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  1. #1
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    Zinn Big Sur 29er

    Hey all. I've posted about this possibility before, but I never came back and updated ya'll. So here goes

    I ended up ordering the Big Sur 29" from Zinn. I spoke with Lennard at length about my goals, needs, wants, size etc etc etc. The Big Sur made good sense. I put my deposit down and a couple weeks later, I gave the go ahead on this:



    Its designed for a Rohloff Speedhub. The build will include a Fox 32 29er fork, custom 215mm crank, Avid Code 203mm discs front and rear, Salsa Gordo wheels wrapped in Panaracer Rampage rubber, and held together with DT Swiss competition hardware. Other odds and ends include Crank Bro's 5050XX Pedals, Ergon GC2 bar ends, a Thomson stem, Cane Creek headset and a Brooks B17 saddle carryover from my old bike. All in all this should be one hell of a rig when its done.

    Speaking of which, the only part of this process that I can't say I'm enjoying is the waiting. Unfortunately, I've been given three different ship dates now over the last three weeks with the latest saying the bike should be done tomorrow. I'm hoping so. Communication with the guys at Zinn has been hard too lately; apparently they're very busy (which is great to hear, but kinda sucks when you ask a question and it takes a couple days to hear back).

    All in all, so far I'm still really stoked about this. Hopefully these minor shipping issues are over with soon, and I'll be able to throw up some pics of this bad boy!

  2. #2
    1*14*29*2.1 & 1*1*29*2.4
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    I'll look forward to seeing your bike ....I love the Rohloff, and I think you will too. that drawing isn't to scale right? You going sliders or EBB?

  3. #3
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    Thanks finch! Not sure if that drawing is to scale (I doubt it too), but obviously the stated angles and measurements are accurate. I'm kindasortareally tall .

    And we'll be using (Rohloff) sliders for chain tensioning.

    Can't wait!

  4. #4
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    Quote Originally Posted by finch2
    I'll look forward to seeing your bike ....I love the Rohloff, and I think you will too. that drawing isn't to scale right? You going sliders or EBB?
    did some ruler-to-the-monitor measuring and it does appear to be to scale. 28.2" ETT sized frames tend to make 29" wheels look just a teeny bit smaller

  5. #5
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    Quote Originally Posted by boomn
    did some ruler-to-the-monitor measuring and it does appear to be to scale. 28.2" ETT sized frames tend to make 29" wheels look just a teeny bit smaller
    Hah true that. We went back and forth regarding the ETT for a while. In the end, my "bomb proof" requirement decided it for us; even at 28.2" its already reaaallly long. To go longer (as demanded by my size) would stress the steel a bit too much in the long run for comfort (even though is extra thick walled stuff). So instead we shortened it as much as we could, and ran the stem length out to 5.1" to make up the needed difference.

  6. #6
    1*14*29*2.1 & 1*1*29*2.4
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    oh that explains it...you have a 7 1/2" head tube! You must be huge You also have some hefty BB height. I use rohoff drops on sliders too, they are great. The only thing I would mention is if you run the cables on the DT, watch where they cross over the fork dials just to make sure they clear.

  7. #7
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    Yep, that frame's built for one seriously tall hombre! Those 215mm cranks will be something special as well! I imagine that Rohloff will be perfect for a build like this. Out of curiosity, what size chainring & sprocket are you planning to use? The reason I ask is because with the OP's build and those 215mm cranks, there'll be a shed-load of torque at the cranks when climbing.
    Brisbane, AU

  8. #8
    1*14*29*2.1 & 1*1*29*2.4
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    that's a good point Hootsmon....funny because proportion wise that bike looks exaclty like a 26er! 29" wheels are too small for you he he

  9. #9
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    That is going to be one impressive bike! I bet you could make a 36er look proportional.

  10. #10
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    Hah thanks guys... I think :P

    Yeah I'm 6'9" 330lbs. I've ridden "off the rack" bikes for years, albeit not very well. Seems like I was going thru a frame every 6 months there for a while, not to mention the sheered gears, snapped chains, etc etc etc...

