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Discussion Starter · #1 ·
I am going to build up my Monkey with a Lefty fork I have decided.

To those who have done the conversion, did you convert a 100 or a 130mm model?

The 100mm has a 470mm height, which is close to the rigid Monkey fork.

Any final verdict on spacers? I know some have and some have not installed spacers from searching old posts.
 

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Just because you can, doesn't mean you should.

frankenbike said:
I am going to build up my Monkey with a Lefty fork I have decided.
If you value your teeth, you'll reconsider. There have been several cases of people eating it badly from running such a conversion, and cdale themselves issued a cyoa press release on the matter. Seems they're not quite up to the task. Still, there's something to be said for being a risk-taker. Where would the mtb be without people pushing their luck?
 

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use new search

frankenbike said:
I am going to build up my Monkey with a Lefty fork I have decided.

To those who have done the conversion, did you convert a 100 or a 130mm model?

The 100mm has a 470mm height, which is close to the rigid Monkey fork.

Any final verdict on spacers? I know some have and some have not installed spacers from searching old posts.
http://forums.mtbr.com/showthread.php?t=33678&highlight=lefty+29er

http://www.fooriders.com/webmain/index.php?name=PNphpBB2&file=viewtopic&t=55931

lots of non c-dale bikes with lefty, it's not simple or easy!
 

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Dr Gadget is IN
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Work in progress....

I am in the process of doing the 29er/Lefty thing - but I have an '05 Max which gets you 140mm rated travel. I have been running a 130 Max on my 26er for a bit more than a year with nothing but smilies - and just took the adapter/steerer system apart for inspection (and upgrade to a Project321 custom clamp setup) with no signs of anything bad whatsoever.

My approach for the 29L will be: Finish building frt wheel - install on axle, measure knob-steerer clearance, subtract from 140mm. Take out stock stop spacer, make new one just that special bit longer. I note that my 26 wheel/tire is really 26", whereas my 29 is actually 28.5" (horrors! It ain't actually 29" :p ).

So the 5.5" travel will probably be reduced to around 4.25" or so, which may require running a heavier spring or damping setup to eliminate bottoming - but I'll do a writeup when I know.
 

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Harmonius Wrench
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I agree

flyingsuperpetis said:
If you value your teeth, you'll reconsider. There have been several cases of people eating it badly from running such a conversion, and cdale themselves issued a cyoa press release on the matter. Seems they're not quite up to the task. Still, there's something to be said for being a risk-taker. Where would the mtb be without people pushing their luck?
I've brought this up several times with the Cannondale rep when he visits our shop. He has told me that the Lefty causes unusual forces to be exerted on a frame. Unusual in that most dual legged forks do not exert forces on the headtube in the same way as a Lefty in Cannondales lab tests. Cannondale had to change the way they make their tubing choices and had to adjust the design. Obviously, other frames are not designed around a Lefty. Add to this any "homegrown" modifications, and you have multiplied the chances for failure. Will it fail on you? I'd rather not find out while flying down the trail!
 

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KM frame

A KM frame is probably able to withstand a roadside bomb.
Asymetric loads or not, whatever fails, not the frame.
Are those things HEAVY!

Guitar Ted said:
I've brought this up several times with the Cannondale rep when he visits our shop. He has told me that the Lefty causes unusual forces to be exerted on a frame. Unusual in that most dual legged forks do not exert forces on the headtube in the same way as a Lefty in Cannondales lab tests. Cannondale had to change the way they make their tubing choices and had to adjust the design. Obviously, other frames are not designed around a Lefty. Add to this any "homegrown" modifications, and you have multiplied the chances for failure. Will it fail on you? I'd rather not find out while flying down the trail!
 

