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I just bought a Surly Ogre (2022) and want to convert it to a Rohloff hub - but am having a really difficult time finding what I need - i.e., info, parts, etc.

I plan to do a lot of touring but also want to ride locally on both pavement and single-track, figuring on changing the tires when going on extended tours.

1. Which hub. From what I can tell so far, the "Rohloff Speedhub 500/14 TS DB OEM2" is the I want. I would prefer a quick release, but (and please correct me if I'm wrong) I understand it would difficult to remove the wheel, hence the "TS" version.

2. External gearbox. I don't see this model with the "EX" spec. Does the "TS DB OEM2" come with the external gearbox by default?

3. What additional parts will I need to purchase separately?

Do I also need to purchase any of the following:

  • PM Bone (#8555) - (or a Speedbone or Monkeybone)
  • OEM2 Plate
  • chain tensioner?
  • chain guide?
  • What else...?

4. Chainring. This is the most maddening part! The Ogre came with a 94BCD SRAM NX 32T chainring. I want a 44T chainring. The Rohloff requires a 54mm chainline. Does anyone know of a chainring that will work? Will I have to replace the crankset? The bottom bracket?

I am NOT a bike mechanic but I am pretty handy. This seems like a fun project, a real learning experience (and a way to release a lot of curse words).

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  • A 44T chainring requires a boost crank but can work: surlybikes.com/bikes/ogre
    – Andy P
    Commented Jul 24, 2022 at 21:56
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    I think I would stay away from a surly ogre. Commented Jul 24, 2022 at 22:01
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    @DanielRHicks and they say cyclists don't have a sense of humour.
    – Noise
    Commented Jul 25, 2022 at 8:17
  • @Noise it took me until reading your comment to 'get' it, so maybe its true that we don't :D
    – Andy P
    Commented Jul 25, 2022 at 9:50

2 Answers 2

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When you're ordering parts for a Rohloff installation, it is very helpful to think in terms of the Rohloff part numbers so you can make sure of what you're getting and what's included or needs to be bought separately. What's confusing is that TS DB OEM2 is a model code that describes a hub variant, but it's not itself a part number. Rohloff has part numbers for the various kits that include most of what you need for an installation, and then all those parts are available individually with their own part numbers as well (like for when you have a used hub you're reconfiguring for a different bike).

You can get all the part numbers and a list of what's included on Rohloff's b2b site.

  1. Rohloff recommends using the nutted axle version (TS) on any horizontal dropout bike. They seem to be concerned about the wheel security. You can find pictures of people using chain tensioners like the Surly Tuggnut to add wheel security and use the QR Rohloff version (CC). I don't have an opinion on how good of an idea this is. The actual chance of the wheel slipping probably has to do with the skewer used and your habits with it. Rohloff is pretty standout for making good recommendations for how to use or not use their products so personally I think it's hard to recommend messing with the QR version here.

  2. All the disc (DB) versions come ready for the external gear mech.

  3. If you buy one of the kits such as 8065Z, the things you need to buy separately are your splined sprocket carrier and sprocket of choice and your rotor. The PM Bone isn't needed on any of the Surly bikes that use this dropout. The bolt in the torque anchor slot on the dropout is your torque anchor. One note is I'm not sure whether you get that bolt as part of the hub kit, but it's just a regular M6 bolt, washer, and nut. It does come with the OEM2 axle plate kit (8228) if bought separately.

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  1. There are a lot of versions of the NX crank and SRAM doesn't offer an abundance of technical nitty gritty on them. You appear to have the Powerspline version and the stock chainline for your bike is probably 49mm. The piece of information I couldn't find readily is what spindle length of Powerspline BB your version uses to get to 49mm. They come in 108, 113, and 118, so if you have the 108 or 113 now you could conceivably go up a size to get the chainline good or into the ballpark (or two sizes if it's 108). However, I don't think there are any chainring options to do what you want, so if you want to run bigger than 32 you're probably buying a crank. There are various hacky aftermarket chainrings for your crank and those kinds of products come and go and are of variable quality, so there is a gray area there but we try to avoid specific product recs here because of their tendency to become obsolete, and this is a good example of that. It probably makes sense to ditch the crank completely, keep it with the old drivetrain parts to do whatever you plan on with those, and replace it with something nicer. All Powerspline cranks exist only to make something cheap that looks modern and fancy, and the bottom brackets in particular are not suited to a high-mileage bike.
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Maybe my answer is too late to help? I bought a complete Ogre (3x9) in 2012 and switched to a Rohloff in 2018. Like you, I'm handy but not a great mechanic. I was at first confused by the spec choices, but Neal at Cycle Monkey built the wheel and his advice was quite valuable. Rohloff's installation manual was easy to follow and showed everything i needed to do. The hub has been trouble free all along; yesterday i had more trouble than expected replacing a worn out chain and thought a tuggnut would make that easier, thats how i found your post. Here's my 2 cents worth on your questions: 1&2) OEM2 w/ external gear box is what fits the Ogre. 3) you don't need any of those extra parts though they say a tuggnut makes chain tensioning easier. Tricky part for me is getting the brake caliper, torque anchor, and chain length to match and not end up with the axle too close to the open end of the dropout. Maybe my problem is just getting the chain length right. My biggest mistake in the conversion was in not removing the dropout spacer that's there to locate the axle for a derailer. It worked anyway but left a lot less space in the dropout. 4) Chainring just wasn't a problem for me. I ditched the inner and outer and mounted the new one in place of the middle. Chain line was just right. My Ogre originally came with a Truevativ Firex GXP BB and Crank, they're still on it. I have a 36 tooth Surly chain ring with a 16 tooth cog. Can you accept a smaller/larger chainring by adjusting the cog? i fooled with a bunch of combos on Sheldon Browns gear app to get the range I wanted; 36x16 works great but other combinations would have too. good luck.

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  • I am planning to use the Surly 42T stainless steel chainring, so I will need to replace my crankset. The problem I am having now is finding a 110BCD, 5-hole, crankset with a 54mm chainline (+/-2 or 3 mm).
    – Greg
    Commented Nov 23, 2022 at 15:48

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