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  1. #1
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    Rolhoff Belt drive on a 29er+ help please

    I'm looking at a new 29er+ frame that is belt drive compatible and I would like those who run Rolhoff belt drive's help please.

    I'd like to get near the gear range of my standard 29er - 3 x 9 (44 - 32 - 22 front & 32 x 11 rear), now I know this isn't possible high end but I could do with the spinny gears lowdown for climbing.

    The front will fit a 46 tooth/pulley Gates cog (no larger), how close will a 19 tooth/pulley on the back give me to what I'm after?

    What difference a 20 or 22 tooth/pulley make the gear range?

    Please keep your answers simple for an idiot like me to understand...

    Thanks and Happy Christmas to you all

  2. #2
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    Check out Cycle Monkey....They have the answers....I'm running Rohloff chain....38t-16t and is the same as conventional 3X9 drivetrain...also check out the Rohloff or Sheldon Browns site for gear ratios....A 46x16 would be the same as a 24x30..for climbing. So an 18, 20, or 22t would climb a tree....

  3. #3
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    Cheers Ladljon, but I don't think the Gates belt pulley's are the same spacings as chain teeth spacing.

    Does anyone know how different the pulley to tooth ratio is.

    Anyone using a Gates Belt over a chain out there with the answer?

    Cheers

  4. #4
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    What matters is the tooth ratio and not the spacing.
    Use a spreadsheet.
    Start with the gear ratios of your 3 x 9 setup and sort them.
    Get the 14 gear ratios of the Rohloff hub.
    Use a multiplier (call this A) to scale the Rohloff ratios to get as close as possible to the 3 x 9 gears.
    A = teeth in front pulley/teeth rear sprocket
    The number of teeth in the rear sprocket is 46/A.

  5. #5
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    U really have to go by the size chainring will fit UR frame....

    conventional 46/12 =rohloff 40/15=belt 50/19

    conventional 22/34=rohloff 38/16=belt 46/19

    conventional 24/32=rohloff 36/13=belt 55/20-60/22

    I would say 46/19

    Gates carbon Rohloff drive manual

    Front chainring 104 mm for MTB
    Last edited by ladljon; 12-25-2013 at 09:40 AM.

  6. #6
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    Quote Originally Posted by ladljon View Post
    U really have to go by the size chainring will fit UR frame....

    conventional 46/12 =rohloff 40/15=belt 50/19

    conventional 22/34=rohloff 38/16=belt 46/19

    conventional 24/32=rohloff 36/13=belt 55/20-60/22

    * ***** *** **/**

    Gates carbon Rohloff drive manual

    Front chainring 104 mm for MTB
    I don't understand a word of the above


    But I do understand and feel relieved about the following

    Quote Originally Posted by ladljon View Post
    I would say 46/19

  7. #7
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    A 46/19 would give U the same low climbing ratio of a 22/34 conventional gearing....

  8. #8
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    Belt drive gear ratios are calculated the same as with chains. The different pitch doesn't matter, because it's different by a same amount through the system.

    For example 46/19 with a belt drive has the same gear ratio as 46/19 with conventional chain drive.

  9. #9
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    Thanks to you all for helping out a maths idiot like me.

    I really liked the comment above "22t would climb a tree"

    I'll post up pictures of the build at the end of Jan when it's here and I'll let you know my luddite thoughts as well.

    Happy New Year

  10. #10
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    Important thing is to stay in the length of the chain stay

    The Gates application for iPhone works really well to find the right combo.
    "There is a big difference between kneeling down and bending over" -FZ

  11. #11
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    Quote Originally Posted by Johnclimber View Post
    I'm looking at a new 29er+ frame that is belt drive compatible and I would like those who run Rolhoff belt drive's help please.

    I'd like to get near the gear range of my standard 29er - 3 x 9 (44 - 32 - 22 front & 32 x 11 rear), now I know this isn't possible high end but I could do with the spinny gears lowdown for climbing.

    The front will fit a 46 tooth/pulley Gates cog (no larger), how close will a 19 tooth/pulley on the back give me to what I'm after?

    What difference a 20 or 22 tooth/pulley make the gear range?

    Please keep your answers simple for an idiot like me to understand...

    Thanks and Happy Christmas to you all
    Sounds like a fun project!

    Most of our customers are okay running a 46/20 ratio on standard 29ers, but most of our 29+ customers have preferred the lower 42/20 setup.

    We built both up of the bikes below with a 46/20 ratio at first, but the customers eventually decided to switch to 42/20.

    The Monkey Lab: Twenty2 Cycles Belt Drive Rohloff 29+
    Rolhoff Belt drive on a 29er+ help please-twentytwo29-_wholebike_main.jpg

    The Monkey Lab: Surly Krampus with a Rohloff and belt drive
    Rolhoff Belt drive on a 29er+ help please-black-krampus_wholebike_main.jpg

    Let us know if you have any other questions.
    www.CycleMonkey.com
    Rohloff & Schlumpf gearing. Custom wheels. Suspension service.

