The Gearing Primer
09-21-08, 08:58 PM
#1
Bicycle Repair Man !!!
Thread Starter
The Gearing Primer
One of the most frequent questions asked here in ss/fg pertains to gearing in that folks want to know how to determine what combinations yield what gearings and what gearing they should run.
A favourite tool for determining gearing is Sheldon Brown's Gear Calculator... it will take your specs and give you results in gain ratios or gear inches and also tell you what speeds you can attain at various rpms.
https://www.sheldonbrown.com/gears/
This applet came highly recommended as well:
https://software.bareknucklebrigade.c...it.applet.html
And if you want to work things out the old fashioned way, gear inches can be calculated by multiplying the number of cogs on the front ring by the diameter of the rear tyre (in inches) and then dividing that by the number of teeth in the rear cog.
Most folks here use gear inches as a reference.
The more difficult question is always the "what gear should I be running?"
The problem with this question is that every rider is different and their choice of gearing will depend on the way they ride and where they ride.
As a general rule I build up new ss and fg bikes with a 65-70 gear inch drive which seems for most, to be a good all purpose gearing and a lot of people never change from this gearing.
If you are a stronger rider or perhaps live in a place where the wind does not blow as much then a gearing in the mid 70's might be perfect.
Gearings in the high 70's and low 80's are for monsters or for kids who like to take slow rides around the block... spend a day riding 81 gear inches into the wind and you will know what I am talking about.
Since I commute and tour on a fixed gear I have a bike that runs a 59/65 on a flip flop hub as it has to carry a lot more weight and that extra low gear comes in handy for long climbs or stretches where it's all in to the wind.
This chart is also a very handy tool for determining gear inches at a a glance and it also will help you determine how many skid patches you get with different setups, if that's your thing.
The ratios in green are typical gearings for road use.
A favourite tool for determining gearing is Sheldon Brown's Gear Calculator... it will take your specs and give you results in gain ratios or gear inches and also tell you what speeds you can attain at various rpms.
https://www.sheldonbrown.com/gears/
This applet came highly recommended as well:
https://software.bareknucklebrigade.c...it.applet.html
And if you want to work things out the old fashioned way, gear inches can be calculated by multiplying the number of cogs on the front ring by the diameter of the rear tyre (in inches) and then dividing that by the number of teeth in the rear cog.
Most folks here use gear inches as a reference.
The more difficult question is always the "what gear should I be running?"
The problem with this question is that every rider is different and their choice of gearing will depend on the way they ride and where they ride.
As a general rule I build up new ss and fg bikes with a 65-70 gear inch drive which seems for most, to be a good all purpose gearing and a lot of people never change from this gearing.
If you are a stronger rider or perhaps live in a place where the wind does not blow as much then a gearing in the mid 70's might be perfect.
Gearings in the high 70's and low 80's are for monsters or for kids who like to take slow rides around the block... spend a day riding 81 gear inches into the wind and you will know what I am talking about.
Since I commute and tour on a fixed gear I have a bike that runs a 59/65 on a flip flop hub as it has to carry a lot more weight and that extra low gear comes in handy for long climbs or stretches where it's all in to the wind.
This chart is also a very handy tool for determining gear inches at a a glance and it also will help you determine how many skid patches you get with different setups, if that's your thing.
The ratios in green are typical gearings for road use.
Last edited by Sixty Fiver; 09-21-08 at 11:20 PM.
09-21-08, 08:59 PM
#2
Bicycle Repair Man !!!
Thread Starter
Please PM me with any suggestions you feel might improve this primer.
SF
SF
