Bicycle Mechanics - (Another) Question about spindle lengths and BB
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09-30-12, 05:01 PM
I am looking into getting a new BB and I'm getting a bit confused with the measurements. From what I understand the BB size is the width of the BB as well as the length of the shaft that sits inside it. I measured the spindle length of my current BB and it is 135mm! I did the measurement again and got the same answer, but this seems to be 10-20 mm too long. I then looked up my current crank specs here:
and it says BB length is 117. I don't get how this can be. The BB and crank are stock with the bike as far as I know (I bought it 2nd hand)
If your spindle is solid and takes nuts, you might be measuring the total length, and not just to the ends of the sq. taper, which is the correct spec.
Since the screw studs are about 10mm tall, that may be the difference. In any case reconfirm, measuring to the ends of the taper.
BTW- 135mm (or so) spindles aren't all that rare, at least on older bikes. Search through Sheldon Brown's spindle length chart (http://sheldonbrown.com/bbsize.html) and you'll see them listed.
09-30-12, 05:12 PM
Do you have a nutted spindle? If so are you measuing the stud? A pic is worth a thousand words, post a pic of the spindle with your calipers.
But in answer to your question Yes. The first two measurements pertain to your bike 36x24 would be Italain threading in a 70mm shell. 1.37x24 would be English at 68mm ( and some early MTBs with a 73mm shell) and the the third number is the spindle 36x24, 117 or 1.37x24 x 113.
Your crank isn't a triple is it?
10-01-12, 12:35 AM
I am looking into getting a new BB and I'm getting a bit confused with the measurements. From what I understand the BB size is the width of the BB as well as the length of the shaft that sits inside it. I measured the spindle length of my current BB and it is 135mm! I did the measurement again and got the same answer, but this seems to be 10-20 mm too long.You want to measure from end-to-end of the square-taper tips. Do not included the threaded section if your BB-spindle uses nuts.
Measuring with bolt-type hollow BB-spindles:
Simple way with both is to install the nut/bolts and measure the inner distance:
10-01-12, 01:03 AM
Thanks everyone. I think that was exactly my mistake :)
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