[Closed] Singlespeed ratios for 29er

I personally run between 32/18 and 32/20 for my riding. Try it and see what works for you and local place 👍

32:19 for me but it does depend on what terrain you usually ride. Setting it up so you can get up your local climbs without wildly spinning on the flat in-between is the key.

32:18 when i had one

Here's a gear inch calculator so you can replace like for like:

https://www.bikecalc.com/gear_inches

32:18 does it for me on the local undulating rolling hills (mtb off road mix from fire road to tech).

For a town/gravel bike that would be too low geared though, IMO

32:16 is a 2:1 ratio & on a 26er that's a 52" gear so on a 29er with a 2.35" tyre 32:18 gives you a 52" gear & a 1:178 ratio.

32:18 when I was fit enough to ride SS

32:18 here in the Chilterns.

34:19 on my Stooge. Chunky 2.6 tyre on the back (a big tyre will increase your gear inches) Good for lumpy East Devon.

Will occasionally go 32:20 if I'm going somewhere hillier, like Dartmoor or the Quantocks.

30:17 with an oval chainring and 29+ wheels for eastern Peak District borders riding for me.

For a town/gravel bike that would be too low geared though, IMO

Agree. For your intended use of town/gravel/adventure one ratio is not going to cut it.
The ratio that is low enough for adventure riding with be a chore on road and gravel but that is just a simple case of changing the rear cog as presumably you won't be doing all 3 of those scenarios on one ride.
For road and gravel I would be using around 66GI and for adventure/hilly I would be using around 53GI

I'm 32:19 in a hilly area. Average fitness. Occasionally I have to get off and push, nearly all rides are offroad.

On my Niner air I run 34/18 to 34/20

This sounds counter, but when I rode ss, and went from 26 to 29 I found I could go lower ratio, making some hills possible that previously weren't, with little impact for overall speed. I think it's because the larger wheels carried momentum better in steady or freewheel sections, and it was a bit easier to accelerate out of corners and get back on top of the gear and build momentum up again.

32:19 for the Lakes and Peaks with lightweight tyres. 32:20 with something more burly. 32:18 for most local stuff, again with lightweight tyres.

As above, 32:18 will get you a similar gear to your old 32:16 on 35”, but that’s an MTB gear, not a town/gravel/adventure gear (at least by my definition; YMMV—and “adventure” in particular could mean all sorts of things).

My town bike and gravel bike are both somewhat higher geared; I think the former is 38x16 on 26” wheels and the latter is 46x17 on 700x37. (I might be out by a bit.)

One thing I did do for a while was run a dinglespeed: one ratio for off-road and the other for tarmac/gravel. The latter added two teeth to the chainring and lost two from the rear sprocket, so if you used 32:18 for one then it’d be 34:16 for the other (I forget which exact numbers I used, but I think I aimed for the low gear to be a bit over 50” and the high to be something like 65” or so). The only thing here is that I’ve only found that to work well with track ends. Any other frame type (EBB, sliding dropouts, tensioner) will be a faff at best. The slight change in effective chainstay length didn’t require adjustment of the brake callipers, but did warrant a few turns of the screw on the chain tug.

Will occasionally go 32:20 if I’m going somewhere hillier, like Dartmoor

Dartmoor rider here (also on a Stooge but running B+) and I'm happy with 32:20 which gets me up the steep-ass bridleways up onto the moor, and then all the climbing once I'm there. It's a bit spinny on the flats but I can hold 25km/h on it, just. I'd plump for a gear as a starting point and take it to your steepest usual climb, see how it goes, and adjust from there.

30:18 around Matlock.

Works well for pretty much everything from local spins to Lakes or Highlands trips, Golfie/Inners days and enduro races, big rides like the South Downs Way.

Can get up most of what I can climb with gears and it seems about right for DH tracks and uplift days. Maybe a touch low for trail centres but don't feel the need to go harder. Spend more of my time mashing than spinning as it is. Never a problem on the flat if I chill out a bit or I can go full hamster and more or less keep up with geared friends.

Most singlespeeders I know are on similar ratios, regardless of wheel size, although interesting to see that most on here run harder gears.

32:18 for the traditional hard work single speeding experience (and probably fine on the road). 32:20 (or lower) was a revelation off-road though. You don't get dropped by your mates and you don't spend the entire ride gurning along at <70rpm.

My "gravel" SS is 39-18 though (or 39-16 fixed). But that's with cross tires, not 29er. And the fixed is a compromise between comfortably pedaling at 14mph on the flats and not spinning out on every slight decline.

Anywhere between 32/17 to 32/20 will work perfectly fine if you were happy on 32/16 on a 26" bike.

You rarely have the perfect ratio on a singlespeed anyway.

The important thing is that to remember is you can rarely find another ounce of grunt, but you can usually find a few more rpm when necessary.

For your proposed usage case of mixed surface riding...

32:16 on 29er was my ratio of choice for the flatlands of cambridgeshire - combo of bridleways and back roads.
I did the smoke ring on it and only walked 1 hill.
I did hell of the north cotswolds and had to walk quite a few in the second half.

A few uphill walks is preferable to miles of maniacal spinning

I moved away from SS, but thats more driven by change in riding. Not sure I could go back to it now.

32:18 oval on 29x2.6 here (Stooge) - local hills are short and sharp or more gradual.

The important thing is that to remember is you can rarely find another ounce of grunt, but you can usually find a few more rpm when necessary.

Beautifully sums up more thoughts on SS gearing.

32:20 here.

Most rides are ~5-10 minute hills, usually pretty steep, ~1500ft climbing per hour and I prefer 6+ hour rides to short hour blasts.

I want a gear where I can climb everything and I can always go faster (climbing included) with spinning faster/ more effort. The difference on the flat of losing a tooth or two off the sprocket is quite minimal but having to walk loads because you can't turn over the cranks sucks IMO.

You just have to go with something and tinker from there. 32 with 18-20t seems to do most people as others have already said.

I've set up an older cross bike single speed for commuting, gravel and some road use. I run it 42-18 with 35mm GravelKing SKs.

Start spinning too fast above 30kph but can get up 10% (short) off-road climbs as well.

Hesitant in recommending specific ratios as to the degree of variables at hand. I will say though that I've found picking a gear that doesn't spin out too quickly on flat and accepting the odd hill walk works best for me. I also like bigger cogs for more chain wrap - eg. 34/20 is better than 32/18.

I was running 34/19 on my local trails, rolling with some short sharp climbs, and occasionally some long stready ones which were a chore in that gear

I've run a tool-free dingle before with a tensioner, which is great: it just needs two jockey wheels on the tensioner like below

Personally I wouldn't bother running dinglespeed without a tensioner: that requires an axle adjustment everytime you change gears, which realistically I'm only going to do before a ride (and my issue is long roads/easy trails to get to the moors)