Lefty Forks for Fat Bikes
Mendon Cycle Smith provides custom clamps designed for use on any number of Fatbikes to add front suspension. The industry standard 17.5mm horizontal offset is created by the clamps themselves. A Fat Lefty can run the fattest combos known to date, and have the ability to go EVEN FATTER, as this segment continues grow adapt and change to the whims of it's adherents.
The beauty of this system is an outgrowth of the wonderfully flexible nature of the Lefty system itself. Virtually any Lefty starts life as a 26" wheeled fork. Plug in 30 mm of travel reduction and possibly some air spring volume tweaking, and it becomes safe and functional as a fork for 29" wheels.
Since Fatbikes are effectively 29ers, the Lefty in 29er mode, is a solid choice for those wanting a little more out of their Fatbike. Be it speed, comfort, calming and controlling that big basketball on the front end a bit better, etc this will deliver on all fronts. Many riders note the ability for the front end to stay stuck to the ground better on climbs, which is always nice.
The other potential plus is availability of used forks, keeping costs down.
The set up requires use of the older movable clamp style for Lefty, so a modern OPI upper, bonded clamp, or carbon, won't work. There are a huge number of these forks out there though, and due to being inexpensively serviceable, a fork found unusable, can generally be brought to factory fresh, ridable condition for around $100.
2001-2004 Lefty DLR/ELO, Titanium axled forks are a good choice with 100mm original travel (tuned to 70mm for fat use), and an axle to crown of 480mm.
2005-2007 Lefty Max 140mm FFD/TPC/SPV alloy's are the flexible choice, as they can be used in original configuration, or, drop a modern 2012 Cannondale PBR or XLR damper in, and have the choice of 110-70 mm of Fat travel, and axle to crown of 520 to 480. Anything in between is possible too, allowing for exact wishes to be met, this set up nets a fork at 4.67 lbs, or 2100 grams with an uncut steerer.
Ultimate travel is a complex factor, tied to the stack height of the head tube and headset. Maximum stack height is currently 168mm, but I have a taller dropped top clamp in the works, will will allow 198mm, enough for almost all currently available configurations.
Once the fork is installed, assuming one isn't using the absolute max clamp spacing, the user can often add some more travel to the fork by sliding the fork downward and removing spacer clips, but this needs to be done with an eye to personal safety, so test with a softened fork and some serious stabbing in a parking lot, prior to hitting the trail. I'm not your Momma, you gotta look out for your own fool self!
Wheels do require a Lefty hub, of which there are a number to choose from, Cannondales own basic black version, to Project 321's technicolor dreams, Tune's Euro funky version, DT Swiss, Woodman, the list goes on. Rims are laced with offset to the drive side, using a Surly 17.5 offset build spacer on the drive side of the hub. Cross laced wheels are out there, but do require a very patient builder, and to date, the offset rim builds have proved perfectly solid and more than adequate. Due to the free rotating ability of the fork in the clamps, you can also tweak dish issues, wheelbase/fork rake, to your personal preference.
Clamps are $220 for black, $240 polished. The Uber drop top clamps are $240.
I am a one man shop, who is open to the public 5 days a week, and do a sizable volume of mail order Lefty and Headshock suspension fork service on top of that as well. I will do all I can to help anyone with interest in getting themselves set up, from shipping a set of clamps, to refurbishing a used fork from eBay, building you a wheel, to shipping the whole set up, bolt on ready, to answering questions via email, in person, or over the phone.