Now physics was always my weak spot at school but with a singlepeed set up one turn of the cranks results in a greater forward motion with a 29er than a 26er if I understand it correctly. So to get the same sort of ratio that I have for my 26er SS should I go smaller than 2:1 or is the forward motion offset by the supposed easier rolling over the lumpy terrain? 😕

I swap between 32/18 for Summer and 32/20 for Winter. I’ve got a 21 cog for days in the Lakes.

Most people start adding 2 teeth to the rear cog compared to a 26. And most people on a 26 ride 32:16.

So give 32:18 a try to start with – unless you’re riding somewhere way hilly as Ben is. 32:18 is fine for Surrey but I couldn’t get up a proper fell on it.

2 teeth easier (2 less at the front or two more at the back) is a general rule of thumb over 26″. But if you are going to be buying a new chainring for single speed i would suggest trying a BETD Goldtec one…. Linky

Edit -bah too slow 🙁

Yup I do indeed ride 32:16 on the 26 SS and do a lot of climbing on it up to nearly 1000 mtrs high. Only problem being when I ride around here it’s predominantly flat so I am spinning like a loon to get anywhere as I am just too lazy to change rear cogs.

I find 4.1m about right.
http://sheldonbrown.com/gears/

2 teeth easier (2 less at the front or two more at the back) is a general rule of thumb over 26″

With a 2:1 ratio, 2 teeth on the front will be equivalent to 1 tooth on the back.

chainrings now added to the menu at

Yup I do indeed ride 32:16 on the 26 SS and do a lot of climbing on it up to nearly 1000 mtrs high. Only problem being when I ride around here it’s predominantly flat so I am spinning like a loon to get anywhere as I am just too lazy to change rear cogs.

I believe 32:18 on a 29er is a snadge easier than 32:16 on a 26 – but it’s as close as you are going to get.

As per Gotama I bought a wobbly ring too and like it – with that you go +2 on the front, so I’m now 18 on the rear and 34 (wobbly) on the front.

I’m liking the wobbly and am actually thinking I could have gone to a 35 – so if you are a strong climber AND/OR you’re riding flatlands, that would defo be a contender. I’d get a 35 if I was riding flatlands.

I believe 32:18 on a 29er is a snadge easier than 32:16 on a 26…

If you’re spending ~£50 on a chainring and sprocket, wouldn’t it be better to put the numbers in to http://sheldonbrown.com/gears/ and get it right instead of guessing.

Nothing personal, mattjg, I’m just constantly surprised by the number of people making hit and miss guesses at gear ratios when it’s so easy to get the real numbers.

Only started riding my 29er singlespeed in the last couple of months. Based on chat on threads on here about singlespeeds generally, went for a 16:32 ratio as it seemed to be the done thing in a MTFU sort of way. It never occurred to me that wheel size would make any difference. 🙁 Lots of short, sharp inclines in a typical ride on the IOW that were a bit of a struggle.

Have only just fitted one of the aforementioned Goldtec oval rings, a 34T, cos I needed a new chainring anyway, and have gone to 18T ring at the back, one of two that came with my singlespeed conversion kit.

Am I going to be flying up hills like a man possessed now? 😀

I’ve found 32:18 just about spot on for my 29er

but… i’ll be jiggered if i can get the chainlength correct on my scandle 29er (even maxing out chain tensioner)

anyone else had this problem? perhaps i’ll have to stick a 19t on it

did try a 1/2 link, but kept breaking it, so rather stick to normal chain)

32:20 here on the Downs around Brighton for my 29er.

Usually run 32:17 on my 26er.

32:20 is good for me all year round, easy in the summer, but lets you clear the mud in the winter too.

@mtg I didn’t guess.

@stef yes you will find it way easier I think, & I am finding acceleration more snappy with the wobbly ring.

^ Matt, did you find any weirdness in adapting to the wobbly ring? Any need to fine-tune your pedalling technique or owt like that? I’ve only been up and down the street on it thus far to check it was working.

