Fresh Goods Sunday - USE Ultimate Sports Engineering - Seat Post Shim

I have used seat post shims for many years now and have mixed success. Some have been made from alu and depends on the frame material can seize in so always apply plenty of grease / copper slip. Some have not been manufactured to the correct tolerances and the seat post has slipped. The best by far and never had any problems with have been manufactured by USE here in the UK. They manufacture four different models for the most common seat post sizes 25.0, 27.2, 30.9 & 31.6mm. Then they make loads and loads of different sizes in each model to reduce down, too many to list but here is a LINK.
I bought this one from Evans Cycles for the Cube E mtb to reduce down from a 30.9mm to 27.2mm as I wanted to fit a longer seat post I in stock. It arrived within a couple of days to the Durham branch for free and as ever it fitted a treat and have had no problems of seat post slippage. You cannot really notice it when fitted in the frame as the seat collar is black and the seat post is carbon. It has a nice tapered top to blend in. I have a few other spare ones in my parts box vary in sizes which have been used / fitted to numerous different bikes / frame / seat post sizes over the years. USE are good value for money but sometimes hard to find and most popular sizes tend to sell out. Try the likes of Wiggle, CRC and Evans or if your local bike shop has an account with USE they will be able to order one in. Failing that you can order direct from their website.
Please note that some frame / bike manufacturers may not recommend fitting shims and may validate any warranty in a claim.
RRP £6.99 and I paid £6.87

Manufacturers blurb -
Shims are available in Aluminum and Thermo Plastic, despite the latter being a lighter solution its material characteristics limit the thickness of the ID - OD measurements. Aluminum is used to achieve the thinnest shims as it is a more robust material.
Rolled Aluminum shim - the very thinnest shims are rolled from sheet metal. 25.4mm shims need to be so thin as they are etched down in acid to the correct tolerance and are too thin to anodise (show as silver).
Machined Aluminum shim - machined to very high tolerances from 6082 T6 Aluminum and then black anodised to protect from corrosion.
Machined Plastic shim - larger size shims are machined to very high tolerances from "filled" engineering thermoplastic UPVC. This keeps the weight down, as the shims get thicker.
Shim design characteristics may affect weight.
Weights are accurate to the nearest gram.
Shims allow a rider to adjust the ID of a frame for a range of different sized posts.