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Hello I have a sub compact Claris 8x2 on a gravel bike and would like to reduce the gear ratio. I didn’t realise I couldn’t get smaller chainrings. Any ideas on how to do this on the cheap. I think MTB gearing would be too low. Thinking 30/40
Cheers in advance
Really can't get smaller rings? Or just not Claris ones? How many arms, BCD, etc are you after, must be something out there which would fit.
Although givn the price of rings its often cheaper to buy a second hand full chainset, which would also solve your compatibility issues if there really aren't any rings which would fit.
Spa Cycles do a sub compact chainset which will fit your square taper BB. Available as low as 40/24.
Chainrings:
https://www.workscomponents.co.uk/chainrings-19-c.asp
These guys made a chainring for me to my specified BCD/teeth/thickness. Recommended.
https://www.bikepunx.com/drivetrain-166-c.asp
(Part of Projection-Racing)
The problem with getting chainrings on their own is the difficulty of finding something smaller than the 34 tooth which is on the Diverge which has 110BCD.
Absolute Black do sub-compact down to 46/30 on a BCD of 110 but they are 4 bolt (DuraAce down to Tiagra). Oh and they are pricey.
Stick an old MTB chainset on there? 104bcd, run middle and big at 32/4x, or hunt the touring sites and go granny/middle with 28/38 or something. I think both spa and sjs may be able to help with the rings.
Edit:. You may need to go up an axle length with a big granny, but you may no as the chainline is 2.5mm wider, and the frame may have the space anyway.
Also, I think I've seen 12-36 8 speed cassettes somewhere, so swapping out a traditional and road cassette may help too?
We've 3x8 Claris on a bike. It's wearing out.
My current plan is likely to go with Microshift Advent 9sp wide range cassette and mech, coupled with new 2x touring chainset with 150mm arms from Spa cycles (titchy sized bike owner).
Should give her a 28x40 as lowest.
If you've got 3x already, just fit an MTB triple? 22-32 as your lowest gear on a standard cassette should surely be enough? Or stick a 24t on your existing chainset ringer you most of the way there for <£10. I've a 26t on mine and it required no mech adjustment at all, and would do 24t I reckon
So a change of shifters too matt_outandabout?
Yes, we've basically decided new drivetrain and old deore shifters from the spares box.
I can't put smaller chainrings on, as the op is finding I can't go lower on the middle ring, and the jump to a smaller ring won't play nicely with a shifter.
At the back, the Claris mech has limited capacity (32t / medium iirc) and we have a 11-30t on there already.
Basically it's a case of older, restricted road bike gearing on a bike we want to tour on, with a load on board.
A lot of Claris seems this way...
How about the Spa Cycles sub-compact chainset I linked to earlier, MTB rear mech with Wolftooth extender and Sunrace cassette 11-40?
24x40 bottom gear! Big jumps though.
https://www.wiggle.co.uk/shimano-altus-m310-78-speed-rear-derailleur has 43T capacity, official max size sprocket 34T
I got an untrendy used claris three speed shifter and mech off of here for penny's
Fitted a deore touring triple 26/36/48 and 11-32 at the back.
Rode up Vancouver Island across BC and down the Rockies with it fully loaded.
Much lower gearing and I'd have fallen over on some of the sustained climbs.
Claris is the same as the Altus, 43 capacity, 34 max sprocket (which the Diverge already has).