ason

I am currently taking a break from the Panamerica. I’m currently in Ecuador and have an opportunity to take a break and do some maintenance. I’m currently running 32/17 combination (since Alaska) and can foresee longer and harder climbs as I go further south. I just bought an 18 tooth cog and looking for confirmation or advice against going below the 1.9 threshold that Rohloff suggests. I’ve been using the Rohloff hub for over five years without any problems with increasingly easier climbing gear combinations, both belt and chain. The hub has been working great without any problems other than some play (1mm) with the spring clip, and I may go back to the lockring with chain just to tighten that up in the rear. Could be rear cog wear on the 17. I’m looking for success or failure stories from people who use their Rohloff hub with combinations below the 1.9 threshold that Rohloff recommends. What’s the worse that could happen?

I could use the extra climbing gear, especially for grades over 12%.

boomhauer

I guess the worst that can happen is the nylon shear pins inside the hub break. I would imagine this would likely happen when standing on the pedals and cranking hard, probably when you shift while standing and putting excessive force on the unit. Glad to hear you went with 32/18 and nothing bad has happened yet. I’m considering this also.

ason

Nothing has happened yet at 32/17.

IPassGas

This will be a function of total weight. Rohloff changes the ratio at 220 lbs, which I could imagine that a fully loaded touring bike approaches or exceeds. We are running 44/17 on a 460 lbs tandem. The people with the most experience about bending the rules are on the Thorn forum, perhaps post the question there.

Rick

IPassGas: You are at 2.5882 my 50/20 is right at 2.5. I have a Co-Motion Pangea Rohloff. It has 26" wheels. The kinetics gear calculator says I have a 17.6 gear inch on the low and a 92.8 gear inch on the high. I'm currently running Schwalbe Pick-Up tires.they are the largest volume tire that will fit under my french 60 mm fenders. I ride mostly rode and will run out of wind before I run out of gears. I can't stand on the pedals and have learned to just keep spinning in a low gear instead. When I was in the military and started riding bicycles to escape the barracks. I broke the spindles on pedals 8 times and snapped a crank arm once. I am bow legged and currently use pedal extenders.

Tourist in MSN

For touring, I run a 36/16 ratio of 2.25. That has worked for me. But my cadence is usually in the 60s and on hills my torque goes up. I weigh about 80 kg.

Perhaps you are a naturally high cadence rider that would have a high spin rate with less torque than me? In that case, reducing gearing further is probably not a problem.

Or perhaps you are a heavy person that wants to pedal slowly up a steep hill with a heavy load, in which case you could be putting undue stress on the innards of the hub.

You have given us very little detail here.

djb

first of all, cool trip. Wish I was there.
I've done a few shortish Mexico and Central America trips, on a Surly Troll I originally had thought of putting a rohlof on for these trips, but stayed with derailleurs.
As you say, if you feel you'd like one lower gear now, you'll be certainly dealing with more climbing at higher altitudes which is an extra factor, not to mention the ever possibility of feeling ill from even a dodgy tummy.

do you know what gear inch range you have on your bike now?
What bike is it, ie what wheel and tire size.
I actually have never looked up gear inches for a rohlof bike.
My bike had a low of just under 17 gear inches, 16.7-103 g.i. and I certainly used my low gear often. I'm a light guy and wasn't stupidly overloaded, maybe max 50, 55 lbs? But I wasnt higher than maybe 32-3300m and on paved roads on steep stuff.

IPassGas

Hi Rick: Yes, we are not below the Rohloff limit of 2.5 for a tandem. We use 26 x 2” tires on tour: 18.6/98 gear inch. We have climbed some 10% hills with full load and standing at times. If we are putting in roughly twice the force of a single bike, then I suppose our single bike ratio for 44/17 is half: 2.58/2= 1.3, well below the 1.9 limit. But such a calculation must be wrong since going from single to tandem, Rohloff’s ratio changes from 1.9 to 2.5 (not doubled). Perhaps the single bike equivalent limit would be 2.58 x 1.9 / 2.5 = 2.0, so we are good. The Rohloff has been great, but I do wonder if we are actually somewhere between 1.3 and 1.9 for a single bike equivalent.

Rick

djb: Kinetics and Sheldon Browns internal gear calculator.

djb

Thanks
Maybe this fellow will pop back in and give more info on his bike

Rick

djb: I have a Co-Motion Pangea Rohloff. it came with a drop bar setup and I have changed it to the Crazy Bar with the lefty shifter.








I have a Spur Cycle Bell and an AirZound horn on the right. The Rockgeist Honeypot is holding a Nalgene 48 oz bottle with a silicone drink straw and lid setup by One Bottle Hydration. The Nitto extension bar has my Edelux light and a Padrone computer on it. I Have since put the Edelux light on the front of the Grand Expedition Rack. Yes that is a can of general purpose spray for things that attack.

Tourist in MSN

This calculator has the gearing for the Rohloff built in, you simply choose your tire size, chainring size and sprocket size.
https://gear-calculator.com/?GR=RLSH...N=MPH&DV=teeth

The link above is set for my heavy touring bike tire sizes and the gearing I use for touring.

For riding around near home unladen, I add four chain links and change the chainring to 44 to give me higher gearing. But for touring,I need the lower gears for a heavy load uphills.

That gear calculator also works for derailleur systems, this is the setup I have on my light touring bike with a 3X8 half step drive train. I also have that website set so that it shows the cross chained gears I try to avoid in light gray, that is set with max chain angle. I try to only use the six least cross chained sprockets per chainring, for a total of 18 effective gears.
https://gear-calculator.com/?GR=DERS...N=MPH&DV=teeth

Since you are not a Rohloff user, you probably do not fully understand the OPs question. Rohloff wants to avoid people putting too much stress on the internals of their hubs. The way that they do that is to set minimum ratio of chainring to sprocket sizes. Lighter riders can use lower ratio than heavier riders or tandem users. The OP is basically asking if anyone has thoughts on using a ratio outside of Rohloffs specification.

djb

thanks T, I have read about you guys in the past talking about the rated "lowest ratio" for not exceeding stress on the internals, so sort of understood the concept.
Always interesting to learn more about stuff, so this thread is good that I've learned about the rider/bike/load weight factor.

I hope the fellow or lady comes back and hope this helped them with their decision depending on their weight and total bike weight situation.

Rick

I like that gear calculator. Where did you find it? It is more accurate than the others I have found.



I have grown used to this setup that came on my Pangea Rohloff. Before the Pangea I was riding my old Tandem and it had at 24" low gear.