EXT Introduces Superlight V2 Coil Springs

Sep 28, 2021
by Seb Stott  

EXT has launched a lighter coil spring, the Superlight V2. It fits the Italian brand's Arma and Storia dampers and is compatible with other manufacturers' shocks using adapters. Depending on spring rate, the V2 springs are claimed to be lighter by "up to 30% compared with previous EXT Superlight springs and other competitor products". However, using numbers from a table they provided (below), the V2 spring works out to be between 9% and 23% lighter than the unnamed competitor(s) in this comparison. That's a 33-80g absolute weight difference - not something to write home about, but nice to have if you're after a new spring anyway.
Superlight V2 Coil Spring Details

• Claimed to be up to 30% lighter than competitor springs in some configurations.
• Two length options: up to 65mm or up to 75mm stroke.
• Spring rates: 225 to 600 lb/in (75mm) and 325 to 800 lb/in (65mm).
• 25 lb/in spring rate increments.
• +/- 3% spring rate tolerance.
• 109€ + VAT

In this chart from EXT, the V2 spring is claimed to be lighter than the competitor springs by (from top to bottom) 33g, 80g, 62g, and 55g. Or as a percentage, 8.6%, 22.7%, 14.8% and 12.8%, respectively.

When asked how the weight savings were achieved, EXT were tight-lipped about the material composition but say the steel alloy contains a higher percentage of Vanadium. "The capacity to make lighter springs is due to the possibility to apply higher stress on the material," EXT's Technical Director, Franco Fratton said. "This allows a different design with a smaller coil diameter and shorter material for a given spring rate and travel, which finally results in lower weight."

EXT say they're able to save weight without compromising on safety, lifespan or resistance to cracking.

*Springs over 600lbs/in are not compatible with ARMA V3, STORIA V2, ARMA V2 and previous Storia and Arma models. Springs over 600lbs/in must be assembled with a reinforced abutment.

The springs are available in two lengths to suit shocks up to 65mm stroke or up to 75mm stroke. The travel of the spring is built to closely match that of the shock in order to avoid wasting material to provide extra travel that's not needed. As a result, it's important not to preload the spring more than 2mm to avoid the coil binding before reaching full travel on the damper. (Preloading a coil more than about one full turn is usually a bad idea anyway.)

They're available in a wide range of spring rates (stiffness), from 225 to 600 lb/in for the 75mm length and 325 to 800 lb/in for the 65mm length. The gaps between spring rates remain nice and small, at 25 lb/in throughout most of the range, increasing to 50 lb/in gaps above 600 lb/in. That means the steps between spring rate options are as low as 4.3% and no higher than 11%, depending on the starting spring rate.

The V2 springs will become standard on future Storia and Arma shocks and are available through EXT's website at a cost of 109€ + VAT.


  • 69 26
 "+/- 3% spring rate tolerance" is not good enough...
for a 500 lbs/in it yields 485 to 515
for a 525 lbs/in it yields 510 to 541
meaning that a labelled 525 can be slightly softer or equal to a labelled 500...

I had a EXT V1 475 professionally measured at 458lbs/in. That's 3,6% off.
It felt exactly the same as the 450 that came with. The 450 measured 444lbs/in
  • 23 0
 That's why I only use sprindex, probability of buying a proper spring is much higher. Even if you buy 3 traditional springs you can still have them too close or too far given this 3%. Sprindex FTW, if you have spring damper chanses are you do not care about weight anyway.
  • 70 0
 +/- 3% is already a low tolerance for a spring rate… Getting mechanical properties (yield strength or even a Young’s modulus) bellow a 3% span is virtually impossible
  • 24 0
 As Armand said, 3% is already great. Standard off the shelf springs often have a range of 10% or more.
  • 31 1
 @Happymtbfr When there are up to 10% gaps between spring rate options (which is not bad for coil springs), a +/- 3% tolerance is not the main problem. It's not like we're fine-tuning spring rate on the single-digit percentage scale anyway.

