Vorsprung Introduces the Secus Air Spring System
Press Release: Vorsprung
Yeah, we know - “coil-like feel” from air springs has been marketed for years now, including by us. And over the years, air springs have mostly gotten closer to that predictable, plush feel coils give, but while the easy adjustability of pressure and end-stroke ramp have always been significant advantages for air springs, even our market-leading Luftkappe and Corset air springs never quite matched the linearity of coil springs for bump compliance, particularly in the early and mid travel, because whenever the initial stroke stiffness was reduced, the ending stroke progression was increased - eventually creating a practical limit on negative chamber size. We looked carefully at the limitations of traditional fork air springs to work out how to overcome those obstacles, and we’re excited about what we were able to achieve.
For the first time, we created an air spring with a truly better spring rate curve than a coil, without it actually being worse in any part of the travel.
Yes, you read that correctly.
Yes, it’s a big claim.
Yes, we can back it up.
It’s called the Secus.
The Secus is the first and only air spring system in a fork where the spring rate at 40mm travel is actually higher than it is at 10mm travel.
Three Stages of Control
Initial stroke - enlarged negative air spring chamber delivers a soft, supple initial stroke for ultimate small bump compliance
Mid stroke - where traditional air spring rates drop off in the midstroke, our proprietary Midstroke Support Valve technology boosts the midstroke spring rate to maintain linearity, for support, predictability, ride height and compliance
End stroke - enlarged lower leg volume reduces overall progression even at higher pressures and allows for a wider range of end-stroke ramp options to be utilised with standard fork volume spacers.
What’s it all mean? The Secus upgrade attaches to your factory air shaft assembly to deliver the first and only air spring system to really come indistinguishably close to the linear spring rate of a coil fork for the entire first 2/3rds of its travel, with the advantage of a gentle end stroke progression to prevent bottoming without the “wall of force” harshness that excessively progressive springs create.
By independently optimising the beginning, middle and end portions of the stroke, the Secus gives you the linear-to-progressive spring rate that coil springs and traditional air springs alike wish they had.
Secus Advantages:
• Distinctly improved small bump compliance, particularly in the early travel (yes, even compared to the Luftkappe)
• Midstroke Support Valve improves predictability and support beyond the sag point
• Reduced lower leg pneumatic ramp means better scalability of the air spring, particularly for light riders who previously struggled to use full travel
• Plush and predictable like a coil, bottomless like an air spring
• Allows full use of travel in both directions - fully extends to top out without any quibbles (including on Debonair B1 air springs) and fully compresses without an excessive ramp
• Considerably lighter than coil conversions - adds approximately 130g
• Allows lower leg bath oil to be used for superior lubrication
• Simple setup - inflate fork, bounce on it a few times, press MSV charge button, go ride
• Compatible with OEM volume spacers for end-stroke progression adjustment
• Compatible with other aftermarket top-cap systems such as DSD Runt and MRP Ramp Control
• Lower compression ratios mean a more consistent spring rate
• Transferrable between any Secus-compatible forks with only a footstud to change at most
12 Month Crash Replacement Guarantee
We will replace any damage to your Secus in the event of a crash or accident for the first 12 months of ownership - no questions asked. Just email us a photo of what’s damaged and your proof of purchase and we’ll do the rest.
We will replace any damage to your Secus in the event of a crash or accident for the first 12 months of ownership - no questions asked. Just email us a photo of what’s damaged and your proof of purchase and we’ll do the rest.
Secus Disadvantages:
• Costs more money than not having it
• 130g is still more than 0g
• Can be damaged if you have it, can’t be damaged if you don’t
• Still has seal friction like any air spring - since we use the factory moving seals, friction is unchanged
• Bottom out control is not externally adjustable - need to use volume spacers which still entails removing the top cap
Compatible Forks
Most Fox forks with Float NA2/Evol air springs (except StepCast forks or forks with footbolts recessed in the lowers). 32/34/36 available immediately, 38 and 40 fitments coming soon.
Most Rockshox Debonair 2019-21 forks or prior year forks updated with 2019-20 Debonair airshafts. Pike, Revelation, Lyrik, Yari available immediately, Boxxer fitments coming soon.
Not currently recommended for use with 2021 Debonair C1 shafts due to inadequate topout control and incorrect overall length - 2021 forks need to be retrofitted with the Debonair B1 air shaft assemblies from 2019-20.
For full compatibility information, see our website.
Air or Coil? Secus or Smashpot?
