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  1. #1
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    29er conversion: spacer AND air volume reducer?

    I have parts on the way for a 29er conversion (140 carbon PBR to 110mm) for my Tallboy.

    I understand the travel limiter is pretty easy to install, but I have not heard much about the air volume reducer.

    As I understand it, since you are limiting the travel you need to "re-tune" the air spring by reducing the air volume so it does not bottom to heavily and the air pressure "ramps up" quicker with the reduced volume.

    Makes perfect sense... anybody have any photos posted or a desription of converting a Lefty into a 29er that show the spacer and volume reducer install? What does it take?

    Thanks all!
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  2. #2
    All Lefty's, all the time Moderator
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    Quote Originally Posted by CactusJackSlade
    I have parts on the way for a 29er conversion (140 carbon PBR to 110mm) for my Tallboy.

    I understand the travel limiter is pretty easy to install, but I have not heard much about the air volume reducer.

    As I understand it, since you are limiting the travel you need to "re-tune" the air spring by reducing the air volume so it does not bottom to heavily and the air pressure "ramps up" quicker with the reduced volume.

    Makes perfect sense... anybody have any photos posted or a desription of converting a Lefty into a 29er that show the spacer and volume reducer install? What does it take?

    Thanks all!
    Unscrew the bottom cap of the fork, your TPC, FFD, SPV plug. With the o rings installed, carefully work the reducer into the hole, taking care not to roll the o ring upon install. An oscillating motion seems to help. Once in place push it up in a bit, install your schraeder plug, and go.
    This is a Pugs not some carbon wannabee pretzel wagon!!

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  3. #3
    mnt bike laws of physics
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    I am waiting for the same Lefty for my Tallboy. It should be awesome. I ran the 130 PBR until the inner bearing races all moved up on me. I am really looking forward to the 140 though. I put a Cane Creek Thudbuster elastomer in the air chamber and it worked perfectly. You will want to get the right sized socket to remove the cap for the air chamber. I believe it is a 22mm. Otherwise you will most likely damage it. The air chamber reducer just fits into the air chamber. I ran (2) 10mm reducers in the top instead of 3 and I haven't had any problem bottoming out. They attach to the damper shaft just above the bottom out bumper. Just check to see if the tire hits the lower clamp before putting in any air after you install the 10mm spacers.

    Keep me posted on how it is going and the quality of the ride. FWIW, I changed the damper fluid to Golden Spectrol 7.5 wt. and it made a huge difference over the 5wt., but I am about 190 pounds.

  4. #4
    Kam
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    like all have said above....

    remove air, push button, top cap and cartridge using proper tools.

    i placed a shaved down cane creek elastomer in the air chamber....1-2 spacers will work fine....then put everything back together. you will have to shave the sides of the elastomers because they are two wide to fit in the chamber.

    you can use 2 or 3 travel spacers...they go onto the rod above the cartridge.

    i ran 2 travel spacers (20mm worth) with a bontrager 29-3 tire (which has a very tall profile) and never rubbed the crown on the fork.

    if you do not use air volume reducers, you will need 30mm of spacers....or you will rub the crown. some say this isn't a big deal, but i think it is.

    i ran a 29er with a pbr ultra but have sinced moved on to a 2011 fox f29 terralogic. the lefty was good, but the 2011 fox stuff is flat out amazing!
    "forget kings...forget hadleys......they all have crap engagement. just run your bike fixed gear." - FoShizzle

  5. #5
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    Quote Originally Posted by Kam
    i ran a 29er with a pbr ultra but have sinced moved on to a 2011 fox f29 terralogic. the lefty was good, but the 2011 fox stuff is flat out amazing!
    Thanks All for the info

    That's what I'm running now, a 120 F29 terralogic... great for no-pedal bob and racing... I want to get a little cushier... and stiffer (less flex).
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  6. #6
    All Lefty's, all the time Moderator
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    Quote Originally Posted by CactusJackSlade
    120 F29 terralogic... great for no-pedal bob and racing... I want to get a little cushier... and stiffer (less flex).
    I've got a 120 2010 F29 FIT on my Milk Money, and this is not a slam cause I want to love the Lefty more, that thing sucks. I ride it, and feel every hit. Small bump performance is on par with a rigid fork. I push on it, and feel it un stick itself, every time, so it's not initial, that goes away with use, and it has more than enough hours to be broken in. Low speed compression is fully soft, thought I'd love the lockout, and adjust the blow off to be a perfect platform, um, no, never use it cause it has natural platform all the time!. It has more stiction that should be legal. It's been back to Fox twice, and still feels like donkey dung. Interestingly, I've felt a few others,they feel the same, however, the Rebas I've squished of late, don't.....