    That's why this bike is spec'd to be "bomb proof". I'm ready to step up and get something that will last. And hopefully be safe out there. And get me home.

    As for the gearing, I plan to start with a 32t chainring up front with the Rohloff provided standard 16t sprocket in the back. What do ya think? Good place to start?

    Edit: Ya know, now that you've got me looking into this (been so focused on the build that I forgot to really check into the gearing. Doh!), if I'm reading this chart correctly, a 32t chainring and 16t sprocket isn't recommended with the Rohloff. Would someone doublecheck me and make sure I'm reading this right please?

    http://www.rohloff.de/fileadmin/rohl...tabelle.en.pdf

    Edit again: Yep, I just got confirmation that a 32t is no good. We'll probably start with a 40t instead.

    Edit a third time: a 40t won't clear the stays. So we're going back to the 32t chainring, but also replacing the 16t sprocket with a 13t one. And that combo puts us right back in range.
    Last edited by JasonWilliam; 08-06-2010 at 03:13 PM.

  11. #11
    1*14*29*2.1 & 1*1*29*2.4
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    Hmm, I had a similar dilema as I needed lower than standard gearing for our steep pinches. Basicly, the minimum ring for a 29er wheel is 38t, with the 16t sprocket (from memory don't quote me). I'd try really hard to keep the 16 if I were you, as it should last longer, and is reversible. the 13t is also made for a specific setup and the chainline is different.

    You may be OK, as don't forget that the chainline for the rohloff is 54mm, which should be the outer ring. Now, your problems are your weight and crank length. Rohloff state I think over 100kg you need a bigger ring...possibly why you mentioned the 40? Anyway, oyu have compounded it with your long cranks, which means you need a bigger ring again. You'll need to do some calculations, but probably wise to contact rohloff to ask them their recommendations. I'd guess you need to go to a 44, but then you need to work out if your gearing is low enough for you.

  12. #12
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    To the OP: Finch is right; contacting Rohloff would be the wise thing to do.

    Also, how steep are the climbs on your preferred trails? I mean Finch2 is a hill-climbing machine (imo), with steep hills right by his backyard. :-) So on that basis I'll go out on a limb and say 16T sprocket and a chainring somewhere in 38-42T range sounds about right for OP.
    Brisbane, AU

  13. #13
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    Thanks again guys.

    Finch, I think you're right on all accounts. But, it turns out a the biggest I can fit up front is probably going to be a 35 or 36t. A 32 is a comfortable fit. The geometry dictated that reality, from what I understand.

    So a 13 in the rear is pretty much my only option. I think this is a case of it is what it is, at least at this point.

    Unless I'm misunderstanding? I'm certainly no expert in any of this stuff. I put a lot of faith in Zinn to do it right, focusing on strength and sizing. After I brought this up with him, Lennard (Zinn) told me he runs the same 32 and 13 setup with his Rohloff and that he loves it.

    Hopefully I'll be alright?

  14. #14
    1*14*29*2.1 & 1*1*29*2.4
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    well, unless Lennard is also running 215mm cranks and weighs over 100kg you may have issues. Don't get me wrong, I am running a 36t chainring which voids my warrantee by 2 teeth, but it is a small risk I am gambling. The end result is a bike I can ride where I live even when I am not in decent shape. It's worth checking with rohloff just to get a figure, and then see what you feel is comfortable to risk. Based on that you may have to ask lennard to do some modifications to the stay area, or maybe offer a garrantee you won't break the hub. The hub is about 2100 AUD here, before it is laced up so I try to be safe with it.

    Thanks Hootsmon...he he. I am OK at some short steep climbs but I'm not fast that is for sure. Possibly if Jason is very strong he may be able to go higher than the 36t...I nearly went for the 13t sprocket too Jason, and maybe lennard is basing his minimum chain ring on the different chainline of the 13t. I can't remember what he chainline is for it though. The standard sprocket is 54mm.

