Review: Formula Belva Dual-Crown Enduro Fork
Formula have been teasing their dual crown enduro fork for years now, and Joe Connell raced it at EWS in La Thuille, 2021. Now it's finally ready for release. It's based on the Selva enduro fork but with new upper tubes and crowns to improve stiffness, adjustability and travel for modern enduro and e-bike use.
Formula haven't started from scratch with this project. The lower legs, air spring, axle and damper are all virtually identical to the single-crown Selva S fork. They've just extended the damper shaft and fitted a spacer in the air side to make it work with the longer upper tubes. So, unlike a downhill fork, there's a 15 mm axle, tapered steerer and 43 mm offset, making it a drop-in replacement for a single crown enduro fork.
Formula haven't started from scratch with this project. The lower legs, air spring, axle and damper are all virtually identical to the single-crown Selva S fork. They've just extended the damper shaft and fitted a spacer in the air side to make it work with the longer upper tubes. So, unlike a downhill fork, there's a 15 mm axle, tapered steerer and 43 mm offset, making it a drop-in replacement for a single crown enduro fork.
Formula Belva Specs
• Intended use: enduro, e-bike, park, freeride
• Travel: 170-180mm (internally adjustable)
• Wheel size/offset: 29"/43mm
• Adjustments: Positive air pressure, Compression, Rebound, Interchangeable CTS compression valves, Neopos volume spacers
• 35mm stanchions
• Brake mount: 180mm
• Weight: 2,456 grams (actual)
• MSRP: from €1850, $2150 CA (ex tax), £1590 GBP, USA TBC
• rideformula.com
• Intended use: enduro, e-bike, park, freeride
• Travel: 170-180mm (internally adjustable)
• Wheel size/offset: 29"/43mm
• Adjustments: Positive air pressure, Compression, Rebound, Interchangeable CTS compression valves, Neopos volume spacers
• 35mm stanchions
• Brake mount: 180mm
• Weight: 2,456 grams (actual)
• MSRP: from €1850, $2150 CA (ex tax), £1590 GBP, USA TBC
• rideformula.com
The main advantages promised are improved fore-aft stiffness, less chance of crown creaking, potentially more travel for a given axle to crown length and adjustable axle to crown length, which can be used to alter a bike's geometry.
Back in 2021, Formula claimed their early prototype was 2,300 g with a target weight of 2,270 g. However, the fork they sent me to test weighs 2,456 g with fork bumpers - 93 g more than a Fox 38. Formula say they strengthened the stanchions to prevent ham-fisted mechanics from damaging them while tightening the crowns. The other obvious downside is the steering lock, which makes it hard to get around very tight corners.
To see how it stacks up, Formula invited me to their factory in Prato, Italy to test it on their local rocky test tracks, To their great credit, they asked me to bring my favourite single-crown fork to benchmark against. They also let me take it home to test on familiar trails.
Technology & Features
Like the Selva S, the Belva uses a coil negative spring below the piston with an adjustable air chamber above. The negative spring (which counteracts the force from the positive air pressure at the start of the travel, making it easier to enter into the travel) is composed of three coil springs, which together get stiffer as you move towards full extension. This helps prevent top-out, but the negative spring is non-adjustable, so the shape of the spring curve and the available travel will depend on the rider's weight and therefore air pressure. With the minimum recommended air pressure (50 psi), I measured 175 mm usable travel and a buttery smooth beginning stroke; with 75 psi, the travel increased to 184 mm and the beginning stroke was noticeably stiffer (even relative to the rest of the travel), and at the maximum of 85 psi, it tops out harshly like a coil spring with way too much preload.
The extended damper cartridge (top), Neopos spacer (bottom left) and air piston assembly with a triple coil negative spring.
Formula makes a Selva R fork with a dual air spring (both positive and negative chambers are adjustable to suit different rider weights) but that spring is not available on the Belva.
The Belva uses Formula's Neopos spacers, which shrink with increasing air pressure, thereby boosting mid-stroke support relative to the end-stroke, so it's easier to access full travel. In other words, they make the spring force more linear throughout the travel.
The CTS compression valves all use the same single shim, but different ports to achieve a different damping curve.
The air piston sits on a ball joint, which Formula say reduces friction when the fork is flexing.
On the damper side, the interchangeable CTS valves make it possible to radically alter the compression damping characteristics, from highly digressive (lots of low-speed damping) to progressive (lots of high-speed damping) to linear (somewhere in between). This is in addition to a low-speed compression dial that adjusts a parallel oil flow path and makes a considerable difference to the overall damping behaviour in its own right, without the need to change the valve. There's a lockout lever too (mostly to make it easier to change the CTS valves) and a rebound dial. There are no bleed buttons.
