Results 1 to 10 of 10
  1. #1
    PeT
    PeT is offline
    Occasionally engagedů
    Reputation: PeT's Avatar
    Join Date
    Jan 2004
    Posts
    1,409

    Needing to reset Lefty too often

    I have a Lefty carbon of indeterminate age that has been serviced and retrofitted with a new PBR damper and fitted to my 29er using a Project 321 adapter. I'e reset the bearings and got it to what I assume was the right extension (~695 mm) -- I've done it several times over the approximately 250 miles it's been ridden since the PBR has been installed. The insult here is that after a fresh reset, the fork worked well for about 40 miles of a 50 mile race (the Steamboat Stinger), but for the final 1500 foot descent it was completely compressed -- no suspension (attached photo). It happened over the course of a few miles -- not all at once -- but it was quickly noticeable and eventually quite problematic -- no suspension action, harsh clunks from the fork in the chunky sections, low bottom bracket causing pedal strikes.
    Needing to reset Lefty too often-compressedlefty.jpg
    After getting home, I pulled the top cap and the damper unit popped out of the top a good 5 cm or so (photo attached).
    Needing to reset Lefty too often-compressedlefty2.jpg
    I reset the bearings and for the moment it's just fine again. So what's the deal -- I can't even finish a mid-ling long race without the bearings coming out of alignment? It's happened to me in the middle of a ride before, but I was hoping it was just a one off event -- apparently not. Suggestions and advice appreciated!

    One additional tidbit -- my son's Caffeine 29er with a DLR Lefty hardly ever needs a bearing reset and it is easier to reset. My PBR reset process is significantly more strenuous and never ends with a satisfying "thunk" like his does -- mine feels "stickier" as I try to reset the bearings.
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

  2. #2
    Ridin' dirty!
    Reputation: cdalemaniac's Avatar
    Join Date
    Jun 2007
    Posts
    1,896
    Send it in for service is all I can tell you.... it can simply be adjusted by using different needle bearing races, they come in various thicknesses and once properly shimmed will cause no future issues of this kind.
    Mendon did mine sometime last year and all I can say is "Wow!"....can't believe how much of a difference it makes once you have it dialed in by a professional that takes your riding style and how much preload you run your fork with into consideration!!
    "Common sense isn't always that common!"
    Custom Prophet and Custom Delta V

  3. #3
    All Lefty's, all the time Moderator
    Reputation: MendonCycleSmith's Avatar
    Join Date
    Feb 2005
    Posts
    12,683
    Two thoughts, if it happened all at once, that sounds like a bad Solo Air piston. Happens, some just "are". If it's a new one, which it sounds like it is, you should be able to get a new SA piston no charge....

    Or, yeah, you need a higher preload for the weight you are, the way you ride, etc.

    Either way, fixable.....
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  4. #4
    PeT
    PeT is offline
    Occasionally engagedů
    Reputation: PeT's Avatar
    Join Date
    Jan 2004
    Posts
    1,409
    Quote Originally Posted by MendonCycleSmith View Post
    Either way, fixable.....
    One would hope so.

    Anyway, another data point here -- rode 10 miles last night at a medium clip on standard fare for around here -- up and down singletrack with it being a bit rocky. The fork had been reset to 695 mm (again, it's stiffer and harder to reset than the DLR2 I've reset) and after the 10 mile ride the fork measured at 685 mm and reset to 695 mm. So, in 10 miles I had a cm of change in the fork measurement -- I expect that the change is gradual, say 1 cm every 10 miles and it takes me 30 or 40 miles before I've lost enough travel to start noticing the hard bottoming out. And as I experienced at the Steamboat Stinger, fork will be completely compressed after 50 miles and stay that way until a bearing reset is performed. Upon resetting, everything is initially kosher, but progressively migrates out of alignment, on the order of 1 cm every 10 miles or so. I don't notice it so much initially as I don't ride in a way that uses all of my 70 to 80 mm of travel -- a big hit for me will maybe use half of that. So what's involved in the "fix"?
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

  5. #5
    All Lefty's, all the time Moderator
    Reputation: MendonCycleSmith's Avatar
    Join Date
    Feb 2005
    Posts
    12,683
    Quote Originally Posted by PeT View Post
    So what's involved in the "fix"?
    Thicker inner races. Depending on how "loose" it is, replacing two, if really loose, bump all 4 up by a thousandth.
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  6. #6
    mtbr member
    Reputation: devilish_dwarf's Avatar
    Join Date
    Nov 2009
    Posts
    118
    You can always try to choose short races...