Besides, at ten-degree (celsius) change in temperature will cause about a 3% change spring rate of an air spring. (Ambient temperature is around 300 Kelvin so ten degrees, or ten Kelvin, change causes a change in starting pressure of about 3%). If you're noticing that and adjusting air pressure as temperatures change throughout the morning then fair play, but I'm not. I did notice a difference when I went from freezing conditions in the UK to thirty degrees in New Zealand, where I had to let some air out, but otherwise, it's a pretty small thing.

You said it yourself - the spring that measured 458 felt the same as the one that measured 444lb/in - that's a 3.2% difference!

Having said all that, I agree with you that it's not ideal, especially for the smaller percentage rate gaps where the tolerance could, in a worst-case scenario, overcome the difference.
  • 49 1
 these springs are 109€ + VAT. Isn't it possible to check the real spring rate after production and label it correctly? Or am I getting something wrong?
  • 23 0
 @seb-stott: I understand the limits of the manufacturing process and the changes caused by temperature.
What I find less acceptable is buying a stiffer spring and getting one that is similar to the one I had before.

Maybe each spring could be measured and labelled with its real rate?
Or this is just showing that the 25lbs steps are too close to each other above 450lbs/in...
  • 12 0
 @tofhami: I was just about to say that. Measure it and write it on the spring with a Sharpie. its not that EXT is crazy mass producing. I'd be happy to pay even a 5er extra for that.
  • 1 1
 @Happymtbfr: Short answer: yes it is possible. Long answer: not easy since the spring rate is firstly calculated « by design ». It depends on the wire diameter, the number of coils and the mechanical properties of the material.
  • 8 0
 @Armand74: it's still possible to plan certain batches of certain spring rates and recategorize all springs after testing. Spring rate tests aren't hightech or expensive. Since the deviations should be somewhat random, the number of planned and actual springs per category should be roughly equal. If not, they can adjust the production process to account for the measured bias.
  • 6 2
 @Mac1987: I think this is just a pain in the a** for sales. Instead of having like 5 spring weights, you would have to precisely list them, or make like 10lb increments and have lot's of randomness in production (you never know how many pieces of which weight you are going to produce). Would still be possible, but probably would result in much higher prices.
  • 1 0
 Ha, interesting, I wasn't aware of that. I have an EXT spring that should be to hard for me (for a rider that is 5kg heavier) but it gives me 38% sag and bottoms out way to easily.
  • 9 0
 Just a tip - but when you get your shock serviced, you can usually ask the tuner to measure your spring rate for free, so worth including the spring in the pack.
In the years I've been having this done, Fox springs are by far the least accurate. Surprisingly (for Sram) Rockshox have been the closest to accurate, in my experience.
  • 1 0
 I have 2 springs of the same spring rate for my Dh bike. I know which one is the firmware and depending on how working from home has treated me, I change accordingly. You wouldn't not measure your tyre pressure and leave it to chance, so why not measure or quantify your spring rate.
  • 3 0
 I guess the 3% corresponds to the extremity of the Gauss curve, the chance to get a couple of spring with crossed characteristic should be limited in that way...
  • 2 10
flag ctd07 (Sep 28, 2021 at 5:42) (Below Threshold)
 @lkubica: an alternative to sprindex is just use a progressive spring, as you wind down preload to get sag, you are also changing spring rate, basically achieving the same result without the extra cost
  • 9 3
 @Armand74: Its very easy : you fabricate it, then you test it and finally you write the real test number on it.
  • 3 0
 Didn’t you just say “How much fun you have riding your bike cannot be quantified by numbers! F**k numbers!” Like a month ago? Apparently you either don’t like have fun and picked up a fondness for math since august.
  • 2 0
 @ctd07: I don't think so, progressive springs become progressive only in the end of the stroke, so you basically make the spring less "sensitive" by using preload. Sprindex is not that extra costly, I do not know hot it's possible, but it costs about 90EUR in Poland (the same as CC Vault) and 130EUR in Germany Wink
  • 11 4
 First, to everyone commenting on the 3% tolerance, I really don't believe it is relevant in any way. I think we frequently imagine ourselves as being much more sensitive than we really are. Unless, that is, everyone commenting weight themselves before each ride, have a ultra sensitive tyre pressure gauge and is constantly measuring temperatures across the entire system.

