Rohloff for a Mountain Bike?

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Powered by Rohloff…

John posed this question in the comments on another post . I figured it was worthy of its own post.

“Hi Vik I like your blog and particularly enjoy the reviews. I know you use a Rohloff IGH on your bikepacking rig. Would you use a Rohloff on your “regular” trailbike? What would you see as the pros and cons? They recently came out with a few new models with thru axles and various hub widths AND there is now a gear box that uses sram shifters which sounds pretty exciting to me. How much of a weight gain would you expect to have by adding a Rohloff + necessary parts and dropping the traditional drivetrain? Thanks!

John”

Thanks for the question John. So back in 2009 I got a Thorn Sterling Rohloff specific mountain bike frame and a Rohloff hub for the purpose of building up an IGH mountain bike. I also thought I might use that same hub on my Santa Cruz Nomad full-suspension trail bike. I really only got as far as building the Rohloff into an all mountain rim before I killed that project.

The Rohloff wheel was so heavy it was a deal breaker for a day-to-day mountain bike where I really had no issues with derailleurs. The problem is not just the weight, but the fact it’s unsprung weight right at the back of the bike which affects handling and suspension action significantly.

Now if I was dealing with awful shifting, tearing off derailleurs and/or wearing out drivetrains regularly I’d reconsider for sure, but the reality is that despite all the shitty PNWet weather I throw at my trail bike it handles it just fine with a derailleur. So my motivation to make a Rohloff work is low.

You mentioned a gearbox option. This would definitely be better from a suspension/handling perspective, but it would still be heavy and would require a very expensive frame that was custom designed for the gearbox. I am quite particular about my full-suspension designs so the idea of compromising on that choice to get a gearbox that would cost me an arm and a leg is not particularly appealing.

I did try a Hammerschmidt 2 speed crankset on my Nomad for a year. It was sort of a 2 speed gear box. Ultimately I sold it because there was too much drag from the internals to make me enjoy using it so it ended up being a very expensive and heavy 1 speed crank in practice. Instead I just started running my first 1x single ring crank setup and haven’t looked back.

Another issue is that mountain bike standards are changing very fast and the economics/service life of a Rohloff is measured in decades for most riders. If you invest in an expensive IGH or gearbox you really need to ride it for the rest of your life for it to make sense financially. How do you do that when it won’t work a new bike you buy 5yrs later?

Circling back around the question when would I consider running a Rohloff in my trail bike?

  1. If I frequently rode serious sticky mud that was screwing up my shifting
  2. If I was tearing off derailleurs from sticks or rocks
  3. If I was wearing out drivetrains at a high rate and missing rides
  4. If I was riding a hardtail where rear suspension wasn’t a factor
  5. If I lived someplace real remote and having a bombproof bike was critical

So far I really don’t tick any of these ^^^ boxes so I have no compelling reason.

You asked about what a Rohloff adds in weight. This link has a good comparison. Aside from the numbers one thing you will note picking up any IGH bike is all that weight is focused on the rear vs. spread out with a derailleur equipped bike. So although the difference is relatively small the impact is much greater than you might think.

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No bikeshops out here if your derailleur gets damaged…

All that said I do have a Rohloff on my Surly Krampus bikepacking rig. For that application it makes sense to me because:

  • extra weight at the rear wheel matters a lot less on a hardtail/rigid bike
  • riding in remote areas a drivetrain failure is much more serious
  • traveling with your bike there are many opportunities to damage a derailleur [bus/train/plane]
  • I don’t ride the same level of gnarly trails on tour as I do at home
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5 thoughts on “Rohloff for a Mountain Bike?

  1. Thanks. You are too kind.

    I appreciate you clarifying the gearbox issue for me. Now that I understand John’s comment about the shiftbox aka external gear mechanism what I would add about it is:

    – the Rohloff system is a well defined and understood quantity given all the abuse they have seen
    – the failure modes of the Rohloff are well known
    – if you add in new aftermarket part that will be used in limited quantities you now have added some potential problems that will likely not be well understood for a long time or ever…depending on how many are sold and how extensively they are used and reported on
    – so when you are evaluating the modified Rohloff system on a pro/con basis you can’t tick of the reliability box with the same certainty as a stock setup
    – this may tip the balance of the analysis against the IGH

    Like

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