Fox Evol vs Vorsprung corset

Discussion in 'Parts 'n Stuff' started by Hools, Apr 5, 2017.

  1. Hools

    Hools Likes Dirt

    Who's used both? I've been using the corset on my Fox CTD and while the overall feel of the shock is much plusher I struggle to get proper sag. I know this is a fairly common complaint, but is the Evol can any better?
     
  2. Nautonier

    Nautonier Eats Squid

    I have used both and can confirm that the Evol can is far superior (in my opinion). The issue I also had with the corset was getting the correct sag; it was sitting at around 33% with 230psi in it, whereas the Evol sits at around 28% with 200psi. I've also found that both of my Corsets leaked air and had to be topped up before each ride if left for more than a couple of days. The Evol holds air the same as a regular Fox can.

    In terms of plushness, I think the win goes to the Evol, although there's not much in it. I think this is due to simply running less pressure.

    The other thing that really annoyed me about the Corset was that it bottomed out far too easily, whereas the Evol holds up better in the midstroke and only bottoms out where it should (with the same volume spacer installed). I was told that the Evol has a smaller internal volume than the Corset, which is why it ramps up better.

    I was ready to swap out my Fox Kashima CTD on the Santacruz 5010 for something else, but since trying the Evol air can it's transformed the bike.

    The only thing I would say though is that next time I get the shock serviced, I will get it revalved so that climb mode is a bit firmer. The issue with negative air chambers is that whilst they are super plush, they do cause a bit more pedal bob in climb mode, which can be solved by an $80 revalving. On the plus side, if you're more of an XC rider and like tech climbs, you will love the additional rear wheel traction. Personally I'd rather less traction and more energy going directly to the pedals. If I could have full lockout I would.
     
  3. S.

    S. ex offender

    Hi Hools, shoot me an email if you're having difficulty with the setup of your Corset and we'll help you get it sorted - steve at vorsprungsuspension dot com

    Sorry to hear you've had issues with your Corsets - can you shoot me an email with the details of your shock and what was going on so we can get them sorted for you? Obviously air leakage is not normal and needs to be fixed as it's very annoying. We had issues with the second batch of 7.875 LV sleeves that were made not sealing well due to some chatter issues in manufacturing, but that was sorted out a good while ago now so if the sleeve is more recent than early 2015 then it may be a separate issue. Email is steve at vorsprungsuspension dot com

    Regarding the sag issue - if you were running 230psi and having too much sag as well as bottoming out too easily and not having enough mid stroke support, the solution there is simply more air, as every indicator is that it was simply too soft. Comparing air pressure between the sleeves isn't really relevant as they don't provide the same overall (average) spring rate at any given air pressure. The Corset is fine up to 350psi so you have plenty of room to move there. With a bit of time spent playing around with air pressure and volume spacer configuration I'm very confident you can get distinctly better performance from the Corset than the Evol sleeve on the 5010. I say this not as the usual BS marketing spiel (especially since you have already bought it anyway) but because we have verified its performance quite thoroughly on that particular frame.

    Any other questions or issues, please don't hesitate to get in touch - we want to get you sorted out and enjoying the ride, and we also want to be fully aware of any problems people are having, so if you've had issues with any of our products we always want to hear about it. I don't check the forums much these days so email is the most reliable means of contacting us!

    On a somewhat related note - the concept of "correct" sag is a tricky one as there really is no way to define exactly what that is except by what problems your current spring rate gives you. If you want less sag because you're finding the bike too low or too slack then that's legit, and likewise wanting more sag for traction and compliance or handling, but chasing semi-arbitrary sag numbers rather than performance characteristics is not something I would generally recommend. Couple of videos we did regarding the concepts of correct setup and sag here for anyone interested:
    http://bit.ly/2nCCsAX
    http://bit.ly/2nCzaxy
    http://bit.ly/2oYpoae
     
  4. Hools

    Hools Likes Dirt



    Thanks for the excellent info, Nautonier. I have read of a few similar experiences, but it's always good to hear a first hand experiance. And if the EVOL is easier to use then it does sound like a winner. Before I go dropping any more coin, however, I will get in contact with Steve to see if he can make this work for me. It is tricky accurately putting more than 300psi into a shock though.
     
  5. Zaf

    Zaf Likes Bikes and Dirt

    Just get the EVOL can:
    + less expensive
    + greater adjustability in sag levels
    + works better
    + works "out of the box"
    + works without exceeding manufacturer recommended pressures
    + works without an additional upsell of volume spacers
    + you don't need to replace cans for any warranty servicing
    +you don't need to explain why your bottom out bumper has been crushed into a fine paste
    + you get to keep your warranty!

    - you won't look like a special snowflake
    - your bike will wear and tear faster on account of being in a usable state that you enjoy riding
     
  6. Hools

    Hools Likes Dirt

    A unique and beautiful snowflake?
     