We aren’t purists on the air vs coil debate - we offer the Smashpot coil conversion as well because while this is flat out the best-performing air spring on the market, air springs still have moving seals and the friction and service requirements associated with that. Likewise, coil springs work extremely and have no friction, but are less adjustable in their spring rate and heavier.
Secus Price: MSRP $425CAD (approx $320USD at time of publication) including free shipping anywhere in North America. First batch available immediately.
See our list of elite-level tuning centres here. Get in touch if you'd like to become a dealer.
Proudly designed, tested & manufactured in Whistler, Canada.
More information at www.vorsprungsuspension.com
@vorsprungsuspension | Follow us on Instagram & Facebook
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- costs more than doing nothing
- weighs more than nothing
- more breakable than nothing
Would be curious to try if I wasn't already on a MRP Ribbon Coil - my days of "grass is always greener" are done now.
To be clear, I'm not knocking this product but y'all need to chill and realize that not everyone needs the best of the best of everything considering how expensive this sport already is.
But now I want this
ep1.pinkbike.org/p4pb8936838/p4pb8936838.jp
Kept the forks and changed frames.
There is also a strategy at Vorsprung here too: wait to introduce these things to a wider market until you see what the big players are doing. DVO and MRP are in a great position to capitalize on Fox/RS/EXT already showing their hands, and Vorsprung has added another spice for them to add to their future product development recipes.
Same reason a brand like Honda doesn't buy or compete with Greddy, Tein, etc.
It's a no brainer = Vorsprung.(for now)
Not speaking from experience there at all....
It’s not a gimmick - their products are improving significantly.
Sometimes the secret is putting all those rejected ideas together into a fine tuned package.
@VorsprungSuspension I'm hard pressed to pay for it right now, but I'd love to try it.
Also, a Tech Tuesday on the Secus would be cool!
1. Air spring curves vary hugely depending on setup (pressure/volume spacers and fork config) so there would be virtually infinite possible curves along with a ton of different ways that you might interpret an "equivalent" (same sag, same average spring rate, same mid stroke spring rate, same bottoming force, same energy absorption) for each fork.
2. We're in a position to legitimately compare it to a coil spring (the linear one) so it didn't necessarily make sense to just compare it to a stock air spring curve that is for all intents and purposes a worse performer than a coil.
Thanks for the suggestion - we may do a tech video on it for anyone interested.
ibb.co/RzmsgWH
As you can see it's pretty close to a 3 chamber dorado, hence my scepticism above. However technically Mr Vorsprung is correct, it is flatter at 40 than 10.
It will make a big difference to a more normal spring though.
1. Same sag
2. Same bottoming force
3. Same average spring rate
4. Same mid-stroke spring rate
5. Same energy absorption - and if so, at what combination of pressures and volumes
Because if you set it up to be the same for any one of those, all the others will differ significantly, because the spring curve is significantly different.
That made me laugh out loud - ty
My bad I still keep upgrading old Lyrik coil :-). Would love to compare it with "this linear air" and modern damper.
The air spring side for most forks has an equalization dimple to equalize the pressure between the positive and negative air chambers of the air spring. The damper side doesn't have those.
So you could do it, but you'd have to swap the stanchions as well. So yeah.. kind of possible, but not really an option unless "swapping stanchions" sounds like an afternoon project.
Don't think it's worth it though
jk don't do that
Maybe I could keep the lowers oriented normally... but then flip the crown around
I mean, that would give you some incredibly long trail numbers, but from a damper/spring perspective, it would totally work.
Anyhow, I like your tributes to French suspensions!
Great job from you bringing innovation to suspension and pushing the big brands to improve in order to keep up with you!
"Not currently recommended for use with 2021 Debonair C1 shafts due to inadequate topout control and incorrect overall length"
I have the new parts fitted to my 2020 Lyrik, and it seems fine other than I suspect the lubricant (3ml) in the air spring is making its way through to the lower. Gets a feeling of friction to it that goes away if I open up the air spring and add a little oil or rest the bike upside down (and cycle the legs).
Also, a bit of a tangent but many people are preferring the Rockshox 2021 air spring (myself included), finding it more supportive than the previous Debonair spring without excess harshness you'd expect when reducing the negative spring volume. Are people who like the new air spring just wrong/uninformed, or is there anything in the new air spring you'd identify as improved?
