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I've built a few bicycle frames and it's a known issue among framebuilders that you should point the opening of the front dropouts rearward a bit on disc brake
by dwater 4y ago
I've built a few bicycle frames and it's a known issue among framebuilders that you should point the opening of the front dropouts rearward a bit on disc brake forks. Disc brakes can generate serious torque.
- paulgb 4y agoWouldn’t rearward make the problem worse? If you imagine slamming on the front break, the wheel wants to stay put while the rest of the bike wants to move forward. If the dropouts face rearward and the QR has wiggled loose, there’s nothing to stop it from slipping backwards.
- c0nsumer 4y agoNo. The issue is with the torque of the brake pulling the wheel out of the dropout. Changing the angle of the dropout changes this. Look at figures 3 and 4 on this article: https://cyclingtips.com/2015/10/road-bikes-are-headed-towards-through-axels-but-why/ https://cyclingtips.com/2015/10/road-bikes-are-headed-toward... What is needed is the dropout not aligning with the direction the axle is forced when the brake is applied.
- dendrite9 4y agoFigure 4 shows the front dropout facing down and forward, not down and back. I agree that down and forward makes more sense in terms of preventing the axle from moving. the middle image in fig 4. says that the axle is moved down and to the rear during braking as the brake pad acts as a pivot point.
- c0nsumer 4y agoIf the dropout faces rearward enough it'll still be effective. What needs to happen is the dropout needs to not allow the brake pad to be the pivot point for removal. But a rearward wheel removal path is problematic for other reasons: hitting the downtube during removal, requiring caliper removal to allow the rotor to clear, etc.