[some_guy282]

My seatpost is 31.6mm. What size clamp should I get? 32mm, or 35?

 

[DirtDawg]

My seatpost is 31.6mm. What size clamp should I get? 32mm, or 35?

They usually say that they will fit 31.6mm or 28.6 and so on - taking a swing at it - it seems like you should look at a 32mm, but it would be best to use your digital calipers and mesure the ouside of the seatpost tube (wher the clamp is going to go)
Usually your LBS can tell you what clamp will fit what size. For my bike the clamp said it would fit 31.8 seatpost tubes - like a good little MTB rider I measured the seatpost tube before venturing out to the LBS and I got exactly what I needed.

 

[Bikinfoolferlife]

Yeah, go ahead and get a 32. That makes a lot of sense, eh? That would have to be one of the thinnest seat tubes ever made, assuming your seatpost size is 31.6. The clamp sizes offered refer to the outside diameter measurement, not your seatpost's measurement. Measure it or if you can't have someone else do it.

 

[DirtDawg]

Yeah, go ahead and get a 32. That makes a lot of sense, eh? That would have to be one of the thinnest seat tubes ever made, assuming your seatpost size is 31.6. The clamp sizes offered refer to the outside diameter measurement, not your seatpost's measurement. Measure it or if you can't have someone else do it.

I was not advising him to get the 32 if thats what you were saying- I was telling him that it seems like he should look at the 32, but it would be best to measure and then go get one instead of trying to guess at what one to get and ending up with the wrong one. We all know that there is no MTB frame with a seattube thickness of around 2mm which it would have to be to go from a 31.6mm inside diameter to a 32mm outside diameter. When I was beginning at building bikes I made the mistake of guessing about which size parts to get and ended up wasting cash on items that did not fit.
Guess Once - Buy twice- or three times Measure Once - Buy Once is my motto when purchasing such parts.