The air shaft connects to the air spring piston - which slides inside the upper tube - via a ball joint. Formula says this reduces side-loading and therefore friction in the piston while the fork is bending due to a heavy impact or braking (all forks bend back and forth during normal riding). Formula call this IFT (Internal Floating Technology).
The Test
With the help of Formula's engineers (and even the CEO), we got the fork set up on my Privateer 161 long-term test bike, ensuring identical axle-to-crown and bar height measurements as the stock Fox 38. We then shuttled four laps of a rocky three-minute track, tweaking the setup until I was happy with it. Then I swapped to the Fox 38 with my regular settings for two full runs, before swapping back for another two on the Belva. This allowed me to feel the differences between the forks in both directions.
Setup
Based on the chart printed on the lower leg I started with 70 psi, but found this too soft so stepped up to 75 psi. Any more than this and the touchdown feel at the start of the stroke became too firm. I added a second Neopos spacer and wound on compression damping to around the halfway mark to add support without adding more air. I ran the rebound fully open. To match the axle to crown height of the 170 mm Fox 38 (590 mm), I ran it with the crowns at the full height and with the spring at 180 mm travel - the Privateer test bike's massive 145 mm head tube reduces the scope to extend the axle to crown length. It wasn't my intention to compare the 170 mm Fox 38 to the Belva set to 180 mm, but if the fork length is the same you may as well make use of more travel.
I compared the Belva to the Fox 38 that came with the Privateer. I've done a load of winner-stays-on comparison tests over the years and the Fox 38 is still the benchmark in my book. I don't think the black Performance Elite version performs differently from the golden Factory version. My settings are: 100 psi, 1 spacer, HSR 1 from open, LSR 5 from open, LSC 4 from open, and HSC 4 from open. (Yes, I know it's conventional to count clicks from closed but when you're closer to open it's easier this way.)
Performance
Formula has done a good job with friction reduction and bushing sizing. The Belva bobs when pedalling smoothly and moves for the smallest bumps in the trail. The spring is frustratingly firm at the very start of the travel, making it feel like breaking through the surface of a crème brûlée when the wheel touches down, before sinking into the silky travel thereafter. Most of the time, the fork is in that 10-100% travel range and here it feels superb. Everything from small sticks to big boulders are dealt with in a smooth and controlled way.
Compared to the Fox 38, the Belva was more damped and less lively. This is probably because, once you get past that initial sticking point at the start of the travel, the Belva has a softer spring rate in the rest of the stroke. I also needed more compression damping on the Belva to make up for the softer mid-stroke, and the rebound wasn't super fast even fully open. The result was a calmer feel, especially in the big, low-frequency rock gardens in Italy.
The Fox 38 felt more predictable in a sense due to its relatively consistent spring rate throughout the stroke, so the fork stayed closer to sag with less pitching. The firmer spring and lighter damping made for a livelier ride in the big chunks, but not to the point that it was hard to manage. It was more supportive and quicker to recover, making it feel more eager and less lazy. But the downside is a less soothing feel through the rocks, especially toward the end of the descent.
On the biggest frontal impacts, I did find the Belva more composed, which could be down to the additional fore-aft stiffness or the different spring and damper characteristics. Perhaps Formula's IFT internals help here too.
Back home in the Tweed Valley, I was less impressed. In colder temperatures the rebound was a little too slow for my liking, making the fork feel lethargic and slow to respond over high-frequency roots. While I never found the steering lock to be an issue while descending, it can be annoying during slow-speed climbing, when doing a U-turn on the wrong trail, or when track-standing. I did find it useful to play around with the fork length for steeper or flatter trails, though.
