Cassette is a 9-42 with 32T oval chain ring at mo on my 26″.

Going to a 29er from a 26″ am I better off going for a 28T or 30T oval chainring to compensate for bigger wheels?

Oh, I like oval chain rings as better for my bad knee…

Im pretty unfit I should mention! However I mainly just ride the North and South downs… not mountains!lol

Thanks for the info guys.

Sorry guys, forgot about the online gear calc! Doh!

28t is closer on gearing, assuming similar tyre profiles, but will it fit?

Basically as you go up a tyre size drop 2 teeth on the chainring. So 32T on 26″ is roughly the same as 28T on 29″. But you might struggle to fit a 28T chainring if you’ve a standard 104BCD spider, I think 30T is the smallest you can fit in that case unless you go (or are already) direct mount.

To be honest I swapped from a 32t to a 30t on the same bike mainly for the chainline and I couldn’t really tell the difference in top and bottom gears.

http://sheldonbrown.com/gear-calc.html

Hmmm… assuming I am using it right, going from a 26″ with 32T to a 29er with 30T should give me same low gear for climbing but I will spin out a bit easier on the flat/ downs??

Calc done with 26x 2.35 and 10 to 42 cassette

Vs

29x 2.30 and 10 to 42 cassette.

Have I made a mistake?

Having same granny gear is fine, dont mind spinning out a bit sooner at speed…. need help on the ups though! 😀

I struggled to work this out recently. I was running 22/36 on the 26er. New 29er is 26/36. This made bottom gear much much higher. The net effect after a fortnight is I got much faster. I’m also a bit fat and slow. It’ll be ok.

I have a 32t (round) on my Reign (650b) and 30t (round) on my Smuggler (29). Easiest gear feels approximately the same, would suggest you would need to be on the equivalent of a 28t round.

Right, decided to go with an oval 30T and see how it goes.

Thanks for the help guys!