Technical & Reference Section > Tech and Restoration
Bottom Bracket Fitting Help Needed
motomagII:
my standard frame was real twot to do too took me ages to get cups in they were mega tight
TwoBobRob:
Yip. Very tight tolerances. My mates was perfect though, never gave him a moments problem :daumenhoch:
perry:
this is bmx right ::)
ive seen cups literally fall into the shell when on its side and others that were simply the wrong size
to use a lathe you need to know what size the shell is in the first place and once that calipers out i can guarantee no shell measured will be the same
decent chrome will add no notable thickness and skimming it will have it flaking off and rusting the frame
if anything more than hand tools are needed to pop some cups in then doesnt that say they are the wrong size :uglystupid2:
id love to know do those peoples bearings spin freely or do they require a little "push" ( and thats without the cranks on )
if the cups are alloy get a file and take your time , if they are steel get measuring ( precision tools ) and if they are a close tolerance warm the shell
TwoBobRob:
My bearings spin beautifully thankyou. As do my friends in his Lengthy I mentioned earlier. No problems here.
MartyC:
--- Quote from: perry on January 28, 2008, 08:14 PM ---this is bmx right ::)
ive seen cups literally fall into the shell when on its side and others that were simply the wrong size
to use a lathe you need to know what size the shell is in the first place and once that calipers out i can guarantee no shell measured will be the same
decent chrome will add no notable thickness and skimming it will have it flaking off and rusting the frame
if anything more than hand tools are needed to pop some cups in then doesnt that say they are the wrong size :uglystupid2:
id love to know do those peoples bearings spin freely or do they require a little "push" ( and thats without the cranks on )
if the cups are alloy get a file and take your time , if they are steel get measuring ( precision tools ) and if they are a close tolerance warm the shell
--- End quote ---
It's all down to manufacturing tolerances, a very tight fit is unlikely to make any significant difference to bearing cups other than making them hard to fit, the bb shell will most likely "stretch" or flare to accomodate. Get a set of vernier calipers to check the insider diameter of the bb and the outside diameter of the bb cups. A good quality BB is more likely to have a better fit than a cheap one, that said in 1982 my Profiles were a fooker to fit to both my Patterson and then my Haro so maybe that ones not right :LolLolLolLol:
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version