Did this fall off my bike?

August 10, 2007 6:42 PM

Please identify this piece of hardware that I think fell off my bike.

While I was putting my (Marin) mountain bike away after a fairly strenuous ride, I noticed this piece of metal on the floor. I didn't see it fall off my bike, but it certainly looks like it could have. Can you identify where it goes and how I might fix it?

pictures here: one two three four

posted by aberrant to Sports, Hobbies, & Recreation (8 answers total)

Best answer: looks like a lock washer. I'd guess it came off the axles of one of your wheels.
posted by doctor_negative at 6:48 PM on August 10, 2007

Best answer: It's a lock washer. Check the ends of the crank axle: Is one side missing its dust cap, nut, and lock washer? (You could easily not notice because the crank arm will still be compressed onto the axle.)
posted by gum at 6:49 PM on August 10, 2007

Best answer: Well, that's a lockwasher. Usually those can't come off unless you're missing the nut that goes on top of it. It fits over the bolt, just under the nut to keep the nut from unscrewing (as easily).

So check everywhere you have a nut on the bike, like wheel hubs, seat post, top of the upper bracket where the handlebar mount is (on some bikes). Anywhere a reflector was mounted is a good candidate, too - you may have lost the whole assembly and not noticed.

Or it came from something other than your bike (there unnoticed before you brought your bike in.)
posted by ctmf at 6:51 PM on August 10, 2007

Best answer: that's not just some 0.5 cent lockwasher, that is a nice one. i would focus on the critical areas, gears and brakes.
posted by caddis at 7:27 PM on August 10, 2007

Response by poster: OK - I checked the bike up and down, and I didn't see anything. I guess the next trip is to the bike store for an inspection... I really don't want to have the bike fall apart on me in traffic. Thanks to all.
posted by aberrant at 7:50 PM on August 10, 2007

looks too small to be from the bottom bracket or hub. if it were from one of those places, it would be a deadly serious safety hazard, so you should make sure!

by the size and colour, i'd guess that it's a reflector or rack washer. something like that.

personally? i don't think it did fall off your bike.
posted by klanawa at 9:54 PM on August 10, 2007 [1 favorite]

Other than a reflector or a luggage rack, I can't see it coming from a bike. Wheel axles are definitely larger, but on top of that, most bikes use nuts with integrated locking flanges (when the fastener isn't quick release)..
posted by Chuckles at 1:11 PM on August 11, 2007

Response by poster: Went to the bike store; the guy there said that it wasn't from my bike. Took it out for another ride the other day and everything seemed fine. Thanks for the help!
posted by aberrant at 10:47 PM on August 17, 2007