A lot of people do like the reduced sag of the 2021 shafts because it results in a higher static ride height (which is often noticed most as an increase in bar height) even if it does actually dive further from the sag point under brakes for example, but this is basically a form of correcting geometric concerns by altering the spring rate curve, which isn't what we'd typically recommend. Geometric concerns should be addressed directly with geometric adjustments (ie fork length and bar height), and suspension behaviour concerns should be addressed with suspension adjustments. Otherwise you end up compromising one or both to try to fix the other.
I'm experiencing huge increase in harshness with the 2021 spring. They suggest keeping pressures the same, but that's insane. I went down from 105 psi to 95, it's better but still harsh. I very dislike the upgrade.
This spring literally hurts more: riding trails 2 miles from my house that I've ridden hundreds of times, and my shoulders are all of a sudden sore after even a quick ride with this spring. Of course it rides higher, its a way firmer spring rate, even with less pressure. But if I go much lower on pressure, I don't get enough support in the middle to push against and traction goes away. I'd rather ride the 2014 Float 32 130mm on my hardtail!
I'm done with this silliness, going back to Fox: 2019 Factory 36 GRIP2 160 on the way that cannot arrive soon enough. There will be a Pike RC 150 with the C spring already installed and the B parts included, with ~300 miles on it and 2 oil changes, in the BuySell real soon now!
I read all the glowing reviews of the new spring and, as a proper mountain biker with an insatiable need to be told I need new stuff, I put it in my fork. And the fork become noticeably 'divey'. Naturally, I assumed I was just setting up my fork incorrectly or that I just need to learn to ride a bike. Particularly given that it was claimed to ride higher up in the travel with the new spring. Either way, I went back to the old spring.
I agree to some extent. It feels harsh when you are on your saddle.
I ended up running 62 psi instead instead of 80 recommended with one volume spacer inside, 8 clicks of lsc from fully open, 1 click of hsc from fully open, 9 clicks of rebound from slow.
Like I have said in my first statement, it is harsh when you sit on the saddle. As soon as I'm out of it and I, basically, sag the fork, it transforms itself in the plushes thing I've ever ridden; it makes my 2018 and 2019 factory 36s look like a low lvl suntour.
What I did initially wrong was to try and keep the lsc as open as possible, thinking that if I add more than 1-2 clicks, I will ruin the plush-ness. In fact, none of that happ. In fact, I may actually increase 1 or 2 clicks, depending on the trail.
So, just do a good set-up on it and don't expect the plushness of the top like the prev. model. I mean, it is of the top; just that this of the top is after the sag point.
One more thing to clarify:
Reco for me is 80 psi, no volume spacer, at 170mm fork.
I run 1 volume spacer and 62 psi.
If you have 160mm of travel on your fork, then you probably must put two.
For 150mm, three.
Cheers and sorry for stealing the thread a little.
My 2018 fit4, coming from a 2016 lyrik, was diving waaaay too much. I started fiddling with and, at one point, in order to compensate for the increased dive and the lack of smoothness of the top, ended up with 4 orange volume spacers. That was almost mimicking the feel of my '16 lyrik but I never managed to use more than 140mm of travel(from 180) due to the insane progressivness. I finally settled on 3, with 2 hsc, 4 lsc, both from open and 5 of rebound from slow. Still, with this set-up, I never managed to bottom out the fork, always remaining with 10-12 mm of travel untouched. Grip 2 was better, only needing 2 volume spacers.
My '21 lyrik, in the current set-up blows them to the sun. But it does have that harsh-ness at the beginning of the travel. Even the foxes were smoothere there. As soon as I am in the pedals and out of the saddle, it becomes the best fork I've ever ridden. It so good it puts my super-deluxe to shame, making me think I should get a coil or to have again a float x2 on my bike.
Well, yeah, no shit you're not using all the the travel with all of the spacers. And 10mm left "unused" on a 180mm fork? Who cares? It's a tiny bit of extra cushion to save you if you screw up a line or a landing. You're still using 170mm!
Dives too much but doesn't use all the travel? Remove spacers and increase pressure.
And super confused: you said the Lyrik is harsh off the top, but the Fox was smoother, but then you also said the Fox with Fit4 had lack of smoothness of the top...
Also, I'm not talking about harsh from 0mm into the travel, thought the C spring sucks at that too, I'm talking about near sag, whether sitting or standing. At ~100 kg, Pike RC 150 with C spring, 1 spacer, 95 psi, it literally leaves me hurting, while the B spring or a Float spring on the same trails does not bother my shoulders and wrists. Less pressure (for more comfort) means shite support and a loss of front traction, where the other springs manage to be both comfortable _and_ supportive.