Pros
+ Very calm and composed during big head-on impacts
+ Wide range of compression damping options
+ Dual crown design allows for more geometry adjustments
Cons
- Initial portion of travel can feel too firm due to coil negative spring
- Steering lock during climbing is a downside compared to a single crown fork
Pinkbike's Take
 | A dual-crown enduro fork was always going to be a niche market, especially considering that modern single-crown forks are generally stiff enough. For the most part, Formula did a good job with the Belva. It's smooth and sensitive once into the travel, the compression damping adjustability is intuitive and effective even without playing around with the CTS valves, and it deals with all sizes of bumps with sensitivity and composure. But the coil negative spring lets it down. For heavier riders like me, the extra air pressure creates an abrupt feel on touchdown, forcing me to compromise on support. For lighter riders, the spring should work well, but then the rebound could become too slow. If Formula could install their dual-air spring from the Selva R (or redesign it to make use of the longer leg) and recalibrate the rebound range, they could be onto something. |
Author Info:
Must Read This Week
Just to stay on topic: I love my Selva and I can't imagine needing anything stiffer, but then again - I'm shit at riding, so there's that
For an alloy frame I will rather go RAAW Madonna, Knolly, or Pyga Slakline / Slakline HP4
If I'm honest I've got a Bird AM9 and its looks can also be divisive
AM9 looks proper and balanced .... most of Birds bikes look proper. Just more people need to know they exist since they are in theory the ultimate pinkbike bike (external routing etc).
Saying that, I've heard some opinions that their bikes look agricultural. I personally don't think is a negative, but it looks like not everyone likes them.
As for the ultimate Pinkbike bike - maybe not so much AM9, as there's no sensible room for bottle with a piggyback, even with offset adapter, The Aether 9 on the other hand, looks like the real deal - internal or external routing, room for a bottle, good geometry and a straight seat tube.
On top of that, they do have amazing customer service, like nothing I have ever experience anywhere. I could speak for hours about my experiences with Bird.
How dare you compare Jim Henson's the Muppet Show to Sesame Street!?!?
Also, Muppet, might be my favorite term for some people,
Absolute muppet...
They are cheap frames cheaply made, and I do own (a heavily modified) one.
us.76projects.com/products/water-bottle-space-saver
So water bottle AND tool storage. Guess they never heard of OneUp?
@powpowpow : Cheers!
You’re absolutely right about one thing, though — in the end, it’s their call. Totally their priority. They made the decision to build this thing. Now they have to stand by it and reap the consequences, good or bad. I don’t have a dog in the fight, really, but in this case I just don’t see it going well.
I won’t even address your comment about the trucks. Complete non sequitur and false equivalency.
That being said, if you're into industrial looks the gen 1 is in my opinion one of very few near aesthetically perfect enduro machines that have been made. Its a killer bike and I'm very happy to own one as there's no level of offsetting performance that could lift hard earned bike bucks out of my wallet for the gen 2!
But I do gotta ask one thing — after coming up with the design and maybe seeing the initial prototypes, was there anyone who acknowledged the bike’s looks? Someone who said something along the lines of, “Yeah, the way that bike looks won’t be for everyone…”
Anyway, for what it’s worth, I’d really lean into it. Market it like, “Yeah, we know it looks like a beast, but that’s the way it performs and holds up to the abuse you’ll give it.”
As for my size, I’m not familiar with your sizing, but I’m typically on a large, with a 470-480 reach. I’ll check it out.
Can't really imagine a rider who needs dual crown because of stiffness and not needing bigger rotors
It would be great to have custom lowers for each model but that would be a half million euro set up cost every time, so in reality it's not feasible.
If we did offer it with a straight steerer for reach adjust headset compatibility (which is pretty niche) we'd have comments that it was just a DH fork. We can't win 'em all. And we're okay with that.
Right now, the straight steerer option doesn’t meet the threshold. That doesn’t mean we’d rule it out though. If enough Belva owners ask for it we’ll look into it. Otherwise the risk is we end up with a product that ties up money, time and R&D opportunities.
If someone else wants to compare all the forks with such a high level of attention to detail and publish a review then I will be delighted to read this too. Until then I'm happy to accept Seb's expert opinion.
Meanwhile my Lyric from 2020 is still going strong with no repairs needed aside from servicing.
It's terrible compared to a basic zeb.
Different folk like different things though.
I have 51 DH podiums, 6 years Scottish vets champion and 2x national champion for my age category (currently hold them both, but now a grand vet!!).
I have only raced against Seb twice a long time ago where I was 9.4% then 16.8% faster, one in Dh and the other in Enduro.
Have I tested suspension.... lots, many times, many many hours of testing and base my preference on performance against the clock (thats a racer thing), not just feel (although I do like feel too for my trail bike). I am a design engineer, so love some performance testing, I once wrote numbers on my dials in gold paint and a reference dot so I could check my settings before every race run!!!
I have the basic 38 and it feels terrible compared to a Zeb, different folk like different things though.
Maybe you could write a blog post or youtube video about it, as it would help to share your experience on the product.
