Adjustable-Rate Coil Spring (Sprindex)- Mtbr.com
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  1. #1
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    Adjustable-Rate Coil Spring (Sprindex)

    FYI: https://m.pinkbike.com/news/sprindex...irst-look.html

    What are your thoughts?

    The glass-reinforced polymer Sprindex unit comes pre-installed on one end of their coil springs - it can't be purchased on its own.
    Good idea! Bad business!

  2. #2
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    Price wise isn't it cheaper to buy two springs?
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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  3. #3
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    Could be . Hence why itís a shame not to be able to buy the unit/device by itself! (They would sell a looot more) and it would be practical for us ... the riders.

  4. #4
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    Quote Originally Posted by Dougal View Post
    Price wise isn't it cheaper to buy two springs?
    Unless you're buying from someone who has actually tested the springs rather than making one that tests correctly then another thousand that are hypothetically the same you don't really know what you're getting.

    So if you are good enough at setting up your bike to feel the difference between a 400 and a 425 two springs is likely not enough and if you can't tell the difference you might as well only buy one.

  5. #5
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    What if you are between spring rates?

    In theory could you not also set it up differently between flow and tech type trails. People dick with fork and shock air pressure depending upon what they are riding, so what about doing the same on the rear end with coil. This is even easier, just reach down and give it a turn, no pump required.

    Whatchoo got against coil, man?

    This devils advocate stuff can be fun
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  6. #6
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    Quote Originally Posted by digev View Post
    Could be . Hence why itís a shame not to be able to buy the unit/device by itself! (They would sell a looot more) and it would be practical for us ... the riders.
    It's gotta interface closely with the spring pitch and how it's wound at the end so I don't think it would be feasible to have it work with random springs. I really do like the concept.
    Do the math.

  7. #7
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    Quote Originally Posted by digev View Post
    Could be . Hence why itís a shame not to be able to buy the unit/device by itself! (They would sell a looot more) and it would be practical for us ... the riders.
    The device appears to be designed around a very specific spring. Using it on any other spring would potentially greatly compromise the function of the device due to the many variations of springs out there and not being calibrated or fitted to them, leading to morons posting ranty reviews and lots of time wasted with customer service issues.

  8. #8
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    Quote Originally Posted by mykel View Post
    What if you are between spring rates?

    In theory could you not also set it up differently between flow and tech type trails. People dick with fork and shock air pressure depending upon what they are riding, so what about doing the same on the rear end with coil. This is even easier, just reach down and give it a turn, no pump required.

    Whatchoo got against coil, man?

    This devils advocate stuff can be fun
    This is exactly what it was designed for. There's a good article here:

    https://m.pinkbike.com/news/sprindex...irst-look.html

  9. #9
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    Quote Originally Posted by Dougal View Post
    Price wise isn't it cheaper to buy two springs?
    Come on...
    If this is an EXT/SAR quality coil, you know the adjuster is actually being sold pretty cheaply. There is definitely an "if" in there though.

    It makes sense to not be sold separately as the adjuster has to match the spring.

    Seems like a set of these along with a spring tester could be pretty useful to a tuner. Tweak the rate on bike, measure the rate where it worked the best, sort through a bunch of normal springs and match up that rate.

  10. #10
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    Quote Originally Posted by PhillipJ View Post
    Unless you're buying from someone who has actually tested the springs rather than making one that tests correctly then another thousand that are hypothetically the same you don't really know what you're getting.
    Sure you do. You're getting one firmer and one softer. One will feel better.

    Like with air pumps, most people take their incorrect settings to extreme precision!
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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  11. #11
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    If your 500lb spring really measures around 460lb, and your 450lb spring really measures 480lb though, you are bound to get confused. I feel like I've ran into this and this is not just a hypothetical situation. I picked up a titanium spring that was 50lb lighter than the previous spring, but the bike felt stiffer with the titanium spring.

  12. #12
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    Iíve never seen an overlap that big, every spring Iíve measured was within 3% of itís labelled rate. I suspect they arent always ground very square, especially once powder coated so when they are installed some will be more preloaded than others without realising it

  13. #13
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    Quote Originally Posted by mike156 View Post
    If your 500lb spring really measures around 460lb, and your 450lb spring really measures 480lb though, you are bound to get confused. I feel like I've ran into this and this is not just a hypothetical situation. I picked up a titanium spring that was 50lb lighter than the previous spring, but the bike felt stiffer with the titanium spring.
    That sort of mismatch only happens with springs from completely different suppliers. Two springs of the same brand and different rate will be a relatively consistent offset.

    I have gone from a 450lb/in spring of one brand with good results to a 450 lb/in spring in another brand and found it way too stiff. So yes that problem exists.

    I'll get my spring checker built one day.......
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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    That's probably an accurate statement as I was going from 550lb SAR Enduro to a 500lb Renton titanium.

    Could have been difference in preload too. Could have been that the SAR was used for 6 months or so and the Renton was new? Not sure how much a SAR spring relaxes with use?

  15. #15
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    Quote Originally Posted by Dougal View Post
    Sure you do. You're getting one firmer and one softer. One will feel better.

    Like with air pumps, most people take their incorrect settings to extreme precision!
    So your reason shooting it down is that you feel itís impossible to be in between spring sizes?
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  16. #16
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    Quote Originally Posted by Jayem View Post
    So your reason shooting it down is that you feel itís impossible to be in between spring sizes?
    No. But with 25 lb/in increments it is kinda hard.

    The average person is running the completely wrong rate.

