QR Wheels & Disc Brakes - a lethal combo??

KonaKurt

Like many other riders, I have QR hubs and disc brakes, and have never had any isues concerning safety. But I came across this article which suggests that using disc brakes and QR wheels together is a lethal combination. What do you think?

http://www.ne.jp/asahi/julesandjames/home/disk_and_quick_release/index.html

KonaKurt.

cooldad

Obvious trash. Think about it, how many people are out on QR with discs, how many die?
Hardly lethal.

nicklouse

the user was a fool.

for a wheel to come out he must have been riding with a loose wheel for some time.

law tabs are there for a reason.

The Northern Monkey

Yep lethal... thats why there are no bikes whatsoever with QR skewers.... oh.... wait a sec...


There is truth that disk brakes can undo a QR, but i'm lead to believe that that is why there is a lip on fork dropouts (RS at least).

Was a thread on something similar a while back.

ilovedirt

I only read the first couple of paragraphs, and that's enough to know it's absolute tosh.

1. It may lead to the QR undoing over time. As true as that might be, it's the rider's responsibility to make sure their bike is safe to ride, as it sure as hell can't happen of the course of one ride.

2. It may push the QR down over the retention lip of the fork. Sure, I can't argue that it won't. But if you're braking when there isn't weight pushing down on the wheels (ie IN THE AIR, or with the wheels unweighted, equally pointless) then you're definitely doing something wrong.

Again, tosh. If this were a major issue (or even an issue at all), it would have come to light years ago. The writer is a moron.

KonaKurt

I agree. Thank you all for agreeing with me that this article is complete overhyped nonsense!! )

I honestly do not think any manufacturer would be stupid enough to produce any skewer product that had not been safety tested to a high standard, including withstanding the forces involved with disc braking. Nor any manufacturer of a complete bike, for that matter!

There are certainly some riders out there who through their own carelessness do not use QR's correctly, by not locking them down all the way, or not clamping them down with sufficient force. But of course that is a different matter.

A big 'murdoch' of a custard pie in the face, to the writer of that article!!

KK.

Growmac

While I don't agree that it's a problem in practice, I do think the writer has an interesting point. It had never occurred to me that by mounting the brake on the back yo would set up the forces in that direction. It's obvious when you think of it, and it would make sense on non-maxle bikes to put the caliper in front of the axle.

Still, I don't think it's a real problem.

Anonymous

I'm sure the vast majority are down to not doing up the QR tightly enough in the first place, even if they claim it was tight. I've always been told that it should be done up hard enough to leave an imprint on your hand.

Less than that can feel tight when you check it, but have to say mine have come undone over time when like that.

It's not unsafe, just do it up properly, and check during rides before you're about to do some big descents. Seems to be normal procedure from what I see of a lot of riders and no need to go suing manufacturers.

madmole

Loads of bikes come into my workship with the QR not done up right, pointing down or pushed against the fork or rear frame preventing it fully going past the 90 degree sweet spot

Basically you need the QR done up so its a pain to release and pointing up or forward of the forks, You can clearly see the front QR while riding.

Golden rule is the the QR MUST go past 90 degrees, the end should be closer to the wheel than the centre, this is clearly visible. Thus if it releases a) you can see it and b) the lawyer tabs will stop the wheel coming off and you will feel the wobble

To have the wheel come off you must be a complete muppet

nickel

Growmac wrote:

While I don't agree that it's a problem in practice, I do think the writer has an interesting point. It had never occurred to me that by mounting the brake on the back yo would set up the forces in that direction. It's obvious when you think of it, and it would make sense on non-maxle bikes to put the caliper in front of the axle.

Still, I don't think it's a real problem.

Surely if the caliper were mounted on the front of the fork lower it'd be extremely exposed if you were to crash, which is why obviously the brake hose is run round the back of the fork.

nicklouse

Nickel wrote:

Surely if the caliper were mounted on the front of the fork lower it'd be extremely exposed if you were to crash, which is why obviously the brake hose is run round the back of the fork.

why? how? there is a great big thing in the front called a wheel.

madmole

Not when the wheel just missed the boulder, but the caliper didnt

Lewis A

madmole wrote:

Not when the wheel just missed the boulder, but the caliper didnt

and if the calliper wasn't there it would hit the forks which (potentially) is a far more costly fix...

supersonic

Your fork would probably be dead if the caliper got smashed, might rip the mounts off!

madmole

Fork is strong and designed to resist rearward impact, Capliers only resist rotation

Hit the fork and its a scratched outer and a rapid dismount, hit the caliper and its a busted caliper and a new fork when the mounts are ripped out, as well as a dismount

Hitting the rotor just results in a bent rotor (guess how I know?)

nicklouse

madmole wrote:

Not when the wheel just missed the boulder, but the caliper didnt

which would mean that on a normal fork you have just killed it.

