Rohloff speedbone on Mary SS brake mount?- Mtbr.com
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  1. #1
    ridin' Mary
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    Rohloff speedbone on Mary SS brake mount?

    downhilljill or ssmike,

    I'm mounting a Rohloff speedhub onto a Mary SS. The manual says to check with the frame manufacturer before mounting the speedbone which is used to transfer the rotational torque of the internal gear mechanism to the brake mount for the rear disk.

    The Mary looks to have quite a robust brake mount. Do you believe there would be any issues with this installation on this frame?

    Here's a picture of Rainman's installation of a Speedbone for comparison (blatant theft of an great picture from another MTBR thread). The third pin on the right connects to the hub to handle the rotational torque. This is on a SIR9, which has almost identical dropouts and a similar brake mount mechanism as the Mary. The Mary is welded the full length of the brake mount to seat-stay line, which is the only notable visual difference.
    RainmanSIR9_speedbone.jpg

    Thanks!

  2. #2
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    I'll have to tell you that we don't recommend it as it does place a lot of stress on the disc tab. Since the Rohloff system isn't original equipment, we really can't tell you whether or not the tab will hold up because we don't stress test using that system (Rohloff).

    Obviously, we can't keep you from giving it a shot, but just be forewarned that it may cause disc tab failure. It will also void your warranty if failure does occur.

  3. #3
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    Thanks for the reply. I figured that I had a much higher chance of getting this response than a response stating "everything's fine, go for it". But it was worth asking anyways.

  4. #4
    Crazy C
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    I'm not saying everything will be fine but I went through the same thing myself years ago building a sevencycles ti frame. Seven would not authorize this application but I proceeded when Thomas with Rohloff told me that torque from the hub is about the same as torque from the brake. Five years, plenty of hard riding, and NO problem. Good luck have fun!

  5. #5
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    I typed out a reply earlier this morning stating "everything would be fine", but thought better of it not knowing the Haro design and after reviewing the disc brake tabs I have attached Speedbones to, over the past few years.

    In gear 1, 98% of the torque you transmit at the cranks will be applied to the Speedbone, in approximately the same direction as applied by the disc brake caliper. However, I don't know what rear brake tabs are stressed for, and can't imagine the rear wheel disc brake force <u>ever</u> approaches the max you can dish out mashing on the crank.

    However, with all those disclaimers out of the way, I have yet to hear of a Speed<u>bone</u> causing a frame failure.

    Speedbones have been around since 2001, and Rohloff (probably wisely) required a waiver to be signed for a time. But lots of riders are running Speedbones on all sorts of frames, and I can't recall a single problem reported on MTBR or USENET, and nothing comes up in a Google search.

    So take a chance and go for it. If something goes wrong, you can be the first to talk about it online!
    speedub.nate
    MTBR Hiatus UFN

  6. #6
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    Thanks Nate,

    I'm gonna order and use the speedbone anyways. The thought of using that hokey chainstay arm on my beautiful Mary is sickening. I just thought that I would ask the question that the Rohloff manual requested that I ask. In return, I recieved the expected "will void warranty" message.

    I looked carefully at the Rohloff manual at the force directed to the brake mount when using the Speedbone. In the above picture from Rainman's bike, you can see that the 98% force of the cranks exherted in a counter-clockwise rotation of the hub would result in most of the force directed along the seat stay, and only a small portion of the force pulling the end of the speedbone vertically away from the seatstay. Since most of the force is in-line with the two bolts and a long welded seam, it seems that this is rigid enough for my wimpy mashing.

    If I was strong enough to make it up steep hills in high gear (with lots of torque on the pedals), then Mary would remain a SS since I wouldn't need gears. The need for the Rohloff is so that I can get some assistance up the hill so I'm not mashing on the pedals as much. Yes, I'll stand and grind for short hills, but this will be the exception and not the norm.

  7. #7
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    How did it go?

    I'm about to do the same thing on my Mary. How are you liking the final setup?

    I also found a guy who sells an alternative to the speedbone. Super bonus: He is located in the Bay Area (California) which equals quick shipping to me in SD county.

    http://www.cyclemonkey.com/monkey_bone.shtml

    Oh yeah, one more thing. I am worried about the front chain ring size. From the looks of my frame, I can't go up in size very much before the ring will run into the chainstay.

