Front mech - multi dia clamp. 28.6/31.8

[PpPete]

I need a new Shimano front mech for a rebuild project. Old steel tube frame so 28.6 mm dia seat tube. Generally I just get a 2nd hand 28.6 mech but this time I'm looking at the newer models.

They seem to in 3 flavours:

• Braze-on
• 34.9 band
• band suitable for 28.6 AND 31.8

How does that third option work? do they just supply a 31.8 mm band and a shim for 28.6 - or is it some kind of clever Japanese wizardry that enables it to fit either?

 

[jimboalee]

The mech itself is 31.8.

There will be a 'reducer' ring / collar that fits in the mech.

 

[02GF74]

^^^ wot he said - there are usually two reducer collars supplied.

in the past I am pretty sure I had a Shimano front mech with a band that was adjustable, a bit like a jubilee clip, but much neater.