Secondly, to those saying "just measure every spring", do you have any idea how much of a clusterf*ck that would be for sales and supply chain? If you indeed want the consumer to know what precise rate he's ordering, just imagine the nightmare of inventory management, SKU creation, etc etc etc
  • 6 0
 @Arierep: I can assure you, that 15lbs difference in spring is easily noticeable (checked on Sprindex, so it really was ~15lbs).
  • 7 1
 @notai: Yeah in professional racing even when we buy springs from reputable spring manufactures like Renton, you always rate the spring in house. Preferably after some practice time and a race on it, you rerate it again because the spring rate and spring free length will settle into "place". Getting a good full travel spring rate is also important because even the best springs rate varies along its displacement, then you get towards the coil bind portion of max travel and you start picking up rate. And sometimes certain springs will let you travel further before big rate increases and other springs aren't as good, just the nature of springs!

  • 1 20
flag ctd07 (Sep 28, 2021 at 7:20) (Below Threshold)
 @lkubica: haha thats not how springs work, preload adjusts the initial starting point to suit the rider weight/preference, doesnt affect their sensitivity, just means you'll use more of the progressive part of the spring than the initial more linear part if you were running no preload
  • 1 14
flag ctd07 (Sep 28, 2021 at 7:41) (Below Threshold)
 @lkubica: just looked up sprindex again to refresh my memory on how they work, they are literally just progressive springs with a twisty bit of plastic that locks out the softer part of the spring instead of compressing it like preload does, they're exactly the same as any other progressive spring just with the added complexity of a fancy plastic dial.

The idea is marketed to help people determine what spring rate on a normal linear coil spring they would need to use, but because the only way the concept can work is by having a progressive spring, it doesnt help with that at all, such a useless idea.
  • 11 1
 @ctd07: You are wrong, when you set preload you simply make spring "work" after certain load, so yest, it definitely makes it less sensitive, degrading its performance to an air-shock level. Because that's why you use coil - it has less breakaway force than air. If you preload the spring you increate a force needed for damper to move into travel (even for the first 1mm of movement).
  • 3 19
flag ctd07 (Sep 28, 2021 at 7:45) (Below Threshold)
 @lkubica: you literally have no idea what you're talking about, i'm done, all the best
  • 2 0
 This may be dumb question, but why don't they just test the springs at a set temperature and label them with the actual spring rate at that temp?
  • 2 0
 @tstrunk33: I forgot that we have a setup like this somewhere at work. I just hope we haven’t disassembled it to use the load cell elsewhere.
  • 2 0
 @Happymtbfr: Maybe just buy a spring rate up and ride the hell out of it. The fatigue life is probably pretty low.
  • 1 0
 @lkubica: The spring rate will change throughout the fatigue life.
  • 2 0
 @downcountry: I would assume fatigue life actually pretty high, they are designed to be springs.

Anyone seen any research into this.
  • 1 0
 @tofhami: This is exactly what you should do or buy your springs from a reputable tuning company which will do it for you.
  • 1 0
 @usedbikestuff: fair point. I don't take myself too seriously, neither should you!
  • 3 0
 It's definitely too much variation. Having measured other brands springs it is nice to see a tolerance specified but this is quite large (especially when they are selling in 25lb increments). I was seeing more like 1.5% variation.

