Shimergo query

[LuckyLuke]

Afternoon all. Am building up a Surly Long Haul Trucker for commuting, shopping & general transport. I fancy trying Shimergo. (I found previous posts and CJ's guide v. helpful. Much obliged to one and all.) I plan to use a mix of spares and parts from my current bike. I'll try to convert pre-2007 Campag Mirage 9 spd Ergos to 10 spd (have ordered the parts from Merician). I've a Campag Mirage 9 spd compact double chainset, BB and front mech. I plan to use these with touring wheels sporting an 8 speed shimano cassette (haven't decided between road or MTB gearing yet). I've a couple of queries, perhaps someone could advise?

Could I use my 9 speed Campag Mirage rear derailleur with the above? Or would an 8 speed Shimano rear derailleur be required? If so any recommendations?

The 9 speed chainrings on my chainset are probably due replacing. Forgive my ignorance, but are specific 8 speed chainrings available? If not how will an 8 spd chain run with aftermarket 9/10 spd chainrings?

Thanks in advance for any help, all the best,

Luke

[mercurykev]

You'll need a shimano rear mech but you should be able to run the chainset with little difficulty. I use a 10 speed chainset on my shimergo 9 speed set up and it works fine.

[CREPELLO]

The mech should be fine, as will the chain rings. To optimise the compatibility of these parts, use a 9 sp chain - it'll be fine on an 8 speed cassette, as the internal width of the chain is the same both both chains. But why not make the bikes gears 9 speed? It won't cost you anything extra and the parts will be easier to get in the future than 8 speed. The critical point to all of this is the clamp position on the rear mech. It don't know what is compatible in your setup, but it likely that you can get a good outcome by reffering to Highpath Engineering's information on this.

I'll see if I can get a photo of how I've re-clamped my Campag rear mech's to work with Shimano cassettes.

[cycleruk]

I would consider the advice from Crepello about going for 9 speed.
A 9 speed Shimano cassette will fit a Shimano 8 speed freehub.
If you have the Campag' mech' and Ergos already then why not give them a try.
According to the tables there is 0.2 mm difference per sprocket pitch between Shimano & Campag 9 speed cassettes.
That's an overall range difference of 1.6 mm so a slight re-clamp position of the cable would soon compensate for this.

If you still decide to go with an 8 speed Shimano cassette then a 10 speed Ergo and Shimano rear derailleur matches exactly.
You could stick with the 9 speed Ergo / Shimano RD but will have to alter the clamp position or use a "shiftmate".

You will need to take into account whether you use an MTB or Road cassette as this will effect which derailleur you can use.
A Campag' RD will probably have difficulties with an MTB cassette.

[CREPELLO]

You will need to take into account whether you use an MTB or Road cassette as this will effect which derailleur you can use.
A Campag' RD will probably have difficulties with an MTB cassette.

From experience a medium cage rear mech is good for up to an 11-28T cassette (11-30 may work, but I don't know). The long cage mech is good for an 11-32T cassette (again, 11-34T may work but I haven't tried). These are with triple chain sets with a 22T difference between big and small rings(I'm about to fit a smaller 26T granny on one bike so that will be a 24T difference - I hope it works!). Using a double chainset may be more forgiving for the lack of length in the mech's cage if ever such a combination were needed - unlikely.

[LuckyLuke]

MercuryKev, Crepello, Cycleruk, thanks for your replies. 9 speed via Hubbub sounds appealling. However, I've already picked up an 8 speed chain so I'll try that route first. I'll buy a shimano 8 spd road cassette and try it all out with my existing Campag mech (while crossing fingers and toes).

Thanks again gents, all the best,

Luke

[CREPELLO]

I said I would try and take a photo of the reclamped Campag mech, so here's three...

You can see how easy it is to rotate the Campag clamp. It's important to make sure that when the mech is pulled right over that the cable doesn't move position. The little lugs on the clamp mean that the cable can rest against the lug to stabilise potential movement. With the normal setup the stability is provided by the groove in the mech body.

I've only just fathomed this out myself. I've been experimenting with this setup for a while but couldn't understand how I was getting perfect shifting throughout, except the largest sprocket, where the chain would be inclined to want to fall back the next sprocket down. It was that the cable was moving slightly when pulling the mech right across, altering the pull ratio just in first gear. This is made worse, if you're fettling and re-clamping a lot (as I've done much of, kinking or squashing the cable in the process, getting through a fair few cables).

[cycleruk]

This is my Shimano derailleur operated by 9 speed Veloce shifters on 8 speed Shimano cassette:-



Note the slight shift in position of the cable.
I hacksawed a new shallow slot next to the original to make sure the cable was located securely.
You can see the original slot under the clamp.
This is an MTB derailleur (STX.RC I think) and has been in use now for many years and thousands of miles.
I think the Veloce Ergos are "old style" and very nearly matched the Shimanos but weren't perfect. That's why I altered the clamp and now it shifts spot on.

[CREPELLO]

I've recently changed an Shimano RX rear mech that was connected to a Veloce 10 speed control. Despite the 'Shimergo book' saying that it would be compatible, I had to alter the clamp for a wider pitch shift; then it was fine. I've now put an XT mech on the bike (same cable pull as the RX) and it was fine clamped regular style.

Sometimes you just gotta fiddle and fettle and it'll come right eventually.