Cranks Locking?

[(B)MX_4-Ever]

Well, my cranks keep locking up after riding for less than a block. I thought it was the bearings, because they were tightning and loosening on as I pedal. I fixed that and my cranks are still locking.

I have WTP crank arms, euro bb, and Im sure its not my freecoaster, because they lock up even if the chain is off. They seem to only lock up when I pedal forwards, and sometimes, when I pedal backwards, they unlock.

Please help, Im really confused.......

[(B)MX_4-Ever]

you mean the bearings are shot?? or i need to regrease something? or what? anything that can fix it or do i have to buy new ones?

[ediot]

glad that you mentioned the setup. it could be a few different possibilities, check them to see if any hits the nail:

1) most likely, the euro BB cup has cracked/ crossthreaded in the frame. this would explain why the BB locks up when rotated in one directio nand unlocks in the other

2) unlikely, BBs themselves are shot. since they're just axial rotating bearings, it's unlikely that they'd seize up in a particular direction. but if the cups have cracked and you have pedalled to realise there're problems, the bearings are likely to have been damaged already due to their small sizes

3) have a look at the chainring bolt on the crankarm, when you rotate the cranks, does it keep itself a safe distance from hitting/grinding anything? it could be hitting something. specially if there're not enough spacers between the chainring and the BB

4) chainring - is the chainring itself nice and straight? is it aligned in the cranks properly? you can check by rotating the cranks and see if the teeth follow the rotation in a striaght line

5) are u using the converntional euro BB? if you're using things like ISIS or other axle/bearing systems that fit a euro BB frame, it could be that.

hope you can find out and fix it soon