[motard5]

I broke down then rebuilt my bike that has full Shimano XT 12 speed, Fox Transfer dropper, OneUp pedals and these o-rings were lying on the ground. Wondering if they look familiar to anyone? Cheers.

 

[tjhspapa]

One of my bikes has tiny o-rings like that on the tail end of the bolt that holds the brake pads in the caliper. If I forget to pull them off before backing out that bolt when I change pads, they pop off onto the floor. They don’t seem to serve any purpose, but I put them back on every time.

 

[AndrewHardtail]

What is the diameter?

 

[wschruba]

Looks like a standard 7/8 roll of masking tape, so while we're all here guessing, I'm going to say they were under valve locknuts.

 

[Arm&Hammer]

One of my bikes has tiny o-rings like that on the tail end of the bolt that holds the brake pads in the caliper. If I forget to pull them off before backing out that bolt when I change pads, they pop off onto the floor. They don’t seem to serve any purpose, but I put them back on every time.

Those are designed to help not lose the bolts in assembly. They should NOT be on the bolts for final installation which create an uneven mount.

 

[127.0.0.1]

presta valve gasket ?

maybe brake bleeding gaskets ?

 

[BermLover1980]

looks like extra o-rings for your oneups?

 

[noapathy]

They probably fell out of your fork. Happens all the time.

 

[749800]

China.

Maybe Indonesia, or Vietnam, or Malaysia.

 

[mcsd]

Did you bleed your brakes? Looks like the o-rings on the lever bleed port.

 

[MudderNutter]

Them sure look like valve stem O rings to me. Look to see if your lock nuts have the little intention for them on the valve stems

 

[Ironchefjon]

looks like valve stem gaskets or the brake lever reservoir port gaskets.

 

[FlaMtnBkr]

Did you ever figure it out? How far was the bike disassembled?

They look like the o-rings that go on the back side of Shimano brake lever mounting bolts (to tighten levers on handlebar). So when you take levers off the bars the bolts stay in the clamp and don't fall out. But if you pull the bolt out of the clamp, the clamp catches the o-ring so you slide it off the bolt as well.

Only place I can think of where you can inadvertently pull off an o-ring without meaning to remove it.

What does the winner get?! Hopefully at least the satisfaction of learning they were correct, so let us know if you figure it out! Or cash works too...