Suspension forks are not an easy thing to design- or build.  At a time when former powerhouses have all but disappeared from the market and rider demands and expectations are at an all-time high, it’s a surprise to see a new player jump into the market.  But that’s just what Italian brake maker Formula have done.  Why?  Because they felt that they could bring a new perspective to the market- and maybe even build a better fork.

Built around stout 33mm stanchions and using specially designed low-friction bushings and seals, the ThrirtyThree is designed to be an active fork.  While that may say ‘trail fork’ to many, the sleek bolt-through axle and impressive 3.33lb weight (1 1/8in steerer with 15mm thru axle) for our 120mm sample puts it solidly in the marathon category. So, with a trail-ready attitude and a race-ready weight, does the Formula bring something to the ride that the competition doesn’t?  Hit the jump to find out!

Like many riders, my USAC racing days are behind me.  Never a sprinter, the short formats and high costs of entry have kept me away for the past decade or so.  Which isn’t to say I don’t like to throw my hat into the ring from time to time.  Here in the Southwest, a solid informal endurance (rather than enduro) racing scene has sprung up, featuring long (40-100+mi) courses often covering technical terrain.  When riding for 6-10 hours or more, things like suspension action easily trump a bit of weight here and there- and when the bumps begin to add up, a bit of forgiveness is appreciated much more than outright efficiency.

It’s in events like these and on multi-day races that the ThirtyThree thrives.  As tempting as it would be to call the damping simple, doing so would undersell it’s capabilities.  The reality is that Formula have put together a smooth-running fork with a damper that controls the fork’s motion without ever interfering with its ability to respond to bumps.  There’s no complex platform or excessive compression damping to overcome before bumps are absorbed.  While this can mean a bit of trail fork-style movement when honking on the bars, the payoff is a (85mm, 100mm, or 120mm) fork that responds to small and medium bumps better than most 6in forks.

How have Formula done it?  A coil “helper” spring handles the first 40mm of suspension movement before calling much on the fork’s air spring.  This allows for lower air pressures than in competitors forks (some 30-40% lower) and reduces the pressure on the seals- and as a result less stiction.  Out of the box, the ThirtyThree is a very linear-feeling fork, and the company recommend playing around with a bit of Ballistol (The World’s Most Useful and Environmentally Friendly Lubricant!) in the air chamber to adjust the spring curve.  A light rider, I found that 10cc of the German miracle juice added just the right amount of progressiveness to the fork’s stroke, keeping it from bottoming on big hits without ever feeling harsh.

Despite its low weight (just shy of the claimed 1,510g once cut to 8in), the ThirtyThree is an impressively solid feeling fork.  Everything that can be touched is nicely machined from aluminum without being overstyled or overly sharp.  In a surprise move, Formula have foregone any quick release on the front axle- you’ll want a 6mm Allen key to get the front wheel off.  Formula figure that if you have the supplies needed to fix a flat, you’ll have a mini tool along as well- logic that is hard to argue with.  Any misgivings on my part were overcome by the remarkable smoothness with which the axle threads into the far leg: manufacturing tolerances are obviously tight and things just plain line up and continue to thread together smoothly.

The ThirtyThree’s external adjustments are pretty standard: air pressure, variable compression damping/lockout, and rebound damping.  The adjustments’ actions are pleasing and make noticeable differences to the fork’s performance.  The air pressure recommendation label (complete with space for your own settings) extends down to 120lb (hooray!) and even has a place for the owner’s name (just in case).  Going with a relatively quick rebound damping setting really does make the most of the fork’s small bump action without ever compromising control.

In nine months, my only complaint is a bit of weeping around the seals.  According to Formula, when the weeping stops, it’s time to clean lube the lowers (6 months in my case).  Removing, cleaning, and replacing the lowers is a simple procedure and had the fork feeling (and weeping) like new in under 45 minutes.  In operation, the fork can be a bit dirty- but it’s hard to argue with the performance.

Compared to other forks in its weight/travel class, the ThirtyThree is both stiffer and more active.  Paired with a similarly active rear suspension design, the Formula is a great fork on which to spend long, technical days.  It’s always difficult when it comes time to discuss four-figure price tags for suspension forks, but the majors are already there price-wise and in this case $1,060 buys anyone willing to commit to semi-annual maintenance a truly unique and supple suspension fork.

Unfortunately, the 26in trail/marathon market has all but died out here in the ‘States, in favor of bigger wheels and/or longer travel.  Fortunately, Formula’s upcoming ThirtyFive platform will bring 120-160mm travel to 650b-wheeled bikes and 100-140mm travel to 29ers- we’re expecting full specs shortly.  If those forks perform anything like the ThirtyThree, they’re bound to be winners.



  1. Hmm. Combining a Manitou Mars style spring with metal adjusters and a chassis that goes where it’s pointed? That sounds like the kind of innovation I could live with.

