MTB Double Chainsets with high tooth counts?

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I need to buy a new Shimano compatible chainset for a bikepacking/mountain bike, either a double, or maybe a triple set that I can convert into a double. My problem is, I want a main large ring of 40t or 42t, and a small ring of 30t or 32t. A 38/28 is not enough for the ratios I need :sad:

I am surprised to find myself having real problems finding such rings, or even a 30t or 32t ring with BCD of 64mm to fit to an old SLX crankset.

Any chainset suggestions folks?

I nearly bought the new M6000 Deore double set, but learnt that the ring bolt pattern is unique and not symmetrical, meaning nothing larger than 38/28 is possible :sad:
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
You won't find an MTB chainset. A 38 vs a 40 is minimal - you just won't quite go as quick. Pedal faster.
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
I run 2 x 10 on my full suspension - not keen on 11/12 gears as it's used on the flat and hills, so I need tighter gaps. Mine is 38/28, and yes I run out at the fast end...
 
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User84300

Guest
Success!! Or, partly at least :smile:
Thank you folks for your messages. I have bought a Shimano Deore M617 double chainset at a bargain price :smile:
It now has the correct main outer 40t ring fitted to it (104BCD).
All I need to do now, is find a 64BCD inner ring (4 arm) with either 30t or 32t, and I will have perfect gear ratios at my fingertips :smile: I am assuming that for a inner ring, I can use any brand I like.

Any suggestions?

The only one I can find, is a "9 speed" but a good quality ring. Would that work ok with my KMC X10 chain and 10 speed train?
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
9 speed will work
 
OP
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User84300

Guest
9 speed will work

Thanks Fossyant :smile:
I've now successfully calculated and sorted out my perfect gears :smile: I've managed to find and fit, a good quality 30t ring to my crankset, and although it's technically 9 speed, it is running and shifting up and down as sweet as a nut :smile: I have also fitted a new 10 speed cassette (11t-28t), but will keep my newish 11-34 one as a spare.
The result is finally, perfect gear rations, with plenty of 4.5+ ratios to give plenty of road speed when needed, without needing to run to the end of my cassette :smile: and crossing my chainline awkwardly. Perfekkt! Now I'm ready for all round bikepacking touring action :smile: while still having three hillclimbing ratios for those gradients. My philosophy is, for touring, if a hill is too steep for a tough hillclimb, save energy and don't struggle...just walk :smile:
 

I like Skol

A Minging Manc...
Similar situation here. Was just browsing the net for a new chainset for my MTB as I fitted a pretty basic chainset last time I rebuilt it and the middle ring is getting worn.
I currently run an M442 triple as a double (the two big ones, dropped the granny ring as I don't use it) with 32/44T rings and the ridiculously small current chainsets just won't do. I did want to 'upgrade' to something XT to match the rest of the bike but in the end just bought a couple of genuine 32T chainrings for my existing set-up, just under £9 each :okay:
 
OP
OP
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User84300

Guest
Similar situation here. Was just browsing the net for a new chainset for my MTB as I fitted a pretty basic chainset last time I rebuilt it and the middle ring is getting worn.
I currently run an M442 triple as a double (the two big ones, dropped the granny ring as I don't use it) with 32/44T rings and the ridiculously small current chainsets just won't do. I did want to 'upgrade' to something XT to match the rest of the bike but in the end just bought a couple of genuine 32T chainrings for my existing set-up, just under £9 each :okay:
Well done for finding those 32t chainrings, they are becoming rare.
 
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