acera ST chainset 8/9 speed

[Sweep]

Scroll down and you can see that someone asks if this acera 371 chainset can be used with an eight speed cassette and chain. And evans says no, only 9 speed. Surely they are wrong? Or have i missed something?


http://answers.evanscycles.com/answers/ ... stions.htm

[Sweep]

Just noticed that the eminently sensible and down to earth edinburgh bike co-op seems to say the same thing:

http://www.edinburghbicycle.com/product ... 1-chainset:

Or am i getting muddled up with the 361?

http://www.chainreactioncycles.com/shim ... prod106885



What is the actual difference?

[CREPELLO]

The chain rings will be the same, but I'd expect the rings to be spaced a bit wider on the 8 speed version. I doubt a 9 speed chain on the 8 speed M361 would get jammed in between the rings (but it could be a possibility). The main issue would be the chance of an 8sp chain rubbing on the outer ring of the M371, when on middle ring and smaller cogs at back.

[Gattonero]

I agree, worst you'll get is a bit of chain rub, at that point you may just want to shift on another chainring

[gregoryoftours]

I've used 9sp chainsets on 8sp everything else plenty of times without problems, and 8sp chainsets with 9sp setups, but if you want it for an 8sp drivetrain you can save money by getting the 361 chainset from rosebikes for about £27 posted.

[531colin]

Scroll down and you can see that someone asks if this acera 371 chainset can be used with an eight speed cassette and chain. And evans says no, only 9 speed. Surely they are wrong? Or have i missed something?

Swapping chainsets around has many pitfalls, for example.......
road and MTB chainline are different
road and MTB front mech. cable pull for indexing are different
road front mech. is likely to foul the chainstay before you can get it low enough with MTB size chainrings
Bearing all this in mind, the on-line shops are likely to only recommend a straight swap....MTB for MTB, 8 speed for 8 speed, etc.

Is the chainring spacing actually different on Shimano 8 and 9 speed stuff? Stronglight make no such distinction that i know of.

[blackbike]

I built up a store of Alivio square taper chainsets and spare rings without realising that I had bought some 8 speed ones and some newer 9 speed ones.

I found out when I tried to fit new chainrings to a spider and they would not fit. The chainrings for 8 and 9 speed are a different internal diameter and the spiders are different even though 8 and 9 speed chainrings have identical bolt spacings.

As I have always used 8 speed chains I now know that these chains work just as well with 8 and 9 speed Alivio chainsets with no problems whatsoever.

I expect it is the same with Acera.

[fatboy]

I use a 9 speed chain on my 8 speed tourer to minimise chain rub (my shifters have no trim function) so if you were worried you could match the chain to the chainset and it'll be fooled that you've got 9 speed all round. I suspect that it really won't matter.

[531colin]

I built up a store of Alivio square taper chainsets and spare rings without realising that I had bought some 8 speed ones and some newer 9 speed ones.

I found out when I tried to fit new chainrings to a spider and they would not fit. The chainrings for 8 and 9 speed are a different internal diameter and the spiders are different even though 8 and 9 speed chainrings have identical bolt spacings.

As I have always used 8 speed chains I now know that these chains work just as well with 8 and 9 speed Alivio chainsets with no problems whatsoever.

I expect it is the same with Acera.

They went to a lot of trouble to make those parts incompatible. That can be either to save us all from making a dreadful mistake fitting a 9 speed ring to an 8 speed spider, or its good old built in obsolescence.....you choose.
Meanwhile, back in the real world, here is a Stronglignt Impact chainset with a Spa middle ring, on a 9 speed bike, but running an 8 speed chain, because all the other bikes are 8 (or 7) speed, and I can't be pestered to keep 2 lots of spares, as it works perfectly. friction front shift, though.

[Sweep]

Yes blackbike that is pointless complication. I would have just assumed shimano, alivio, right bcd, all well. Nice pic colin - really like the fact that the bcd is so clearly marked on that chainring. Very businesslike.

[blackbike]

Yes blackbike that is pointless complication. I would have just assumed shimano, alivio, right bcd, all well. Nice pic colin - really like the fact that the bcd is so clearly marked on that chainring. Very businesslike.

Just another typical Shimano compatibility issue.

There is way round it as you could just file away the millimetre or so of metal that stops some rings fitting on the spider that that takes the ones with the larger internal diameter. The bolts hold the ring in the correct place so the job needn't be done accurately or prettily.