The tradeoff of static ride height with the C spring is not worth it. Get a higher rise bar if "too low static ride height" and/or "excessive dive" is an issue with B or other springs.
(Yes, I know mountain biking is supposed to be hard and not necessarily comfortable, but there is a difference between working hard vs getting beat up by the bike.)
Hi man. It is incorrect to remove a spacer when a fork dives too much. What I did was adding 3 from zero and decrease the PSI. What I optained was a near similar feel with the 2016 Lyrik.
The 2021, with the set-up I have, basically 18 PSI less than recomended, it is harsh from zero travel(feels like I have put much more PSI than I should have) to near sag but, after that is the best fork I ever had. Just last weekend I did a 18kms down the hill trail from a mountain crest to the village in the valley..no hands problem, no problem anywhere. It gave me such confidence that I took some risks I never took in previous years on that route/traill. It was sublime. And my hands(wrists) are weak as a boilled spaghetti.
The foxes were more smooth until sag. I could hit a kerb at 90 degrees no problem sitting on my saddle and the response was smooth. On the run though, something was always missing and despite days of testing it, working through diff set-ups and fifdling with on the side of the trail, the end result was never than 90% satisfactorily.
This new lyrik..10-15 minutes for the first set-up then another 15 for the current version. I tried to cure the harshness from zero to sag but I was unsuccessfull. It does not really matter as I am more than impressed with how the fork works from sag to full travel.
Tbh, it puzzels me how you can have such a harsh ride with only one volume spacer when, in fact, from the factory, for 150mm it comes stock with two already inserted to counteract the positive-negative volume chamber changed ratio.
If I understood correctly what VorsprungSuspension said, then the C1 increased the positive chamber. Before you throw off your fork, I would suggest adding 2 more volume spacers and lower the PSI even more, anywhere between 18-to-20 PSI more. You have nothing to lose by doing that, correct?
You can increase pressure without removing the volume spacer.
A volume spacer does not only affects the end part of the travel; it affects every part of the travel. The avantage is that, for the same lvl of mid-support, you can have a smoother first part by lowering the PSI.
I kindly disagree. Any volume spacer will change the positive-negative ratio; thus, it will have an effect on all fork travel. The more spacers you put, the higher the effect. That is why you can sense an increase in mid-support even from only one spacer
It is a progressive curve, not a straigth line with a 90 degrees up in the 2/3 of the travel, as per your description.
Yes, it is a curve, but reducing the volume of the main chamber really doesn't have very much effect in the beginning 2/3rds of the travel. This is where the idea of the the "wall of force" comes from: air springs ramp _rapidly_ at the end. The smaller the overall positive chamber, the faster it ramps, but it still doesn't really ramp much until that last 1/3.
Yes, technically adding spacers and keeping PSI the same will increase the spring force slightly around 50% travel, but not very much. The main bonus of adding spacers is being able to reduce pressure to get low starting force while maintaining ending force. Removing spacers will require more pressure to maintain the final ending force, which also adds force to the beginning _and_ the middle.
The only way to significantly increase the midstroke spring force is by adding positive pressure _OR_ getting the negative spring to have more influence further into the travel by making it larger (which also allows/requires higher positive pressures, so double bonus). This is the whole point of the Corset, EVOL, DebonAir, MegNeg, and now Secus (though Secus has other pluses as well): allow increased pressure, for midstroke support, without making beginning stroke too harsh.
I am running a 2020 Pike Ultimate 140mm on a Evil Following MB.
I have a Helm coil on my HT and a Smashpot on the front of my Enduro.
Going to air was a deliberate decision as this is a trail bike, weight and feel both pointed to air.
So I just couldn't get on with the Pike in standard form. I'm 90kg in kit and ride pretty hard on very mixed terrain.
The fork was sucking into its travel by 10mm which was ok, i'd allowed for that but the lack of mid stroke was very evident and I had to run 3 tokens to get the pressure dropped enough to give good grip on the wet roots etc I ride often.
Enter the Secus.
Fitting was straightward, the fork was as ever pretty dry and poorly lubed from the factory.
Aired up the Secus to around 20% higher pressure than before, opened all the compression up and set the rebound in the middle of the park.
Firstly, the ride height was high, too high in fact and the initial sensitivity wasn't quite as soft as expected, good and controlled but not as soft as I had imagined. Support through the stroke was too high to. I had trouble driving the fork into the ground for grip.
