Technical > Transmission

Nomad Rohloff gearing

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KDean:
What's the smallest gearing ratio  you can have a a Nomad MK2   38---19?

mickeg:
If for a solo bike and if your weight is less than 100 kg, the ratio of 1.9 of chainring to sprocket.

See:
https://www.rohloff.de/en/experience/technology-in-detail/specifications

For touring, I am running a 36T chainring and 16T sprocket, ratio of 2.25. 

But if you are a spinner and want a high cadence, you could certainly go down towards the 1.9.

If you weigh more than 100 kg, ratio is higher.

KDean:
I'm under 92kg  , What the best for steep hills , Sorry I switched off looking at all these charts .

martinf:
For me, the best gear on hills is the lowest possible that still gives me a "reasonable" top gear.

I currently have 38 x 16 on my tourer, because that was the lowest permitted ratio when I bought the bike in 2012. I very rarely use the highest gear, so I will probably go to 38 x 19 at some stage.

38 x 19 gives a range of 14" to 74" with the 26" by 2" tyres I run. Top gear 74" at my preferred pedalling cadence of 90 rpm is 33 km/h, that speed will be OK for me on a loaded tourer, as I can only go that fast for any significant length of time on downhills or with a substantial tail wind.

I can still get the speed up to 43 km/h for a short period by increasing cadence to 120 rpm, for example if I need to integrate traffic on a big roundabout.

I have a 71" top gear on my 8-speed utility bike, and don't miss not having a higher gear on that.

As Mickeg says, it also depends on your pedalling style.

mickeg:

--- Quote from: KDean on October 12, 2021, 05:56:52 pm ---I'm under 92kg  , What the best for steep hills , Sorry I switched off looking at all these charts .

--- End quote ---

I can't tell you what the best is for steep hills for you.  Everyone is different.

I find the slowest I can ride and maintain horizontal and vertical stability is about 3.5 mph.  And the slowest cadence I can run with it being smooth and not a pulsating slog is about 72 rpm. 

So, after some calculations, with my 559X57mm tires I find that I need a 36T chainring and 16T sprocket to have a first gear that is about 3.5 mph with a cadence of 72.  That is what I use for touring.  I spin out on some shallow downhills but the steep uphill gearing is more important than shallow downhill gears.

But that is touring, with a heavy load of camping gear on the bike.  When near home with an unladen bike, I switch to a 44T chainring instead, add four chain links.  That way I have the lowest gears I need on an unladen bike and I have better downhill gearing for shallow downhills.

You likely will want something different, everyone is different.

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