The not-so-minor details
Formula 35 fork
Class leading weight.
Plush and lively performance.
Some oil seepage.
A bit mushy on out of the saddle climbs.
Getting your hands on a product with which you’ve had no previous experience is always enjoyable: will it open your eyes to a whole new product line, or it will reaffirm why you’ve generally stuck with an offering from the better known brands?
The Formula 35 is definitely one of those products. We didn’t even know that Formula made suspension forks! So it was with a little bit of excitement and a little bit of trepidation that we removed the FOX fork from our bike and fitted up the Formula 35 before heading to Mt Buller for three days at the Kona Bike Buller and then to Rotorua for five days of riding.
Our test fork was the 650B version, but Formula also make the 35 to suit 29ers.
Features and setup:
As we noted in our first impressions piece, it’s a very light fork, coming in at 1750g. This is a class leading figure, over 100g lighter than a FOX or RockShox with equivalent features. That alone is reason enough for many riders to give the Formula a go, but there’s much, much more to like about this fork. Part of the weight saving comes from the axle which does not have a quick-release function, requiring a 5mm Allen key for removal. Overall, the finish quality of the 35 is pretty good, though not quite in the same super slick league as FOX.
The unique arrangement of damping adjusters on the right fork leg control the low-speed compression, lockout and lockout threshold adjustment, while rebound is at the bottom of the leg. For our riding, the only dials we touched were rebound and low-speed compression, both of which have a very usable range.
The fork’s air spring runs at a lower pressure than most, and for our scrawny 63kg rider just 53-55psi was all that was needed to provide the ideal sag and spring rate.
Travel is adjustable internally, from 160mm down to 120mm; the fork is supplied with two 20mm spacers and two 10mm spacers, so you can add these in combination to select your desired travel. We fitted one 10mm spacer, bringing the fork down to 150mm which felt like a good fit for our Giant Trance Advanced SX test bike (140mm rear travel). The process is pretty easy, just pull the lower legs off, remove the air spring assembly and clip the plastic spacer onto the air spring rod. Refitting the coil spring onto its little retaining perch is the only fiddly element.
Rather than standard fork oil, the Formula 35 is lubricated with Jagermeister. Ok, that’s not true – the fork’s splash oil and air-spring lubricant is actually a product called Ballistol, which smells like a herb-based liquor! We’d never seen this stuff before, and a bit of searching revealed that it’s usually used for lubricating gun mechanisms. Hopefully it’s easily sourced locally.
To help overcome any initial friction in the fork’s stroke (as is sometimes associated with air springs) and to provide maximum small bump sensitivity, the 35 actually relies on a coil spring for the initial part of its travel. Coil-sprung forks are a bit of a rarity in this style of riding now, but by combining a coil with an air spring as well, the fork is able to deliver an ‘old school’ plushness while keeping the weight and tuneability benefits of an air spring.
The feel this configuration delivers is one of the defining characteristics of the fork – it has a very lively, responsive and plush feel in the beginning and mid-stroke. Over roots, loose rocks and repeated medium sized impacts, the fork chomps up the bumps. Or more accurately, we should say ‘slurps’, as you can hear the damping working away with every hit, making little sucking noises.
Occasionally there’s also a little bit of noise from the coil spring, a slight metallic clunk sound, particularly over hard repeated hits, but this doesn’t seem to be accompanied any decrease in performance.
Because of the very plush beginning stroke, there is a tendency for the fork to bob when climbing out of the saddle. More low-speed compression helps, but comes at the expense of that buttery smooth bump response. Like most fork lockouts, we found this feature of limited use; we dialled the lockout threshold right back to minimum and only used the lockout on the road.
On our first couple of rides we found it quite difficult to use the last two centimetres of travel. A quick call to the distributor (Eighty One Spices) and we were advised to reduce the amount of oil we were running in the fork’s air spring chamber. Adding or reducing the oil volume that rests on top of the air piston allows users to tube the spring curve. Formula are also producing future versions of the fork with a slightly shorter air piston rod to deliver a more linear spring curve as standard. After removing a few mills of oil and dropping the pressure by two or three psi, we found the sweet spot.
This is a fork in which small setup changes can make a real difference, so be prepared to experiment for the first few rides. Once we had it all dialled in, the fork’s spring rate felt absolutely perfect, happily using the mid-stroke and ramping up neatly as it approached full travel. Checking the o-ring revealed we were getting full travel, but not once during testing did we feel the fork bottom out harshly.
On the whole, we’d rate the Formula’s sensitivity and spring curve as being as good as any other offering on the market. In fact, the only area in which we could mark the Formula down a smidgen is its performance on sudden, super-harsh impacts, such as launching into a corner full of braking bumps. In this instance, the fork seemed to make the rider work a little harder than with a Pike or FOX. This sensation didn’t feel like a damping spike, more a product of the fork’s lightweight construction sending a bit more lateral twist through to the bars. Hey, we’re being picky here!
With around 50 hours of ride time on the fork so far, we have noticed a very small amount of oil seepage from the seals. It’s certainly not a blown seal (we’re talking a couple of millilitres here) but it’s enough to indicate that perhaps the seal tolerances are a little on the loose side in the name of reducing friction. Keeping up the regular oil changes and topping up the lubricating oil will be important in the long run to keep stiction at bay. As noted before, stripping down the fork requires an Allen key and 10 minutes of your time, so this kind of maintenance isn’t really a headache.
We’ve got to say, we’re very impressed. We definitely didn’t expect this level of performance from a such small player in the suspension arena. The weight, the lively and plush ride quality and the ease of service/tuning are all big ticks for the Formula 35, and there are precious few negatives to complain about. It’s always nice to see a little bit of Italian exotica too.