I’ve found 32:18 just about spot on for my 29er

but… i’ll be jiggered if i can get the chainlength correct on my scandle 29er (even maxing out chain tensioner)

anyone else had this problem? perhaps i’ll have to stick a 19t on it

did try a 1/2 link, but kept breaking it, so rather stick to normal chain)

Yep, having this prob with my inbred running 32:18, tried numerous chains, 3/32, 1/8, 9sp…V frustrating, just ordered some more half-links….The fettling continues! 😈

fenred – not just me then (that makes me feel a little better)

My Scandal Mk2 is ok at 32:20 and was also ok for chain tension at 32:18 just a bit too much on the steeper/longer hills.

Mine came with 33:18, seems OK to me but I’ve not ridden 26″ SS to compare it with

@stef I’ve only done one 15-miler on it but no, it felt totally natural. see http://singletrackworld.com/forum/topic/tazzys-wobbly-rings-anything-current-anyone-keen/page/4#post-4618168

I’ve no good reason not to carry on with it.

In fact I suspect if I went back to a round ring it would feel lumpy. That makes sense really, they are.

Most of us have done hundreds of thousands (millions?) of revolutions on round rings so they’re always going to feel ‘right’ compared to something else.

Liking those Goldtec rings but just wondering if it will mess up the legs if all my other bikes have standard rings. ❓

Fairly hilly round here (Inverness) and running 32:19 but with quite small tyres.

RStern – I settled on 32-19 29er for the oft-claggy chilterns, use a wobbly 34 in summer but save the wear for my stock of cheap 32s in winter. No issues going from wobbly SS to round on other bikes, or swapping between them on the ss. 32 round does feel a little easier than 34 wobbly at the mo, but a few rides on the wobbly and it’s ‘normal’ on the climbs and a bit faster spinning on the flat. found that you need to be able to keep momentum / grip etc on climbs to get best of the wobbly, so when it’s muddy and sloggy the benefit feels less.

According to Sheldon Brown for my crank length (180mm) 34:19 for a 29er has the same ratio as 32:16 on the 26er.

29erSS here and use 32:17 cos I’m ard’ but have recently changed cranks and have gone 36:20 with a 19 waiting to be tried.. South Downs bumps and lumps. Shall be taking a range of rear cogs with me for HTN as I’ve no idea what the terrain will be like.
😉

32 x 18 ss and 32 x 16 fixed……

32:18, riding round bristol mostly, but I’ve beasted it round W2 at afan and used to live in Scotland, so that’s done the pentlands, tweed valley stuff etc. too.

At the end of the day, it comes down to how strong a rider you are, like any SS. There’s not a lot I don’t get up in 32:18, I could probably go higher and be a bit better/faster a lot of the time. I’m 6’4″ though, easy to be strong with long legs I think – long levers.

Went 32:17 on 26″ to 32:18 on 29″ – all good so far but also went rigid on the front which I think helps a bit…

At the end of the day, it comes down to how strong a rider you are, like any SS

This is true but I have already been riding and racing 26inch SSs for years and so wanted a direct comparison for a 29er rather than buying lots of chain rings until I found one that felt right.

Actually while we are on the subject of gear ratios is there any real world difference of having a 32:16 to say a 44:22? I once raced against a chap with such a ratio (beat him soundly mind 😉 ) but wondered if there were any benfits with it.

Ah ok, in that case if you’re on 32:16 on 26 (i’ve also ridden a lot of 26″ SS) then crack on with 32:18!

You do get hung up on stuff less so maintaining speed is easier, but you still want the gear you can turn to haul out of boggy ground and power out of corners etc.

44:22 will give you less clearance but wear slower – you spread the force over more teeth. Might allow you to get similar use out of alu rather than steel ring & cog – perhaps lighter? But then need more chain too…. someone needs to get anal with spreadsheets and work out the weight and measure wear…

32:19 here

32-19 down in sunny SW Wales