  7. Nautonier

    Nautonier Eats Squid

    I disagree, you will look like a unique and beautiful snowflake as the Evol can has no Fox branding on it. Corsets are a dime a dozen, but you don't see many unbranded Evols around.
     
  8. Boom King

    Boom King Wheel size expert

    I'm sure your high specced carbon hire bike in Finale Ligure will have one.

    Sent from my LG-D855 using Tapatalk
     
  9. Nautonier

    Nautonier Eats Squid

  10. Boom King

    Boom King Wheel size expert

  11. Nautonier

    Nautonier Eats Squid

  12. waldog

    waldog Likes Bikes and Dirt

  13. S.

    S. ex offender

    Appreciate your feedback, but have to disagree with you on a few points there Zaf:

    I will say though that there are some bike/rider combinations that the Corset does not work well for:
    1. If you're especially heavy
    2. If you're on a particularly high-leverage bike (the most common ones being the Enduro and the Stumpy, which we make specific sleeves for in order to address that leverage ratio)
    3. Especially a combination of #1 and #2. See equation below.
    4. If your frame is very progressive (eg Norco Range)
    5. If you don't want to spend any time setting your suspension up. Not trying to be snarky here, but if you want to improve suspension performance with any self-install product, you're going to need to spend a bit of time playing around with it and getting it right. We are always more than happy to help with setup or any other questions you may have though, just email us.
    6. If your frame geometry is already slacker than you'd like - because the Corset focuses specifically on providing suspension performance (which requires a minimum amount of sag to work properly), on some frames that means running more sag than the amount where the geometry functions best. If you want an XC race bike where climbing performance and steep geometry is your #1 priority, the Corset is not for you - that's the main reason why we don't make them in the 6.5x1.5 size. Likewise, if you have a bike with a particularly slack seat tube angle and a low BB that you want to take up a lot of steep climbs, any increase in sag is going to hurt that climbing ability.

    If you're concerned about rider weight or leverage rate, you can calculate whether the Corset is likely to be a good fit for you with the following equation
    X = W x (T/S)^2
    Where:
    W = rider weight in kg
    T = frame travel in mm
    S = shock stroke in mm
    X = dimensionless value we're calculating

    If the calculated value of X is less than 700, you'll be able to run the Corset within the 350psi limit provided your bike isn't excessively progressive. If you're getting close to this value, shoot us an email with the specifics of your bike so we can give more accurate advice.
     
    Last edited: Apr 13, 2017
  14. Zaf

    Zaf Likes Bikes and Dirt

    Now before you come back and say "if you add air to an air can, it can only reduce the sag point"; because that should be how it works, and the logic holds up. But if it disagrees with experiment, it's wrong. No pressure addition, that remained within the safe recommended limits, corrected this (except for the first compression before the negative spring equalized). I spent plenty of time, and still do, setting up my suspension. Although I never tried the EVOL on the Yeti, instead moving over to a coil-over on that bike, the Camber was run with the Corset, switched back to its autosag can, and then later serviced and upgraded to an EVOL, which did not display the undesirable behaviour the Corset did with regards to blowing into travel.
    I currently run Float X Evol on my Canyon Strive, a significantly more progressive and higher leverage ratio frame than the Yeti with nothing but an amazing rear end performance. Might also add that I'm currently heavier than when I was(ride weight sitting around 92kg), which you seem to make out will be detrimental to the enjoyment of a Corset.

    I was an early adopter of the Corset as well, I even got one of the first batch cans with a concern in the manufacturing (a replacement was sent out before the first had arrived). I wanted to believe the marketing hype around it, I even tried to wish that I liked it whilst it was installed, but the moment I went back to a properly performing shock the game was well and truly over.
     
  15. S.

    S. ex offender

    Having owned an SB66 myself (when we were first developing the Corset no less - it was the main frame we used in development!), I find it interesting that you say that. I found the slack seat tube to be a hindrance to climbing for sure (I'm the same height and similar weight to you), though having compared the original Fox sleeve, the Evol and the Corset on that frame, the Evol (and even moreso the original sleeve) frankly sucked by comparison in terms of actual suspension performance ie bump absorption, traction and support. It did allow you to run less sag though which on that particular frame did make a considerable difference to climbing, and as I said, if that's your number one priority then the Corset isn't for you (and maybe neither is a long travel enduro bike!). FYI the leverage ratio on those things varies so little that it is basically dead linear compared to almost any other bike out there. Again, this has been measured and verified. Of course, no surprise that I preferred the performance of the product I designed, in addition to whatever degree of maker/confirmation bias is present, I designed it to suit how I and my test riders felt suspension should perform, and that aspect is somewhat subjective.

