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Cannondale Lefty SuperMax Teardown

Words Andrew Major
Photos Andrew Major
Date Apr 6, 2016

Lefty Apart

There are three ways of doing things around here: the right way, the wrong way, and the way that I do it.”

-Ace Rothstein (Casino): based on the real life Frank “Lefty” Rosenthal

There are three types of forks: regular, inverted, and Lefty. Oh sure, if you want to really simplify things it’s an inverted fork, and if you wanted to be technical/argumentative it isn’t a fork at all, but the Cannondale Lefty, their super stiff, one-sided, needle bearing, suspension strut is guaranteed, to this day, to garner more looks, questions, and opinions than any other suspension product you can bolt on your bike.

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Steerer clamps bonded to a carbon upper tube. 36mm Stanchion. Hybrid system combining the best features of a ‘standard’ inverted fork – namely lubrication of the stanchion/seals/bushings – and the previous Lefty struts – namely the needle roller bearings and square stanchion interface for smooth operation and maximum stiffness.

In this case, Cannondale has provided me with a 160mm Lefty SuperMax to test on our Jekyll Carbon 2  vs. the stock 2016 RockShox Pike RCT3 Solo Air, but thanks to Cannondale’s Lefty-For-All steerer or Project 321’s Lefty Adapters you can choose to run a Lefty on ~ any frame on the market.

The new Lefty “Hybrid” combines the best features of a standard inverted fork (lubrication of the stanchion/seals/bushings) and the previous Lefty struts (needle roller bearings and square stanchion interface for smooth operation and maximum stiffness) and in the process ditches the ugly boot in favour of a very clean looking stanchion guard.

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Rebound knob, push button lockout, bonded clamps, bolt on steerer tube, carbon upper, clean graphics, & stanchion guard.

Our friend James at SuspensionWerx recently became a Cannondale Factory Authorized service center, servicing Leftys and DYAD shocks, so I asked him to tear down our Lefty SuperMax so I could see the evolution of the unique one-sided suspension layout. There are some special tools required (available from Cannondale or Andreani Group) that allow the single stanchion/upper to cleanly house both the air system and damper. For the record, there are a number of professional bike shops and home mechanics regularly performing basic services on these forks, so if self-serviceability is a deal-breaker for you then Lefty serviceability, to whatever level you currently service your standard fork, is a few tool purchases away.   

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Andreani Group Castle Tool; Original Answer-Manitou 1.5” steerer/vice clamp.

The Lefty’s basic layout consists of a damper unit oriented on top of an air system. Interestingly, especially given I will be directly comparing the SuperMax to a Pike, Cannondale borrows a number of components from SRAM/RockShox. The SuperMax uses Cannondale’s own Push Button lockout system, but many of their forks use a RockShox hydraulic remote. Depending on the model, Lefty hybrid struts also borrow the basic design and a number of components, including top-out bumpers, from RockShox’s very well received Solo Air air system.

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Easily accessible Push Button lockout and rebound adjuster located at the top of the strut.

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Air system located at the bottom of the strut. Also note the unique brake adapter mount and tapered axle to accept their hub mounting system.

Lefty gets particularly interesting once you start removing components. As the damper and air system come out as a complete unit, minus the Schrader valve cap/assembly and the adjuster knobs, and are further dissected from there. Before we start pulling pieces out of the strut, I thought this brief write up from SRAM’s own website did a great and/or hilarious job of explaining the basic function of the solo air system for those unfamiliar with its benefits: Solo Air is like a Buddhist monk. Its enlightened design lets you add air to your forks through a single Schrader valve, filling both the positive and negative air spring chambers simultaneously. So they’re always in perfect equilibrium, like Yin and Yang. Giving you a plush, predictable ride you can set up in seconds, with the lightest weight air spring on the market.

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Bottom of strut with air cap assembly removed.

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Top of strut: metering rods visible with adjusters removed.

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Damper & Air System removed as a unit.

One of the key benefits of the Solo Air system, aside from very easy set-up, is the ability to customize the ride by adding volume spacers. This carries over to the Lefty. Cannondale specs different volume spacers depending on the size of bike you are buying but if you qualify as extra-beefy for your height, one of those giants who weigh less than the average person skeleton, or are buying a Lefty aftermarket, it is not rocket surgery to change the progressiveness of your air spring.