  7. #7
    PeT
    PeT is offline
    Occasionally engagedů
    Reputation: PeT's Avatar
    Join Date
    Jan 2004
    Posts
    1,409
    Quote Originally Posted by MendonCycleSmith View Post
    Thicker inner races.
    So, did the races get changed out when the internals went from DLR2 to PBR? If not, why do I have a problem with the fork now that it has the PBR damper but not when it had the DLR2 damper? If the races were changed out upon going from DLR2 to PBR, how does the technician decide what thickness races are used? A bench test? Trial and error?
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

  8. #8
    Not dead yet, just playin
    Reputation: ohpossum's Avatar
    Join Date
    Dec 2003
    Posts
    909
    I'm not sure this would even cause the problems you're describing but...

    When you swapped the DLR damper for the PBR, did you remember to put the "damper washer" on the PBR damper?

    The damper washer is the one on the lower right of the picture.

    www.msmtb.org - Mississippi Mountain Biking

  9. #9
    All Lefty's, all the time Moderator
    Reputation: MendonCycleSmith's Avatar
    Join Date
    Feb 2005
    Posts
    12,683
    There's basically three levels of preload that I find work acceptably. Depending on rider, weight, trails, style etc, one may work well, the next not so much.

    Why it's now an issue is a puzzle. Same telescope build, with two different dampers, shouldn't be any different, but stranger things have happened, and I certainly don't claim to know every last subtlety that can happen across generations, swapping dampers, etc. But out of the box, there should be no reason to believe the PBR swap had anything to do with it.

    Determination is by feel, or weight on the un sprung telescope.

    Basically, barring some sort of internal "issue" bumping up a thousandth on two or four, should bring it all into check.
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  10. #10
    PeT
    PeT is offline
    Occasionally engagedů
    Reputation: PeT's Avatar
    Join Date
    Jan 2004
    Posts
    1,409
    For the sake of providing some information if anyone now or in the future cares, I'd like to report that I believe my problem to be largely solved. Perhaps it should have been obvious to me (but no one suggested it so maybe it isn't so obvious), but applying grease to the races as per the suggestion for regular maintenance has minimized the migration of bearings (now on par with the fork when it had DLR2 internals and my son's DLR2 fork). The fork was smooth before and adding grease didn't improve the action of the fork, but the bearings migrated barely at all over 40 miles of reasonably rough riding, something that would have had me bottoming out the fork with even minimal bumps prior to the greasing. The races were effectively "dry", not at all like I expected. So, if your races migrate more quickly than you expect, check the grease and see if a reapplication of it doesn't fix your problem.
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

Similar Threads

  1. Lefty bearing reset
    By VICpt in forum Cannondale
    Replies: 3
    Last Post: 01-06-2013, 12:09 AM
  2. When to reset Lefty bearings?
    By adambikes in forum Cannondale
    Replies: 13
    Last Post: 11-22-2011, 08:07 AM
  3. Frequent Lefty reset
    By struckman@charter.net in forum Cannondale
    Replies: 2
    Last Post: 09-06-2011, 04:40 AM
  4. Over reset the bearings on my Lefty
    By jhandy in forum Cannondale
    Replies: 7
    Last Post: 08-22-2011, 01:30 PM
  5. Lefty Max XLR bearing reset HELP!!!
    By packfill in forum Cannondale
    Replies: 8
    Last Post: 05-26-2011, 08:52 AM

Posting Permissions

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