Recumbent - Which Front sprocket?

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Desk Rider

03-28-05, 10:26 AM

Hi all,

I'm currently home-building a Bentech (SWB with 26' rear wheel) and I'm wondering what size front sprocket I should use. I'm new to bents and my wedgie has a Nexus 7 epicyclic with a 21/42 arrangement. I asked Rohloff support for recommendations but they told me to compare with a normal 21-speed arrangement.

Well, since I don't have anything else than my Nexus 7 bike I cannot find a frame of reference to compare and select a chainwheel.

I think the Rohloff hub comes standard with a 16-tooth sprocket...

Anyone pedals a Rohloff-hubbed bike out there and would be happy to recommend a gearing?

Thanks for any help.

BlazingPedals

03-28-05, 03:48 PM

Maybe this (http://www.sheldonbrown.com/harris/rohloff-impressions.html) will help. This is for a 14 speed Rohloff; I didn't see any references to a 7 speed. It appears that for a 26" wheel, using a 50T chainring and 16T hub cog will give you gearing of 25-123 inches. Adjust chainring up or down to suite your tastes. There is references to a lower limit placed on the chainring teeth, so going below 34T or so is not recommended.

Desk Rider

04-02-05, 09:41 AM

Ok, Thanks for the info. I think the StreetMachine GT with Rohloff comes with a 46/16 setting, so around 46 or 50 as you suggest must not be too far off the mark.