[suravida]

Hi there,

I am the proud and happy owner of a 130mm carbon Lefty PBR, which makes me smile everytime i ride my Rize.
However, since a couple of weeks it needs a bearing reset every 50km's or so.
Now I know that the right thing to do is to ship it to Cannondale or 88+ and have it serviced, but unfortunately money is a bit tight, so I was wondering if there is something I can do myself (apart from resetting before every ride)
I do all the maintenance on my bike myself and also have some experience with servicing a Talas, Bomber and Reba.
So apart from the money my goal is to be able to do everything on my bike, however, the Lefty seems quite complicated and I have no idea what could be the cause of the the bearing reset issue.
So my question is: Does anyone have an idea what is the problem with the fork (are the bearings or races broken?) and how I can fix it without spending 250 euros on it?

By the way, I am from Rotterdam, the Netherlands, so a trip to Mendon is a bit to far

Thanks in advance!

 

[cdalemaniac]

Hi there,

I am the proud and happy owner of a 130mm carbon Lefty PBR, which makes me smile everytime i ride my Rize.
However, since a couple of weeks it needs a bearing reset every 50km's or so.
Now I know that the right thing to do is to ship it to Cannondale or 88+ and have it serviced, but unfortunately money is a bit tight, so I was wondering if there is something I can do myself (apart from resetting before every ride)
I do all the maintenance on my bike myself and also have some experience with servicing a Talas, Bomber and Reba.
So apart from the money my goal is to be able to do everything on my bike, however, the Lefty seems quite complicated and I have no idea what could be the cause of the the bearing reset issue.
So my question is: Does anyone have an idea what is the problem with the fork (are the bearings or races broken?) and how I can fix it without spending 250 euros on it?

By the way, I am from Rotterdam, the Netherlands, so a trip to Mendon is a bit to far

Thanks in advance!

The only option besides having the bearing preload set properly is to use a thicker grease on the races.....and to adjust your fork with less sag....
The needle bearings are sandwiched between the steel races.....the ones on the inside (4 ) are all different thicknesses and let's say, set in a unique sequence....
You really need to know what you're doing or you can make things even worse....
It's not like a traditional fork were when a bushing is worn one you just press it out and replace it with a new one in a few minutes.....

 

[yogiprophet]

Mine is on its way back from its 4th trip to Cannondale for the same reason. This last time though was because the inner races were migrating. Awesome suspension when it is working though.
I'm not sure if there is something wrong with the structure on mine for it to go wrong so many times. Mine is a 2009 FWIW.
I am having them put the OPI lower in this time so at least the inner races can't migrate now becasue they will be attached to the lower unlike with the old 2 piece lower.

 

[Sideknob]

Every 50km??

That is crazy!

 

[MendonCycleSmith]

Like cdalemaniac said, bearing preload is the best answer. Thicker grease will likely make the fork do odd things that you won't smile about.

For my $? If times are tight, just reset it and deal. I mean, what's it take? 3 minutes?

The higher the preload, the stiffer the action gets, so if it makes you smile as it sits, run it like you stole it :thumbsup:

 

[suravida]

How do I change the bearing preload? Putting more pressure in the fork?
And whats could be the reason for this issue? Worn bearings?

And you are right, a bearing reset is a very quick and simple procedure, so I'll keep on doing that until my moneytree blossoms again ;-)
I would like to fix it before june, when I plan to make some seriously long trips in the Alps, I dont fancy taking a BB tool with me then....

 

[MendonCycleSmith]

How do I change the bearing preload? Putting more pressure in the fork?
And whats could be the reason for this issue? Worn bearings?.

When it's torn down for a rebuild, you can change it.

It's like setting the gap on spark plugs, it's not something that "happens" it's something that is, and can be changed till it fit's the parameters set by the manufacturer.

Also, it's not an "issue" really, it's part of any needle bearing device, be it a MTB fork, or a large industrial machine. Preload changes are simply a function of fine tuning

It's the inner races job to create it. They are available in thickness differences of 1/1000th. Most forks can be built up with perhaps even 4 different thicknesses resulting in a super stiff acting fork, to a super smooth one.

The trick is to get it in the range that feels good, without allowing migration to happen too quickly.

The problem is, certain riders and certain conditions, or combos of the two, make the benchmark that they are built to, not be quite acceptable to that individuals needs. Other factors include too much or too little grease, races and bearings getting more polished with use, a bit of extra plastic flashing that was on the bearing cages when new, going away etc etc etc.

In your case, I'm guessing that by simply bumping two of the races up a thousandth, the problem will be much reduced.

 

[suravida]

Thanks! Thats a clear answer. I think I'll just bring it to 88+ then, hear they set up your fork perfectly.
By the way, somewehere on this forum I read that there is a kit for the first series PBR that can reduce diving, I just cant find it anymore... Do you know anything about it, and do you think it's necessary?

 

[cdalemaniac]

Thanks! Thats a clear answer. I think I'll just bring it to 88+ then, hear they set up your fork perfectly.
By the way, somewehere on this forum I read that there is a kit for the first series PBR that can reduce diving, I just cant find it anymore... Do you know anything about it, and do you think it's necessary?

