Due to swapping frames over, I’ve got an Ultegra front mech in 31.8 flavour and a seat tube in 28.6, but no shim.

I know that a band on type 31.8 Ultegra front mech comes with a shim for 28.6, but can I find anyone who has one in stock? (Never mind at a reasonable price).

Can anyone help me?

Even if it’s available as a spare, its unlikely to be a stock item, so you’ll likely have to order one, at RRP.

Have a look here

http://www.madison.co.uk/products.aspx?vertical=Cycling&tier1=Transmission+Components&tier2=Front+Derailleur+-+Accessories+%26+Spares

Of course an adapted stem shim or similar would work fine too.

http://www.madison.co.uk/productinfo.aspx?vertical=Cycling&tier1=Transmission+Components&tier2=Front+Derailleur+-+Accessories+%26+Spares&catref=5JD+9802

?

I ised a bit of plastic from a plastic tube works fine

I’ve had this problem twice, the first time i used one of these:

Link

The second time I had the problem I went to buy the same spacer to find the price had gone up to a ridiculous 18 quid and bought a new mech instead.