what sized chain ring and sprocket?

[jonny jeez]

Hi guys. I ride a few bikes,mostly a 9speed Shimano and a single speed from trek (district)

I adore both but want something in-between.

The Shimano is fast but a bit fragile for winter rides...the district is tough as old boots but a little slow for the speedy sections of a commute...and a bit pretty for winter...more of a summer city cruiser.

So, I plan to pick up a cheap hack from foffa or BLB but want something harder to climb and something that wont spin out at 20-23mph. The district spins out at 16-18mph.

I don't understand gearing...any suggestions on chain ring and sprocket sizes?

 

[GGJ]

What gearing is on your single speed?

 

[midliferider]

In very simple terms, devide the number of cogs in the front by the number in the rear. Lower the number, easier to climb hills.
Example:
Front 32, rear 32 = 1
Front 40 rear 20 = 2
gear ratio of one is easier to climb than 2.
But lower the ratio, slower the speed and you are spinning fast with slow movement on flat.
Does that make sense?

 

[Deleted member 1258]

Gearing is an individual thing, whats suits one may not suit another, 46 x 18 67 inch gear and 48 x 18 70 inch gear are both good gear combinations to use as a starting point, ride the gear and see how it feels and if you feel you need to change it change it up or down as required.

http://cycleseven.org/bicycle-gear-inch-calculator

 

[3narf]

Your single gear is always going to be a compromise. It's not possible to get a gear that you won't spin out on occasion, which you'll still be able to shunt up any kind of hill.

There are people on here who advocate 52x16, for instance. I don't know how fit or strong you are, but I do a lot of single speed cycling and to put it mildly, I'd struggle with that.

Best to find the sweet spot that will give you good acceleration at the speeds where you spend most of your time. It's very subjective; I love 46x17.

 

[raleighnut]

http://www.sheldonbrown.com/gears/

If you use this but swap to MPH at RPM it should give you an idea of what to use.

 

[al-fresco]

I'm a geriatric living on the Welsh border and I find 42 front, 16 rear to be a good compromise for the local hills and plains.

 

[totallyfixed]

52x16? Yes, right, jolly good. Presumably it is pan flat and the wind never blows. Only ever ridden socially with one other who was riding a big gear and he was walking up the hills, seemed a bit pointless.

 

[midliferider]

I'm a geriatric living on the Welsh border and I find 42 front, 16 rear to be a good compromise for the local hills and plains.

42, 16 on hills.
Either you are superfit or your defintion of hills and mine is totally different.

 

[3narf]

42, 16 on hills.
Either you are superfit or your defintion of hills and mine is totally different.

I wouldn't have thought 42 x 16 to be too outrageous as a compromise for hilly roads...

 

[derrick]

I ride 48 x 14 round N London way not to many hills some can be a bit hard, but i still spin out going downhill, I think it's a case of trial and error, You can pick up cheap fixie cogs so not really a problem, And as long as you have horizontal drop outs you will not have to many problems with chain length, A good start point would be 48 x16 then go from there.

 

[al-fresco]

42, 16 on hills.
Either you are superfit or your defintion of hills and mine is totally different.

It always amazes me what you can do when changing down isn't an option! I find I can cope with 1 in 7 (about 14%?) for brief periods and a shelving climb over 2 or 3 miles is part of my normal ride to the pub. If I'm plunging into darkest Wales I'll use a geared bike.

 

[totallyfixed]

Yes, it is amazing what you can do, up to a point. Comparing what different folk ride on t'internet is a bit like the age old piece of string question. Much more interesting to meet up and ride together in the real world.

 

[Milkfloat]

First dibs on the District now that you have decided it is unsuitable.

 

[jonny jeez]

Your single gear is always going to be a compromise. It's not possible to get a gear that you won't spin out on occasion, which you'll still be able to shunt up any kind of hill.

There are people on here who advocate 52x16, for instance. I don't know how fit or strong you are, but I do a lot of single speed cycling and to put it mildly, I'd struggle with that.

Best to find the sweet spot that will give you good acceleration at the speeds where you spend most of your time. It's very subjective; I love 46x17.

Okay so this might suit me as I am pretty strong and manage hills in a pretty high gear...small hills that is.

What gearing is on your single speed?

I've no idea I afraid

In very simple terms, devide the number of cogs in the front by the number in the rear. Lower the number, easier to climb hills.
Example:
Front 32, rear 32 = 1
Front 40 rear 20 = 2
gear ratio of one is easier to climb than 2.
But lower the ratio, slower the speed and you are spinning fast with slow movement on flat.
Does that make sense?

So do I need a a 40 20 to cruise at 20mph without spinning out?