J-Stock springs cancelled..?

Springs and shocks. What keeps your car tight around corners?
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Re: J-Stock springs cancelled..?

Postby M20_fever » Tue Sep 10, 2013 9:51 pm

They pop up for sale on the forums a few times per year, I'll keep an eye out.
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Re: J-Stock springs cancelled..?

Postby Nsquared97 » Wed Sep 11, 2013 5:09 am

blasphemy101 wrote:I'm sorry to hear that Ryki - it may be possible to go with the J-Stock dampers and use appropriately-rated Ground Control springs. Actually...That sounds like a nice setup!

Actually, yes yes it does. Although I'm not sure if you could get progressive style rates like the J-stocks.
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Re: J-Stock springs cancelled..?

Postby Yoshi » Wed Sep 11, 2013 11:33 am

You can make your own. get two short springs and stack em. 200/900 iirc is their front rate spread.
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Re: J-Stock springs cancelled..?

Postby M20_fever » Wed Sep 11, 2013 4:42 pm

stacking springs is not the sane as a true progressive coil. I find it hard to believe you can buy progressive springs for coil overs?
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Re: J-Stock springs cancelled..?

Postby Yoshi » Wed Sep 11, 2013 5:05 pm

What's the diff?
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Re: J-Stock springs cancelled..?

Postby Ryki » Wed Sep 11, 2013 5:06 pm

Hmm, not a bad idea but my preferences and OCD pretty much have me set on the J-Stock. If it takes a few years before I grab a set of springs that's fine, I'll probably use stock for that long or longer anyways :P Thanks for the suggestions and for looking out for me : )
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Re: J-Stock springs cancelled..?

Postby Nsquared97 » Thu Sep 12, 2013 5:32 am

Yoshi wrote:What's the diff?

lol springs don't work that way Yoshi.
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Re: J-Stock springs cancelled..?

Postby Yoshi » Thu Sep 12, 2013 1:30 pm

The progressive rate is literally 2 rates. Works like a stronger helper spring. It's not progressive like it's 200 for a bit, then 300, then 400. Nah. It's 200 until it's fully compressed in that section, then it's 900.

At least that is my current understanding.
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Re: J-Stock springs cancelled..?

Postby blasphemy101 » Thu Sep 12, 2013 5:58 pm

Yoshi wrote:The progressive rate is literally 2 rates. Works like a stronger helper spring. It's not progressive like it's 200 for a bit, then 300, then 400. Nah. It's 200 until it's fully compressed in that section, then it's 900.

At least that is my current understanding.


Springs in series don't work that way. While you're compressing the top spring, it is still applying force to the bottom spring. It's not like the top spring would compress 100% (coils bind) and THEN the bottom spring would start compressing.

1 / [total spring rate] = (1 / [rate of spring A]) + (1 / [rate of spring B])

That's the limit of my knowledge, though. I imagine progressive spring rates increase exponentially for the same reason springs in series work the way they do...Not one rate and then BAM! Another rate.

For what it's worth - it feels like the 'curve' of the way the rear j-stock rate increases is pretty significant. I can bounce the rear of the car down a noticeable amount, but I can't get it to go down further than a certain amount, no matter how hard I push.

Of course I could be entirely wrong. My knowledge of springs is limited to Physics I. Hopefully Dynamics will change that...

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Re: J-Stock springs cancelled..?

Postby Yoshi » Thu Sep 12, 2013 6:27 pm

I agree. I was over simplifying. I don't see how the Jstock is different from stacked regular coils. My point was, there isn't a 200lb section, 300lb section, etc. It's a 200lb section then a 900lb section and I guess some transition in the middle but not enough to make a diff.
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Re: J-Stock springs cancelled..?

Postby Ryki » Thu Sep 12, 2013 7:08 pm

Your equations are certainly close and I wish I still hadn't old books to double check my work but it should work like a modified bell cube, you'll see nearly every spring rates possible the time spent in each area of the curve would depend on force applied. I've definitely done this before but I feel like a car parked for five years trying to get moving again...
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Re: J-Stock springs cancelled..?

Postby blasphemy101 » Thu Sep 12, 2013 7:22 pm

Yoshi wrote:I agree. I was over simplifying. I don't see how the Jstock is different from stacked regular coils. My point was, there isn't a 200lb section, 300lb section, etc. It's a 200lb section then a 900lb section and I guess some transition in the middle but not enough to make a diff.


Gotcha - I wasn't trying to be a smart ass. I'd say that the reason there aren't 200, 300, etc. sections is exactly how they AREN'T like stacked springs :P

Two springs stacked on top of each other function like ONE spring rate - the rate is constant.

Using the formula above, a 200 lb spring and a 900 lb spring stacked together would behave like one spring with a rate of 163 lb...

With a progressive spring, the rate isn't constant.
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Re: J-Stock springs cancelled..?

Postby blasphemy101 » Thu Sep 12, 2013 7:25 pm

Ryki wrote:Your equations are certainly close and I wish I still hadn't old books to double check my work but it should work like a modified bell cube, you'll see nearly every spring rates possible the time spent in each area of the curve would depend on force applied. I've definitely done this before but I feel like a car parked for five years trying to get moving again...


Thanks Ryki - I assume you're talking about the progressive spring? That would go with my assumption - the rate/distance graph of a progressive spring should be a continuous function. The rate should 'ramp up' like a skateboard ramp, not change like a stairstep.
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Re: J-Stock springs cancelled..?

Postby Ryki » Thu Sep 12, 2013 9:41 pm

Yes sorry, trying to type after a work day probably wasn't the best idea. From my memory your assumptions on spring rates are correct : )
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Re: J-Stock springs cancelled..?

Postby Yoshi » Fri Sep 13, 2013 12:57 am

blasphemy101 wrote:Two springs stacked on top of each other function like ONE spring rate - the rate is constant.


Eh yes... but for the entirety until one spring is fully compressed. The Jstock spring is a short 200 and a long 900. So it would be whatever the combined would be until the 200lb short spring is fully compressed then it would be 900lbs. The debate isn't how they work, the debate is what the difference is having it as 2 identical spring (or spring sets) but physically separate.
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