Single-speed ratio for commuting

Drfabulous0 · October 2007

I commute on my mountain bike at present but With my new job it is on the road all the way, ant the MTB is just too slow. I am building a road bike for commuting (out of only parts I can cadge, trade or already own) and I want to make it single-speed, (not fixed wheel). My route has a few hills but nothing really steep, what gear ratio would you guys reccomend with a 700 wheel?

reverendmark · October 2007

Drfabulous0 wrote:

I commute on my mountain bike at present but With my new job it is on the road all the way, ant the MTB is just too slow. I am building a road bike for commuting (out of only parts I can cadge, trade or already own) and I want to make it single-speed, (not fixed wheel). My route has a few hills but nothing really steep, what gear ratio would you guys reccomend with a 700 wheel?

I use 46/17 on my 9 mile London commute. That includes some hills (I live 300 feet up, but have a route that doesn't lay it on me in one go!). It seems a good compromise between decent speed, and decent pace off the traffic lights.

peejay78 · October 2007

i use 48:16. my riding is fairly flat. i ride fixed.

i can recommend 48:18 or 46:18.

Black Keith · October 2007

70 to 74 gear inches.

BentMikey · October 2007

I ride 48x19, a nice spinny 66". I reckon it's better to learn to spin, because anyone can grind a massive gear with a bit of training, whilst finesse is usually better than brute force and ignorance.

el_presidente · October 2007

I use 42x15 on my 26" MTB

secretsam · October 2007

interesting, as bike 2 (the London machine) is an old 12 speed but I only really use 2 gears on my commute - a 57 and 67 ish gear (in old-fashioned inches). I guess for a single speeder you'd go with something slightly higher 'cos you're not lugging round the weight of block/mechs/multi-chainwheels/etc.???

the grinder · October 2007

What I did was ride in one chainring/sprocket that felt comfortable on my geared bike in both directions to see how it felt and then stuck with it. That was 39:15 and seems pretty close to 48:18 on lighter fixed/ss pompino. I don't grind too much going up or spin out going down (though still not fully sold on the fixed business).

I guess compared to mtb maybe go up one sprocket size.

Drfabulous0 · October 2007

Thanks for the tips, to be honest I forgot about gear inches. On my mountain bike my favorite gear is 38:14, which I've use before for singlespeed MTB and works out at 61.2. Should I be looking for a higher ratio on a road bike or stick with something closer to what I like? I'm not much of a spinner but I do prefer fast acceleration at the lights.

Black Keith · October 2007

something around 68-70 is good for spinning in london.

crank length plays a certain part too..don't forget you spin faster with a shorter crank, but a longer one gives more leverage.

bent mikey's 66" would be too spinny for lots of people, I have a few hills around where I usually ride and I like to be able to get up AND down them at a decent speed.

I find 73" easy enough to spin with, and not so strong that I have to stand up all the time or get knee pain. (in fact, I have had no leg pain from riding fixed ever, touch wood so far! )

Yellow Cliff · October 2007

Well last year I used 42 x 16 and 17 mostly. I like to spin!

If you have ridden a road bike before, or have any idea of how fast you might ride, Sheldon Brown's calculator is great. You can put in your expected cadence (which is easy enough to count when riding, I generally ride at 100-115 rpm) and it will calculate your speed at the designated rpm (amongst other options).

http://sheldonbrown.com/gears/

If you are converting to singlespeed with a freehub (which takes a cassette) it is very easy to just try some different combinations and see how you get on.

BentMikey · October 2007

Black Keith wrote:

bent mikey's 66" would be too spinny for lots of people, I have a few hills around where I usually ride and I like to be able to get up AND down them at a decent speed.

I've had that gear up to 37mph, btw., and often do the Crystal Palace hill in either direction. There's more rpm left to spin to as well, and I'm far from a fast spinner. I believe many people ride too big a gear on fixed instead of focusing on the essential technique of pedalling properly.

Black Keith · October 2007

I agree.

but I disagree that you're not a fast spinner!

try a roller race, if you haven't already.

seriously, hardly anyone runs down as far as that in town. I've gone to 69" before, might go somewhere near it again sometime, but I don't feel the need to go above what I have, I can spin down and get up all the hills in richmond park, wimbledon hill, crystal palace and the ones out to Sutton.
Very, very rarely do geared riders go by me on the flat, so I'm happy with the whole deal really.

IsledeBlanc · October 2007

I ride 48x17 in London, what is that in gear inches please?

jam1ec · October 2007

here is an interesting article on cadence:
http://www.trifuel.com/triathlon/bike/cycling-cadence-and-pedaling-economy-001048.php

I would recommend a gear of 48:17 or 48:18 depending on the steepness if the hills. I use 48:16 but it is almost completely flat where i ride, averaging around 20mph is about 85rpm.

I agree with erring towards higher cadence.

37mph on a 48:19 ratio is 182rpm, to me that is fast spinning

48:17 is 74.2 inches if you have 700c wheels with 700x23 tyres

BentMikey · October 2007

I was quite seriously considering going to 48x20.

buddha · October 2007

BentMikey wrote:

I was quite seriously considering going to 48x20.

I use 48:20. But then I am a lard ar$e :oops:
Though I can't imagine riding the likes of Titsey Hill (nr Westerham), and a lot of the hills on the north downs, on a higher ratio. Especially as I am usually faster than those with gears on the these climbs.

Single-speed ratio for commuting

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