# Gear Ratio for Commuting on SS 29er



## nhmtns (May 4, 2004)

I've been riding a SS 29er all summer using a 33/16 setup with 29" MTB wheels and 29x2.3 MTB tires. I've decided to try commuting to work this school year. It's 19.6 miles RT and is mostly flat with a few small hills. I'm going to use either Schwalbe Marathon Plus 700x35/37 tires or Schwalbe Big Apple 29x2.0 tires. Still deciding.

I'm confused about what to do regarding the chainring/cog setup. Do I keep the 33T chainring and get a smaller cog or do I keep the 16T cog and get a larger chainring? The smaller cog seems to be the easiest route, but how small with a 33T chainring? Does 33/12 with commuter tires make sense as a place to start?


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## solo-x (Feb 16, 2010)

Yes.

Either works to achieve a higher speed at the same cadence. Your choice which end to change. Do you have the tools to swap out either? If not, buy for the end that you have tools to work on, or that the tools cost the least to work on if you don't have tools for either.

I run 36/18 for CX/road on my MonoCog. I'm all over the place for gearing off road. I have run 32/18, 32/19, 32/21, 34/19, 34/21 and 36/21 so far this season. Picking the right gear for a race is part of the fun!


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## mack_turtle (Jan 6, 2009)

I would not go smaller than a 16t cog in the back and just get a larger chainring.


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## nhmtns (May 4, 2004)

Okay. Next question: If I keep the 16T cog, what's a good chainring size to try? Obviously there are many variables, but before I start buying new chainrings, what's a good suggestion for a ___/16T commuter setup? 

Another consideration is that I'll still use the bike (Salsa El Mar) for trail riding with another set of wheels/tires, so swapping cogs is easier than chainrings. Curious why is was suggested not to go smaller than 16T?


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## J.B. Weld (Aug 13, 2012)

Borrow a friends geared bike and go for a ride on the type of roads you'll be commuting on and shift around for awhile until you find a comfortable gear that you like. Pull over and note the gear combo, then plug it into a gear inch chart and find out how many gear inches it is. Then find out what size chainring you need to make your 16 tooth cog match that number.

Sounds techie and complicated but it's real simple and fast.


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## J.B. Weld (Aug 13, 2012)

nhmtns said:


> Curious why is was suggested not to go smaller than 16T?


Generally better (less friction and wear) to use larger sprockets but it's not that big of a deal to use a slightly smaller rear cog.


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## febikes (Jan 28, 2011)

nhmtns said:


> Another consideration is that I'll still use the bike (Salsa El Mar) for trail riding with another set of wheels/tires, so swapping cogs is easier than chainrings. Curious why is was suggested not to go smaller than 16T?


A lot depends on your route and your goals.

I ride a 38/22. This is a 1.72 ratio and works well for me offroad. The big ring and big cog keeps everything running smoothly. I don't like to bother with chain tension adjustments and using big stuff means I can let the bike go many thousands of miles between adjustments.

My commute is 10 miles each way. With my gearing I general average 12mph so it's quite slow but helps me develop a good spin. It's nice to go easy and I am usually not in any rush.

I have a mix of roads, and off road. The gear is tediously for the roads but feels good for the off road seconds . I often ride single track in the afternoon with the same bike.

Little narrow road tires are a bit too metrosexual for my tastes. I personally think for single speed you want big fat knobby tires even on the road. The big tires give you a workout although they wear faster. I simply use the same tires that I would use for off road. The off road tires keep the speed down and mean that my commute bike feels good on the road, off the road, and for riding stairs, sidewalks, etc. The rear tire gets pretty slick through wear after a few hundred miles so no need to buy a tire like the big apple that is already bald.


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## nhmtns (May 4, 2004)

Ohhh, thanks! Didn't think of that. Duh. Makes a whole lot of sense and will save on the "buy and try" method.


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## Cygnus (Jan 7, 2004)

as you go to a bigger chainring, keep an eye on your chain stay to make sure you have clearance.


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## cr45h (Jan 13, 2007)

i run 39x18


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## bspstp (May 7, 2007)

32x17 with 2.2 knobbys for me. Yeah its spinny but strangely it is only 3 min slower on my commute than my geared cross check, plus a better workout. My commute time is super reliable being gear limited, which helps with scheduling my day. I prefer the more upright riding position once I hit town.


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## jl (Feb 23, 2004)

40x16 fixed. I've used the marathon's and the marathon supremes. But I'm now sold on the Little Big Bens (38s).


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## trevrev97 (Jul 19, 2009)

I have a 42 mile RT commute, my fixie is 42x16, my MTB i do gravel events and commute on is 36x16 with 2.1 Geax Mezecals


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## LuckyCharm4x4 (Dec 16, 2011)

Download the free "gear calculator" app (for android) and nerd out on paper before you buy.

I run 2:1 on all surfaces (32/16, 34/17, etc.). For me it's a jack of all trades, master of none. I CAN ride gravel, and I CAN do CX Races, and I CAN ride MTB Trails with it, but it's not PERFECT for any of them. Overall, it is a really comfortable feel for me though. Mine is set up as a rigid 29" MTB on 2x2.25" tires, with MTB being my most important factor. If I have to spin faster on the roads, that's okay, it's a different workout for my legs but I can comfortably average ~16.5mph over a long haul.


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## Joe_Re (Jan 10, 2011)

Once upon a time, I ran a 48x16 on road and 32x16 off road on my old 26" MTB. On my road fixed gear I run 42x17 or 18. My 29er MTB runs 32 or 34 x 18, 19 or 20. My old 29 which did some urban duties was 34x17, but I would not want to commute 20 miles a day on that gear. way too spinny.

FWIW, if you will ride in snow, run skinny tires. I commuted through 4 New England Winters, no car. 23s or 25s are much better than 35s and way better than 2.0+ in snow.


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## theruns (Jul 25, 2016)

I ride a 26er to and from work singlespeed and 36/16 is what I run. It's a happy medium where if I'm spinning I can hit 20 but just my normal cadence puts me around 15 or 16mph. The gear inches on a 29er will be different though from my understanding.


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