who knows about spring rates?
 

ok, i have kyb agx which were recently put in and i thre these APEX springs in that my buddy got and they are from holland or something... anyway, i looked it up, it drops your car 1.8" and i figured they must be better than stock... on the springs there are different numbers on the front and on the back... the fron says something like 275 and the back says something like 260. i guess those are the spring rates?

i find them a little bouncy, but not back, but i find the back slams the tires down on like any bump... if you get what i mean, its got like the same stiffness as the front and not nearly as much weight... any ideas on this? from looking at other spring rates i find that like eiback pro=kits are 280 front and 190 back... if mine were something like that would the back be smoother?

The harder the spring rate, the less travel it has. Therefore, you need a shock that is made to go with that particular spring rate - to absorb the dampening.

In this case, I think your shocks are softer. If you "bounce", I think the spring and shock aren't matched. For stock vehicle, the spring and shock are mated for a softer ride, so they absorb the road condition as a whole.

For racing combo, though the spring rates are higher, the shocks are made to match. You feel the bump, but you won't "bounce" more than once, you know what I mean?

When I go over a lump in the road, the back tires roll over, sink in then come back up, then the rear end lifts up, then come back down onto the road. All in one motion, and it won't "bounce" again. No second bounce.

That's how I interpret it.

there are a few things to try, try all kinds of settings on those AGX and see if that helps. I doubt the rate is 275/260, thats way to closely matched plus they are never so close to the fronts....NEVER. and you can only get rates like that from custom rates like Eibach ERS (ground-control) and even then its usually 50 increments. mass produced springs lean heavily towards understeer, so common is like 280/180, or 330/230, although H&R sports are some of the closest at 330/280.

You describe it as bouncy, I wonder if the shocks aren't blown or the springs haven't been cut alittle or are well past the end of their life, cause with good AGX and even a cheaper aftermarket spring it shouldn't be bouncy, should be soft or firm depending on set-up but not bouncy

to get a shock/spring perfectly matched you have to either go coilovers or have the shocks custom valved, pretty much a racing only proceedure, since shocks like Koni Yellows can handle up to 500-600 without needed a revalve. dosen't really matter for street driven only, I loved my Illumina's/H&R Sports, damn nice ride that i'm hoping my new coilover are capable of with soft settings (probably wishful thinking :( )

I had Illumina's/H&R Sports that I just sold, they were never bouncy when the shock was at 3 or more, at 1 they were cadillac bouncy so AGX should not be bouncy either. Have you had someone inspect the AGX to make sure they are not blown? let someone who knows what they are doing (not meaning you don't, but i'll admit i certainly don't when it comes to shocks) to see if they can help

oh, no worries on that. i haven't got a clue on how to tell if the stuts are blow... i stopped by my local shop on two occassions for different things and i asked them about the shocks and they werre like, oh, they are a cpl months old? no worries then, they are fine... should i mention something in specific?

also, about the spring rates... those were just numbers i got off the springs... and remember it was the dutch that made them, and the dutch do things differently than we do things here... amsterdam and all those wonderful things in it, 3 wheel cars and all other interesting inventions... so, is it likely they could be? also, if not, how would i go about finding out the spring rates... i just know they are ****ty springs and thats why they are like that...

and to clarify, i guess its not bouncy, cause when i go over a bumb, its like back end raises, drops then levels out in like a split second... its just a weird feeling on that turn on the QEW with all those connector strips by palace pier... cause it is constantly bumby so its bumb, level out, bump level out, bump level out and that could all be in like 2 seconds... so i guess they do work ok... my thing is that it seems my back end is too light or something and that when i go over bumps or dips in the road, it seems my front takes it really well, but it seems like my back end just slams down on the ground sometimes...