Lewis A

supersonic wrote:

Your fork would probably be dead if the caliper got smashed, might rip the mounts off!

yup!

quattrojames

madmole wrote:

Loads of bikes come into my workship with the QR not done up right, pointing down or pushed against the fork or rear frame preventing it fully going past the 90 degree sweet spot

I've looked before and wondered what position to do the QR up in, if you're looking at the bike from the RHS (chainset side), using the clock face (12 - 3 - 6 - 9 ) what position should I lock the QR in?

Anonymous

I've been told not to have my QR lever pointing forward or exposed as you risk a branch catching it and flipping it free. Advice based on experience apparently.

I push it right in pointing back at the front, and it definitely goes over the 90 degree mark. At the rear it's pushed deep and buried into the frame to nothing can catch it. Again past the 90 degree mark. Always tight enough to leave a mark when doing it up and to be a right pain in the arse to undo them.

cooldad

Both of mine face backwards - 9

madmole

Convention always has the QR handle on the Non drive side, too much going on on the drive side

I dont think there is a perfect right or wrong place, different forks and frames suit different positions.

Use your common sense and dont have it down where it will hit or get long grass/brambles wrapped around it

On my Fox 100's its seend more tucked in and protected verticall y up just in front of the forks, It cant go behind forks cos of the Hope Mini Mono caliper, if I go below that its too exposed. My rear tucks beautifully into a space between the rear subfram and the caliper on my Old mount vision, very protected (But a pain to get pingers in to open). on a conventional frame forward into the V of the rear triangle is normal

Dont have it facing down or forwards (vegitation can catch it and drag it open)

Ryan Jones

What's with the moron brigade, claiming compensation through being berks ! We have people falling off on black graded routes and trying it on, people hitting fences and suing and now this numpty !

Not good for the sport having cretins like this that's for sure !

trooperk

There is some truth about the article, if you look at the date of the article and is about early design disc brake forks with the brake caliper mounted much lower but now All the fork have the caliper mounted much higher, the old design sees the open drop out at 90 degree from the line of wheel axel and piston so if great braking force was applied the rotating force will shift the center point and if the QR not done up very tight it will force the old center point (wheel axel) at 90 degree inline toward of the open drop out.
If don’t belief me go to your bike with a ruler, hold it at center between the wheel axel and piston and run an imaginary line 90 degree from the wheel axel and you won’t see a open dropout inline therefore the wheel will not be force out, but on the other hand go and look at some retro forks and will see the dangerous inline open drop out, some people will know what I mean.
Hope this been helpful.

bike-a-swan

Cotic roadrat forks have the tabs on the front-
http://www.cotic.co.uk/product/roadrat

There's a bit on it here- http://www.cotic.co.uk/geek/#forks

trooperk

bike-a-swan wrote:

Cotic roadrat forks have the tabs on the front-
http://www.cotic.co.uk/product/roadrat

with this setup the braking force is reverse and will push the axel againest the dropout and the wheel will never pop out during hard braking.

quattrojames

madmole wrote:

Convention always has the QR handle on the Non drive side, too much going on on the drive side

Yeh sure, I just said looking from the RHS to keep things simple for my tired brain

Anonymous

madmole wrote:

Convention always has the QR handle on the Non drive side, too much going on on the drive side

I always used to have my front QR on the driveside, and the rear on on the non-driveside. The levers just seem to sit better like that.

Raymondavalon

I have 4 bikes, 2 with QR and 2 with Maxle, but I am a Maxle fan, solely for the superior rigidity of the front end, I weigh 90Kgs and when riding any of my bikes with QRs, I can heat the caliper rubbing the front disk due to flex when turning at speed.

I've not had a QR ever come loose because I check them prior to every ride. A good mate of mine who is a roadie had his rear QR "come loose" on the trail, but I am not convinced he tightened it properly as he removes wheels when transporting his bikes.

Now with the "lawyer lips" as Sheldon Brown terms them, a front wheel shouldn't just come loose, although I've never seen or heard of anyone I know randomly just losing a front wheel.

I still believe that the person who sued Fox over his front wheel "coming loose" was a cheesewand who didn't bother to make doubly sure his QRs were tight..

The Northern Monkey

QR lever pointing backwards.

doesn't matter which side you have it on, as long as it is done up tight.

bike-a-swan

trooperk wrote:

bike-a-swan wrote:

Cotic roadrat forks have the tabs on the front-
http://www.cotic.co.uk/product/roadrat

with this setup the braking force is reverse and will push the axel againest the dropout and the wheel will never pop out during hard braking.

Yes, that's sort of why I posted it.... it's also what it explains in the second link. It was also one of the reasons on one gave for moving the rear brake mount to between the seat- and chainstays. With track dropouts, applying the same principal, a normally positioned rear brake will try and drag the wheel out backwards while a lower position pushes the wheel up into the dropout.

nicklouse

trooperk wrote:

bike-a-swan wrote:

Cotic roadrat forks have the tabs on the front-
http://www.cotic.co.uk/product/roadrat

with this setup the braking force is reverse and will push the axle against the dropout and the wheel will never pop out during hard braking.

shame they did not think about the rear. if that was their reason for doing it.