Sturmey Archer 3 speed gear ratios ?

[BADGER.BRAD]

Hello all,

I've posted this in this section because I am exploring the possibility of using an old folder for some low speed forest gravel track riding with my working dogs, I am restricted in both space at home and in my small car so I thought cheap folder may get me on the bike again. My question is what sort of difference is there between gears on a 3 speed hub compared to derailleur gears ? I don't intend to go fast but will need enough gear range to get up hills but not be peddling like mad on the flat.

Thanks all

Brad

 

[N0bodyOfTheGoat]

My goto for bike gearing has been the old Sheldon Brown site for years...

https://sheldonbrown.com/gear-calc.html

 

[TheDoctor]

Working out hub gear ratios isn't too bad.
Assuming 3 speed, middle gear is 1:1 - so divide chainring teeth by sprocket teeth, and multiply by wheel size. It'll be around 60" or so.
Bottom gear is 3/4 of that, top gear is 4/3. 45", 60" and 80" or something like that.
You can raise or lower the range by changing the chainring or sprocket.

 

[mjr]

Working out hub gear ratios isn't too bad.
Assuming 3 speed, middle gear is 1:1 - so divide chainring teeth by sprocket teeth, and multiply by wheel size. It'll be around 60" or so.

Maybe, but mine's set to 42" in line with Sheldon Brown's advice.

 

[TheDoctor]

Maybe, but mine's set to 42" in line with Sheldon Brown's advice.

To give top as your cruising gear? Not a bad shout.

 

[Chris S]

Most old Raleigh folders have 69, 52 and 39 inch gears. You can do most urban hills in a 39 inch gear. A 52 inch gear is ideal for start/stop city cycling and a 69 inch gear will give you a cruising speed in the low teens. You will find yourself freewheeling down hill though.

They'll probably be OK on a gravel track as well.

 

[BADGER.BRAD]

Thank you everyone much appreciated. It seems they give a fair range ! I will be free wheeling down hill anyway at a relatively slow speed and not going any major pace on the flat so the dogs can keep up easily.