Dude...88+ charges way too much...it would be cheaper to send it to Mendon even if you're in Europe....
A friend of mine paid almost 300.- euros and that was only a regular tune up with seal replacement on a Lefty Max spv.....
That's like $360.- .... ridiculous!

 

[[email protected]]

My lefty 29er has the same problem. The needle bearings wear at the top of the stroke of the fork. I solved this problem by assembling my top-cap and c-clips in a different configuration. The top of the dampener has a 1 inch diameter disk with a groove in it. This groove is where you put the two half-moon shaped c-clips. If you set the c-clips on top of this disk, it extends the fork out by about 5 millimeters. You have to assemble the rest of the top-cap and lockout lever differently to make it work. Since I did this, I have had no stiction or bearing migration at all.

 

[MendonCycleSmith]

My lefty 29er has the same problem. The needle bearings wear at the top of the stroke of the fork. I solved this problem by assembling my top-cap and c-clips in a different configuration. The top of the dampener has a 1 inch diameter disk with a groove in it. This groove is where you put the two half-moon shaped c-clips. If you set the c-clips on top of this disk, it extends the fork out by about 5 millimeters. You have to assemble the rest of the top-cap and lockout lever differently to make it work. Since I did this, I have had no stiction or bearing migration at all.

No disrespect, but what you've done has no impact on anything related to nearing migration. It's akin to saying that longer travel forks don't have migration. You simply lengthened the fork a smidge, that's it.

Also, the bearings don't wear any more at one portion than another. The top end of the races will get a bit more polished due to more action happening there, than deeper in the stroke.

I can't see as what you did, causing any danger, but it isn't taking care of anything, mechanically speaking, and while you may have a different experience with your migration for some inexplicable reason, all needle bearings migrate, period.

Not being a jerk, please understand. What your saying makes as much sense as saying your car is faster with the windows down, the two factors aren't even related.....

 

[[email protected]]

The bearings do wear most at the top of the stroke. The wear on the needle bearings causes stiction (maybe it isn't stiction, but it gets hung up) where the bearings are worn. Since most of the telescoping action is done in the first inch of the stroke, this is worn more.

You can put 150psi in your fork and it will have enough pressure to push past this "stiction". But then you might as well have a rigid fork.

When you extend the fork out by 5 to 8 mm, the top of the stroke is rolling on "new" needles. Your fork will go way longer without having to reset the bearings, and you can run the fork at 100psi.

 

[MendonCycleSmith]

The bearings do wear most at the top of the stroke. The wear on the needle bearings causes stiction (maybe it isn't stiction, but it gets hung up) where the bearings are worn. Since most of the telescoping action is done in the first inch of the stroke, this is worn more.

You can put 150psi in your fork and it will have enough pressure to push past this "stiction". But then you might as well have a rigid fork.

When you extend the fork out by 5 to 8 mm, the top of the stroke is rolling on "new" needles. Your fork will go way longer without having to reset the bearings, and you can run the fork at 100psi.

Um, okay. How many of these do you work on? Just curious, as no one I've ever spoken to @ Cannonale, has ever mentioned this, and I'm fairly certain that the other folks with experience around here haven't either.

 

[cdalemaniac]

Um, okay. How many of these do you work on? Just curious, as no one I've ever spoken to @ Cannonale, has ever mentioned this, and I'm fairly certain that the other folks with experience around here haven't either.

I guess what he wants to say is that if you extend it a bit the needle bearings touch unworn race surface, resulting in a bit more preload overall....
Makes sense, but is only a band-aid fix like the other options that were mentioned and to be honest I don't believe that a few mm of "new" race surface will make a huge difference overall....

 

[[email protected]]

I don't work on any lefty other than my own and you can take that however you want Seriously though. I have been taking notes on this fork daily for a year now. It is a 2008 carbon 29er.

In November 2009 the fork had seals changed and bearings/races replaced by Cannondale as routine for a fork ridden hard for a year and a half. Immediately, the fork felt short. This is where I first heard about bearing migration and the procedure on how to "reset" the fork by removing the top cap and extending the fork out all the way. It takes some banging around for this. By June 2010, I sent it back to Cannondale because it wouldn't make it a ride without the fork extending all the way out (about a half inch too short). They rebuilt it and nearly $300 later, the fork worked perfect... for about a month.

This is when I had the idea that a machine shop could make those half-moon c-clips, only so it holds the top of the dampener in place, but offsets the dampener about a centimeter down into the fork leg. This would increase the axle to crown, but would use a unused part of the bearing race. I mean, the fork can telescope out two more inches when you reset the bearings.

Like a puzzle, I played around with the top of the dampener and the c-clips until I came up with "my" solution. The only problem was how to prevent the fork from telescoping out the remaining 2 inches. This could cause disaster.

I used the top-most 10mm hex nut (the one that holds the lockout lever on to the top of the dampener) to keep the fork from telescoping out.

The only down side to this is that the lockout lever really shouldn't be used. In other words, don't use the lockout lever.

Now, I think that is a smart thing to do.

I have been riding it this way for 6 months without a hitch. I finally did have to reset the bearings, once.