    However your claim about adding air not affecting the sag or spring rate in the early or mid stroke just isn't true (you don't want to know how many measurements I've personally taken on the SB66 with the Corset). It doesn't affect sag disproportionately like the Evol and old sleeves do, that is true - increasing your air pressure by 10% doesn't change your sag by 25% like it did with the old style sleeves, it changes it by about 10% (ie the difference between 30% and 27%). In the case of very progressive frames, particularly those where it's especially progressive in the first third of the travel, the increased leverage ratio early in the travel does effectively put a limiter on how little sag you can run. This is a function of those frames being designed to compensate for the generally terrible air spring curves that we all put up with for some reason up until a couple of years ago, and being designed around the low sag percentages that old-school air shocks needed to run in order to not be excessively soft in the mid travel, instead of the sag percentages that traction-oriented suspension performs best at.

    Where you say "adding volume spacers doesn't help with sag" - this is what I'm talking about when I'm saying setup is critical. It seems that the current trend with volume spacers is that people add them to fix any problem that they have (this is what we see day in day out in the workshop), even when the reverse is what they should be doing. The Corset should not be run with the same volume spacer as the stock sleeve (it should be at least one size smaller if not removed entirely with the LV sleeves, and absolutely should not be larger than the stock one!), and that excessive progression is why you found that cranking the pressure up simply made it harder to bottom out before it got the sag where you want it. The solution in those situations isn't to add spacers or just add air, it's to remove spacers AND add air at the same time. Initially we were telling people that the pressure limit was 300psi because that's what Fox were rating their units at and we weren't sure whether that was an arbitrary rating or something to do with seal life, even though we'd tested it and run FEA to over 350 from day one, but once they published the Evol rating (with the same seals) at 350psi we altered our rating to match. Whether this was relevant to you or not I'm not sure, as if you had one of the earliest sleeves then it was most likely at the time we were advising people not to exceed 300psi.

    However, all else aside, I accept that my priorities are not necessarily your priorities or preferences, and that you simply didn't like the way it rode, and please be aware that we do take that feedback on board. I (and everyone else at Vorsprung actually) come from a downhill background and the way we build suspension to perform is typically descent-oriented as a result, and I do understand that it isn't necessarily to everyone's tastes. In fact, for all the "marketing hype" around the Corset (consisting of one press release and a page on our website), I'm pretty sure we are about the only company ever to publish a page on our website detailing what kinds of bikes our product does NOT work well with.
     
    Last edited: Apr 13, 2017
  16. Zaf

    Zaf Likes Bikes and Dirt

    I said it ruined "pedalling performance", not just climbing. One of the advantages of running a suspension system like the switch link and VPP designs is how they rocket forward when you stomp them in any situation; having a shock that dives into its stroke every time you breath on it has a way of ruining the immediacy and spritefulness that the frame usually exhibits.

    The bike would not achieve a sag below 33%. There's no other way of saying it, so I'll add repetition to drive the point home. Any pressure addition to (if I remember correctly 260PSI+) had any effect on where the bike say into its travel. It would, in every case, settle down at about 33% once equalised and would slip through to it very easily, almost as if your top 30% was now a measurement of your damping hysteresis. Though I'm guessing you could make it sit at 10% by having a massive pressure differential between the positive and negative can...which will be great until it equalises. But all the calculations in the world still wont account for the whole "If it goes against experiment, it's wrong" problem it presented. It doesn't matter how smart you are who makes the guess, it doesn't matter how great the hypothesis is; if it goes against experiment, it's wrong. I can't alter the results, trust me, I tried to!!

    Completely aware of how volume spacers work. The shock had them installed to begin with, when non-ideal sag and no mid travel support was achieved, they were removed so that I had a more consistent spring rate throughout the stroke...only to find this had no effect on the sag still, and extra pressure just ramped up exactly like it did with the spacers installed; that is to say "violently and blowing through the mid stroke as if it were undamped", until you started getting above 300PSI, at which point it "bottomed out" with 5-10mm to spare.

    It didn't work for me, it made the shock feel unsupported and didn't aid traction when pushed nor inspire confidence in the rough. In fact, the only improvement felt was on small bumps.
     
  17. S.

    S. ex offender

    The numbers I'm giving and the claims I'm making aren't calculations, they're based on measured, quantified numbers based on testing on exactly that frame as well as actual dyno testing to measure the results, which demonstrates very unambiguously that increasing air pressure proportionally increases force (and spring rate) at every point in the travel. If you're ever over in Whistler I'm happy to show you all this in person.

    However, again, if it didn't work for you, that's fine and I accept that - we take your comments and feedback on board as a consideration for our ongoing development work. Maybe I sound like I'm being argumentative, and if so I apologise - I'm not trying to tell you that you "should" like something if you don't, because at the end of the day the aim of the game is to ride bikes with a smile on your face, and if that means you prefer some other product to ours, that's the way it goes and we'll put that feedback to good use. The Corset isn't all things to all people (nor is anything else) and we don't beat around the bush about that.
     
  18. hifiandmtb

    hifiandmtb King of his castle

    Kinda OT, but hey S. - want to update your profile to something other than "S.ex offender"?

    You are representing a major MTB suspension brand now :thumb:
     
  19. jrewing

    jrewing Likes Bikes and Dirt

    No keep it Steve. It's historical. And fuck political, businetical correctness... In both holes
     

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