Tommy d Posted April 5, 2007 Report Share Posted April 5, 2007 (edited) Just been looking at my BB cos it's sort of bodged at the moment and I need to buy a new one.I measured my frame (Iolo) and the BB shell is 73mm. Interestingly the BB in there at the moment says it's a 68mm one (Shimano UN53)... Does that mean I can buy another 68mm BB and it will fit? At the moment there's a bodged spacer thing in between the driveside cup and the frame if that makes any difference, but I can't use that again because it's broken.So do I need a 73mm BB or can I use a 68?It needs to be a pretty wide axle (square taper), like 127mm minumum which is why I'm having trouble finding one in 73... Worry over, found one on Evanscycles.com... eventually! Edited April 8, 2007 by Tommy d Quote Link to comment Share on other sites More sharing options...
Ash-Kennard Posted April 5, 2007 Report Share Posted April 5, 2007 look at the skf bbs at tarty. they have a built in spacer which i removeable so will fit both, and are pretty wide too.will last ages too, mine has so far and ive been giving it alot of abuse Quote Link to comment Share on other sites More sharing options...
Tommy d Posted April 5, 2007 Author Report Share Posted April 5, 2007 Ahh... forgot to say, gotta be square taper. Cheers though Ash Quote Link to comment Share on other sites More sharing options...
basher Posted April 5, 2007 Report Share Posted April 5, 2007 Just replace the washer/spacer problem solved and it won't cost you much either. Quote Link to comment Share on other sites More sharing options...
Mark W Posted April 5, 2007 Report Share Posted April 5, 2007 If you get something like a Shimano UN-52 (or UN-53 or whatever they are...) in 73 x 127.5mm, then you can just add the little 2.5mm wide spacer to it to reduce the size a bit if you need to? Quote Link to comment Share on other sites More sharing options...
RobinJI Posted April 5, 2007 Report Share Posted April 5, 2007 With a 73mm shell you need a 73mm BB, its when you put a 73mm BB in a 68 shell that you need the spacers.I've got a UN53 in 73 x 122.5 in my Iolo, but I guess the chainring clearence is better on a 24". I think your going to have a job to find a 73 x 127.5 but someone somewhere will make them. Just get searching. What cranks are you running? I'm suprissed you cant use a 122.5 unless your using a FFW. Quote Link to comment Share on other sites More sharing options...
Bionic Balls Posted April 5, 2007 Report Share Posted April 5, 2007 i remember having this problem ages ago....and i'm pretty sure bikedock told me that 73x127.5 isn't made anymore..i had to settle for 122.5... Quote Link to comment Share on other sites More sharing options...
Tommy d Posted April 5, 2007 Author Report Share Posted April 5, 2007 I've got a UN53 in 73 x 122.5 in my Iolo, but I guess the chainring clearence is better on a 24". I think your going to have a job to find a 73 x 127.5 but someone somewhere will make them. Just get searching. What cranks are you running? I'm suprissed you cant use a 122.5 unless your using a FFW.My cranks are fairly ordinary Burns (Pro Trials), I guess it must just be the different frame shape for 26" that's making it tricky. The BB that's in there now looks about 123/124mm (doesn't say on it) and the chainring is really close to the frame, like under a millimetre away, and that's even with a spacer thing sitting in between the drive-side BB and the frame to push it out a bit.So to run it without a spacer (the spacer on there has snapped) I'll need at least a 127 BB really. The non-driveside crank was only about 2mm away from the frame as well!I'll keep looking, give me a shout if anyone finds a 73 x 127!Cheers Quote Link to comment Share on other sites More sharing options...
basher Posted April 5, 2007 Report Share Posted April 5, 2007 I dont think one is made. So i think you may have to change to isis if you cant make do with a 73x 122.5 bb and put a spacer in. Quote Link to comment Share on other sites More sharing options...
Tommy d Posted April 7, 2007 Author Report Share Posted April 7, 2007 Yay! Shimano UN54 73 x 127.5! It was on Evans Cycles, about the 50th website I tried...I am pleased. Although today I was riding with a rather special cable tie bodge to keep the broken spacer from falling out Quote Link to comment Share on other sites More sharing options...
Bionic Balls Posted April 7, 2007 Report Share Posted April 7, 2007 get a smaller chainring...well done anyways. Quote Link to comment Share on other sites More sharing options...
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