Orientation of QR lever with a disk brake

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reohn2
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Re: Orientation of QR lever with a disk brake

Post by reohn2 »

Blondie wrote: 26 Jan 2022, 1:38pm
reohn2 wrote: 24 Jan 2022, 9:58am
Blondie wrote: 23 Jan 2022, 6:38pm I’ve yet to have a qr loosen on a disc brakes bike. Been using discs for 19 years.
I've had it happen twice in 15 years,once when bikes were stacked outside a cafe and once when I leaned my bike on a wire fence.
Luckily it was spotted on both occasions.

After that I decided the qr function wasn't needed as I don't race so don't need fast wheel changes,and in the event of a pucture allen key wheel removal/fitting isn't that slow with the multitool I always carry anyway.
So I equiped my bikes with Halo hexbolt skewers which were a better alternative,no chance of accidental opening,less chance of a wheel being stolen if the bike's left unattended.
All of which is about catching the lever and not orientation left or right. You just have to mindful if your bike is tangled up, or in a situation where it’s a possibility
Point being qr skewers are superfluous unless racing,hexbolt skewers are more secure on two points IME.
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andrew_s
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Re: Orientation of QR lever with a disk brake

Post by andrew_s »

TheBomber wrote: 22 Jan 2022, 4:26pm
andrew_s wrote: 22 Jan 2022, 12:43am One possible reason is that if the QR isn't tight enough, braking can force the disc end of the axle downwards in the dropout
Hmm… clamping force should be even at both ends of the skewer.
It's not that the clamping force isn't even, but that the force trying to move the axle in the dropout is applied at the disc end of the hub, so it's the disc side that moves.
With hard braking, it's doubtful that external cam skewers are capable of gripping tightly enough to prevent movement.
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andrew_s
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Re: Orientation of QR lever with a disk brake

Post by andrew_s »

Blondie wrote: 23 Jan 2022, 6:38pm I’ve yet to have a qr loosen on a disc brakes bike. Been using discs for 19 years.
That doesn't mean it doesn't happen.
Maybe you aren't in the habit of braking really hard, but ride in a more controlled fashion.

The time I did see a wheel get popped out of the dropouts was a case of playing with nice new, powerful disc brakes.
The rider concerned had spend a week freewheeling down alpine cols, leaving the braking for each hairpin as late as possible, and the drop off the Galibier must have been the last straw, as it was stopping from about 12 mph in the entrance to Briancon campsite that finally popped the wheel out.
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kylecycler
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Re: Orientation of QR lever with a disk brake

Post by kylecycler »

andrew_s wrote: 26 Jan 2022, 8:49pm
Blondie wrote: 23 Jan 2022, 6:38pm I’ve yet to have a qr loosen on a disc brakes bike. Been using discs for 19 years.
That doesn't mean it doesn't happen.
Maybe you aren't in the habit of braking really hard, but ride in a more controlled fashion.

The time I did see a wheel get popped out of the dropouts was a case of playing with nice new, powerful disc brakes.
The rider concerned had spend a week freewheeling down alpine cols, leaving the braking for each hairpin as late as possible, and the drop off the Galibier must have been the last straw, as it was stopping from about 12 mph in the entrance to Briancon campsite that finally popped the wheel out.
"That doesn't mean it doesn't happen."

Exactly - Safety 101 - it's not whether it has happened, it's whether it can happen.

It would help if the manufacturer was to explain why they insist that the QR should be on the disc side, but whether their recommendation is valid or not, it's safer to assume that it is.

Saying that, I didn't know any of this - I've always just had the QR on the disc side and I've never thought to change it anyway, although I can see the pros and cons. But I'll stick with the sure option, even if it's unlikely for the alternative to be an issue.
reohn2
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Re: Orientation of QR lever with a disk brake

Post by reohn2 »

Wheels don't eject out of dropouts under heavy braking strain if those dropouts are forward facing on the front and either rearward or vertical facing on the rear,as braking forces the wheel into the dropouts not out.
Other types are socketed or pronounced lawers lipped front dropouts which aren't as safe as forward facing ones but need the skewer to be completely slackened right off to allow the wheel to eject.
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TheBomber
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Re: Orientation of QR lever with a disk brake

Post by TheBomber »

andrew_s wrote: 26 Jan 2022, 8:35pm It's not that the clamping force isn't even, but that the force trying to move the axle in the dropout is applied at the disc end of the hub, so it's the disc side that moves.
Sure it is the disk side that moves if there is insufficient clamping force, but why would the clamping force be any stronger on the disk side just from the orientation of the QR lever? Unless the skewer is seized in the axle Newton tells us that it will be equal on both dropouts.

For the record the bike has regular (not forward facing) fork dropouts with lawyers’ lips. It came with an external cam skewer and 160mm disk rotors. I’ve already dug out a spare Shimano skewer, left over from a wheel that has been fitted with security skewers a bit like those linked by Reohn up thread.
Blondie
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Re: Orientation of QR lever with a disk brake

Post by Blondie »

andrew_s wrote: 26 Jan 2022, 8:49pm
Blondie wrote: 23 Jan 2022, 6:38pm I’ve yet to have a qr loosen on a disc brakes bike. Been using discs for 19 years.
That doesn't mean it doesn't happen.
Maybe you aren't in the habit of braking really hard, but ride in a more controlled fashion.
Indeed I ride in a smooth manner, anticipating things ahead. The sharp brakers, are often the same in a car, and as a passenger you really notice the late and sharp braking and then accelerate again.

It does mean it’s highly unlikely to happen in my case. Doesn’t mean it’s highly unlikely in your case.
Stevek76
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Re: Orientation of QR lever with a disk brake

Post by Stevek76 »

I've only ever had the rubbish external cam ones loosen which was on an old MTB. Never had the internal cam ones even feel like they might have been loosening. They have higher leverage so much easier to get a proper clamping force on them.

Also the correct orientation is obviously between the stays. :roll: :lol:
reohn2 wrote: 26 Jan 2022, 2:12pm Point being qr skewers are superfluous unless racing,hexbolt skewers are more secure on two points IME.
Agree with that, unfortunately it means bothering to actually go and buy some as QRs are almost universal (pre thru axle). Have to say that despite having QRs on the pub bike and never locking the front wheel up I've never had it nicked. :?
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reohn2
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Re: Orientation of QR lever with a disk brake

Post by reohn2 »

Stevek76 wrote: 29 Jan 2022, 2:12pm ........ Have to say that despite having QRs on the pub bike and never locking the front wheel up I've never had it nicked. :?
That's done it now :shock:
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