RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: priv on July 24, 2008, 08:28 PM
-
i've fitted some primo cranks to a euro bb,but when i tighten the nuts into the spindle(http://)(http://www.radbmx.co.uk/archive/albums/o50/priv_2006/primo-tibolts.jpg)
it tightens up onto the bearings and after a few pedal strokes the cranks seize up
if i loosen the nuts in the axle slightly it frees the cranks,but then they're only finger tight and evenually they undo completely and drop out
any ideas how to tighten up the crank arms without seizing the bearings?
i've only really used isis bb's in mountain bikes so this is all new to me
priv
priv
-
Have you got a spacer tube in there (in the middle of the bearings with the spindle running through it) ?
-
no mate,is it like a tube about 2-3 in long?
-
no mate,is it like a tube about 2-3 in long?
like this
(http://www.radbmx.co.uk/archive/albums/aa255/trev2hip/selling/bb-cover-black.jpg)
-
thanks you two,i'll have a root about to see if i've got one
would one of those stop it then?
-
yep it sits between the bearings so when you tighten the bolts you dont crush the bearings which is what you were doing....
it needs to be measured correctly so that it sits snug between the bearings
dont worry its a common problem/mistake....
-
oh priv i have a couple spare if you need one
-
oh priv i have a couple spare if you need one
thanks mate,i'll have a look tomorrow to see if i've got one,if not i'll take you up on the offer :4_17_5:
priv
-
no worries will be at MK will have one in the tool box or can post if you need it sooner
-
i've put my sealed US BB into the Hyper and in my rush i forgot to put in the spacer :(
will it do the same thing when i pedal? or should it be okay.........the whole thing seems fine but i haven't pedaled yet as i need the spacer for the chainwheel. :-\
-
i've put my sealed US BB into the Hyper and in my rush i forgot to put in the spacer :(
will it do the same thing when i pedal? or should it be okay.........the whole thing seems fine but i haven't pedaled yet as i need the spacer for the chainwheel. :-\
take it out and do it properly.... you'll only regret it otherwise.... trust me im a doctor!
-
yeah i know you're right............just a right ball ache! the minute i hit it into the frame i though FOOK! :shocked:
-
yeah i know you're right............just a right ball ache! the minute i hit it into the frame i though FOOK! :shocked:
we've all been there before, when i built my retro quad earlier this year the two i got with my profiles were too short so had to get a mate to machine me one to the right length! pain in the ass... quic tap with a socket extension and itll pop out again... you can do it in your lunch break :LolLolLolLol:
-
Just done it mate! you should see the look on the guys faces who i share my office with :2funny: :2funny:
-
:) You can sometimes get away without a tube spacer in a US bb,but not a euro,especially with a 22mm spindle as the bearings are miniscule!
-
Just done it mate! you should see the look on the guys faces who i share my office with :2funny: :2funny:
had a feeling you might - i wasnt really joking.... ill pop the top hat washer in the post tomorrow - would it be easier to send to your office?
-
no mate, it'll get lost in the post at work......home is fine and dandy mate :daumenhoch:
-
okeydokey
-
no worries will be at MK will have one in the tool box or can post if you need it sooner
i'd like to take you up on that please,i'll see you at MK about it :daumenhoch: maybe do a deal on some coca cola or beer?
priv
-
no worries will be at MK will have one in the tool box or can post if you need it sooner
i'd like to take you up on that please,i'll see you at MK about it :daumenhoch: maybe do a deal on some coca cola or beer?
priv
no worries, its in the tool box - look out for a electric blue FA limo and im the lump on top of it...
-
Just sharing a trick with you. You know the spacers you use on your flights on the outside. Well if your tube spacer is too small on the inside you can use the correct spacer to make it the right width. The internal tube prevents the lateral presure on the bearings inner races. If you imagine the outer race is fixed in position by the cup in the BB shell when you tighten the spindle you are trying to push the inner races of the bearings sideways and inwards. That is what the tube is for to prevent sideways movement on the inner races. Ooohh sorry got a little carried away. Hope my tip may help some of you guys. Cheers :)