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Discussion Starter · #1 ·
How do you do the conversion for a Carbon Lefty with the Project 321 kit?
The Carbon Lefty clamps a bonded, so do you have to have an exact fit with your
headtube/headset stack height?
How do you adjust for this?
Do you buy a Lefty Carbon that was on a certain size frame?
 

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I've just bought this exact setup from Craig at MendonCycleSmith. I should have everything in the next week or so, and will let you know exactly how it all goes together. The P321 info says a max headset stack height of 5.417" and my current setup (18.5`` Giant NRS with Cane Creek ZS-2 zero stack headset) has a stack height of 5.375``. I`m told there are shims from Cannondale to use to take up most of the slack, and that a very minor amount of flex (a couple thou.) in the upper crown can take up the slack in the headset bearings.
 

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Hi guys,
The bonded lefty's have all have the same space between the top and bottome crowns
no matter what size c-dale they come on. That distance is the 5.417" that blowncivic is talking about. If your stack height is larger than that your out of luck. (at least for a carbon lefy, the aluminum leftys let you go up to 6.125" stack height) If your stack height is smaller than that you just add standard 1.125" headset spacers between the top of your headset and the bottom of the top crown untill they almost touch the top crown. Then you
drop in the top spacer that comes with our adaptor and that spacer moves up and down inside the top crown and is machined slightly thicker than the top crown. It will slide up and down to take up any slop. Once you have installed your stem and compressed your
headset you tighten the top clamp on our top spacer (that is split) and it squeezes the steerer tube and fixes the top clamp in place. Your done. Ride Safe!

Hope that answers your questions. If there is any confusion I am here at the shop to answer questions during normal business hours. 559-906-5253 or e-mail [email protected]

Jake
 

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Thanks a million for the info Jake. That puts my mind at ease. So does the top spacer have enough "slack" to take up a difference of 5.417" - 5.375" (.042")? That's the height of my headset stack. One more question though: How do I press on my bottom headset bearing race? You know the one that normally presses onto the steerer of a normal front fork? I believe I have to slide the steerer in from the bottom into the lefty bottom crown - bottom bearing race - bottom bearing - headtube - top bearing - headset bearing split sleeve - headset top cover seal - top crown - split spacer - stem. Is this right?

I'm really looking forward to putting this all together.
 

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BlownCivic,
The .042" will be no problem for the top spacer to close up.
Now if you had more room like .125 or more you would just use
standard 1.125 headset spacers untill the gap was small enough
for our top spacer to close.

You are going to press the lower bearing race on to the steerer before
you slide it through the clamps and headset. Most headset lower races
have a smaller o.d. than the lower clamp i.d. and they slide right through.
There are a couple headsets out there that need the lower bearing race
turned down a little. Its not much in fact I havn't ever had to do it but I
have had a couple customers tell me that they had to do it. So check
the diameter of that part before you press it on. If you don't know a machinst
or have access to a small lathe mail it to me and I will turn it down for you for
free and mail it back. No problem!

Hope I didn't post this too late to be help, I have been super busy lately and
not able to check the forum. Let me know how it goes together!

Jake
 

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Thanks Jake for the reply. Yup! A little too late. My lower race was definitely too big to fit through the lower clamp. I assembled everything losely, and then proceded to tap the bottom of the P321 steerer with a plastic mallet till the bottom race was fully seated. As I understand it, Craig from Mendon CycleSmith also did an assembly late last week, and used the same method. Its all together now, and though I haven't had the chance to ride yet, I like the setup alot.

I went with the new Lefty Speed Carbon SL at 110mm travel, and the Reba I took off, which I thought was set to 100mm travel had an axle to crown length of 485mm, and the Lefty is 468mm. So not only did I pick up 10mm of travel (though I never saw more than 90mm or so with the Reba), but I also somewhat restored the OEM geometry of my Giant NRS frame (meant to be used with an 80-85mm fork).

Jake, I'd love to see a full carbon version of your steerer to satisfy the weight weenie in me.
 

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Glad you got it together.

A carbon steerer would be cool.

What is more likely would be a weight weenie version
where we machine holes or pockets through the top
and bottom spacers to shave off weight.

Post some pics of your ride now that it's done!

Thanks,
Jake
 
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