As other people have said measuring and sorting should be expected when paying $160CDN for a spring. People selling fork coil spring conversion kits (*cough* Vorsprung) are almost certainly doing this as the rate variations become even harder to manage with the long travel low rate springs you get in forks.
  • 5 0
 @ctd07:Check your first principles - unfortunately, you're wrong mate. Spring formula - F=kx. If you increase preload you increase x and therefore you increase Force. Any increase in force means less sensitivity off the top. For maximum sensitivity i.e. F_initial = 0 - x must be 0.
  • 1 1
 @Arierep: seconded. I do laugh when people talk about the difference between a 160mm and an 165 or 170mm bike being noticeable. Noticeable to a professional who rides three hours a day maybe. Probably not to your average Joe.

Since EXT shocks come from the factory to your spec, why not just have a stack of springs on hand with actual spring rates and sell them to customers accordingly? People are pigeon holed into shock strength brackets because they aren’t offered in smaller increments… this solves that issue, at least for people buying new EXT shocks from the factory or an official supplier.
  • 1 0
 @tofhami: if not a label, at the very least include a verification/calibration card with it. Does it really add that much to production cost? 109 euros + vat is a heck of a lot of money for a spring. That's over $130 USD which is absurd for a coil spring. My Cane Creek VALT was $60 MSRP.
  • 2 0
 3% tolerance is pretty much the best you could get, due to the mechanical characteristics of the steel, and the manufacturing process (if you don't do really specific engineering, or for instance measure the rates, and throw away the springs out of the tolerance, which is not something a MTB brand will do)
this is also the tolerance that is comonly used in

the question would be more do you really need 25 lbs improvements between 2 springs ?
  • 1 0
 @tofhami: I was thinking the same thing. Measure each spring, can't be hard...
  • 1 0
 @Arierep: you don't need to tell the precise rate. If you manufacturer a 450 spring and it turns out closer to 475 than 450, just label it 475. This way, as a customer, you at least know a 475 spring will be stiffer than a 450 spring. It might still be 465 instead of 475, but changing a 450 labelled spring for a 475 will always get you into the desired direction.
  • 1 0
 @Mac1987: except the 450 to 475 gap is way over the +-3% tolerance. The top value for the declared spec would be 463,5lb.
  • 1 0
 @Arierep: Which means you can get 450 which is higher rate than 475 and EXT does not say that the weight distribution is normal which means that you even cannot calculate the probability of such unfortunate event ...
  • 37 5
 The outside banner is here! For the pb-puritans: reminder that you can block things like that using most ad blocking browser extensions (right-click -> block element)
  • 8 0
 Install uBlock on your browser to block all ads.
  • 3 0
 @blaaaaaaaaaah: thanks for that, the element picker mode on ublock is perfect. removes it permanently and makes the site look normal again. They could've at least made the outside header black with white lettering to make it blend in more (not that I would've kept it anyway)
  • 2 0
 Custom filter for uBlock:

Works great!
  • 2 4
 I had not even noticed until i read this, and still took two looks to find it. Pretty unobtrusive at this point.
  • 1 0
 Any Safari recommendations - uBlock not available in UK...
  • 19 0
 this Outside Banner does my head in
  • 1 0
 download the ublock extension for your browser then use the element picker mode to remove it completely and permanently.
  • 1 0
 @hi-dr-nick: Show me! I need that thing gone!
  • 7 0
 The magic art of measuring spring;

-Place spring in a gravitational field, e.g at the surface of the earth

-Introduce a ruler

-measure length of spring along its major axis

-introduce an object of known mass, e.g. a 98.1N kettlebell

-place object of known mass on top of spring along its major axis and place spring along the axis of the gravitational field

-now measure the spring length again, and subtract that from original length

-you now have the spring deflection under a known load. Divide the latter by the former and you noe have the spring rate. Multiply by the appropriate concersion factor to ger imperial units if that’s your cup of tea, e.g. * 25.4mm/inch / 0.450kg/lb
  • 6 0
 For those wondering what the * was on the chart, here is from their website:
*Springs over 600lbs are not compatible with ARMA V3, STORIA V2, ARMA V2 and previous Storia and Arma models.
*Springs over 600lbs must be assembled with a reinforced abutment (Product Code: AB028B ) .