I see how this solution could be particular to my fork. Machining elongated c-clips could also be a cheap way to safely lengthen your race-to-crown.

 

[onbelaydave]

In November 2009 the fork had seals changed and bearings/races replaced by Cannondale as routine for a fork ridden hard for a year and a half. Immediately, the fork felt short. This is where I first heard about bearing migration and the procedure on how to "reset" the fork by removing the top cap and extending the fork out all the way. It takes some banging around for this. .

The owners manual that came with my 2006 Lefty Max detailed the reset procedure.

I've "reset" the bearings once, not because I needed to, but just to find out how it was done.

I've maintained an ave. ~ 120 mi +/ week/ 8 months out of the year, with mileage the rest of season more weather dependent.

I don't know if ~ 25,000 mi in 5 yrs constitutes "riding hard", but it's only had it's bearings reset once and is still working as good as new.

 

[cdalemaniac]

I don't work on any lefty other than my own and you can take that however you want Seriously though. I have been taking notes on this fork daily for a year now. It is a 2008 carbon 29er.

In November 2009 the fork had seals changed and bearings/races replaced by Cannondale as routine for a fork ridden hard for a year and a half. Immediately, the fork felt short. This is where I first heard about bearing migration and the procedure on how to "reset" the fork by removing the top cap and extending the fork out all the way. It takes some banging around for this. By June 2010, I sent it back to Cannondale because it wouldn't make it a ride without the fork extending all the way out (about a half inch too short). They rebuilt it and nearly $300 later, the fork worked perfect... for about a month.

This is when I had the idea that a machine shop could make those half-moon c-clips, only so it holds the top of the dampener in place, but offsets the dampener about a centimeter down into the fork leg. This would increase the axle to crown, but would use a unused part of the bearing race. I mean, the fork can telescope out two more inches when you reset the bearings.

Like a puzzle, I played around with the top of the dampener and the c-clips until I came up with "my" solution. The only problem was how to prevent the fork from telescoping out the remaining 2 inches. This could cause disaster.

I used the top-most 10mm hex nut (the one that holds the lockout lever on to the top of the dampener) to keep the fork from telescoping out.

The only down side to this is that the lockout lever really shouldn't be used. In other words, don't use the lockout lever.

Now, I think that is a smart thing to do.

I have been riding it this way for 6 months without a hitch. I finally did have to reset the bearings, once.

I see how this solution could be particular to my fork. Machining elongated c-clips could also be a cheap way to safely lengthen your race-to-crown.

That is really "Mac Gyverish" of you
Can you post pics when you have the time?

 

[[email protected]]

Here are some pictures of what I am talking about.

 

[[email protected]]

The middle and bottom pictures show the clips in offset position and normal position, respectively. This is what I did to reduce the frequency of resetting my bearings. I'm tired of spending money on this fork and waiting a month for the fork to get back to me, just to have the thing start acting up again a month later.

If you don't mind not having a lockout lever and rebound knob, you can offset this more using other types of spacers.

 

[MendonCycleSmith]

I guess what he wants to say is that if you extend it a bit the needle bearings touch unworn race surface, resulting in a bit more preload overall....
Makes sense, but is only a band-aid fix like the other options that were mentioned and to be honest I don't believe that a few mm of "new" race surface will make a huge difference overall....

Even if it were a "fix" it would only work till the wear he suggests moved upward. And since they don't wear in any appreciable sense, it's a moot point. Also, moving it up a few mm's would only create an impact on perhaps two or so of the 22 needle bearings per strip, which won't have any difference at all. It also wouldn't increase bearing preload, but for the sake of argument, if it did, any amount of sag once you get on the bike, would put you right back in the "worn" area he's referring to. Also, by his thought process, longer travel forks wouldn't migrate by nature of being longer, as that's all he's affecting.

I'm not saying he isn't experiencing some sort of change, and I can't parse out the cause with so little background info, but being around these things many times a day as I am, what he's saying is having an impact has no function in mechanics of the thing.

To impact reset intervals, you need to increase bearing preload along it's whole length, since as soon as it gets into the travel, it's away from the area he impacted. And, sadly, no, the race and bearing aren't worn, (thus he isn't increasing preload at all) they polish in, but you can mic a used race against a new one, and it's consistent it's whole length, every time.

My only guess is that since he has a few more mm's, he has more time cushion before getting as migrated.

I'll also add, nothing against Cannondale but I hear this comment often, I sent it back for X, and it wasn't addressed. Why that is, I can't say, and I won't cast aspersions, but if I have a customer tell me migration happens too fast for them, it's a no brainer, and I have a customer without the problem once they get it back. Perhaps because I'm dealing one on one and know the complaint when I see the fork, and take the obvious solution steps, as opposed to just saying, "we checked it when we serviced it, and it's within correct parameters", might be the difference.....

Please understand [email protected], I'm not trying to be a jerk, or say you're wrong, but you're suggesting something that makes no sense (if it did, Cannondale would have addressed it YEARS ago, trust me they're always playing around and tweaking things), and the one thing I try to do on this board, more than anything else, is to politely correct bad or false information, before someone damages their fork, or themselves, as both, get rather costly.