The reason I value Seb's work is because he publishes it. Doesn't mean someone else's opinion isn't equally valid, it's just that without a balanced supporting article it's hard to weight the importance of your preference.
Seb might ride my bike and think its terrible and go slow on it and vice versa.
The best advice for people is to test things themselves against a benchmark and draw conclusions that fit themselves, their needs, riding style and desires.
Personally I would change handlebar shape before a fork as it has a large "feel" bias on riding, maybe not as much performance difference in my experience of testing different bars, but feeling comfortable is important too.
I have lots of data but its data, so not that interesting and relevant to me, my riding style and body kinematics.
I would like to try the high end Fox, but knowing how good the standard Zeb is its hard to justify the expense to try something like a high end Fox.
You say yourself you never found an issue with lock while descending and i care alot less about it when climbing, you can plan or manage for that so the A2C benefits far outway it in my eyes.
It certainly does seem like a niche product maybe better suited for racing an enduro bike rather than a daily driver which you might use for all purpose riding.
What issues with steering lock do you have on trail?
Other than that, props to Formula for offering Seb the opportunity and support (with mechanics etc) to test their fork back to back with his own favorite fork both near Formula as well as on his home trails. How many other brands do this?
Would love to see some data on this. Set up a steering angle data-aq input, go ride some tight trails, see if you ever actually do turn a single-crown further than a dual-crown would allow. I have a feeling this is an overestimated issue re: corners. The place it might be an issue though is slow approaches to something steep: sometimes you're basically in a track stand while trying to line up for a sniper line, and _that_ might need a bar input further than the dual-crown allows.
Loads of missing info.
Also, basic Trig mental maths, not a lot for 10mm. More offset would have a greater effect initially.
But especially for enduro bikes which are designed around reduced offset forks, I feel like the smart play is to build the offset into the crowns, rather than the lowers (the axle is in front of the lowers). Putting the offset in the crowns would push the fork stanchions forward, giving you more steering range.
Interesting to see that they stick to the negative coil, seen as they sell the Selva R as a development on the S with the independent negative air spring. Both systems have their benefits I guess and I wouldn't be surprised to see an upgrade kit at some point. But still, why not put the R Airshaft in, you can still dial it in so that the negative spring is stronger than the positive and it performs like the S for lighter Persons.
Mine was horrible...sold it after a couple of weeks.
Combined with the large amount of high speed compression on all valves which you can't decrease it was almost unusable and I never had as much front wheel slip and as much arm pump (which I usually don't have). Tried the blue, gold and silver CTS. At the end I tested them all fully open. The rebound was also noticeably worse than any fork I had before, never being able to find a balance between suppleness with traction and sucking up big hits.
Sent it in and aparently the bushings were too tight and adjusted but it only increased the suppleness a bit and did not fix my problems. If I road over a square edge hit like a curbstone, the fork almost did not move at all (around 20 mm).
Would be nice to hear a bit more about general steering precision and composure, compared to an SC fork.
Love formula purple, though.
I like MRP as a company, appreciate what they're doing, and definitely understand that the Ribbon I rode was a while ago and was a sample size of one.
I currently own a Morc 36 which has a Formula S air spring in it. The fork is great but a coil version would be even better.
sounds like it would be a pretty magic product without the things seb struggled with
Location: Tweed Valley, Scotland
Age: 31
Height: 6'3" / 191cm
Inseam: 37" / 93cm
Weight: 187 lbs / 85 kg, kitted
They typically post it when reviewing bikes. This was taken from a Whyte bike review.
I get that fox and rs makes pogo-sticks, and you can get accustomed to a «lively feel» by excessive weightshifting and throwing the bike about, but how does this give you more control?
A fork with a triple negative spring cannot have a harsh break-in force, being close to max spring rate with dual neopos should mean more rebound, not fully open. This doesn’ t make sense.
Fork set-up 101:
1) Adjust spring to 25(xc) - 33%(dh) static sag in attack position.
2) Adjust rebound from fully open to achieve a controlled ride without wallowing and being thrown up after compression at your typical speed and terrain
3) Add LSC for chassis control, especially to avoid excessive brake dive
4) Add a hint of HSC for «pop», and maybe go back a tad on the LSC if too harsh a result
#mezzer
I don’t recall having felt better on either Fox36/38, RS ZEB which i rode since transitioned to 29” for my enduro ride, the only thing i’d say in the negatives (not really a negative but) it’s the time you need to spend to fine tune for your bike and riding location, i have extensive list of all the test i’ve done with the different combinations air/CTS/Vol spacers/compression and rebound as they are hardly a limits with that many variables. But once you get to know it, really this is the best fork to date i’ve ridden.