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Air System. If you’ve serviced a recent RockShox fork you may recognize some parts.

The Lefty’s damper system is a particularly nice collection of machined components including a high flow piston. One of the knocks on the fork is the lack of adjustable low-speed compression; however, if you do find yourself needing more, or less, support from the damper your Cannondale service center can custom valve the shim stack for you to add support. Cannondale has developed different base tunes depending on the application of the fork with the Lefty SuperMax shown here having a different shim configuration from the more XC-oriented Lefty 2.0.

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Cannondale Lefty Damper.

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Brains of the operation.

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Metering rods allow rebound to be adjusted and lockout engaged from the top of the strut.

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Rebound shims to the left of you, Compression shims to the right, Piston stuck in the middle.

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You can hand bleed the damper, but a vacuum pump — such as the Andreani Group unit shown here — guarantees a perfect bleed.

In the case of the SuperMax’s 36mm stanchion, and the Lefty 2.0’s 32mm stanchion, the suspension strut achieves its well-reported stiffness from square faces machined into the stanchion that are captured by, and roll on, needle bearings as opposed to sliding on a standard fork bushing like other regular and inverted forks. This overcomes the major complaint of inverted forks – stiffness under twisting loads – and allows Cannondale to build the uniquely one-sided suspension without resorting to the common key-way design we see in most dropper posts as well as future inverted single crown forks from X-Fusion and RST.

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We didn’t go this deep into the Lefty as part of our basic service with SuspensionWerx; however, the amazing Greg at Cannondale’s Factory Tech facility in Connecticut tore one down to bare bones to send me a photo of the needle bearings and square faces machined into the stanchion tube. Thanks Greg!

I’ll be riding this Lefty SuperMax, and comparing it directly to a 2016 Pike RCT3, as part of the long term Cannondale Jekyll review. For pricing on a Lefty to upgrade your current Cannondale bike, or if you are interested in running one on a non-Cannondale, you can consult your local Cannondale dealer. In addition to a fork you will need a front wheel, unless if you have a Chris King 20mm hub in which case the latest generations are convertible with an axle kit.

Thanks James!


Are you Lefty curious? Maybe just a little?

 

Comments

brian
0
Brian Goldstone  - April 8, 2016, 1:41 p.m.

Lefty is a superior chassis to conventional singlecrowns. I've got a feeling the pike damper will give it the edge, but if the dampers were equivalent lefty is better. Just on stiffness merits alone. While singlecrowns foam rings have dried up and stopped lubricating round bushings… lefty needle bearings keep going strong. Another big advantage of the lefty not discussed is a lower axle to crown. Just as a dual crown 200mm boxxer has an almost equal axle to crown as a 180mm fork, the lefty has a ~10mm lower a2c than equivalent singelcrown. Nice to see nsmb giving the lefty some attention.

Reply

Captain-Snappy
0
Merwinn  - April 7, 2016, 12:23 p.m.

Great quote and introduction. Hook, line and sinker.

Reply

drewm
0
DrewM  - April 7, 2016, 7:40 p.m.

Thank you.

Reply

slimshady76
0
Luix  - April 7, 2016, 8:29 p.m.

I like Homer Simpson's version better:"There are three ways of doing things around here: the right way, the wrong way, and the Max Powers' way"
Bart asks him "Isn't that one like the wrong way?"
And Homer answers "Yes, but faster"

Reply

shrockie
0
Shrockie  - April 7, 2016, 12:16 p.m.

I want to see impact testing simulating fast rock strikes in slow-mo, from the front, to see how it performs..

Yes, car wheels are only supported from one side, but they're matched with another wheel on the other side for symmetry, so the forces balance out..

Reply

drewm
0
DrewM  - April 7, 2016, 7:49 p.m.

Do you mean compared to other forks or in general? I haven't ridden the SuperMax but I have some time on a Lefty Hybrid 2 (32mm stanchions vs. 36mm on SuperMax) and it compares favorably in the stiffness department against any fork in its weight class.

