j3ns

Hi there,

The cassette is 7 speed Shimano MTB and I need a new trigger shifter, most decent shifters available are either 8 or 9 speed.
According to Sheldon Brown a 8 speed shifter will work with 7 speed cassette although there is a slight difference in sprocket spacing, is this correct? Will the difference in sprocket spacing between 7 and 9 speed cassettes be too much for using a 9 speed shifter on a 7 speed cassette?

cs1

Yes it is correct. 7 sp is 5mm and 8 sp is 4.8mm. Contrary to what most people say, that will make a difference.

Try using a 9 sp cassette with the 2 cogs removed. Then the 9 sp shifter will work perfect for the first 7 speeds. The shortened cassette should fit nicely on your current cassette hub body. Good luck

j3ns

Thanks for the the reply and advice.
You say that the different spacing between 7 and 8 speed will make a difference. Would you then advice against using 8 speed shifters with 7 speed cassettes?
Currently I'm looking for a solution with only a replacement of the shifter, not the cassette. The option of going back to friction shifting is actually more likely than changing a cassette as well as the shifter.

shelbyfv

I think you need to use 8 cogs of a 9 speed cassette on the 7 speed hub. You can then use the 9 speed shifters.

SmallieBiggs

https://www.niagaracycle.com/product_...ucts_id=449735

My experience with the 'lower end' rapidfire shifters (not the E-Z-Fire hich have the release trigger on the top of the brake lever) has been 100% positive... robust, long lasting, and they work great.

BikeWise1

Yep. I can't believe how durable those cheap little things are. I put them on my wife's commuter about 7 years ago and she rides almost everyday in all weather. Never a problem.....

FastJake

As suggested above, just get some 7 speed shifters if that's the only part you're trying to replace.

I've run 8 speed shifters with a 7 speed Shimano freewheel and it worked fine, but why buy the "wrong" thing?

j3ns

Thank you guys for the input. Although Niagara Cycle Works won't ship abroad I can get the M310 shifter quite cheap from a different source. I will do so, you have convinced me that they will be good enough.

BCRider

I'm running one bike with the 8 speed shifter cotrolling a 7 speed cassete. Yes it works but you're going to find that you need to "overshift" here and there. So while it works it's not a clean shifting setup and you'll get a little bit of noise in the extreme gears at each end of the cluster as the differences add up through the shifting. You'd actually be better off to try to source a 7 speed setup if you can. Or live with the 7 and 8 speed mix for the time being and when the cassete needs replacing THEN do the trick of getting an 8 speed and leave out one gear so it fits your freehub. Then your shifting will be back in synch.

Burton

In theory I agree with all the info posted. In practice I`d personally go to bar mounted friction shifters before letting myself get forced into `upgrading` all major drivetrain components just because I needed to replace a discontinued shifter.

Even a Tourney 7 speed shifter would look like a better alternative

But I`m known to be a little stubborn at times

HillRider

Actually, it's a 9-speed cassette with one cog removed that fits on a 7-speed freehub but you need a 9-speed shifter and chain. That, of course also requires 9-speed shifters.

This thread reminds me of a hilarious posting I saw on a bicycle forum years ago. The poster was given a "free" set of 8-speed Ultegra STI's, which at the time were the current state of the art. He then details all of the various upgrades and changes he needed to make these free brifters work on his bike and by the time it was over a new bike would have been cheaper. I wish I could find the original as the story was a wonderfully entertaining.

DannoXYZ 

You can get the 7-spd cassette to work with 8/9-spd shifters by replacing the 3.15mm spacers with 3.0mm for 8-spd or 2.65mm for 9-spd (depending upon the levers you get). So you'll have a 7-on-8 or 7-on-9 combination. I used to do this type of upgrade all the time when 8 & 9-spd came out. It let me use all the older wheels I had on my newer bikes. Sometimes I'd get the spacers from shops, other times I'd just slowly spin them over a grinder and measure often with calipers.

I've managed to build many Shimano-compatible Suntour 8-spd freewheels this way too.

fietsbob

Friction thumb shifters will cover all the variance, of cramming more cogs
into a limited space.