    Oh, and the larger chainring size should be offset by the extra torque produced by your weight and crank length, so hopefully you'll still be fine with the bigger ring. The idea is to try to match the overall input torque to rohloffs maximum.
    Last edited by finch2; 08-08-2010 at 02:49 AM.

  15. #15
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    Finch when you say it might void the warranty, are you referencing this chart? http://www.rohloff.de/fileadmin/rohl...tabelle.en.pdf Or some other bit of info?

    Just trying to educate myself so that I can speak somewhat intelligently when I call and talk with them/Lennard.

  16. #16
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    Cool build. OP - I'd recommend running the largest chainring that will clear your chainstays. Seems like a possible oversight, IMO, if Zinn wasn't all over this issue.

    I'd love to run a Rohloff but have avoided it because of the chainring ring size required and the resulting loss of clearance on my bikes. Surprised a 40t won't clear your stays. Is there anything unusual about the CS design or is it a chainline issue?

    The 13.5" BB height designed for the 215mm cranks should help offset the clearance concerns I've had. Strikes me that running a really tiny rear cog under the torque imparted by a large guy and those long cranks may really stress the chain due to the lack of wrap.

    Smarter, Rohloff ninjas please weigh in. Look forward to seeing the final build.
    Professional Amateur. Disagree? Submit your grievances here.

  17. #17
    1*14*29*2.1 & 1*1*29*2.4
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    Yes I think that is it jason. Where it says not permitted is the limit of the torque. I didn't see a 29" specific listing and I can't rmember where I got the info from, but probably from talking to rohloff. Lennard will have the manual, or you can download it I guess. Those listings should be based on a specific crank length. Weight is also mentioned in the manual along with tandems for special mention. Both of those things are the things you'll need to consider, but hopefully you'll be OK with a large ring as mentioned before as you'll generate more torque to use it. Yes, I agree with soupboy that (esp at your weight and crank, and chain stay length) it would be best to go bigger than 13 onthe sprocket. 16 is an easy standard but I'd even consider bigger if possible.

  18. #18
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    Again, you have my thanks finch.

    I sent a link to this thread to Lennard. Hopefully he'll follow up with me regarding this info. No question in my mind he's got it handled. I just don't know enough to comment either way. Hoping he'll educate me a bit.

  19. #19
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    glad to be of some help there I hope Jason....I am sure it'll get sorted out and I'll look forward to seeing the finished bike!

  20. #20
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    wow awesome build! Once you adapt to using the Rohloff your going to love it. Definitely go bigger than 13 in the rear. I would say play around with the Sheldon Brown gear calculator's to find something similarly geared to what you like now.

    If you poke around on the IGH forum you'll see many are running out of spec setups with no issues. The Nor Cal Rep runs a 34*16 on his 29er. If you do happen to have Herculean legs the only things that would fail is the nylon pins or axle plate so it would not be a crazy expensive repair.

  21. #21
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    That's good to know RipRoar. Thanks for the info. (Yeah I do have some pretty powerful legs; the result of being a starting pitcher for 15 years (no never made pro; was drafted and pitched thru college till my arm gave up)

  22. #22
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    Welp, here it is (seatpost and seat aren't mine; just on there for the test ride)





    Do those 29ers look tiny or what??

    On its way to me now. I should have it Monday or Tuesday of next week.

    For now, the 32t x 13t combo is the way she's gonna roll. You can see by the pics that there's zero room for a larger chain ring. If it turns out I need something else, we'll handle it then.

    Thanks for all the advise guys!

  23. #23
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    Nice! And yes the wheels look small.

  24. #24
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    Looks cool. The only major drawback of the 13t is it will wear faster and Im pretty sure you cannot flip it (not a major deal breaker) . Looking forward to a ride report. How long is the stem? it looks monsterish...

  25. #25
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    Your next bike may need to be a 36er!

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