Quite an important piece of information ...
  • 6 0
 Fair point, I'll add that in.
  • 1 0
 @seb-stott: Thanks Smile
  • 1 0
 @Ploutre: Thank you for checking the website.
  • 1 0
 Where can I find the reinforcement abutment? I can't find it anywhere on their site for the life of me.
  • 7 2
 @hi-dr-nick: You know people with the Outside+ thing are just people that added the Pinkbike membership (probably years ago) to help support the site and gain a few options. It's not their fault Pinkbike change it to say "Outside+". So chill out tool.
  • 1 1
 Actually you’re wrong, it’s a whole different add on, but congrats on commenting outside the original comments and not understanding what a tool is.
  • 5 1
 "33 to 80grm less"
Great! More donuts!!!...
Wait, wait, wait!...
more donuts, more weight, different spring rate....dahmm
  • 1 0
 It's a vicious cycle
  • 3 0
 @notsosikmik: It's a delicious cycle
  • 1 0
 Is there a way to distinguish them visually from the V1? Doesn't look like it from these pictures.
Either way, I'm in the market for a stronger EXT spring for next season so I'll take the free weight savings.
  • 2 0
 The color is different as well as lettering. Side by side it is pretty easy to distinguish.
  • 2 0
 Is there any word about fatigue over lifetime? I'm wondering since with a lower number of coils every single one is under higher stress?
  • 1 0
 They have the same published cycle limit (500,000) as the V1 springs, which seems fishy.
  • 1 0
 @bigtuna00: thanks, that's not a lot, depending on how a 'cycle' is defined.
  • 3 0
 Do these coils fit Fox/Cane Creek also? Without an adaptor? I think I need a new coil for my CC
  • 1 0
 They will fit with an adapter.
  • 2 0
 For my bike, 63.5mm stroke, the storia is already 70 grams lighter than the cane creek inline coil it replaced. Now it can be, what, 140 grams lighter? This is great!
  • 1 0
 I hope the e-Storia I've paid and been waiting for since July comes with one. Ext said it would be arriving beginning of September, yet they still have no update for me. Wishing I went with push.
  • 1 0
 Why wouldn't the compare the physical weight to their old ones like Öhlins did with their lightweight versions? Instead of a random company?
I got four of my TTX springs checked and only one was close to it's spring weight.
  • 5 6
 I Wonder If a light spring is good... Since the Schock sits so Low in Most frames . I thought it might be good to have a more heavy spring since the Weight is so Low that it might Help a Bit against the heavy Rider. Manny ppl who Ride e Bikes say that it is realy Nice because of the Motor n the bottom so that helps a Lot with the Center of gravity.
  • 10 8
 I don't think your average ebike buyer knows how sag works, let alone are buying EXT springs. The select few who buy them know what they are doing. Anyway, lighter is better, especially for a part where adding weight may not necessarily make it more strong.
  • 5 3
 While the weight can help it feel planted in straight fast sections, their weight is also a serious downside... I've demo'd a few and while the climbing is fun... riding a 50 lb pig down enduro/all mountain trails is not fun. The things are way too heavy, moving the bike around, popping up and over things, jumping and just generally moving the bike around is laborious. Yes, you can just let the bike ride you... if that's your style.
  • 1 0
 Coil shocks, for me, is about keeping on riding witout failed air seals, 80gr weight saving on my 0.8kg avalanche dhs setup on my g16 doesn’t really make any sense…
  • 1 0
 Neither - I’m digging out my Slickoleum
  • 1 0
 Seems weird that a 350lb spring weighs more than a 375lb. Must be varying wire thickness throughout the range of spring rates
  • 1 0
 Now tell me, how many of you are searching for the ext grease instead of sram butter?
  • 1 0
 "The V2 springs will become standard on future Storia and Arma shocks"