  12. #12
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    Quote Originally Posted by CycleMonkey View Post
    Most of our customers are okay running a 46/20 ratio on standard 29ers, but most of our 29+ customers have preferred the lower 42/20 setup.

    We built both up of the bikes below with a 46/20 ratio at first, but the customers eventually decided to switch to 42/20.

    Let us know if you have any other questions.
    I think for the UK the 42/20 might be too spinny, where about's are your customers with this gear ratio? Hills or Mountains?

    I'm planning on 46/19 which will be a touch harder but give me a bigger top end.

  13. #13
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    Quote Originally Posted by Johnclimber View Post
    I think for the UK the 42/20 might be too spinny, where about's are your customers with this gear ratio? Hills or Mountains?

    I'm planning on 46/19 which will be a touch harder but give me a bigger top end.
    Those 42/20 setups have been used for a variety of terrain, including customers here in the SF Bay Area and in the Canadian Rockies.

    Keep in mind the 29+ tire makes for 30.5 diameter wheels.

    46/19 should be okay if you expect to ride a lot of flatter terrain or if you are a stronger rider.
    www.CycleMonkey.com
    Rohloff & Schlumpf gearing. Custom wheels. Suspension service.

  14. #14
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    Thanks for your help CycleMonkey

    I'm going for a 42/20 set up, with a 2nd belt and a 46 front to run 46/20 on flatter local rides.

    I'll post up pictures and reviews once it's here in April

  15. #15
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    Quote Originally Posted by Johnclimber View Post
    Thanks for your help CycleMonkey

    I'm going for a 42/20 set up, with a 2nd belt and a 46 front to run 46/20 on flatter local rides.

    I'll post up pictures and reviews once it's here in April
    Sounds good. Definitely post pictures here; we'd love to see it!
    www.CycleMonkey.com
    Rohloff & Schlumpf gearing. Custom wheels. Suspension service.

  16. #16
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  17. #17
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    I'm running 42/20 on my belt drive Rohloff 29+.

  18. #18
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    Quote Originally Posted by Schmucker View Post
    I'm running 42/20 on my belt drive Rohloff 29+.
    Do you ride it in the hill's, are the hills big/steep/rough etc, etc?

    How would it compare to a 29er 3 x 9 gearing on the lowest gears when going up hill please?

  19. #19
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    @Johnclimber: I also wanted a 29er+ with Rohloff + belt drive. I know Rohloff, but I don't know jack about belt drive. So I'm trusting Cycle Monkey to do my new build—completely. Neil and Co. are setting up a Surly ECR for me now, and I was willing to sell the current Precious (my Fatback) to fund this new monster All-Do bicycle.

    Whatever that's worth.

  20. #20
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    Quote Originally Posted by mangoman View Post
    @Johnclimber: I also wanted a 29er+ with Rohloff + belt drive. I know Rohloff, but I don't know jack about belt drive. So I'm trusting Cycle Monkey to do my new build—completely. Neil and Co. are setting up a Surly ECR for me now, and I was willing to sell the current Precious (my Fatback) to fund this new monster All-Do bicycle.

    Whatever that's worth.
    Can't wait to se the ECR, sounds like exactly what I'd want for a next rig.

  21. #21
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    Quote Originally Posted by rkt88edmo View Post
    Can't wait to se the ECR, sounds like exactly what I'd want for a next rig.
    You can't wait? Dude...

    Neil (from Cyclemonkey) has no idea that I've been sleeping in his closet every night, holding my parts list and my little Cyclemonkey doll, softly sobbing myself to sleep...









    (Wow, that was really creeptastic.)

  22. #22
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    Quote Originally Posted by mangoman View Post
    You can't wait? Dude...

    Neil (from Cyclemonkey) has no idea that I've been sleeping in his closet every night, holding my parts list and my little Cyclemonkey doll, softly sobbing myself to sleep...









    (Wow, that was really creeptastic.)

    I know now. I'm checking my closet from now on before I go to bed.

    -Neil
    www.CycleMonkey.com
    Rohloff & Schlumpf gearing. Custom wheels. Suspension service.

  23. #23
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    Quote Originally Posted by CycleMonkey View Post
    I know now. I'm checking my closet from now on before I go to bed.

    -Neil

    Busted.

  24. #24
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    Quote Originally Posted by rkt88edmo View Post
    Can't wait to se the ECR, sounds like exactly what I'd want for a next rig.
    After riding the Krampus I really wanted the ECR but the lack of mud clearance over here in the UK was it's problem, plus it's heavier than what I've ordered.

    I've gone for the new Ti Angus 29er+ from Travers Bikes, it's so new it's not even on the website as yet, but designed for belt drive/SS.
    Travers Bikes.com - Home

    ETA late March/April

  25. #25
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    The Rohloff's turned up with the Halo front hub and matching rim strips.

    The cog will go when the CDX bits arrive from Gates.



    4 weeks to wait

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