I started to drop pressure around 3psi a time.... once at around 12% more pressure than before it is now sweet.
The ride height is a little lower, the initial sensitivity is superb, not soft but easy to initiate and grip is excellent. I run 4 clicks out on LSC or 2 if its wet on the chalk and clay here. The longed for mid stroke support is spot on, I love how I can leave it late in a turn and then force the front in hard and it grips, supports and just pushes back as you come off the front... flipping brilliant. Getting near full travel in a smooth controlled manner. I now have a token plus a Neapo glued to it.
Overall.... another great product from Vorsprung.
If not & minus a few extra grams, it looks like a great and cheaper way to get close to what EXT has done with their fork.
Very cool idea to utilize the pressure build-up in the lower to create a variable-volume negative air spring. I like the concept and I'm sure it feels interesting to say the least!
One thing that is conspicuously absent in this article is that the rider must run 20% more air pressure in their fork. Probably should have been mentioned. It won't be a viable option for large riders like myself, I would be well into the not-manufacturer-recommended pressure range. For the brave, manufacturer safety factors may help with that issue. Either way, hats off to you for solving a difficult air spring conundrum
Don't all air spring inherrently do this? Air piston moves through its stroke, +ve volume decreases, thus spring rate increases.
I assume he only means 2 chamber air spring.
3 Chambers don't.
Care to clarify @vorsprung?
Compare for example to a dorado set at 180?
Choosing 10 and 40 were key numbers to chose.
However, I'd have chosen the two figures that best reflected my idea too =)
I've not taken in to account the pressures in the lowers, which might just push it past with a Mattoc/Mezzer, however, what'd be the point in trying to prove one counter-example when it's clear your design would make a massive difference on a two-chamber fork which is what most riders are on anyway.
How much volume does it add?
Double-positive chamber designs do definitely improve the mid stroke support while avoiding crazy end stroke ramp, no doubt (IRT/Runt/SD/Doppio/ATA/TALAS1/Formula's thing/EXT's thing/Ohlins' thing/AWK are all variants of the exact same idea) by creating a digression in the spring curve somewhere around the middle of the travel. However, until the second chamber enters fluid communication with the first (ie pressures are equal), they behave the same as a normal single-positive air spring of a much smaller volume. This has only a small benefit to the initial spring rate because the positive chamber/s just don't affect it that much.
Lowers pressure is really significant on some forks, and less significant on others. On a 160mm Pike for example you can get nearly 50lbs (23kgf/230N approx) of force coming from the lowers by bottom out. That's a huge amount if you only weigh say 100lbs.
To get that 10/40 to work in my Dorado with my normal settings you would need to have the negative chamber 25% larger than the primary. That's a ton of milliunicorns.
I can see this making a huge difference on fox/RS stuff with their weird springs.
You now have me wanting to modify the ratio of my primary/secondary.
If I lower to 155 then the ratios all look good.
Do you know if the 29er air shaft is longer than the 650b one (and do you sell one if so)?
Any other ways of lowering the piston by about 30mm you can think of?
I'm not the requisite source of information on Dorado air shaft parts sorry - I'd contact your local Manitou distributor about that.
For mythical migratory equines, you may be getting confused with a pegasus?
If you can't even tell the difference between your magical horses I not sure I'd trust your measurement systems.
Good day to you sir.
p.s. Good idea.
Hi Vorsprung suspension
I was thinking about designing some parts to protect it in PETG but if you already have something it would save me some time.
Thanks
Also, have you explored releasing your own fork?
Its actually a more basic system and described differently with different end goals.
Still interesting read and a lot achieved for a thesis.
WTF are these people smoking??
Want coil; buy coil. Want air; buy air. Want air but want then want coil done less well and your warranty voided; buy a conversion kit for your air forks HAHAAAAA
That Kapfinger fellow seems to be doing okay with his huge undertaking. It can't hurt that returns are disallowed due to customization....
Keep up the good work!!!
Mr Kapfinger is indeed doing some impressive things. He can definitely think outside the box.
The whole “an average rider would never notice” line sounds like something that someone with very little experience would say
More likely because of the overhaul that the fork needed anyways that happened when the luftkappe was installed.
@VorsprungSuspension thanks!
Also worth noting that Fox used coil negative springs in all Float forks from 2002 to 2015 before they moved to negative air (NA) in 2016. DVO's OTT system has some merit, but it's not the be-all end-all either.
Either way, would love to give this a shot--and a good reminder I need to get into Traction Works to get your Tractive tune into my least favorite shock