But I just cant see it…

I want to shim a 30.9 seatpost to a 31.6 frame with one of these: http://www.chainreactioncycles.com/use-thermoplastic-shim/rp-prod43707

Cant for the life of me see what the “select diameter” chart is referring to – seatpost or frame tube?

Please help…thanks.

The first option is the seat tube. Select that first and it narrows down the selection of the second option. FWIW, there isn’t a 30.9 – 31.6 option.

If you select the required range in the bottom chart it highlights the outside diameter in the top chart.

Doesn’t appear that what you require is an option. I do believe that they are available but you are looking for a shim rather than a moulded plastic affair. There is not a lot of difference. I think people use coke cans for this.

They’re designed to shim either 25.0 mm or 27.2 mm USE posts.

That’s not to say you can’t use one, but you need to look for one with a difference of 0.7 mm. It doesn’t look like CRC offer ones that thin.

USE used to sell direct and even offer custom shim sizes. Maybe try emailing them with your requirements?

Wiggle have what you want. I just had two arrive this morning.

ooo, thanks, do you have a link, please?

http://www.wiggle.co.uk/use-309-internal-shim/

That one?

That one looks ideal.

Ah, feeling all warm and fuzzy now. Good work team.

🙂
Thanks people!

Straight from the private stock of Baron Alfred Krupp

ho, ho, NW. 🙂