I believe that we've for the most part made the transition to metric on contemporary bicycles -- at least for the tools we use to repair them, am I right?

For example, while many screw threads are still imperial (or whitworth or some bizarre French/Italian/British concoction), the actual fastener heads or shanks are metric. For example, pedals are 9/16" x 20 tpi but we've standardized on 15 mm for the pedal wrench (or a metric allen). Solid axles might be 9mm x 26 tpi but again we've standardize on 15mm for the nut.

Are there any parts of non-BSO bikes coming off the line where we might still expect to still need a non-metric tool to take a component off of?

  • It seems to me the question is kind of irrelevant since one should always have an adjustable wrench ("Crescent wrench") in any general-purpose toolkit. This saves having to carry two sets of open-end wrenches for when you need two wrenches of the same size. Re a kit for a specific bike, you carefully pick the tools you actually need. Sep 14 '15 at 17:12
  • (But as Ryan suggests, I think that some older/cheaper BSOs still use English axle nuts.) Sep 14 '15 at 17:13
  • 1
    Not really metric vs non-metric, but the phillips or flat heads on derailleur adjustment screws always struck me as odd. Some V-brakes also use them for spring tension adjustment. Mine use hex keys, but I've seen a few that use phillips head screwdrivers. Also, @DanielRHicks, I find that adjustable wrenches, while they work, are really not ideal. I find that I'm constantly loosening them to get them on the nut, and then tightening them to make sure they aren't too loose. With a proper sized crescent wrenche, the job goes much faster.
    – Kibbee
    Sep 14 '15 at 17:36
  • @Kibbee - But with an adjustable wrench you're not constantly walking back and forth between the bike and the pegboard to find the right size wrench. Sep 14 '15 at 17:45
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    I believe that adjustable wrenches are the easiest way to get skinned knuckles and rounded off fasteners....
    – RoboKaren
    Sep 21 '15 at 22:06

Very rare, but I believe some pedals still require a 9/16" spanner to remove them. Not to be confused with the 9/16" axle like you have mentioned. Park Tool still make a pedal spanner with both a 15mm and 9/16" opening. Considering 9/16" of an inch is 14.3mm and the chances you'll actually have to remove one are fairly slim, I'd be happy with just a standard 15mm pedal spanner.

Beyond this I can't think of anything else. Perhaps wheel nuts on very cheap kids character bikes? Some of those seem to come with whatever the factory had going spare at the time of assembly!

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