  2. I’ve been riding a Thirty3 for almost a year now and I couldn’t be more impressed with it.
    I’ve owned several top notch Fox and RS forks in the past and none come close to the overall performance of the Thirty3. It is smooth, active and stiff as a Lefty but much less problematic… Oh, and it can take 27.5″ wheels of up to 698mm in diameter! 😉
    I just can’t wait for Formula to come out with the Thirty5!

  3. Like they said about the hydraulic leaks on the F-14 and MH-53’s – if it ain’t leakin, there’s nothin in it.

  4. Walt,

    Gregg is more or less correct- Formula expect a bit of weeping in normal use. It’s probably exacerbated by the fact that (in keeping with BICYCLING’s Top 101 Mantenance Tips), I hang that by the rear wheel to keep the seals wet. When the weeping stops, it’s time for a quick clean and top off.


  5. Gabe,

    Thanks! Great endurance racing and all-around trail bike- there are now bikes on the market that can compete, but Zelda rides great and is a fun bike to have around. There’s still plenty of support available from Ethan to boot.


  6. Keith,

    Let’s pause to think about how your comment comes across. Now I don’t have a dog in this fight and will admit to being Lefty-curious, but statements that are short on information and signal an unwillingness to listen to others’ experience aren’t terribly helpful.

    Are you saying that because you’ve never had issues, no one else can or has? Over the past dozen years, Cannondale have used dampers from several sources and made forks for several types of riding- I can’t believe that all were perfect. There are always quality escapes and even the best manufacturers have off years here and there.

    A better approach might be to ask Solo to explain what his (her?) issues were and note that you’ve had good luck with yours over the years- and note which models those were. Let’s try to keep things constructive so that everyone can benefit from the discussion. Thanks!


  7. So, they rip off the lever reach adjuster of the Hayes Prime brakes and put it on theirs. They rip off the Manitou MARS system. But they can’t design the fork to not weep, and instead basically call the weeping a performance enhancer? Weak. Very, very weak.

  8. If forks weeps, means dirt can get in. Proper oil seal fixes that. Running all my Magura forks with Enduro scrapers and seals, works just great, no weeping, no noticeable wear after a lot of riding.

  9. Keith

    To be honest, working at shop that sells cannondale lefty’s can be the most difficult forks to service, especially any of the older ones (around 3 year) because you cannot get seals sometimes, and brand new because there is no info about how to service them. To be honest, compared to every other suspension company, cannondale has had the worst track record with the lefty compared to any other fork of the same quality and style. As said before, and i completely agree, with how much the internals of that fork have been changed so often there must have been something wrote with it.

    On the plush side the lefty has great stiffness in the fork, but but but but the axle of the fork is where the fork has its most major weakness and flexes quite a bit there and does not track as well as other thru axle forks.

    And finally, lets be real, if it was that good wouldn’t more people use designs like it?

  10. Guys, I’m pretty sure Formula knows what they are doing.
    They do make forks and brakes for dirt bikes.
    Just sayin
    Johnny Doe, I see what you did there. Calling Formula weak, good irony.

  11. I am a Hydraulics Engeneer with two decades of experience on automotive suspension systems, and a mtb suspensions geek.
    I’ve tested them all, I have studied them all and Formula’s damping and spring mechanisms are among my all time favorites. Their suspension still have room for prefecting, but they are on the right track and getting closer…

  12. The fork is installed on a 4 inch travel version of Yeti ASR. When loaded and with adequate damping applied the fork operates well. The problem is when the fork is lightly loaded i.e. when going uphill. The fork then extends almost fully and there is no damping for the last 5 mm of the travel. So there is metallic chatter around the top out position.

    It seems as if the top out spring is not there or is not capable of
    countering the 90 PSI pressure needed for my weight and when there is not
    enough travel for the damping to kick in the fork tops out harshly with
    metallic feel and sound.

    I had the fork sent back to the people I bought it from (CRC) and they had it serviced by (presumably) Formula mechanic. They advised there was nothing wrong with it and that this harsh top out is normal.

    This can not be normal. Anyone have any idea what might be wrong?

  13. Interesting.

    Sometimes I hear some metallic clunking too.
    Especially when I start the ride.
    Afterwards I cannot hear them anymore.
    I put these noises down to my the brake and shifter cables and their routing, too long and need to be trimmed down.

    Actually I can hear the metallic noises as you say when I am not on the bike and I just press the handlebars to compress the fork.
    The sound is more like the coil sits on a metallic rod and the friction makes that sound.
    Ayway, i will test tomorrow if the sound is there after the ride.

    You need fine ears to hear it too, probably experienced riders would hear it, not normal users.

    During operation I cannot hear it anymore.

    Contrary to this review, I feel the fork a bit harsh on the small bumps and does not have the Cadillac ride of my Fox open bath. But great at speed and rougher terrain. The Fox has to be ridden under pressure to get full travel, while the Formula get achieve it easily at recommended pressures. I had to add Ballistol to avoid bottoming out.

What do you think?