Formula ThirtyFive 29 Fork - Review

Formula has been developing a modest lineup of single-crown suspension forks for over three years, and the moment has finally arrived for the renowned brake maker to release them into the marketplace. We got our hands on the ThirtyFive 29 - and as those familiar with Formula's handiwork would expect, it is beautifully constructed - with anodized aluminum "touch-me" lever and dial adjustments, a forged aluminum crown and big, 35-millimeter stanchion tubes. Inside, the fork is packed with user-friendly features like snap-on travel-adjust shims.a damping cartridge that can be removed while the fork is still on the bike, and an air-spring system that can be tuned for a more progressive spring rate simply by adding oil. ThirtyFive forks can be ordered with either 140 or 100 millimeters of travel, and to fit either 27.5 or 29-inch wheels. Color options are white or black, and the weight of our 29er test fork with an uncut steerer tube was 1760 grams. MSRP is $1250 USD.




Can a Brake Maker Build Suspension Forks?

I was visiting the Formula factory in Prato, Italy, where founder Andrea Becocci showed me a prototype suspension fork. Initially, I was skeptical that the project would achieve success. Formula is well equipped to engineer and build a fork. Its manufacturing facility is absolutely state-of-the-art and it is staffed with some of the sharpest minds that I have come across in the bike industry. That said, the marketplace for single-crown, mid-travel suspension forks is stuffed to the tipping point with offerings from recognized brands - which raises the question: "What motivated Formula to take on such a risky endeavor?" The answer may be simple. The people at Formula ride mountain bikes and motos, they thought they could do as good or better of a job as the top suspension makers were doing, and they were excited to give it a go. Formula is a family owned company. They have no shareholders to answer to, so they have the freedom to make any product they want, and to dedicate whatever resources are necessary to get it right. The ThirtyFive is beautiful, contemporary, expensive and Italian - there will be customers. - RC


remote lever that replaces the low-speed compression and threshold dials on the fork crown. It makes sense that the lockout is hydraulically actuated, as Formula has all the necessary pieces to make a reliable system in house. The remote is reported to add 90 grams to the fork.

Tool-less through-axle: Conventional threads fix the hollow, 15-millimeter aluminum axle to the right dropout and a tapered collet ensures that the axle secures the left side. The quick-release lever functions only as a wrench handle. It is hinged to a 4-millimeter hex shaft that tightens the axle. The handle can be removed completely and stowed, or indexed and closed in a desirable position.

Formula's 15mm through-axle can be tightened with a 4mm Allen wrench or with the faux quick release handle that hinges on an Allen hex and snaps into the axle. The tapered collet on the left-side makes a direct, more secure connection with the dropout.

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Ride Report

Honestly, setting up the ThirtyFive fork was as easy as it gets. We followed the air pressure suggestions in the Formula PDF file, which resulted in 20-percent sag at 60psi. We then adjusted the low-speed rebound six clicks out, to the point where we could just sense it, but waited to fool with the low-speed compression dial until we had some trail time to assess the bike's ride height. We used a Niner R.I.P. Nine as a test sled, and the 140-millimeter-stroke Formula ThirtyFive fork replaced a 130-millimeter RockShox Revelation Solo-Air model. Remarkably, even with the Formula's larger, 35-millimeter stanchion tubes, the two forks weighed the same (1740 grams with cut steerers). so there was no weight penalty in exchange for the extra travel, as well as the sigificant boost in stiffness and steering precision. When we hit the dirt, Formula's default compression setting (six clicks out) seemed about right for fast-paced technical trail work - with enough firmness to keep the fork from diving under braking and when descending steeps, while providing enough cushion to keep the front tire smoothly tracking the surface.

Steering: Formula's ThirtyFive 29 fork has an axle-to-crown length that is 25 millimeters taller than the two most popular 140-millimeter options, which slackened the Niner's head angle by a half-degree. The result was a welcome increase in straight-line stability, at the expense of a slight tendency for the front end to wander while climbing steep trails. Other than that one potential negative, the ThirtyFive performed beautifully in the bends, with a light feel at the handlebar and dependable tracking over just about any surface. Drop a foot and push the bike hard over embedded rocks and hardened ruts, and the fork will drive around the corner without a wiggle. The upgrade in torsional stiffness was such that we could sense exactly what the front tire was doing. The ThirtyFive communicates well without feeling harsh.

Bump control: We did much of the test work aboard the Niner on fast-paced, enduro style trails, packed with natural rock features and intermediate jumps. Set up to ride slightly higher than the shock, the ThirtyFive's low-speed small-bump compliance was on the rough side of comfortable, but that was partly a function of our chosen low-speed compression setting. The fork has almost no static friction, so with the spring pressure set softer and the low-speed compression backed off to a more XC/trail tune, the feel is very supple at singletrack speeds. The firmer tune that we preferred, however, was better suited for charging descents and bashing through the many rock sections in the zone. Through mid-stroke to full travel was where test riders were most impressed with the damping performance. It was progressive enough to take us beyond our comfort levels, while retaining enough bump control in reserve to cover significant square-edge impacts, bad landings or frantic line decisions.

Damping notes: By accident or by design, the damping feels speed sensitive in both compression and rebound. We are referring to damper-shaft speeds, and this is more noticeable during the rebound stroke. We originally set the rebound resistance higher than necessary after discovering that the cartridge's internal valve stack's rebound function had a very broad range. We found that we could back off the low-speed rebound dial until it seemed that there was no rebound force in the parking lot push test and the fork would still feel smooth and in control over chatter. Low-speed compression was effective to the point where, when we found the sweet spot, one or two clicks would alter the fork's ride height by a centimeter.

Lockout function: The curved, gold-anodized lever toggles the fork's lockout function, which was used mostly when we were climbing paved roads. Like most forks with a lockout option, there is an internal blow-off valve that prevents the cartridge from ballooning, or worse, should a rider launch a personal-best huck to flat with the damper's oil flow blocked off. The spring loaded blow-off valve can be tuned with a 2.5-millimeter Allen key, and when it is backed off most of the way, creates the feel of an ultra-firm pedaling platform, while allowing the fork to function in a reduced, but useful manner. We are confident that this tune is not recommended by Formula.....but.

Issues: Formula's fork rates high on the like scale, so there were very few nit-picks from test riders. The first is a nuisance, not a performance downgrade: a persistent hiss from the rebound damping circuit that occurs when the fork cycles to and past mid-stroke. We used to call it AMP-Physemia - after the more-pronounced hiss that AMP suspension forks and shocks made with every bump in the trail. The second is the fork's 44-millimeter offfset is perfect for 29er with head angles near 69 degrees, but a longer offset would be more optimal for the slacker-is-better crowd. That said, it's not a deal breaker. We doubt that any rider would notice the difference between Formula's 44, RockShox's 46, and Fox's 47 millimeter offsets. Most riders, though, could sense the jump from 44 to the 51-millimeter offset that many contemporary long-stroke 29er sliders are switching to.


Pinkbike's Take

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Reviews and Tech Reviews Forks Formula Formula Thirtyfive