Until now, unless you a) own a Cannondale or b) had a frame custom made to fit their standard, you couldn’t run a Lefty suspension fork on your bike.
Assuming you’re not put off by the look of it, there are few reasons you may want to. First, some models are lighter than any normal suspension fork on the mark, bar none. Â Second, they’re very smooth because they use needle bearings rather than bushings sliding on a stanchion. Lastly, they’re very stiff torsionally…we’ve ridden them and the tracking is very precise.
Now, Cannondale has introduced their Lefty for All program that uses reducers and adapters to let you run a Lefty fork on any straight 1.125″ or tapered 1.125″-to-1.5″ headtube. The kit includes the spacers, adapters and appropriate steerer tube for $80. For $10 more, you get the full kit with bearings. Three different headset styles are available: Standard, ZeroStack and Hidden.
UPDATED 8/19/10 – corrected installation notes after the break.
Hit ‘more’ to see how it works…
The top and bottom pieces shown on the included steerer tube are the reducers. Lefty’s typically clamp onto about a 1.5″ steerer, so the reducers let it clamp onto the steerer tube with adequate force to keep it from slipping. The fork should not be clamped onto headset spacers.
From there, the headset cups are pressed into frame, bearings inserted and the steerer tube is slid up into the head tube. Â Put the upper bearings in, the top cap, any necessary spacers and the upper reducer. Clamp the fork down and put spacers above it as necessary, or remove the steerer and trim it to stop just above the top clamp.
Cannondale offers two steerer lengths with different spaces between the clamps to accommodate any size frame: standard at 137.7mm and XL at 163mm.
The tricky part about installation comes if there is an odd distance left between the top of the upper headset and the upper clamp. You (or your favorite shop) may need to, uh, customize some spacer heights to get the gap filled nice and tight. On the carbon Lefty’s it’s not so much of an issue since the clamps are moveable on the fork leg, too. On the alloy Lefty’s though, the upper is one piece as shown here:
Yeah, pretty much all of the above paragraph was wrong, here’s the deal: Both the carbon and alloy Lefty forks have fixed clamp locations. To make the included 5mm, 10mm and 20mm spacers work, the upper reducer that goes between the clamp and the steerer tube is taller than the clamp, allowing you to slide it up and down to remove any gap. That should make installation much, much easier.
Shown here on a standard Independent Fabrications frame, the Lefty for All adapters fit the fork onto the bike with no frame mods.
The adapters let you use any Lefty fork as the fork itself doesn’t change. This is good, because you get the full range of options, and they’ve done some cool things with the internals for 2011, which I’ll cover in a separate post shortly. This also means you can run this with their 29er Lefty forks, as shown here on the Indy Fab.