Front mech and seat-tube sizes advice

Hi,all.

I'm buiding up a basic road-bike as cheaply as I can so Junior can come
out with us. I'm using a Ribble alu frame ( not here yet ) and an
assortment of mostly tiagra group-set parts I have laying around.

The front mech I have ( Tiagra triple, FD-4503 )is stamped 34.9 (
correct for the bike it came off. )

Looks like I need a 31.8 for the Ribble frame.

Clamp band adapters ( shims ) seem to exist, but I can't seem to find a
suitable one. ( to mount 34.9 mech on 31.8 seat-tube ) Any pointers?

Or should I just bite the bullet and purchase a new mech? They seem to
come as 'multi-fit' for 31.8 / 28.6, so I'm guessing the multi-fit comes
with a shim for 28.6, and the 34.9 is a whole seperate unit, supplied
with no shims, and suitable for 34.9 only.

--
Ron

On Mon, 13 Jun 2011 21:07:21 +0100
Ron Lowe wrote:

The front mech I have ( Tiagra triple, FD-4503 )is stamped 34.9 (
correct for the bike it came off. )

Looks like I need a 31.8 for the Ribble frame.

Clamp band adapters ( shims ) seem to exist, but I can't seem to find
a suitable one. ( to mount 34.9 mech on 31.8 seat-tube ) Any
pointers?

The last time I needed a front mech shim I just cut a strip of steel
from an old car panel.

On 13/06/2011 21:07, Ron Lowe wrote:

Excuse me. Ar you talking about Front Mech the local village idiot, or
is it some obscure part of a push bike?


--
Dave - Cyclists VOR. "Many people barely recognise the bicycle as a
legitimate mode of transport; it is either a toy for children or a
vehicle fit only for the poor and/or strange," Dave Horton - Lancaster
University