Results 1 to 24 of 24
  1. #1
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901

    Project Carbine SL 27.5

    Last season, I raced XC on a Carbine SL with a 120mm fork. This year, I want to try 27.5, but I want to stay with my Carbine SL. So I started the process of converting it.

    A few important features that make this possible:

    The Carbine SL and the Carbine are "identical" when it comes to shape. The Carbine SL has shorter travel, by using a 200x50 rear shock, the Carbine uses a 200x57. Same lenght shock on both, but on the Carbine SL, it is not allowed to compress all the way in. This allows a larger rear wheel on the Carbine SL with no risk that it hits the seat tube.

    I can play with the BB height by either using off center bushings for the shock (already using those now to shorten the shock by 3mm, which equals around 9mm at the wheel) or putting on a 200x57 shock, but using the air can from a 190x50 shock. The result is a 193x50 shock, which will lower the rear end around 20mm, which pretty much makes up the difference between a 26" and 27.5" wheel. A tiny bit lower, but I'll be lifting the front end about the same, so the BB height will be right where I want it. I'll get about 1 degree slacker head tube angle, which is fine.

    The Carbine SL fits a Rubber Queen 2.4 tire on a Flow rim. That tire measures 2.6", or 66mm, it is HUUUGE! It ends up bigger than many 27.5" tires.

    Knowing this, I put a Rocket Ron 2.25" on a Crest 27.5" wheel and inserted it into the frame. The tire is a pretty large volume for such a lightweight race tire. It ended up being a bit too big for the frame. So, no go.

    I also happen to know a guy who makes a living repairing damaged carbon fiber frames, and he also designs and makes some wicked saddles. He can repair pretty much any damage.

    Knowing this, I went bananas with a file and a Dremel. The result is below. Not pretty, but with plenty room for a good size 27.5" tire.





    The repair guy has already received the rear triangle, and he says he can make even more room, before fixing it. I'll post more pictures as the project progresses.

  2. #2
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901

    Frame repaired!

    Ok, the repair guy is fast! I got some photos back from him today!









    I've written som more about the project here:

    Google Translate

  3. #3
    bike addict
    Reputation:
    Join Date
    Jan 2004
    Posts
    197
    Hope ur disability is paid up. A repair,no matter how good it looks results in the same strength of the original piece. Without doing FEA, it looks like that section is under torsional load.

    In summary, what you did was stupid. But someone had to claim the darwin award.

    Just because you can, doesnt mean you should.

  4. #4
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    I'm not worried about the repair. The guy doing the repair has long experience doing carbon repairs, and he has never had a single repair fail. He offers 5 years warranty on his work. See some examples of his repairs here:

    Reparasjon av karbonrammer. - Jaeger-Liteseat

    Besides, I live in Norway, we all have full health coverage.

  5. #5
    Dude, got any schwag?
    Reputation: TheSchwagman's Avatar
    Join Date
    Nov 2005
    Posts
    797
    I'm thinking you should have had carbon guy relocate the drops for axle position. Good luck mein Freund.
    Billy

    Speed is sweet, it's like an avenue to
    ... Shredtopia!

  6. #6
    mtbr member
    Reputation: gmats's Avatar
    Join Date
    Apr 2005
    Posts
    2,285
    Awesome! Love this kind of tinkering. I don't have the frame nor the kind of $$ right now to do this kind of experimenting but have always been a fan of engineering and the will to put in to action when wondering what would this or that do. Good luck and keep the updates coming.

  7. #7
    mtbr member
    Reputation: trojans1993's Avatar
    Join Date
    May 2011
    Posts
    485
    Wouldn't the 275 dropouts for the Carbine have been a cleaner, cheaper, safer route to go?

    Hell, my hats off to anyone willing to take a Dremel to $2.5K carbon frame in the name of experimentation I guess.

    Hope it works out for you, I just converted my T2 to 275 last night and it feels amazing.

  8. #8
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    Quote Originally Posted by trojans1993 View Post
    Wouldn't the 275 dropouts for the Carbine have been a cleaner, cheaper, safer route to go?
    Indeed, and that was always my Plan B. But this being a race bike, I wanted to explore ways to keep the weight down. The Carbine 275 rear end, with 142x12 and 160mm rear disc would add at least 300g. If the Dremel-hack doesn't turn out like I hoped, I'll bolt on a Carbine rear end and learn to live with the weight gain.

  9. #9
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    Black matte SID 120 27.5 arrived today. Cut to 19cm it weighs 1504g witout the axle. My old SID 120 WC weighed 1327g at the same length. A bit of a pentalty there. But I must say, the matte black finish goes really well with the matte black carbon on the Carbine SL.

    It's about 2cm taller, and the 27.5" wheel will add another 1.5cm or so. So I basically get the geometry of a 26" Carbine SL outfittet with a 150mm fork, if I manage to lower the rear end just enough to compensate for the larger rear wheel. I think that will be perfect, I have even less need for quick geometry with the bigger wheels, they will roll over some of the things I had to steer around before.

    I can probably ditch the setbak seatpost for an inline one, and I might have to increase stem lenght by 10mm.

  10. #10
    mtbr member
    Reputation: kaymonster's Avatar
    Join Date
    Apr 2011
    Posts
    83

    Project Carbine SL 27.5

    Sub'd

  11. #11
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901

    It's a go!

    Ok, got the bike put together, and here's the spec:

    Rocket Ron 2.25 mounted to Light Bicycle Wide rims. 23mm inner width.
    193x50 rear shock. Frame set to 135mm travel. SID 120 27.5" up front.
    Head angle: 69
    Seat angle: 73
    BB height unsagged: 13.25"
    2mm tire clearance at BB
    2mm tire clearance at full compression

    I might shorten the rear shock another mm or two, and accept slight tire rub at full compression. Or even run 120mm travel rear, since that's really enough for the intended use of XC Racing. I'm not worried about slight tire rub, that used to happen on several bikes I owned in the past, with stock setup.

