Converting a 3x8 to 2x9 or 2x10

[Celtic Dragon]

This mornings ride convinced me of something I have long suspected, my rear cassette is on its way out. I don't use the big ring, so thinking about converting it to a 2x9 or 2x10 setup. Would it be possible? IIRC 8, 9 and 10 speed cassettes are all the smae depth, but with different spaceings between the cogs. I know it will require a different shifter and mech.

[P-Jay]

If you're going to do it you might as well go 10sp unless you want to go sub-deore spec, there's little price difference if anything 10sp is cheaper on CRC.

If you go for a widest of 10sp cassettes you might find you can get away with 1x10 with a 32t front ring.

[sandman77]

You will need new shifters (left and right), new cassette, crank/chainset, front deraileur and chain. Your rear deraileur should be fine but for the sake of £30 you might as well get a new one.

A new complete 10 speed 105 groupset will set you back about £400, that will include brakes too.

A better option would be to buy a 2nd hand bike.

[Celtic Dragon]

P-jay, I was thinking S-ram X5, hadn't considered that Shimano might be sub deore. Deffinatly going to stick with 2 upfront, I'm not that fit! I'd end up walking the uphill trails.

[P-Jay]

Celtic Dragon said:

P-jay, I was thinking S-ram X5, hadn't considered that Shimano might be sub deore. Deffinatly going to stick with 2 upfront, I'm not that fit! I'd end up walking the uphill trails.

Haven't explained myself properly, Shimano don't make 9sp stuff anymore in anything higher than Alvio, stuff is still out there, but its old stock and in a few months it'll be gone and if you bust a bit you might have to replace it all again.

Sram X5 will be good too, but I'm out of the loop om Sram stuff.

[Gumstabber]

If you're changing from 3x to 2x at the front don't forget you'll need new cranks as well.

[Celtic Dragon]

Gumstabber, can you explain why please? I was just going to drop the outer chain ring and fit a bash guard to replace it.

[shouldbworking]

Celtic Dragon said:

Gumstabber, can you explain why please? I was just going to drop the outer chain ring and fit a bash guard to replace it.

No reason I suspect. I've run my hardtail in 3x9 and double + bash guises, kept the front deraileur and just screwed down the high stop.

[AndyDRZ]

I think Gum might be right. Isn't the chain thinner on a 10speed so the front rings will be too wide for the chain.

[Celtic Dragon]

Yes the chain is thinner, but the front mech controls how far it gets pushed about.

[P-Jay]

I'm running 10sp with a standard 9sp SLX crank, no issues. If you drop the outer just turn down the '+' screw as above to stop trying to shift onto the bash.

I haven't seen specific 10sp chainrings for sale, not that I've looked that much, I would imagine 10sp cranks have slightly different sized rings to give a good range of gears. I'm running a 32t ring with a 11-36 cassette and it's pretty much all the gears I need. I've still got the granny on at the moment, just because I'm tight and spending £100 on a chain device and single speed specific ring goes against the grain.

[AndyDRZ]

I meant if the ring is that much wider than the chain, it won't physically fit over the teeth.

I'm interested too as I have a 3x7 and would like to upgrade as mine is wearing out.

[P-Jay]

AndyDRZ said:

I meant if the ring is that much wider than the chain, it won't physically fit over the teeth.

I'm interested too as I have a 3x7 and would like to upgrade as mine is wearing out.

A 10sp chain fits over 9sp chain rings fine, couldn't comment on 7/8sp rings though.