IntoTheWild

My caliper isn't the most accurate, but it's measuring my seatpost to be about 31.3 or 31.4 and it's measuring the clamp diameter to be about 35.2. Now none of these sizes exist, so I'm guessing my seatpost is either a 30.9 or a 31.6, and my clamp is either 34.9 or 35.0 (why do they even have two different sizes for a tenth of a millimeter?)

Does anyone happen to know exactly what I should get?

HillRider

Most seatposts have their diameter engraved on them, usually below the minimum insertion line. Take it out and look. Also, 34.9 And 35.0 clamp diameters are the same thing. The 35.0 just rounds off the number.

If you still can't find the sizes, why not contact Trek directly and ask.

IntoTheWild

Thanks. Good to know about the clamp sizes, although if they're rounding off 34.9, they really should put it as 35, not 35.0.

I'll give the seatpost a look. But I'd assume take a shot in the dark before sitting on hold for 45 minutes with a large corporation. I rarely have good luck getting info out of big companies.

IntoTheWild

Ah n/m...my clamp is actually some really weird size--a 36.4. Apparently it's proprietary to Trek.