This is what I was hoping for.
  • 6 0
 I bought a Geometron G1 from MojoRising about 6 weeks ago. The bike came with 2 x springs for the Storia and both were the new V2 versions..... so my guess is that the future is already here. My brother also bought a new Storia shock at about the same time as an upgrade to his G16 and his shock came with the V1 style springs for him to trial and decide which spring rates he really needed.... I quick call to Mojo and the final versions he was sent were also the new V2 springs. Happy days and great customer service from the Mojo team.
  • 2 0

Yes, I second that! I've already had a chat with Chris to discuss shock stroke and spring rate even though I said I hadn't saved up the pennies yet! Seriously good service from that team
  • 2 0
 How does the ext Storia compare with the 11/6?
  • 1 0
 I bought both because I couldn’t decide between the two, problem is they’re pretty damn close so it’s a hard deciding which one to keep. The 11-6 is a better climber but gets a little harsh in the rough stuff, the EXT is better in the rough stuff but isn’t as good of a climber. The EXT being lighter is a plus but it’s noisy as hell, if noises bother you I’d avoid it.
  • 1 0
 @OU812: What noises does your make?
My V2 Storia makes a topping out noise all of the time and very occasionally a bit of a whooshing noise when descending.
It's very good when I get going very fast though, or in low-grip situations - so I forgive it.
  • 1 0
 I have a storia lok on my 2021 altitude and had a push on my 2018 slayer. They are very similar. the nice thing about the Storia is they come with two springs so you have some adjustability out of the box. I have found that the Storia does make a bit of a whooshing noise on prolonged descents but like @chakaping said it's very good going very fast so it's forgivable.
  • 1 0
 Side note: unless you need a climb switch, get the Arma, not the Storia. Arma gives you adjustable HBC instead.
  • 1 0
 @chakaping: mine makes more than the whooshing noises for sure, I’ve sent it back to Mojo and they said it’s normal. I was told it depends on the tuning as to whether it’s louder or not so some people might not have any noises while others will. The little plastic bumper thing flopping around drove me crazy, I ended up having to glue it down.
  • 1 0
 @OU812: The plastic washer rattles a bit on mine too, but only intermittently for some reason.
Did you just use superglue on it?
  • 2 0
 @OU812: I believe depending on the tune Mojo will remove the titanium check ball valve to allow the shock to free bleed between compression and rebound circuits. That little ball is pretty noisy but I definitely prefer having it in as it gives the shock better energy return and the "playful/poppy" feel that EXT are known for and sets them apart from other coil shocks on the market. However if you are just looking for plush then that may not be your cup of tea.
  • 1 0
 @notsosikmik: I love the shock, it’s just noisy. I’ve got my old wheel set on the bike right now, hydra hubs drown out everything! The biggest issue I’m having is trying to decide which shock I’m going to keep…..Push or the EXT?!?
  • 1 0
 @OU812: good problem to have lol. Which one performs better?
  • 1 0
 arent these the same as sa springs? Maybe same manufaturer different labeling?
  • 2 0
 I like coil shocks
  • 7 0
 Any interest in soil cocks?
  • 3 2
 A few grams won't make any difference to my 25kg eeb.
  • 1 0
 Zo licht als een veertje.
  • 1 0
 Less material means lighter on the wallet...??
  • 1 0
 Never knew there were so many keyboard engineers around here...
  • 4 0
 Are you new here? Big Grin
  • 1 0
 I see… 38mm id
  • 1 0
 Need alert
  • 2 5
 A set of 4 springs for my car £125, a EXT spring, £100 + I really don't get how companies get these prices.
  • 7 0
 The springs for your car will weigh a lot. And will definitely have more than 3% tolerance. And there's huge volumes in the car world compared to the tiny volumes of a boutique bike shock.

That's how.
  • 1 0
 The raw materials to make the phone or whatever you’re typing this on cost less than £1 to source materials for. It’s about the value added and the scale, not price by mass.
  • 1 0
 If you buy an EXT shock you get a couple with it, and if you buy it in the UK the distributor will swap springs with you until you get to the weight you need (well done Mojo!).
If you don't have an EXT shock, you can get a standard spring for £10 off eBay.
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