Like for like, the larger diameter post should flex less so I'd say proper fit.

Personally, a seatpost is about the only thing I would never shim cos I don't want a fatigued and snapped seatpost through my femoral artery. Could just be an unreasonable fear on my part, but there you go.:)

Thanks jahwomble I'd just finished my last session with my therapist to deal with my fear of carbon shards heading for my heart and now you throw that one in. it's going to cost me another small fortune to get over this. I reckon I might take up base jumping it seems so much safer.

I like Thompson because they are designed to bend not break as a failure mode. This may be complete bullspin, but I find my self believing it.

I run a shim in my hardtail to give it a touch more flex, whether it makes any noticable difference to comfort I don't honestly know. Full size in my carbon frame as don't like the idea of shimming carbon. Probably makes no sense at all, but I don't care, works for me!

Shims are fine (so long as they're long enough!), but they're a PITA is your regularly drop your saddle,as when you pull the post back up, the shim always comes out the frame.

So for me, shims as a temporary fix, right size for long term.

(If you're a weight weenie, I also have a feeling that the fatter posts are lighter - they can get away with much thinner walls as the extra diameter makes it inherently stiffer)

My Giant NRS was supplied with a shim and 27.2 seatpost from new.

It probably doesn't make much difference one way or the other on an FS bike but on a hardtail I'd probably run the shim and a slimmer post just to get a bit of flex. I woudl be careful if the top tube was very dropped though - the shims might not reach down far past the TT junction.

shims suck the boabie.

*THREAD CLOSED*

could we not close the thread until someone tells me what a 'boabie' is?

full size it is then no shims for fear of hurting ma boabie !