Would like to extend my 1×10 from 36t

Was going for 40t but should I consider 42t? Is the gap too big or are there other shifting issues with 42t?

I use a 40T with no issues other than a bit of b-screw adjustment. others i ride with have 42T but have also added Rad cages and the like to keep it shifting.

On shimano, I have heard anecdotally that Sram are more tolerant of the 42T.

I guess it depends how hard you find 36. TBH i rarely use my 40T, just keep it as a bail out when my legs are screwed at the end of a ride, and it’s plenty for that.

32T front on a 29er fwiw, as that will also have an effect. I sling a 30T front on for big days out.

I’ve a 40T but if I’d have put a 42T I could’ve used a 32T up front rather than the 30T I need – and then had a higher top gear.

Just been through this exercise.

Initially fitted a OneUp 42T on a SRAM cassette with an X9 mech, couldn’t get on with it. Reaching the 42T was temperamental to say the least. The b-screw was set correctly as were the limits screws but it just wouldn’t reach the 42T reliably. Finally traced it to worn mech pivots (it was 5 months old!!) which meant it wasn’t lining up properly.

Binned the all the SRAM in favour of XT and still had issues. Fitted new cables, cassette, shifter, mech etc but still no joy. Then I fitted a OneUp RAD cage and early indications are this may have improved matters significantly.

As for ratios, I’ve got a 32T up front and the 32-42 seems ok for 99% of my riding. I initially fitted a 26T plus the 32T but no front mech just in case I was desperate for a couple of lower gears but I didn’t need it and removed it in the end.

The bottom line is, it’s temperamental and not as slick as the standard setup, however despite being extremely skeptical to start with, I’m going to stick with it as the benefits do kinda outweigh the negatives, when it works.

40t here, with a RADr cage and 16t, on a 32t oval. Works a treat.

Got both, in the end the 42t just gives more but needs a RAD cage to work with shimano, works fine with SRAM.

32T chainring, SLX mech, and 40T expander. Was concerned about the chainline and jump to 42T. Adding the 40T I didn’t even have to re-index the gears, just a few extra turns of the b screw

whats a rad cage?
just about to fit a ss 40t expander do you really need the long b tension bolt

google says
RAD Cage