    The bike I'm replacing (rest in peace) had a large 42 tooth front chainring...

    Any thoughts here would be appreciated.

  8. #8
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    It worked out just fine!

    Hi YONO, it's OhNooo. ;-)

    I rode the Mary at least once a week with this Rohloff hub for 15 months. It was my only bike, and I took it everywhere and rode it in all sorts of conditions.

    Here's a pic of my first configuration using the Speedbone and the cables routed up the seat tube. I didn't like this because when doing the hike-a-bike over streams I was grabbing a handfull of cables and zipties:



    Later on, I replaced the Speedbone with the Monkeybone you mentioned. Here's the result. This is much cleaner (and a bit lighter) than that bulky Speedbone was:



    I settled on a 34T chainring and the stock 16T cog. This is a bit lower geraring than the Rohloff specs (min 36T with 16T cog), but I'm not that heavy or strong. I don't stress this hub even close to it's tolerance. I think your 42T cog would be hugely big for a 29er unless you are planning on using this solely as a commuter bike. I've found that the 34/16 combination gives me almost exactly the same pedal cadence in 1st gear as a 26" wheeled bike with a standard deraileur setup.

    But the Rohloff was taken off of Mary last month. Mary is once again a single speed, and I have to say that I like her a lot more now that I've made that change. There's something about a SS that just makes life fun, and I'm feeling the love for SS'ing more than when I tried it after first getting the Mary. The Rohloff is now on a Full Sus bike where I think it belongs.

    The only downside I had with the Rohloff on a hardtail was the huge number of pinchflats. That 5lb hub is so heavy that it's tough to manage hits on large sharp rocks with speed. I found that if I kept the tire pressure below 30lbs, I got lots of pinch flats. And if I kept the tire pressure above 30lbs, I got launched off of the rocks by the tire rebound. Hence my moving the Rohloff to a Full Sus bike (Ventana El Rey). I can run higher pressures with a Full Sus bike to avoid the pinchflats and not have the rebound problems like with a hardtail.

    But before I took the Rohloff off the Mary, I took a few more pics of the final configuration. Note the cables were routed just above the BB which shortened the cables a bit, reduced the number of large cable bends, and left the top-tube clean for hike-a-bike grabs.

    I'm also in San Diego. Can you guess the trail here? Hint: North County ;-)




    Enjoy!

  9. #9
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    Great photos of your Mary set up.

    That is an awesome post OhNooo. Thanks for the insight and the photos. My guess is somewhere in Daly Ranch. I've only ridden out there a couple times. I feel like I should know it but I'm not sure.
    Pinch Flats suck. I thought it was just me and bad luck. I was flatting so often I went to a Stan's tubless setup on the rear. It was my first ride with that setup when the frame broke on the ol' Buzz Bomb and here I am.
    I'll let you know how it goes for me and Mary and if the tubless helps.

  10. #10
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    ding ding ding!

    Daley Ranch it is.

    Enjoy your Mary, and post some pix once you get it all put together!

  11. #11
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    What's all this about pinch flats?

    I've most definitely not had this problem with my 2.1 Nano on the rear of my hardtails (first the Buzz Bomb, now the Mrazek). That's at about 35 PSI (I wouldn't dare go lower).

    Rampages pinched like crazy on the back of my RIP. Great front tire, lousy rear. Maxxis' Ignitor has been great in back.
    speedub.nate
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  12. #12
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    Quote Originally Posted by Speedub.Nate
    What's all this about pinch flats?

    I've most definitely not had this problem with my 2.1 Nano on the rear of my hardtails (first the Buzz Bomb, now the Mrazek). That's at about 35 PSI (I wouldn't dare go lower).
    Hi Nate,

    You hit the problem exactly. You dare not go lower than 35 PSI. That seems to be the magic number that I found for my hardtail with a Rohloff as well.

    I've ridden hard tails for 20 years, and I've always run lower pressures around 25 PSI so that there is some small amount of give to provide a tiny amount of suspension. This works great on a typical rear wheel that has a 1-lb hub and cassette combination. When you hit a step at low pressures on a typical wheel, the tire absorbs some of the initial hit, and then the rear of the bike moves up and back to take in the rest of the hit. So 25 PSI works great in that case.

