Is there any reason not to use one of those USE shims to shim a 30.9 seatpost to 31.6mm?

ta!

if the shim doesn’t extend below the top tube/seat stay/seat tube junction by a few cm would be the main one for me.

I had to source and extra long one (120mm) when I was shimming a post for my Titus Fireline.

My Scott CR1 came with explicit instructions not to use a shimmed seatpost.

Used 1 for the first time on the weekend. I tightened the quick release to its normal tension but the seat post would slip a few centimetres every 20 minutes. This was over fairly rugged terrain.

My quick release needs an hex key to tighten it properly so i couldnt be bothered on the trail. Will tighten it slightly and see if it still slips.

pembo6 – try some carbon paste between shim and seatpost.

Thanks wwaswas

mine works fine though it is 27.2 to 31.6

mine works fine too 27.2-31.6

FYI the Superstar shims are slightly longer then the USE shims, only by ~15mm but might be important.

30.9 to 31.6 USE seatpost shim in use here on a Reverb no issues to report .
Carbon paste was used so the torque needed wasn’t excessive

Gives me frame options in the future

I’ve used one without problems but I’m sub 60 kg which may well be a factor.

I’m rather north of 60kg (100kg) and no issues 😀

I’m using a 27.2-29.8 USE plastic one in my P7 with qr seatclamp and have no problems with slippage despite being over 90kg. Used a plastic one as the original alloy one corroded into the seatube and I had to hacksaw it out.