ryac Posted April 23, 2010 Report Share Posted April 23, 2010 Hi all, Had a bike custom-built three months ago, however the crankarms seem to be too close to the frame. Check out the scratches: The first attempt was to put spacers in to widen it out and that seemed to help but still not quite enough. I dont know if it's possible to put more spacers in or if there are other/better methods to go about fixing this? The bike shop mentioned that they'll grind the crankarms but doesnt sound like a proper way to fix this problem. Is this a common problem? Thanks for your feedback.. Quote Link to comment Share on other sites More sharing options...
davey1991 Posted April 23, 2010 Report Share Posted April 23, 2010 Buy a wider BB. Or as the shop suggested grind the very very edge off the crank arm. Quote Link to comment Share on other sites More sharing options...
pogo Posted April 23, 2010 Report Share Posted April 23, 2010 My crank catches the rear slave, hasn't done any damage that'll affect it yet though. Quote Link to comment Share on other sites More sharing options...
Sam Styles Posted April 23, 2010 Report Share Posted April 23, 2010 i had this problem with my mod. dont buy a wider bb cause it will offset your chain line. buy new crank arms with a bigger offset. this is what i did as my old tryall cranks had something like a 26mm offset, and i couldnt ride them with my new frame cause they hit it and the brake... so i just baught new zoo crank arms which had a 36mm offset and now everything is perfect 1 Quote Link to comment Share on other sites More sharing options...
Mark W Posted April 23, 2010 Report Share Posted April 23, 2010 If it's just rubbing on one side, you could try a thin BB spacer between your drive-side cup and the frame? The same one you get to reduce a 73mm BB to a 68mm. That's assuming that isn't the sort of spacer you've used already. Other than that, a bit of grinding might help. Quote Link to comment Share on other sites More sharing options...
Muel Posted April 23, 2010 Report Share Posted April 23, 2010 Buying a wider BB won't effect the chainline much, and anyway you can move the rear sprocket to get it right again. You can add spacers in but then you're probably risking catching the other side. Quote Link to comment Share on other sites More sharing options...
Tux07 Posted April 23, 2010 Report Share Posted April 23, 2010 tarty bike do a 140mm axled bb i've gotta order one wednesday for my t-rex as the chainstay yokes is too wide for the cranks i've got Quote Link to comment Share on other sites More sharing options...
Mark W Posted April 23, 2010 Report Share Posted April 23, 2010 A 128mm BB should give you the clearance you need, but won't batter your chainline too much... Quote Link to comment Share on other sites More sharing options...
ryac Posted April 24, 2010 Author Report Share Posted April 24, 2010 thanks for that. the right crank was ground in the end. it's rare that it will scratch now but still can happen. I do think it's better to get a wider BB or cranks with a bigger offset though. Quote Link to comment Share on other sites More sharing options...
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