I'm surprised some German bike magazine hasn't done a comparative test of fork stiffness across various planes in "simulated real trail conditions" in a laboratory… but I couldn't find anything in a quick google search.

I think the Lefty has been around long enough that generalized comments on stiffness/single-sided-ness are a bit out of date. By my count it's been available for over 15-years. When you think about it the Headshock forks that Alison Sydor, Tinker Juarez, and Co used in the 90's to race on were single struts as well (needle bearings housed in the headtube) just with a fork/wheel attached to the bottom of them.

Anyways, thanks for reading!

Reply

brian
0
Brian Goldstone  - April 8, 2016, 3:06 p.m.

Years ago cannondale published destructive ultimate testing of a carbon lefty vs equivalent single crowns, 32mm ,36mm, and all the way up to a fox 40 dual crown. The only fork stronger than the 140mm carbon lefty max was the Fox 40 DC! Oh and the carbon lefty weighs 4lbs with a coil.

I can’t find the graph online Cannondale took it down. Anyone who makes claims that the lefty should be flexier than conventional SC’s, or the asymmetry will cause this or that problems…. need to sharpen up on their mechanical engineering

Reply

shrockie
0
Shrockie  - April 13, 2016, 2:08 p.m.

The engineering may be there, but a lot of people, myself included, don't get a solid feeling from the one sided fork.. Front view impact testing, with slow mo on the lefty and a pike, 34 and 36 would put those presumed fears to rest..

They say there as stiff or stiffer than others.. okay, fine, show us. Graphs are cool and all, but seeing is believing.

Reply

brian
0
Brian Goldstone  - April 14, 2016, 12:34 p.m.

Sounds to me like your biased against the lefty. A fox 40 dual crown is stiffer than a fox 36. Do you believe that, or do you need laboratory testing to be convinced? There isn't any impact testing data or slo motion camera footage out there as far as I know. If you search online reviews of the lefty you'll find that the stiffness is a common and consistent compliment. If you refuse to believe that then maybe you should ride one and see for yourself.

Overall I think many people are just plain biased against the lefty. They say it looks dumb, it will break or fail, plus I dont think cannondale in general is held in high regard by many aggressive riders. So people poo-poo what they dont understand.

The simple engineering facts remain, the lefty chassis is superior in its class compared to single crown because:
Class leading Fore-aft stiffness
Class leading torsional stiffness
Needle bearings have much less friction than dried up bushings (especially under hard load)
Reduced un-spring mass due to inverted design
*12mm less axle to crown for equal travel compared to single crown

And what are the drawbacks? It looks funny? Just on my last 2-3 points alone I would place it ahead of a single crown.

Reply

shrockie
0
Shrockie  - April 14, 2016, 1 p.m.

I'm with you on all of that, Brian. Especially the inverted design for keeping things supple and the use of needle bearings.

Given that all the points are true, why aren't there more of them out there? I think it's the public perception. I was just suggesting a way to show people that their presumed fears are unfounded… seeing is believing.

with the legs of traditional forks working in opposition to each other, spring on one side, damper on the other, the crown may allow more flex than the lefty would.. I don't know.. ?

I'm not saying a lefty isn't as strong, or stronger than a traditional single crown. I just suggesting some visual testing to support the claims would help people get over the hump..

Reply

drewm
0
DrewM  - April 21, 2016, 9:15 a.m.

It is a bit of work, and a big expense (Lefty fork / Lefty hub / Project 321 steerer adapter) to run a Lefty on a non-Cannondale bike which I would guess is as much of a contributor to not seeing them on non-Cannondale bikes as anything else. There is definitely the "that looks weird" factor to overcome even for those that aren't questioning the products performance history (it's not like Lefty is a new product).

They are expensive to produce and take more work to sell at the dealer level (the same as the DYAD rear shocks), so it is not surprising that even Cannondale does not spec them on everything.

I can't comment on the SuperMax vs. other long travel forks yet, but I have a few hours on a 100mm Lefty SL and it is very impressive (stiffness and performance) compared to other 100mm forks I've ridden -- including more aggressive forks lowered to 100mm.

Reply

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