V Wheels binding

[Akuma]

No one else here seems to have this issue, just similar cases. Maybe the issue is being mis-identified by either those who come accross it or perhaps I'm missing something. Anyway....
Wherever my bed stays on the Y plane, after a few hours (gets worse the longer I leave it) the platform seems to dig in and bind. When you move the bed, you can feel it's as if one wheel is square as it binds against the extruder. However hard I look, I cannot physically see this, just feel it. It is definitely the wheels, as a complete rotation along the extruder finds them bind again in the same spot. It's like driving with a tyre with a nail sticking out of it. The only way I have found to mitigate the effects of this is to pull the bed along, while grabbing a wheel (each in turn) to offset the flat spot on each wheel from all the others. This means the flat spot will be only a quarter of the strength but happening 4 times instead of 1 big bump. I do not get layer shift (noticeable anyway) and prints come out okay, but it is annoying having to do this before every print and I would like a better solution. I tried softening the grip of the wheels but this made no difference. I also get it along the X axis but to a lesser degree. I never had it until I tightened the carriage, which I had to do because my layer lines were affected by nozzle up and down wobble when travelling to the middle of the gantry.
The Z axis is not relevant; the wheels on the side seem too loose but are at maximum.