    I think this is suited as a shop setup tool. It makes no sense as a final product as anyone who needs to adjust spring-rate between rides typically needs a bigger change than it could provide.
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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  17. #17
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    Quote Originally Posted by Dougal View Post
    That sort of mismatch only happens with springs from completely different suppliers. Two springs of the same brand and different rate will be a relatively consistent offset.

    I have gone from a 450lb/in spring of one brand with good results to a 450 lb/in spring in another brand and found it way too stiff. So yes that problem exists.

    I'll get my spring checker built one day.......

    this is you from only a few months ago:

    Quote Originally Posted by Dougal View Post
    Yes. But keep in mind the tolerances involved in spring manufacture mean a 400 lb/in could easily be anywhere from 360-440 lb/in.

    This sprindex isn't going to help if you don't know what you need but surely it's better than just buying two springs if you know approximately what you need but can't be sure that what is delivered to you is actually what it says on the label.

  18. #18
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    Quote Originally Posted by PhillipJ View Post
    this is you from only a few months ago:

    This sprindex isn't going to help if you don't know what you need but surely it's better than just buying two springs if you know approximately what you need but can't be sure that what is delivered to you is actually what it says on the label.
    Yes. What I'm saying is if springs are from one brand/manufacturer the deviation should all be in one direction.

    So if brand A has a 400lb/in which measures 380 lb/in, you'd expect their 450 lb/in to also be on the low side and keep a similar to 50lb/in gap between them.

    Where brand B might have a 400lb/in which actually measures 420lb/in and a 450lb/in which might be around 470lb/in.

    So maintaining brand you'll have far better results than swapping between. In this hypothetical example swapping from a Brand A 450 to a Brand B 400 would not give the expected result.
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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  19. #19
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    This is no more a shop setup tool as a shock pump is for an air sprung damper, there are plenty of riders who know how to use this AND will benifit from it, after all the closer you can get to the "correct" spring rate the closer you can get to the "correct" damper settings, just my opinion though, dont shoot me down !

  20. #20
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    Quote Originally Posted by karpiel View Post
    This is no more a shop setup tool as a shock pump is for an air sprung damper, there are plenty of riders who know how to use this AND will benifit from it, after all the closer you can get to the "correct" spring rate the closer you can get to the "correct" damper settings, just my opinion though, dont shoot me down !
    Not shooting you down, but you are grossly overestimating the competence of the average rider (hint: if you're posting on a message board about it, you probably aren't "average").

  21. #21
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    Quote Originally Posted by Dougal View Post
    Sure you do. You're getting one firmer and one softer. One will feel better.

    Like with air pumps, most people take their incorrect settings to extreme precision!
    So true, the idea that I use the pump pressures as an absolute, then later wonder why it feels different ... perhaps that five dollar shock pump isn't that accurate??

    So Dougal, as a professional tuner and engineer, don't you get tire of lay people questioning your experiences?

    I'm a medical provider, I get the same sort of thing from folks who "read on the internet or talked to a friend", suddenly I'm inexperienced and just plan wrong.

    When did being a trained professional start meaning you're stoopid?
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  22. #22
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    The spring they have installed there is a progressively wound spring That's how they are getting such a change in spring rate! I wonder if it would even work on a linear spring rate, and how much lifespan they remove from that spring.

    So yeah, honestly it seems like they are just playing with an already existing thing - a progressively wound spring. They are removing the benefits of said spring, and calling it a new technology with improved results.
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  23. #23
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    Quote Originally Posted by Nurse Ben View Post
    So true, the idea that I use the pump pressures as an absolute, then later wonder why it feels different ... perhaps that five dollar shock pump isn't that accurate??

    So Dougal, as a professional tuner and engineer, don't you get tire of lay people questioning your experiences?

    I'm a medical provider, I get the same sort of thing from folks who "read on the internet or talked to a friend", suddenly I'm inexperienced and just plan wrong.

    When did being a trained professional start meaning you're stoopid?
    You are inferring that every trained professional in a given field will always have the same answers to a given question or condition.

  24. #24
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    I think this is a great idea and they appear to have thought it through really well, ie the material stress limits are designed around using it in the hardest position

    They test the spring on a rater in that link and it holds up to its claims, which is consistent with the kind of margin of error I've measured across several different brands myself. Even the dirt cheap plain steel DVO springs are within less than 3% of stated rate, so I don't know where the stories of mtb springs having huge discrepancies came from

    I had thought about something like this a while ago, inspired by the u-turn in old Rockshox Psylo's and Pikes. Their travel adjust worked by making the spring seat wind in to the coils so as you reduced the travel, it blocked off part of the spring and increased the spring rate so it would always have an appropriate rate for the travel
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  25. #25
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    I think I've got four springs for my rear shock, from 454, 480 and 502? I really only put the heavy one on for dedicated shuttle days, but even then I can ride it for normal rides too.
    I don't ever recall bottoming my rear shock. The bumper is pretty big on it.
    Looks like Cane Creek might have stolen some thunder though.

  26. #26
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    Quote Originally Posted by Nurse Ben View Post
    When did being a trained professional start meaning you're stoopid?
    To be fair, there are a lot of trained professionals letting the side down in all fields.

    In suspension, the physics and maths are relatively straightforward but we still get huge disagreement on the basics of modelling and even velocities.

    The black art side of suspension is what the spring and damper rates should be and why. That side becomes hugely subjective and that's before we throw in different terrain, riding styles, preferences etc.

    Spring-Rate calculators are an excellent example. I have mine and I'm very happy with the results.
    There are probably a dozen other spring calculators out there and none are in any agreement with mine or each other.
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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