MrJamie
Oaf on a Bike
This is a bit of a weird one, to me at least. I took my bike out for a short ride yesterday and noticed that when i braked the wheel seemed to move left every time and proportionately to the braking force, ie. gentle pad contact had no effect but harder braking would see the tyre move left considerably.
It's hard to tell exactly whats moving, but it looks like the top of the wheel is deflecting left (rotor side) maybe 5-8mm and then springing back as braking stops. Ive had a google and done some reading, I found it's not uncommon and in various guises with lots of different solutions.
>I tried to move the rim with the bike upside down, but there doesnt seem to be any play at all in the hub, also spins very freely so bearings seem okay.
>The rim looks true and the spoke tensions still feel even, its only been on a month too.
>Seems to happen the same with suspension or lockout.
>The suspension fork is rated upto 180mm which is the rotor size im using, I cant see any visable flex but i guess a very small angle could still move noticably at the top.
>Its probably worth noting that bike plus rider is about 140kg so probably larger than normal momentum and forces involved. Id read from Sheldon Brown about how disc brakes apply massive forces and apply forces in silly directions opposite the dropouts.
> I reseated the wheel in thedropout and closed the QR and still moved under braking. Im wondering if it could be the QR skewer not being tight enough. Im a bit ham fisted so have been trying not to overtighten things. The way the wheel looks to be deflecting, ie. pivoting leftwards and what ive read from Sheldon B. about the forces trying to push the caliper upwards and the wheel away from the dropout would agree with this. I havent really had a good test, but this seems to have improved things, but im not sure how tight i can go with a skewer.
Any advice/warnings/stories/jokes welcome
It's hard to tell exactly whats moving, but it looks like the top of the wheel is deflecting left (rotor side) maybe 5-8mm and then springing back as braking stops. Ive had a google and done some reading, I found it's not uncommon and in various guises with lots of different solutions.
>I tried to move the rim with the bike upside down, but there doesnt seem to be any play at all in the hub, also spins very freely so bearings seem okay.
>The rim looks true and the spoke tensions still feel even, its only been on a month too.
>Seems to happen the same with suspension or lockout.
>The suspension fork is rated upto 180mm which is the rotor size im using, I cant see any visable flex but i guess a very small angle could still move noticably at the top.
>Its probably worth noting that bike plus rider is about 140kg so probably larger than normal momentum and forces involved. Id read from Sheldon Brown about how disc brakes apply massive forces and apply forces in silly directions opposite the dropouts.
> I reseated the wheel in thedropout and closed the QR and still moved under braking. Im wondering if it could be the QR skewer not being tight enough. Im a bit ham fisted so have been trying not to overtighten things. The way the wheel looks to be deflecting, ie. pivoting leftwards and what ive read from Sheldon B. about the forces trying to push the caliper upwards and the wheel away from the dropout would agree with this. I havent really had a good test, but this seems to have improved things, but im not sure how tight i can go with a skewer.
Any advice/warnings/stories/jokes welcome