Achieving low gearing on Rohloff Speedhub

[Mark Bromley]

Hi,

I hope I did not post this twice.  Sorry if I did

I'm new to this group and hoping for some advice about changing out the chainring and cog to achieve a lower gearing  on a Rohloff Speedhub.  

I'm a long time tourer and Rivendell rider ( beautifully built up years ago by Peter White) but with old age approaching have ordered a new HP Velotechnik Streetmachine recumbent with Rohloff and would like to adapt the stock 46 chainring and 16 tooth cog to achieve lower gearing suitable for loaded touring.

I'm after a low gear gear inch number close to 15 or 16.  One supplier recommended keeping the chainring at the stock 46 and switching out the cog at the hub for a 21  ( yields a low gear inch of 15.5)

A touring blog mentioned that they had switched to a 39 chainring and 18 or 19 cog .  I was thinking of a 38 chainring and a 19 cog which yields a very low gear inch number of 14.2.  

A  similar blog, If I understand it correctly, -  said you should look for a 2:1 relationship for chainring to cog  for touring to produce a suitable low gear.

The 46/21 combo option  was noted as perhaps a little more "efficient" but I'm not sure why.  ??

Thoughts?

What is Rohloff's limit ?  Do either of these combo's exceed the Manf. limit?  Assuming that is a torque issue  - I can't imagine I'd be introducing much torque in a recumbent position.

I sure would appreciate any advice

Thanks

Mark Bromley

[tnort...@gmail.com]

My wife  has a Rohloff  on her touring bike. And when I  am looking for info I  go to the Thorn Bike Forum as they have a Rohloff sub forum that is excellent. 

Tom 

NE Ohio is