    Why do people like these things so much?

    Saving my pennies for the PBR conversion, I have a 140 carbon Max chassis that would love a new home....

    Sorry, no coffee yet
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  7. #7
    Kam
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    Craig....2010 fox forks were terrible, ditch it and get a 2011!
    "forget kings...forget hadleys......they all have crap engagement. just run your bike fixed gear." - FoShizzle

  8. #8
    All Lefty's, all the time Moderator
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    Quote Originally Posted by Kam
    Craig....2010 fox forks were terrible, ditch it and get a 2011!
    I'm waiting for a few PBR conversions, one for the Milk $. I had a Max on there briefly, early on, and it felt great. I had the Fox coming, and used it in the interim.

    If I got another Fox, it'd be the new Talas, but I don't have the dough right now (PBR's a lot cheaper) and if they suck, it's not worth much to resell. Guess I'll put it on the wifes 29er, she was riding it rigid for a while, then I stuck a POS fork on at her insistence that the beatings cease. This should be a moderate upgrade for her....
    This is a Pugs not some carbon wannabee pretzel wagon!!

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  9. #9
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    To clarify...

    GOT IT....

    My Tallboy is now Leftyfied.... maiden voyage tomorrow....

    Checked clearences carefully I got away with 20mm of spacers and fully bottomed I have about 8mm of clearence.

    Now maybe I'll get a REAL 120mm travel now that I'm on bearings instead of bushings.... and I dropped 3/4+ lb on this conversion too.... I will miss my Terralogic though...
    Last edited by CactusJackSlade; 02-11-2011 at 12:53 AM.
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  10. #10
    All Lefty's, all the time Moderator
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    Quote Originally Posted by CactusJackSlade
    I will miss my Terralogic though...
    Doubt it.
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  11. #11
    mnt bike laws of physics
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    I rode the new lefty on the carbon 29er. That thing is by far the best feeling suspension to date. I am sure the Fox improved but so did Cannondale.

  12. #12
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    does reducing the travel in the lefty physically change how long the fork is? sorry for the dumb question, I recently put a 120mm lefty on my vassago, and haven't installed the spacers yet, and was trying to figure out how drastically going down to 90mm would affect the geometry....

  13. #13
    All Lefty's, all the time Moderator
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    Quote Originally Posted by ryanhugh
    does reducing the travel in the lefty physically change how long the fork is?
    Nope, just stops sooner in it's travel. A to C remains constant.
    This is a Pugs not some carbon wannabee pretzel wagon!!

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  14. #14
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    Lefty -> Fox -> Reba + Lefty

    I had the same experience as Mendon with my '09 F100 RL. I wanted to like that thing, but the stiction was insane even after 20+ hours and seal/oil bath maintenance. If it's setup to get small bump compliance (stiction will still greatly hinder this) on par with the Lefty it bottoms and blows through travel.

    I switched to a Reba Dual Air and stiction was gone once properly tuned. It's a fiddly piece of equipment to tune though, but worth it. It's as comfortable as my Lefty, but not quite as torsionally stiff. I have the QR model. We'll see how durable it is compared to the Lefty.

    In the end my old Speed Bonded DLR2 takes the cake. It's just simpler, stiffer and still weighs less than the Reba. Not that the Reba is a slouch, and I give the Reba the nod when it's sloppy out; it's just easier to maintain in those conditions.

    I swap between the bike with the Reba and a bike with an '08 Lefty Speed DLR2. I like them both, but air damped Fox-up-front will never happen again. Too many reports of full travel being unobtainable and stiction. After experiencing it all for myself I really wonder why Fox has such a following.
    My bicycle gets more dirt than your 4x4.