At 2000gms it's just as capable as the Belva, has a better damper, and I can set it up with a coil, and it'll still weigh less than the Formula Belva.
If Formula can get the weight down and improve the air spring, say 2250gm, this fork would be worth considering.
Also, like 100g weight difference is going to make any difference. If you're so bothered by a couple grams, then you chose the wrong MTB category bike.
Unless you're somebody with a 7% body fat and fighting for the podium at the TDF, those 90g are not going to make any difference whatsoever.
The RRP seems to be in line with the other 38 SC contenders and you still need to see what it will be the actual selling price once broadly available in retailers.
Regarding the issue with the negative spring, I would like to get that addressed by Formula, but I've seen that for the Selva they offer a version for lighter riders, I can only assume it's also compatible with the Belva. Maybe they should also offer another version for heavier riders, or better, US riders.
Can Formula make it better? Perhaps, but at that weight and price, I'd be more likely to choose a truly quality product like the Push fork which is coil, custom build in CAN, and is likely a better product overall.
Who'd drop over 2k USD on a DC fork by Formula when you could pay less and get a Dorado Pro which weighs the same as the Belva?
This ^ is really the competition, not a Fox 38.
That being said, it's still a chunk more (in both weight and $) than Formula had set out to achieve. Coupled with the single air spring only, I'm not very tempted by the Belva- but I am now considering a Mezzer for the sale prices...
Then you claim that the stiffness difference between a DC and a Mezzer is 'debatable' (yeah right). You're peeing all over the place a making ridiculous claims to the point that I'm thinking you must be a bot.
575mm-585mm at 170mm of travel
585mm-595mm at 180mm of travel
www.rideformula.com/products/mtb-forks/belva
Based on the shape of the lower crown, I assume the range is for different wheel sizes... which means this thing has the same fixed AtC length as the 38. This seems like a missed opportunity. There are people out there that want more travel, but don't want to raise the front end. DHs DCs offer this adjustment flexibility, why not this one?
On top of that, none of the DH forks available have an offset lower than 46 (inc. 27.5). Changing the fork DH crown is extremely expensive considering also how much a DH fork costs.
Travel wise, not all of them can be lowered to 170/180. Fox 40 won't go lower than 190 unless it's modified which is not something most people can do.
Weight being the least important in my list for a MTB, you would also carry an extra 400g with a DH fork.
But you can shorten a Dorado as much as you want temporarily with a pump or with clip in spacers. 10mm each.
However, the story is always the same. All of the pure DH forks require a 20mm axle. I've always bought hubs that are compatible with them on purpose but a lot of modern hubs in order to be as light as possible are not.
Ohlins DH38 and Manitou Dorado offer internal travel adjustment, however, with the Manitou the shortest offset is 47 and that's with a head tube shorter than 121mm (inc. headset cups), which is basically only on S and M 29er frames.
If you want a 47 OS with the Dorado you would need to buy a custom upper crown from Rulezman which is freaking expensive. On top of that if you want to get it to a normal 44 OS, you'd also need to buy a Virtual Pivot Headset. If you start adding up all the extra cost and the +3kg of a Dorado, then you can see that it will steer away most riders.
Same for Ohlins, their DH fork comes without crowns. The cost of an Ohlins + crowns is €1K more than the Formula, that's considering you don't need to replace your front wheel.
If we look at Fox 40, there's a 190mm kit option but it costs around €150. Add an offset reducer crown like a Morc 40 or a virtual pivot headset and the costs are going to be considerably higher.
As I wrote above, the Formula Belva only requires a DM stem purchase and depending on your rotors size maybe an adapter. Both of which can be found in any MTB shop with an expense lower than €100.
It also comes standard with a 1.5 headtube, so no headset reducer is needed, it's a simple fork replacement.
@dickpound: My large Chilcotin has a silly short headtube (106mm), so I was just able to fit the 27.5 flat crown, no need for an aftermarket crown to get the short offset. I don't feel the need for a VP headset, because the slight increase in rake is offset by the slightly slacker headangle from the longer a2c.
Absolutely no need to worry about how it handles technical climbing and the added weight isn’t an issue if you’re half pushing, half pedalling up in the second largest gear.
I’m not 200lbs plus (any more!) so don’t have an issue with the Lyrik and Zeb I run, but if I was the benefits of a dual crown fork are huge.