Diameter of a 1 1/8" top cap? Can someone measure one for me?

[tlarwa]

Is the diameter of a top cap made for a 1 1/8" steerer the same as for a 1" steerer? If not, what's the diameter of a 1 1/8" version. I have several that are 1 1/4" in diameter, and I'm not sure what diameter steerer these should be used with, or if it matters.

Thanks,

Tom

[bobswire]

Is the diameter of a top cap made for a 1 1/8" steerer the same as for a 1" steerer? If not, what's the diameter of a 1 1/8" version. I have several that are 1 1/4" in diameter, and I'm not sure what diameter steerer these should be used with, or if it matters.

Thanks,

Tom

1 1/4" top cap is correct for 1 1/8" steerer.

-Bob

[Dave]

1-1/4" or slightly more is the normal top cap diameter for stems made to fit 1-1/8" steering tubes.

Keep in mind that very few stems are made to fit 1" steering tubes these days. Most of the time, a reducer bushing is used so a 1-1/8" stem will fit on a 1" steering tube. Then the top caps will then work with either size of steerer.

[tlarwa]

Thanks, guys. Makes sense, just wanted to make sure I was using the right one.

[allenwhy]

what is a reducer bushing?

i have a 1" steerer and a 1 1/8" stem with a shim. above the stem i have a spacer. i should be using a 1" top cap (as the spacer is 1"), but my 1 1/8" thomson top cap compresses everything fine...