# Gear ratio for commuting



## GFWD (May 10, 2005)

I took some advice from this board and rode my old commuter bike to work today as a single speed, and I loved it. Not sure I am sold yet on off road single speeding (this may come with time), but I am thinking of switching my commuter to a single speed.

Using info from this board I tried a 2:1 gear ratio, 34:17. I managed to climb most hills without getting out of the saddle (although I avoided my two biggest hills today for the experiment) and on the flats I ended up coasting a lot because I couldn't pedal fast enough.

So what gear combination are people using for their commuter single speeds? Before I start buying the parts to properly convert I am going to try some different combos on my bike, but I am limited to the chainrings and cogs I have now, so could use some advice.

So if people could list their commuting gear combinations that would be great.

Thanks


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## iattackthedarkness (Jan 14, 2004)

I use 32/14 to commute, but it is a compromise gear, still do plenty of coasting, but anything taller I struggle up the hills with.


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## Kosk (Nov 1, 2004)

46 / 18 = 2.55


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## Thor29 (May 12, 2005)

*2 1/2 to 1*

Any gear ratio is going to be a compromise - 2:1 for off road is used because you can climb most hills and still have some "kick" on the flat sections. But it is too low for road use where the grades are usually lower and there are long stretches of flatness. If you can climb seated, your gearing is too low (which you knew already). The answer depends on too many variables - type of bike, fitness level, and local terrain. But just to give a starting point - I use 42:16 on my fixed gear here in the hilly city of San Francisco. It works well but I can't climb the most ridiculously steep hills. So I go around them. On the smaller hills I get out of the saddle and attack. I'm assuming that your commuter bike is a mountain bike, so 42:16 on 26 inch wheels would be an easier gear than it is on 700c wheels. Fixed gear bikes often run as a high of a gear as possible because coming down a hill a smaller gear ratio quickly gets out of control.

Way more info than you need. A good starting point would be around 2.5:1, so a 42 would be a good place to start. Sugino makes some nice cheap non-ramped chainrings...


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## GFWD (May 10, 2005)

Yeah my commuter bike is an ancient chromoly Norco Bigfoot, and I am not even sure if I can update parts on it, or what fits on it as I am not sure how different the standards were in 1992 compared to now.

I will ride home tonight using a 2.5:1 ratio with the rings I can work with, and then look into getting some cheap replacement parts.

Thanks for the information.



Thor29 said:


> Any gear ratio is going to be a compromise - 2:1 for off road is used because you can climb most hills and still have some "kick" on the flat sections. But it is too low for road use where the grades are usually lower and there are long stretches of flatness. If you can climb seated, your gearing is too low (which you knew already). The answer depends on too many variables - type of bike, fitness level, and local terrain. But just to give a starting point - I use 42:16 on my fixed gear here in the hilly city of San Francisco. It works well but I can't climb the most ridiculously steep hills. So I go around them. On the smaller hills I get out of the saddle and attack. I'm assuming that your commuter bike is a mountain bike, so 42:16 on 26 inch wheels would be an easier gear than it is on 700c wheels. Fixed gear bikes often run as a high of a gear as possible because coming down a hill a smaller gear ratio quickly gets out of control.
> 
> Way more info than you need. A good starting point would be around 2.5:1, so a 42 would be a good place to start. Sugino makes some nice cheap non-ramped chainrings...


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## GlowBoy (Jan 3, 2004)

*Definitely try something more like 2.5:1*

To get home from my current workplace requires almost 1000' of climbing, so sadly I can't commute singlespeed anymore ... but when I did, I found a gear in the range 2.5:1 to 2.7:1 did the trick (on 700c wheels). No big hills on that route, just a handful of moderate 50'-ish climbs. With bigger hills I'd gear it lower. My rule of thumb is gear the bike as tall as you can while still being able to accelerate decently in traffic and climb all the hills with a fair amount of effort, standing on the pedals. Using that rule, you will probably find that the gear that works for you gets a bit taller over time.


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## lftripp33 (Apr 22, 2004)

I commute up some knar' hills and a 48/16 works super good for me. Some people say its too big but... I spend more of my commute miles/time in the flats then i do going up hill. Plus its nice to have a bigger gear going down those knar' hills. 
N.


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## GFWD (May 10, 2005)

Well I rode home with 34-14 and almost killed myself on a couple of hills, what a difference from 34-17. So that is just under 2.5 and at points I was almost at a stand still forcing my legs around, and waiting for my chain to snap.

So, how do you decide the difference between a too big gear ratio and a "too big because I have never done this before" gear ratio?

What is the difference between a 34-14 2.5 ratio and a 42-16 2.5 ratio? Both should get the wheel moving the same amount if I am understanding things. Would the 34-14 be easier to turn than the 42-16? Does one have a benefit over another?

Thanks for the continued help.


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## redfooj (Aug 3, 2004)

GFWD said:


> What is the difference between a 34-14 2.5 ratio and a 42-16 2.5 ratio? Both should get the wheel moving the same amount if I am understanding things. Would the 34-14 be easier to turn than the 42-16? Does one have a benefit over another?
> 
> Thanks for the continued help.


You are correct: both ratios will result in the same work

2.5:1 is a very good starting ratio for street riding. If you find it difficult to turn, upgrade to more efficient tires (higher inflation, no knobs)

A good way to figure out what works for you is to ride on the flats and find a comfortable cruising gear...that would make a good baseline


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## ernesto_from_Wisconsin (Jan 12, 2004)

*what feels right*

I use my commuter for fitness. I have it at 46/16. which can be a little tough on some of the hills around here. Other than that, go with whatever feels comfortable for you.


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## The Hookler (Oct 30, 2004)

I'm just starting using a 42:16 on a "new" singlespeed commuter. I love it! I had 32:14 on another commuter which was pretty good but I would seem to not have it on the flats. Too slow. The new gear is a bit tougher but as I keep telling myself it will just make me stronger. Use a gear you feel comfortable with for awhile and then step it up. You'll be happy you did.


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## Cygnus (Jan 7, 2004)

*go tall with slicks*

42x16...on 26" wheels and slick high pressure tires. tires make a difference, not just in gear ratio (or inches), but especially in rolling resistance. given the chainline where i like to put my chainring, 42 is the biggest i can go without damaging the chainstay on my frame, and 16 is the smallest SS freewheel. i'm finding 42x16 to be a good all-around road gear with hills, headwinds, and flats on my 26 mi round trip commute.


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