Have got an 853 Sovereign and the seatpost shim is now goosed to the point that the saddle now rotates making the bike pretty much unridable. It appears that these shims are hard to come by and because the tube is a rare size standard reducers will not work. Any help in pointing me in the right direction to solving this would be much appreciated as it really is a cracking bike to ride.

I got this reply from Wheels MFG when I asked them this very Q.

We can custom make 100 mm shims. Cost is $75 plus shipping. 6-8
weeks.

Dave Batka, Founder
Wheels Mfg.
http://www.wheelsmfg.com
303-410-7336

How much!
Robbin gits

Fookin' Nora Toys – did you bite the bullet? Surely there is a more cost effective option

I had one made at work for a mate. I've got the drawing somewhere if you want it (although it's at work, and I'm off next week). A machine shop will charge you £25-£40 to make one.

Local machine shop is your best bet, or can you not get an off the shelf one and modify it to use with yours?

RJ it would be great if you could mail the drawings to my address thanks

Found it. YGM.

Did I fishcakes! No flangeing way.

what size do you need?

can you not use 2 standard seatpostshims like these;
http://www.chainreactioncycles.com/Models.aspx?ModelID=6258

slip the 1st one on your seatpost all the way to the top loose for now, the second one cut the collar off and possibly shorten depending on how long your seat post is and then bond it to the bottom of your actual seatpost with epoxy/araldite.

Let the epoxy cure and insert into frame, the epoxy will stop the bottom-shortened shim dissapearing into the frame.