Sprit Progressive Springs

I would like to hear someone attempt to explain the physics of why the spring needs to be “right side up”. This could be entertaining.

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i understand how the two-stage springs work in theory - but why in the hell they need to be right side up is baffling to me

I don’t think they do

I would like to hear someone attempt to explain the physics of why the spring needs to be “right side up”. This could be entertaining.

SPRiT progressive springs are wound tighter toward the top than bottom.

Sure, but I’m unclear on how the compression rate would differ based on orientation. Shouldn’t the force be distributed mostly-evenly through the whole spring either way?

Tighter wound part is stronger than the sparse part so, when compressed, weaker part will give first. This results in lighter feel at start that gets heavier toward the bottom. As to why having the weaker part on top would differ, I think the overall effect in opposite orientation is similar but not exactly same so the right orientation is the one the spring was designed to be used in.

I’ve verified that two orientations are similar but not exactly same. Which orientation you use is entirely up to you, I’d think.

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That sounds about right! I’d imagine there would not be zero difference but that the difference would not be so much as to fundamentally change the progressiveness of the spring.

I believe that the discrepancy in theory and feel arises from the bigger circumference at the base compared to the stem at the top. The housing could be rubbing against the spring and preventing it from compressing freely.

Yeah I messed around with this too at the time. It’s worth mentioning Sprit took the “reverse progressive” graph off the site pretty quickly once it got out this was something they were claiming and how physics dictate it shouldn’t change the force curve.

I can’t tell a difference with linears, but SOMETHING about orientation in tactiles makes them feel slightly different. It very well could be just the simple idea that there’s more wobble to the looser coiled side or something

This isn’t an explanation based on physics though, and anyone who says they felt a difference, it could be confirmation bias. Did you do a blind test? (meaning you didn’t know which was which when you tested them)

I don’t believe the orientation makes a difference until we see something more credible like a force graph to prove it


Maybe the difference is some combination of lateral stability and changing the center of mass of the system.

I totally agree. If you can’t do a force graph then what you should probably do is make a dozen switches of each variant and randomize them, or better get someone else to do this so you are blinded as well.

Then you should push each one and attempt to sort the switches into two groups. It’s not perfect, but just saying I feel a difference is not a good method.

For the physics of it, I struggle to see what it could be. The only thing I can think of is what was said earlier. That the less coiled end may have a larger diameter so if you put it on the base there is less friction. But if they are “perfect” progressive springs the orientation really shouldn’t matter.

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While I’m all for more scientific tests,

  • I only have time for subjective tests and
  • whether differences are real or not, feel is what matters in context of use-case.

My test results meet my needs. YMMV.

Subjective tests can be done more scientifically too, hence the suggestion about doing bind tests.

I agree feel is what matters, but if you only feel a difference when you already know the difference is there (placebo affect) then it’s not helpful to other people when we’re trying to determine whether the orientation matters.

Otherwise, you could just tell them the springs are all oriented “correctly” and as long as they think that (even if it isn’t true) they’d be happy, right?

I’ll try some testing when i get a chance and see if i can feel a difference, but I’ll do it as a blind test to try and avoid any bias.


Also just a minor correction, the part with more coils is the softer part of the spring.

You can think of compressing the spring like twisting a long piece of steel wire. If you take a section of the spring that has, say, 4 coils for every 2mm of length, compared to a second section that has only 2 coils for every 2mm of length, if you were to take those 2 sections and straighten them into a straight wire, the first section would consist of a longer piece of wire than the second. The deflection is spread out over more wire so it will be softer. If it helps you visualize it, you can also consider a really long piece of wire vs. a short one, and imagine if you clamped one end into a vise and tried to move the other end 6", which would be easier? Obviously the longer wire.

The part with the coils spread farther apart is the stiffer part. To move the spring the same distance, the wire has to twist/bend more per length of wire.


You are probably right. I just tried compressing one of the progressive springs and can see that the part with higher coil count compressed before rest of the spring. Thanks for correcting my understanding of how spring works.

I know this is a very old thread at this point, but I’m still interested in those impressions as I’m starting to explore these springs. If you’ve already written them down (or recorded them, as you do) please point me in the right direction. If not, please enlighten me, lol. I’m mostly interested if they add a bouncy feel, or really reduce the initial force, or even if they make much of a difference at all to you in linears.


IME with spirit progressive springs (various weights , but most exp. with 72g, 68g, & 63.5g P springs) the definitely do not add a bouncy feel. In fact unless you’re going with heavier weightings like 70g & over, the extra ramp up in weighting vs a linear progression is very subtle IME. Although the reason I like them so much is that they definitely do reduce the initial force needed & feel noticeably lighter at top than the same weighted linear spring. 63.5g progressives which I have been using exclusively for a couple months now remind me of 55g linear progression springs as far the starting weighting goes.


The lighter top end with a similar bottom end to the weights I like is definitely the goal. I have no problem bottoming out and don’t want a cherry clear like spring to keep me from doing so – I would just like to have a little more momentum pushing through actuation due to a lesser force needed to get thing started.

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I would say to give spirit progressive springs a try then cause they feel very close to what you described. Definitely not a MX Clear or Halo type heavy ramp up in weighting at the end with the lighter variants at least. I never tried over 68g progressive springs from spirit so I can’t say if heavier ones (80g +) would feel like clears or Halos or not, but I can say for sure 68g & below do not.