Tonight, while riding my e-bike home from work after the end of bus service, my back tire went flat. I was able to find an Uber driver willing to fit the bike into his trunk, but I had to take the wheels off to get it in. The front wheel is just a quick release that comes on and off like nothing, but to take the back off I had to break out my wrench and remove the nuts, and when I got home I discovered I had lost one of the components that goes on the rear wheel axle, presumably on the ground at the gas station where I loaded my bike into the Uber. I’m sure it’s something I could easily replace, but I have no idea what it’s called.
Here’s a picture of its counterpart on the other side of the axle
The component I’m missing is the round bit in between the two sets of washers. It’s thicker than a washer and has that thicker point along one side where it fits into the dropout.
Anyone more mechanically inclined than me know what that bit is called so I can order a replacement and get my bike back on the road.
They come in a bizillion different styles. Ye ol local bike shop should be able to order one for you if they don’t happen to have that exact style in stock.
ETA:
Poking around on google they can also be called a torque washer. This one is from walmart.
That is indeed a torque washer, the tab of which sits in the drop-out slot in the bike’s frame. The axle will be machined flat on two sides, and the torque washer slots onto the axle’s flat sides such that the washer can’t rotate relative to the axle, with the washer tab nestling in the drop-out gap so now the axle can’t rotate relative to the frame. Instructions on how to fit here: How To Install Hub Motor Washers
A tab lock washer can look similar (if a lot thinner), but performs a different function in that the tab lock washer sits under a hex nut and has a protruding tab that is bent post-tightening to lie against one of the nut’s flats, preventing the nut from rotating relative to the washer. Usually the tab lock washer will have a second tab (or similar feature) to prevent the washer turning relative to the body it sits on, thus locking the nut relative to the mounting body. Other forms of nut retaining systems are available, my favourite being the Jesus nut, which are hopefully more effective than the castellated hub nuts I had on an old car of mine - they would fret themselves slightly loose, shear off their split (cotter) pins, and peacefully unscrew themselves.
