Im looking to try out 1x on the gravel bike, i have a clutched 810 grx rear mech that will take at least a 11-40 cassette does anyone know if it will manage an 11-42?
also a cheap try out options as i have a clutch mech, and a spare 105 chainset, i was looking at trying a 39t 105 inner ring (£12) but on the other ring placement, I assume i'll need some new chainring bolts as well. apart from it not being narrow wide is there any other major downfall to this idea?
thanks
Fit a good chain guide with a 39 or you'll get a lot of dropped chains when in the smaller cogs at the back. A narrow wide would be better. And yep you'll need new bolts, I think I used these before.
Sure the mech will work fine with a 42 and enough chain.
Most of the chain retention in a 1x setup is in the narrow-wide ring, not the clutch mech, so as above, you'll need a chain guide of some sort - you could just lock/jam the front mech in the right place if you're currently running 2x
Narrow wide rings can be had for relatively cheap, I'm not sure what BCD your crank is but I can see them for 105 type cranks for £15ish. I wouldn't bother trying a 1x setup without a NW ring or singlespeed specific ring, chain will fall off lots.
narrow wide for around £15 - where please that would be helpful
super cheap narrow wide "snail" brand on amazon or ebay, have used them on MTB's before and they are fine, especially for testing
812 RD works with 51t cassette
yeah, but the 810 is the 2x rear mech, which only goes up so far. Given how conservative Shimano are, I'm sure it'd take 11-42 though.
I'd leave the ring on the inner position of the crank, you'll get a better chainline to the larger sprockets where you have less derailleur arm articulation to accommodate the chain angle.
I'd agree with the snail brand rings - surprisingly good. New bolts are nice, but a washer on each one, between the bolt and the crank, takes up the space of the other ring.
@infovore I always thought rear mech capacity was the total (front plus rear) so if you’re running 1x you can get by with a shorter cage than you might otherwise need for the same cassette? So, a mech that’ll manage 11-40 with a double should be fine for 11-42.
Might have misunderstood though…
There's the issue with the B screw gap between the top jockey wheel and the large sprocket as well, but yeah, I reckon only running 1x up front would gain you a couple of teeth capacity.
