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My front wheel is secured with 14mm bolts, while my rear wheel uses 1/2 inch bolts. Turns out my multitool has only a 14mm wrench, so I can't change the rear tire with it.

Rather than carrying around a whole other wrench, or buying a different multitool, my first thought is to swap the 1/2" bolts for 14mm ones. Assuming I can find a set with the appropriate inner diameter, is there any reason this would be a problem?

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15mm is the bolt size I usually see on axles. – freiheit Apr 14 '13 at 19:13
surely 1/2" implies 13mm, not 14mm? – PeteH Apr 14 '13 at 20:34
If this is a standard axle, the bearing cups thread onto the axle, and would have to be changed with the axle. And if you change the cups the hub would almost certainly need to be replaced. – Daniel R Hicks Apr 14 '13 at 21:28
And commonly front axles are 9mm and rear 10mm, except in beefed-up versions for BMX bikes. – Daniel R Hicks Apr 14 '13 at 21:37
Are you refering to the size of the nut that retains the bearing cones on the axle or the nuts that hold the axle in the frame/fork? – mikes Apr 14 '13 at 23:31
up vote 1 down vote accepted

If you can find nuts with the correct thread (both diameter and thread pitch) but a smaller wrench size, you can replace the ones that are there. But note that the existing nuts probably have a built-in washer, and any replacement should have the built-in washer not too much smaller than what you have. In a pinch you can use regular washerless nuts and a separate loose washer, but that's not as reliable.

It would be easier to find a new wrench. Almost certainly the rear is not an inch sized nut but a larger metric size, and a combo wrench can be found to fit both.

(At least in the US, "bolt" refers to a threaded rod with a head on one end. "Nut" is the small piece with a threaded hole in it.)

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