singlespeed ratio – 27.5 wheels

toying with singlespeeding the HT for fitness

i did it yonks ago on my old 26er but i cant remember what i ended up using as a ratio i think i had 18t at the back and either 32 or 34 on the front.

whats a sensible start ratio for 27.5 wheels. either 30t or 32t front. I`ve a cassette i can butcher to start with.

cheers,

mark

It is easier if you use gear inches via a gear calculator. chainring teeth / cog teeth * tyre diameter. Then everyone is talking the same language.

Typical gearing is 52 inches for single speed which would have been 32 / 16 on a 26 inch so just need to work out which ring /cog combination will get that on given 27.5 tyre diameter

I always had 26 running 32/18 and 29er with 32/20 so either are worth a try or 32/19 🙂

My rule of thumb is:
2:1 on a 26″, add a tooth at the back for 27.5″, add another one for 29″.

32:17 would give a 52.2″ gear on 2.35″ 650b, that’s a good starting point.

My 26er was 32*18, my 29er is 30*19 which is the same ratio.

I’m on 32:19 on 27.5+ (3” tyres). But I’m more of a spinner than a mosher. Somewhere with bigger hills would see me swap to 32:20, maybe.

Or pushing.

My 26er was 32*18, my 29er is 30*19 which is the same ratio.

Might be the same gear inches (haven’t checked) but it isn’t the same ratio!

Smug face emoji here

I had 32/18 on 26, for riding the hills of calderdale, now have 30/18 on my 27.5 and 30/19 on my 29er.

A rough guide was add one tooth to the sprocket or reduce two teeth from the chainring for each wheel size you go up…. Roughly!

32/17 here on a 26er around North Leeds.

Of course, it depends what it’s like where you ride …

It depends on how strong/fit you are and where you ride.

I tried 32:16 (26″) but it was just a bit too much on the Lake District, dropped to an 18t rear and it was much more enjoyable. Then when I moved on to a 29er that came with 32:18, which again was manageable but a 19t rear suited me better.

A friend ran 32:16 (26″), and said it was fine. Partway through the puffer he swapped to a 18t and hasn’t bothered swapping back.

My 26″ Duster, I’ve run 32:16, 34:16 & 15 but now 33:16 which works well on our flattish terrain but mostly because it gives a full arc of adjustment through the EBB.