  15. #15
    All Lefty's, all the time Moderator
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    Quote Originally Posted by MrHappyMedium
    After experiencing it all for myself I really wonder why Fox has such a following.
    They refer to it as "legendary travel" in a lot of their literature.

    Legendary for what?

    Thankfully Cannondale has avoided such claptrappery in their advertising....
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  16. #16
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    How much air volume spacers should I put in my air chamber ? I have a 2006 Lefty Speed 110mm DLR2 and I want to convert it to a 29er 80mm lefty. So Im going to reduce the travel by 30mm by clipping 3 10mm spacers to the top of that "tube" , but How much mm's of air volume spacers should I put in my air chamber ?

  17. #17
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    Quote Originally Posted by Martin12 View Post
    How much air volume spacers should I put in my air chamber ? I have a 2006 Lefty Speed 110mm DLR2 and I want to convert it to a 29er 80mm lefty. So Im going to reduce the travel by 30mm by clipping 3 10mm spacers to the top of that "tube" , but How much mm's of air volume spacers should I put in my air chamber ?


    the way I understand it is; its up to you how many air volume reducing spacers you use. You can tune it to your preference. more AVS's equates to a more progressive stroke toward bottom out. according to craig mendon in a previous post (the way I understood it anyway,) is that you don't have to use any.
    Im going to give this a try this week with my '11 speed PBR. unfortunately its going to be reduced to 70mm
    with my headphones slammin playin, Iron maiden
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  18. #18
    All Lefty's, all the time Moderator
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    Quote Originally Posted by circlepinner View Post
    the way I understand it is; its up to you how many air volume reducing spacers you use. You can tune it to your preference. more AVS's equates to a more progressive stroke toward bottom out.
    Correct.
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  19. #19
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    Hallo,
    I understand that I can adjust the air volume reduction for my likes but is there a standard to start with? how big a volume reducer am I supposed tu run in my Lefty pbr set for 110mm travel in 29er mode?

  20. #20
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    Quote Originally Posted by savo View Post
    Hallo,
    I understand that I can adjust the air volume reduction for my likes but is there a standard to start with? how big a volume reducer am I supposed tu run in my Lefty pbr set for 110mm travel in 29er mode?
    Here's how I went about it:

    if you do the math, you are looking to loose 30mm worth of volume assuming you are using all 3 travel spacers (cannondale recommended).

    The air chamber is 25mm in diameter. I believe the formula for volume of a cylinder is pi x r^2 x h. In this case r is 12.5 and h is 30. Depending on what volume spacers you are using, you simply figure an equivalent volume of spacer remembering to subtract the volume of the hole in the spacer(s). That's a starting point anyway. You can tune from there.

    I used nylon spacers (1x1/2x3/8) I found a Lowes. I cut a slit in each to allow them to compress to fit perfectly into the tube. 4 of them exactly equal the volume gained.

  21. #21
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    Quote Originally Posted by madog99 View Post
    Here's how I went about it:

    if you do the math, you are looking to loose 30mm worth of volume assuming you are using all 3 travel spacers (cannondale recommended).

    The air chamber is 25mm in diameter. I believe the formula for volume of a cylinder is pi x r^2 x h. In this case r is 12.5 and h is 30. Depending on what volume spacers you are using, you simply figure an equivalent volume of spacer remembering to subtract the volume of the hole in the spacer(s). That's a starting point anyway. You can tune from there.

    I used nylon spacers (1x1/2x3/8) I found a Lowes. I cut a slit in each to allow them to compress to fit perfectly into the tube. 4 of them exactly equal the volume gained.
    Ok, thank you.
    My lefty had the 60mm volume reducer (it used to be a 90mm 29er) but I was not so happy because if inflated to have the cottect sag it didn't use all the travel, and if inflated to use almost all the travel it sat too low on sag.
    I now did the math and took the original volume reducer out, replacing it with a cane creek elastomer that fits perfectly and is the exact volume for the 25mm dia x 30mm h needed (actually it's 25mm diameter, 32mm height and have a 6mm diameter hole). Not a big difference in volume compared to the old one, I'll now take some ride to find if it's any better than before.

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