Rear wheel (rim) moving to one side when squeeze brake

[DYAKOV]

Right, so I might have had that happening on other bikes in the past and never really cared much but the older I get, the grumpier I am…

So, I noticed that when I’m squeezing the rear brake the rim moves to one side. I don’t think that the frame is flexing and I’ve got a steel 2 bolt brake booster to stiffen it up. The slave cylinders seem to be at equal distances from the rim, pads are somewhat equally worn. Using echo washerless clamps, so unless the mounts aren’t super straight I don’t see why the rim would move. I can only explain that with one slave cylinder not being powerful enough, so the other one pushes stronger but I’ve recently bled the brake and I’m positive that there isn’t any air trapped in the system.

Any thoughts or tips?

Cheers,

Nas

[aener]

Maybe a question of timing rather than power? If one piston is slightly sticky compared to the other, it will move slower so they'll meet off-centre. Lube up the right slave's piston and see if that evens out the timing?
That's my first thought, anyway.

Edited November 11, 2022 by aener

[thousandwords]

could it be that the axle is less tight on one end allowing it to move along the dropout and thus pushing the whole wheel towards the other side?

[cwtrials]

I've had this happen a few times where one piston is "sticky".  more than once it had been caused by overtightening the mounts binding up the piston.  If you water bleed your brakes, over time the slave cylinders than get sticky.