8 Speed shifter with 7 speed cassette.

drumon

I've got Shimano Alivio 8 speed shifter with a 7 speed cassette in the rear.

Could this be why the chain clicks while it runs on the 7th sprocket?

The chain seems to make less noise when the shifter is clicked in 8th.

supersonic

This combo actually will work! You cant use 8spd on 9spd, or vice versa, but the distance between and thickness of 7 and 8spd cogs is exactly the same. You just have a redundant click in your shifter. Hence your problem lies with adjustment.

AndyTheRocketeer

Shimano 7sp and 8sp have very slightly different spacing.
You've probably got it adjusted so that 6 cogs shift adequately well, but not the 7th, but in the 8th position the H limit screw is holding it in just the right place.

http://sheldonbrown.com/k7.html

drumon

Thanks.

So if I adjust the "H" screw a bit more should I eliminate the clicking or do I need to do something else to make it shift nicely to 7 and make 8 redundant?

Blundell

Yeah but be careful, too much screwing around and you'll be fishing the chain and mech out of the spokes. Make sure the chain is in line with the largest sproket in the easiest gear, that way you should have no ticking. Your ticking is a result of the chainline being slightly off.

Anonymous

Blundell, I think he means the chain is ticking in the smallest sprocket.

drumon

yeehaamcgee wrote:

Blundell, I think he means the chain is ticking in the smallest sprocket.

yup, thats right

AndyTheRocketeer

Since 7sp and 8sp have different spacing, if you get it to work it is just luck. The difference is 0.2mm per cog, so if the centre sprocket is perfect, then the highest/lowest will be misaligned by 0.6mm. That's about half a sprocket thickness, which might just be within the acceptable tolerance.
Set the H/L limit screws as normal, then adjust tension until you get it as best as you can. Check the B screw too if there's a problem on the largest rear sprocket.

Blundell

Oops.. nevermind.. always knew I was back to front! :shock:

drumon

thanks Andy the Rocketeer.
I'll keep an eye on it, it is a tolerable click, only very light, so probably its working just within acceptable tolerance.
TA.