Cycling UK Forum

I've bought an Eqilibrium frame and I'm building it up with mainly parts from my old bike. I've come across a problem with the front mech (band on). I've been using a 10 speed chorus which is 30.8 - the Equilibrium is 28.6. I'm using a Shimergo set up - 10spd ergos with 9 speed ultegra and 28/38/48 rings. The chorus mech was working OK, not perfectly but OK. I've seen that for this size rings an MTB mech would/should probably work better. My Ergos are 2003 vintage.
I'm a bit confused with all that has been written on this - and there is a lot! Could you help me with some answers please?
1. As the front shifter is not indexed can I use any shimano front mtb mech or do I need one the specifies 44-48 teeth?
2. Will there be'pull' problems because the Shimano mechs have a strong spring?
3. There are 'NOS' LX M571 and Nexave mechs about, if the spring is an issue does it apply to newer mecs only?
4. Without resorting to coke cans is there a good way of shimming the Chorus mech should he mtb option not be on?

Sorry to get into Shimergo again but I'm finding lots of little problems with the build that I didn't expect. I'm very grateful for your advice.

There are to many variables to give any absolute answers I'm afraid. But...
1)I think you can use any Shimano MTB mech, or road mech for a 38/48T chainset
2)There may be, just may be, a spring issue with Shim road mech's, I believe not because of a stronger spring, but because the actuation arm is shorter, therefore requires a greater weight to hold and operate it compared to the longer arm of the Campag and Shim MTB, which are virtually the same.
There's plenty of reports from users who have no problems with Shim road + ergos. There may have been more of an issue with early Ultrashift (2009), rectified as I understand it by the addition of an extra diaphram washer. That was my own experience.
3)Dunno, but the above still applies.
4)The Chorus band should be 32. Don't think 30.8 exists. I've used Shimano 28.6 >32. shims to fit a 32. Record FD. Or it's possible to transfere the mech from one band to another. I wouldn't like to try coke can - it would need to be something a bit thicker, I think.

re the shim; you may find it difficult to source a purpose-made shim (some multi-fit front mechs come with such shims; maybe an LBS has one?) but with a little effort you should be able to get one the correct wall thickness by buying a cheap seatpost shim. The diameter does not have to be exactly correct; the wall thickness does have to be accurate though. I agree with Jerry; careful measurement is called for. If the required wall thickness is exactly 1/16" (it should be) then a short length of standard 16Gauge wall aluminium tube can be used. A little hacksaw and file action should see you with a workable shim in no time.

hth

cheers

The hard rubber shims which with come with lights work perfectly well on front mechs. They come in a variety of thicknesses.

Does your left shifter have lots of clicks.? The older ones eg pre 2000 were remarkably tolerant of mechs. I use an ancient Record with the same chainset size as you.

Many thanks for your help, it gives me a couple of options to try. I'm inclined towards a smaller band for the chorus mech or trying a Nexave, which is designed for hybrids with a 28/38/48 set up. I'd rather have something from a higher group but it seems a sensible, economical fix.