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Harmonius Wrench
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Karate Monkeys DO fail

mvi said:
A KM frame is probably able to withstand a roadside bomb.
Asymetric loads or not, whatever fails, not the frame.
Are those things HEAVY!
Nothing is unbreakable, of course, and KM failures have been reported here, on this forum, before. Granted, they were not head tube failures, but then again, there aren't that many out there with a Lefty on 'em! ;)
 

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Discussion Starter · #12 ·

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Frank Tuesday said:
Tell me more about the custom clamps. I've long considered this option, but haven't done anything yet.
Hello Frank!
The custom clamps are from pumpkinbiter, otherwise known as Jake at Project 321. You can see a pic of them in this thread:
Mtbr.com Forums > Manufacturer Forums > Turner
And Now For Something Completely Different!
(sorry, don't know how to hyperlink this - gotta go look)

I've had them in action for 3 rides now with Zero negatives. Let me damn them with faint praise: you can't tell they're there unless you look. Perfection. The only "problem" I know of is that they won't work with the Carbon Lefty, which has the stock clamps bonded to the strut - so then you go with the adapter rings like I had - Terminaut has plans for a steerer w/integral bottom adapter&separate top adapter listed in that thread too.

Once you get Lefty'd you'll stay Lefty'd. Price is the only drawback.
 

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Guitar Ted said:
I've brought this up several times with the Cannondale rep when he visits our shop. He has told me that the Lefty causes unusual forces to be exerted on a frame. Unusual in that most dual legged forks do not exert forces on the headtube in the same way as a Lefty in Cannondales lab tests. Cannondale had to change the way they make their tubing choices and had to adjust the design. Obviously, other frames are not designed around a Lefty. Add to this any "homegrown" modifications, and you have multiplied the chances for failure. Will it fail on you? I'd rather not find out while flying down the trail!
I think that's BS because they say its OK to put a lefty on a headshok cannondale that was made before lefty was even made. the lefty is a big reason people buy cannondales. if you could put it on any bike... well they would sell less bikes. it's an awesome fork.

I would only put a lefty on a bike which can take a dual crown fork, so no lightwieight XC bikes. A KM should be fine. I think I would actually trust a lefty more on a KM than on a cannondale!
 

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jh_on_the_cape said:
I think that's BS...
(snip)
I also call BS. The HeadShok guy ("Brad") is perfectly happy with putting up photos of me on their Cannondale site. Click here and check out the second-from-last photo (there are also a few others on the site on various pages).

Not only that, Cannondale enjoyed a video of my Lefty-Turner in action so much that they asked if I would re-shoot the sequence using a Cannondale bike so that they could put it up on their site!

...Here's a photo of the 321 clamp/steerer kit.

 

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Harmonius Wrench
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Tale of two stories?

Okay guys, you obviously believe what you say. But our rep vehemently denies that Cannondale has in any way endorsed, said it was okay, or even thinks it might be a good idea to mount a Lefty on anything but a Cannondale for the reasons I've specified. I never implied or said you couldn't do it, just that it might not be a good idea, based upon what I was told. I tell him everytime I see him that somebody else has put one on a twenty nine incher.

Hey, it's not the first time I've heard conflicting stories from the same company! (shrugging shoulders) I just wish these companies would quit yanking our chains. Which is it? Is it okay, or not?

Then again, who cares? Maybe it just doesn't matter.
 

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Discussion Starter · #17 ·
I don't think Cannondale will ever outright state that it supports modifying Lefties for other bikes for liability reasons, too many factors out of their control. But that's not to say it cannot be done, they are just covering themselves legally from lawsuits and such. The usual.
 

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Use

Seeing the USE photo's reminded me of this bike circa 2002, correct me if I'm wrong Brant please.





As the picture tells the new invasion of Inbreds has a grandpappy in its closet.....

Anyway I got a fork and hub from Rorey at USE in 2003 and had it all built up but we could never get it to work well, the spring was too soft and the threat of bottoming it out was very real indeed. Rorey is a he l l of a bloke however and if you get a chance to get anything USE like their lighting system etc. then you are on the right track. The last I saw of the fork it was in a box with Jeff Jones address on it......

Another point of some interest was at dirt demo 3 years ago the Avid guy, an older gent who I can't remember his name, was sporting a USE fork on his 26"er claiming it was just the ticket for use with disc brakes.....

Not that this has anything to do with the Lefty fork....I defer to Term on all things to do with that.
 
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