a theory on the compairson of PR and 7's springs aka bocking algebra

[XarnuSonci]

I just wrote a long PM about this so i figured i'd share with everyone and get your thoughts.

I have come up with an interesting comparison between the force required to bend a spring (to bottom out) and the energy returned by that compression.
It is accepted that PR springs are stiffer than 7's springs, and 7's have better energy return, so i tried to quantify that.  the only springs in this list that i've had experience with are PR90120's and 7's srex x and i extrapolated the rest.  I have found that with those two spring i get the same height but it takes less input force to get it out of the 7's.

Given a unit of force required to bottom out a spring x and a unit of energy returned by fully compressing a spring y:
a PR90120 spring takes 4x force to compress and returns 4y energy.
a 7's s-rex X spring takes 3x force to compress and returns 4y energy.
I guess that this can be extrapolated down the list so
pr7090 force 3x return 3x
7's trex force 2x return 3x
pr5070 force 2x return 2x
7's raptor force x return 2x

the relations between different weights is obviously not linear as this suggest but this is a simplification

I bottom out my 90120's fairly often at ~92kg and 2 years of bocking experience, which is why s-rexs are way to soft for me. So what I want to see from the stilt makers is a spring that takes 5x to compress.  From this theory if PR made such a spring it would return ~5y of energy unless they start changing their springs.  If 7's made this spring i would hope it would return ~6y of energy and I'd be on cloud 9 literally and figuratively. 

Comparing skips into this chart is an interesting task.  I've only had about 15 mins on skip springs on stuntman's pretty well used skip 580's.  They felt like they took about the same energy to compress as my at the time 6 month old PR90120's ~3.5x and gave back about the same.  I recall juhv posting something along the lines of s-rex x and skip 640's were very similar so they prolly float somewhere in the 3.5x 4y range as well, but I have not used them, just trying to extrapolate from 2nd hand knowledge.

I'd love to hear what other's have to think about this, and dome, don't tell me any thing about mysteries til you have an actual working product 

[MCTom]

s-rexs are way too soft for you? wow :O

Sounds fairly accurate to me from my limited experience on powerisers.  Where would you reckon stuff like pro-jumps would fit in to this, when I had a go on them it felt like I was putting in about the same energy but that half felt like it was just absorbed by the spring though, but I think they may have been too low a weight and so not really representative

Who was the PM to?

[Mr Frank]

You beat me to it!  I was in the middle of writing an identical topic with a few long quotes from you, then I saw you already did it. (the PM was to me)

Anyway, I have a little to say about Poweriser and Powerskip.

The difference in stiffness between PR7090s and E520s is extreme.  I found the E520s to be much softer than I thought I could ever rationally expect, but found that they gave me about the same height as a broken-in pair of 7090s.  I can't give any numbers, but the Powerskips were effortless to run in and bottom out.  In fact, I did it by accident nearly every time I tried to do a trick and they broke after two days.  However, they were an Ebay purchase and the last guy appeared to have drilled them out to fit Poweriser bolts and they may have been used more than he said, so maybe fresh 520s are stiffer.  I could still not imagine them ever being close to as hard to bottom out as my 7090s.

I also determined after using the Powerskips for a few days that my Poweriser springs give something vaguely close to the same force anywhere between four and fourteen inches compression.  I feel like I get into it, the spring applies an acceleration, and that acceleration remains constant until I'm in the air again.  The sudden changes in acceleration are kinda uncomfortable to me and I think some of the energy loss in the bounce comes from how my body reacts to that.  However, it does seem to get stronger for the last few inches; I can tell when I'm getting close to bottoming out.  This somewhat unpleasant character may just be a product of the fact that my Powerisers are new and have not gotten broken in yet.

[XarnuSonci]

I'm not sure where FL would fit on this chart, I haven't seen a (working) FL spring in over a year and i know they've done a lot to them in that time, so I'll have to do some tests at CB (if anybody's got strong FL's with cuffs, jason).

[Lukey]

Can you photoshop all this onto a chalkboard? That'd look cool.

[XarnuSonci]

if i had a camera on me i'd write it all up on the white board in my office and take a picture, but i don't, maybe monday.

[Theibault]

Interesting assertions there. Wish we had a bocker that works at a tests and measurements lab. We could then have him/her do actual real world scientific tests on bock springs. I'd love to see some quantified energy return numbers. I've always been curious about what the differences are in springs of the same make and weight. Are all 7090's the same,etc...

[Sprog]

Can you photoshop all this onto a chalkboard? That'd look cool.

[Mr Frank]

Sprog, you're the greatest fireman ever.

[Big Bad Bounce Boy]

can we please have 3 cheers for the homo fireman Sprog

HIP HIP


HIP HIP


HIP HIP   YOUR GAY!

 I LOVE YOU U FIRESLAG


lots of love jack

[Sprog]

can we please have 3 cheers for the homo fireman Sprog

HIP HIP


HIP HIP


HIP HIP   YOUR GAY!

 I LOVE YOU U FIRESLAG


lots of love jack

HIP HIP
HIP HIP
HIP HIP
f*** YOU!

Love you too BBBB

Sprog, you're the greatest fireman ever.

Lmao thanks, all in a day's work