    Now add a 5-lb "anvil" in the middle of your wheel called a speedhub. The initial hit at 25 PSI continues all the way into the rim because the bike isn't going to move up and back. The inertia of this hub at the exact center of the wheel (in direct line with the impact of a step) prevents that.

    So I find that I need to run 35 PSI, which is too much for me on a hardtail. This results in no "give" to the tire, so every bump is transmitted up my spine. I just don't enjoy a hard tail at high pressures, which has limited my enjoyment of the Rohloff on my Mary.

    I've moved the Rohloff to a FS bike (my first FS!) where I can run this 35 PSI without compromising the ride. And my Mary now has a wicked-light wheelset that allows me to run lower PSI so that I can enjoy that ride too. Win-win!

  13. #13
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    Hi YONO,
    How did the tubeless setup go for you? I am building up a 29er rohloff (after demo'ing a rohloff, the question I now ask, is why go with anything else!) and wanted to go tubeless in the rear... Realworld feedback would be great!

  14. #14
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    Tubeless 29 with Rohloff

    Good timing....The tubeless absolutely works best for me and my rohloff.
    In the conditions where I am riding, I pinch flat even at pressures upwards of 35 or more PSI. I tried a different tire, with more volume and it did OK but eventually caused me the same grief. I've since committed to tubeless on the back.
    I finally ponied up for a nice pair of 29inch Kenda Nevegals (2.2) that I'm just getting used to. So far they are outstanding.
    I tried to do a ghetto tubeless setup but struggled with the tires blowing off of the rim while trying to bring them up to final pressure. Talk about SCARY!
    I use Stan's rim strip and sealant right now. I'm starting to think I need a new rim strip because the valve stem is very touchy when I setup my wheel and takes a lot of sealant to get it air tight at the base. Has anyone one else had that trouble with their rim strip valve stems?

    Oh and DO carry a spare tube, the torn sidewall DOES happen and it's a deal breaker on the tubeless setup.

  15. #15
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    Quote Originally Posted by YONO
    Good timing....The tubeless absolutely works best for me and my rohloff.
    In the conditions where I am riding, I pinch flat even at pressures upwards of 35 or more PSI. I tried a different tire, with more volume and it did OK but eventually caused me the same grief. I've since committed to tubeless on the back.
    I finally ponied up for a nice pair of 29inch Kenda Nevegals (2.2) that I'm just getting used to. So far they are outstanding.
    I tried to do a ghetto tubeless setup but struggled with the tires blowing off of the rim while trying to bring them up to final pressure. Talk about SCARY!
    I use Stan's rim strip and sealant right now. I'm starting to think I need a new rim strip because the valve stem is very touchy when I setup my wheel and takes a lot of sealant to get it air tight at the base. Has anyone one else had that trouble with their rim strip valve stems?

    Oh and DO carry a spare tube, the torn sidewall DOES happen and it's a deal breaker on the tubeless setup.
    Hi Yono,

    My Mary is back in Single-speed mode with Chris King hubs and Stans Flows rims. I abandoned the Rohloff as it didn't seem to add much joy to me. I love my Mary more than ever now that she's back as a SS. What a great bike.

    I tried using the Rohloff on a new 29er full-suspension frame (Ventana El Rey), but I didn't dig it much at all on that bike either. So I'm back to standard deraileurs on that bike too. My Rohloff is gathering dust in the garage waiting for the economy to pick up so I have a chance at selling it at a decent price.

  16. #16
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    YONO - thanks for the feedback! I think you might just need to fix your stem, from everything I read, it shouldn't be that touchy! Ghetto just isn't worth it, especially if one is out in the middle of nowhere. I was trying to go with UST myself, but there are no 29er UST rims. just wheelsets.. argh. And those wheels have the straight spoke hubs too. grr.
    But its good to hear that a 29er with stans is working. What did you use for a rim??

    ohNooo - sent you a PM about the rohloff....

  17. #17
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    29er stans tubeless setup

    I'm using a rhyno lite rim that I built up with the rohloff. The original stans 29er rim strip works great in this rim. I've struggled with getting the strip to seat correctly in narrower rims with large shoulders where the tire bead sits. So far, with the Nevegal tire, it's been flawless. (knock on wood).

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