems contrary?

Fine, GET me to believe it, and I will. I don't know everything, nobody does, but after many years of riding without ever witnessing this problem, it's going to take more than a baby throwing his toys out of the pram to convince me.

whitestar1

diy wrote:

yes you should have checked it, but they were contractually obliged to. They didn't. They should make good and be lucky that they are not facing a PI claim.

I would certainly complain and expect some sort of gesture to correct the breach.

If the bike was built by one, checked by another and signed off by a 3rd it would be less likely to happen. But they choose not to do it that way and they will suffer the consequences if ever there are any.

I fully agree with that!

cooldad

Take responsibility for yourself, and if you want a safe sport (pastime, whatever) take up flower arranging, just watch out for those nasty thorns.
Can we end this now?
Darwin rules.

cooldad

whitestar1 wrote:

diy wrote:

yes you should have checked it, but they were contractually obliged to. They didn't. They should make good and be lucky that they are not facing a PI claim.

I would certainly complain and expect some sort of gesture to correct the breach.

If the bike was built by one, checked by another and signed off by a 3rd it would be less likely to happen. But they choose not to do it that way and they will suffer the consequences if ever there are any.

I fully agree with that!

Will ignore my previous post for now.
Get real.
That is all.

cooldad

Wait, now I have it. PI claim? You are a claims clerk, not a lawyer.
Presume you mean PL?

diy

andrewjoseph wrote:

From what I understand of the mechanics, having the brake caliper behind the fork leg causes forces on the rotor that try to pull the axle down and out of the fork drop out. This has been confirmed to me by other engineers.

Thanks - makes perfect sense, the rotor under force from the brake tries to rotate around the brake. Preventable by angling the drop outs forward or avoiding radially mounted brakes.

cooldad wrote:

Wait, now I have it. PI claim?

= Personal Injury.

andrewjoseph

mcgee,

I have said nothing that is not public knowledge, because I haven't been told anything in private that is not also now public knowledge.

I'm not going to try to prove anything to you, if you want to search, go ahead, I doubt facts will influence your views considering your stance on the impossibility of skidding.

You can also put up a poll/questionnaire asking for riders who have had a front wheel come out of the forks while riding. There may not be many, but I doubt, given a large enough response, that it will be zero.

Anonymous

You're a π lawyer?

Radial moun brakes wouldn't solve the problem of the wheel fixing undoing itself, but chainging the angle of the dropouts can alleviate it, as does adding the "lawyer's lips" to the bottom of the dropout.
Which, funnilly enough has been done since, mmm. Not sure, but definitely by the late nineties. My first disc brake brake fork had these features, in 1996.

Anonymous

andrewjoseph wrote:

You can also put up a poll/questionnaire asking for riders who have had a front wheel come out of the forks while riding. There may not be many, but I doubt, given a large enough response, that it will be zero.

I would still need some serious convincing that it was as a result of fork design, and not dodgy QRs. I mean, there's a lot of people who swear by Ti skewers, and also inferior, but nicer looking boutique brands.
How would we know what was what?

You're trying to convince me of something, do it. Don't tell me to go convince myself, that's just showing a lack of sufficient knowledge.

andrewjoseph

mcgee,

I'm not trying to convince you of anything, I stated some views and reiterated some facts, as I know them, about a particular case.

You doubted my honesty, and asked me to prove it. I took umbrage at that. I can't 'prove' my honesty, nor do I see the need to try, to someone like you.

Anonymous

I didn't doubt your honesty, as such.
You know when you say something incredible to someone, and they go "REALLY?".
Do you fly off tyhe handle with them as well?

Basically, it's come to this...
You have an opinion on something.
That opinion is in contrast to my experiences, or the experiences of anyone I've known, which makes me dubious, and so I have my own, differing opinion on it.
You don't like this, and wish for my opinion to be the same as yours.

I don't mind your and my opinion being different on this, if everybody looked the same we'd get tired of looking at each other and all that.
Are you willing to leave it at that though?

andrewjoseph

yeehaamcgee wrote:

I didn't doubt your honesty, as such.
You know when you say something incredible to someone, and they go "REALLY?".
Do you fly off tyhe handle with them as well?

From your post above:

Really though? Hand on your heart in all honesty?

and yes, I get really tetchy when anyone doubts my word. There is also no point in my lying, the information I've stated is available on the internet somewhere.

cooldad

I have been led to believe that not all of the information on the internet is correct or honest.

Anonymous

andrewjoseph, you must be an absolute joy to talk to in real life :roll:
Top tip fr you... when someone asks "honestly?" and instead of getting a simple "yes, honestly", they get a ranting madman angrily foaming at the mouth, they tend to be LESS inclined to believe them.

supersonic

I don't know of anyone in 17 years of riding who has lost a front wheel due to quick release. And I believe when a good quality skewer will not come undone if correctly tightened.

The theory about 'wheel ejection' can be seen on this page:

http://www.ne.jp/asahi/julesandjames/ho ... k_release/

The major force diagram is:

Let's assume we have a bike + rider weighing 90kg in total, braking hard and decelerating at 0.6g (6m/s^2) with the front brake alone (this is a reasonable estimate for maximal braking). The rearward force is 90 x 0.6 x g = 540N, and the vertical reaction force is 90 x g =900N (all the weight is on the front wheel). Taking moments around the axle, the force D exerted by the disk is given by D = 540 x r2 / r1. Here r2 = 13 x 25.4mm is the radius of the wheel and r1 = 72.5mm is the effective radius of the disk (ie to the centre of the force at the pads, rather than the outer edge = 10mm less than the full radius of 165mm / 2). So D = 2460N, acting vertically downwards. This acts entirely on the left hand side of the wheel, but the ground reaction force and braking forces are split equally between the two sides. So we are left with resultant forces of 2460 - 900/2 = 2010N vertically down and 540/2 = 270N rearward. The sum of those is equivalent to a single force of 2030N acting downwards at an angle of 8 degrees behind vertical. Resolving this parallel to the dropout opening angle (= 18 degrees ahead of vertical for a head tube angle of 72 degrees) leaves a force of 2030N x cos(18+8) = 1825N out of the dropout on the left hand side!

It doesn't act entirely on one side though, and the force does not rip the axle out of the dropouts. What can happen is that the forces involved start to unscrew the QR. But is so rare that you will see more snapped fork than ejected wheels. I beleive that a good quality QR in a fork designed for its application, adjusted correctly and checked frequently will cause zero problems.

What is also apparent is that smaller discs, not larger ones, create a larger load on the fork dropouts.

NatoED

so what we are saying is that this happens when you don't properly check your bike before and after a ride? good job i check my bike then.