any advice on what gear ratio to use for SS mtb.

im fairly fit and i ride a single speed around town (42-17) so nothing to easy, but i am new to MTB.

i just bought a 36t chainring, but is that too big? most people seem to ride 32 or 34 front chain ring..

thanks

most go for 2:1 off road and 18 Tooth rear is easy to get hold off

Ratio of 2:1 is normal I think, usually 32:16. If in a hilly area 32:18 is better for climbing.

36:18 will do you right. Same ratio as 32:16, but doesn’t wear as quickly.

depends where you ride?

Trial and error to find what suits you and the terrain. 2:1 is a good starting point.

My current is 33:17 purely because it was the magic ratio which didn’t need a tensioner on a standard drop-out frame!

Rear sprockets are only a few quid for the cheap pressed ones. Try a few.

I run 32:17 as I like to spin a bit more – its not particularly hilly round here (other than short steep ones) but can get quite muddy. I have no problem keeping up with the 32:16s

As already stated, it’s dependant on so many factors you really need to experiment to get the right ratio, but 2:1 is a good starter.

As a guide I used to live in Kent and found ran 2 bikes – a singlespeed cross bike at 42:18 and a rigid MTB at 32:16. Both were fine for local trails with not many really steep climbs (N Downs, Bedgebury etc), the crosser was a tad overgeared offroad but really good for mixed riding.

Now live on Dartmoor, which is really steep but have kept the rigid MTB. Tried to tough it out at 32:16 for the first year but really struggled. Now dropped to 32:18 which seems spot on. Still have to carry it up some of the steeper stuff, but mainly on climbs I’d be either pushing up anyway or struggling to make walking pace in the granny gear on a geared bike!

32:16 is a nice round number to start with and adjust from there. If you ride in a hilly area then that adjustment is likely to be in one direction only – don’t hear of two many folk looking for a bigger ratio than 32:16 on the climbs.

As said above 2:1 is a good starting point. Then experiment.

SS is really 3 speed, if you count sitting down, standing up and pushing. 😉

Note 2:1 is ‘standard’ for a 26 inch wheel. 29 inch wheels go further on one revolution so 2:1 is effectively a harder gear. Rule of thumb seems to be to add 2 teeth, I’ll be trying 32:18 on my 29er maiden voyage very soon.

so if i keep my 36t chainring and get 18t on the back?? thats a good start?

32:20 on a single speed 29er.

I like a spinny gear.

Where do you ride Paul?

Yeah, 36t front and 18t rear is a good start.
Mine is running 36t front and 17t rear and that 1t difference is pretty significant really! Quite a bit tougher at times.

Im about to go single speed myself. Theres a hardcore gang of single speeders around where I live, and some of them are talking 36-12 or 14. Considering how hill this are is, Im guessing I should not listen to them and go 36-18 as well then 😀
Now I just need to find a bike!

only 2 posts mention wheel size ) wheel size is effectively a gear ratio also. mattjg’s got it.

36-12? even on a 26″, I’m humbled / amazed if they ride that for long anywhere hilly.

mattjq- Glasgow

32/16 is about 50 inches on 26 inch wheels .Its wheel x chain ring divided by sprocket if you need to work it out for a 29 er .IE much lower than a standard fixed gear of about 72 inches on road or 48/18

Google gear inches, you can get calcs that will tell you how different combos compare, there’s even one of them new fangled apps.

Then run 32-15/16/17 depending on how soon you can live with spinning out.

32-12 is the type of thing you see at the university MTB club, but wouldn’t be a serious proposition in general. Also, a 12 tooth sprocket would be v problematic on a ss conversion – reduced chain wrap would get the chain skipping like a bastard. Might be ok on a dedicated machine, not tried it.

32:18 on my 29er, was the same ratio on my last one too.

“Hilly South Downs area with lots of forest/woods”

On super steep stuff I get off and push like we all do down this way. Don’t encounter too much really steep stuff, certainly not, nooooo we’re soft lads here. If I did I gear it to suit.

Thing is mind. You’ve got to try riding and adapting your style to suit, don’t just jump on and go “nah, not for me that”
It’s a great leveller of both fitness and mates racing.

32:17 is nice in the Peak – 32:16 is doable, but quite grunty – 32:18 is a bit spinny. But 32:17 is just right, said Goldilocks. Though Papa Bear had massive ursine thighs and ran 36:10 because he could… 😉