My QR disc bike has never had an issue with rubbing rotors after putting the wheel in, and it feels like the axle only has one resting place in both my front and rear dropouts. What about QR would let an axle clamp down off-axis that wouldn't be noticed over at the rim brake track?
1
-
Voltaire said "Il meglio è l'inimico del bene". (Loosely translated to "Perfect the enemy of good"). Nothing wrong with QR/Disc, merely it is not perfect.– mattnzCommented Jul 8 at 2:00
Add a comment
|
1 Answer
Nothing. If the QR is clamped out of position, then rim brakes show it worse because they're further away from the axle. This multiplies the error.
The current objection to Quick Release and disk brakes, is that when the brake caliper clamps, the axle experiences a downward force which is in the direction of the dropout. So a loose QR can eject the disk brake wheel from the dropouts under braking.
Through axles prevent that by not being able to exit downward.
Some few bikes have their brake caliper on the front of the right fork leg, and the resulting forces push the axle into the dropout, not out.
-
3It's not without risks to have the brake caliper on the front of a fork leg. Behind a fork leg, the brake bolts preload doesn't matter as the forces push the caliper towards the fork leg. However, in front of a fork leg, the forces pull the caliper from the fork leg, which means the bolts must be tight. If they are not tight, first the force between the fork leg and the caliper reduces, and when the full bolt preload has been taken from the force, then the bolt experiences increased forces, and those cyclical increased forces cause the bolts to fail rapidly.– juhistCommented Jul 7 at 13:10
-
1@juhist fair points - the QR's fastener is undone and retightened more than the caliper mounting bolts over the life of the bike, so more chance for the wheel to be loose than the caliper. Neither caliper position is perfect.– Criggie ♦Commented Jul 7 at 19:35