    Right now I've got the bike back to 26" and 200x50 rear shock due to winter riding with studded tires. Will post pictures when I get around to taking them.
    Last edited by Ole; 02-13-2013 at 07:50 AM.

  12. #12
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    Finally some pictures:

    First in 26" for comparison:







  13. #13
    Dude, got any schwag?
    Reputation: TheSchwagman's Avatar
    Join Date
    Nov 2005
    Posts
    797
    Quote Originally Posted by Ole View Post
    Finally some pictures:

    First in 26" for comparison:






    Kick ass! What's it weigh? How 'bout a ride report?
    Billy

    Speed is sweet, it's like an avenue to
    ... Shredtopia!

  14. #14
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    9.5kg (21 lbs) as pictured. With race wheels, lighter pedals and hopefully Kettle carbon/ceramic discs (if I can get them to work) it should be just a hair below 9kg (20 pounds).

    I can't test it properly until the snow has gone, which means another 2 months or so. :-(

  15. #15
    mtbr member
    Reputation: kaymonster's Avatar
    Join Date
    Apr 2011
    Posts
    83

    Project Carbine SL 27.5

    Holy seat post

  16. #16
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    Quote Originally Posted by kaymonster View Post
    Holy seat post
    Strangely enough, it's just the right length!

    The frame is a Large, and I'm 189cm, or 6' 2.5".

  17. #17
    Dude, got any schwag?
    Reputation: TheSchwagman's Avatar
    Join Date
    Nov 2005
    Posts
    797
    How's she ridin'?
    Billy

    Speed is sweet, it's like an avenue to
    ... Shredtopia!

  18. #18
    mtbr member
    Reputation:
    Join Date
    Jan 2008
    Posts
    1
    How about an update?

  19. #19
    mtbr member
    Reputation: vice grips's Avatar
    Join Date
    Dec 2012
    Posts
    782
    Ole, very impressive! That thing must fly, a true rock, you got some balls. Can't wait for a ride report. Props!
    Once you go slack, you never go back!

  20. #20
    mtbr member
    Reputation:
    Join Date
    Nov 2014
    Posts
    2
    Hi Ole

    Not sure if you're still on the forum as this thread is very old now but I too have a carbine SL and wonder if you'd be able to help me with a little info you mention in your original post:

    "The Carbine SL and the Carbine are "identical" when it comes to shape. The Carbine SL has shorter travel, by using a 200x50 rear shock, the Carbine uses a 200x57. Same lenght shock on both, but on the Carbine SL, it is not allowed to compress all the way in"

    I'd like to do the opposite to you, I.e. Use the full carbine shock (I have a spare fox CTD 200x57 from a 2014 SC Bronson) to extract 150mm travel from my SL (this is a full-on experiment people so please don't shoot me down here). My question is, how can I tell that my carbine SL shock only has 50mm stroke as I have compared all dims to my 200x57 shock and they look identical? Is it an internal thing I.e. Is the shaft ( even though it shows nearly 60mm of shaft externally - same as the 200x57 shock ) not allowed to compress all of the way in on the SL shock? Am I to also assume that this restriction is removed on the 200x57 shock, allowing full compression.

    This probably sounds obvious (even stupid) to some, but I'm a little confused as I kind of expected the SL to have a shorter visible shaft and perhaps a longer air-can?

    Your info (and experience here) would be a great help to my little experiment.

    Cheers

  21. #21
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    The shock on the SL can only compress 50mm before it bottoms out. It's the damper head that is 7mm taller than normal, you'll see it if you remove the air can. The shock can easily be converted to 57mm by a service senter. On the outside, the shock is identical to a 57mm. You can let the air out and check how far it compresses.

    I've done the 50mm to 57mm conversion on a friend's SL, and it worked wonderfully. You can also put on a rear triangle from a Carbine 275, if you want to convert it to 27.5".

  22. #22
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    Quote Originally Posted by vice grips View Post
    Ole, very impressive! That thing must fly, a true rock, you got some balls. Can't wait for a ride report. Props!

    A bit late, but the bike as performed wonderfully. I even had a CCDB Inline on it towards the end. Sadly, I sold it, and is now in the process of building up a Spider 29C as a race bike, with BOS suspension front and rear, plus some nice, lightweight exotics.

  23. #23
    mtbr member
    Reputation:
    Join Date
    Nov 2014
    Posts
    2
    Thanks for the reply Ole, that really helps. I happen to have two shocks (a 50mm stroke from the SL and a 57mm stroke from a Santa Cruz Bronson (2014) ) so I have the luxury of trying both and perhaps having the 57 pushed if necessary (I think the 57 has a low velocity compression tune but I can't find a reliable source for decoding the silly codes on the side).

    How did your friend find the ride with the longer stroke? I take it they were running a 150mm fork up front, did this match up ok?

    How's your SL going? A very brave conversion if I may say so, I hope it serves you well, the carbine is certainly proving a great machine for me. My next conversion will be to try to make a 135x10 bolt thru from my Haven Carbon rear hub so I can run the DT-Swiss RWS 10mm axle in the dropouts. I have a lathe so it's going to happen one way or another, just thinking of the simplest, with the least butchering of the original components.

    Thanks again for the info, exactly what I needed to hear.

  24. #24
    Ole
    Ole is offline
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    901
    The SL is sold, but worked very well for the two race seasons I used it.

    If you put a 200x57 on it, it becomes identical with the original Carbine. Perfect with a 150mm fork.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •