free length of Gen2 rear spring

[Tom F&L GoR]

Anybody know - it must be shorter than Gen1 rear springs because of the shock fork? Thanks.

 

[Joe Dozzo]

I just happen to have a set (rears for 98 GTS) sitting in my office at the moment...

Free length is 12 1/2 inches.

 

[MtHam ACR]

12 1/2 inches?

The length of the rear spring in the GTS is 8", the ACR is 7".

 

[Joe Dozzo]

Maybe I've misunderstood ...

If "free length" means installed in the car with some (or maybe no) load on the suspension or off the car but still in the shock assembly, then bad on me, I've misinformed Tom and will be summarily executed at dawn.

If "free length" means out of the car, disassembled from the shock assembly and laying on the floor, then I stand by 12 1/2 inches - like I said, I have a pair in my office right now. Oh, and if this is the correct definition, you can take your flag and ... oh never mind

 

[MtHam ACR]

Hey Joe,

No disrespect intended, but are you sure that's a rear spring from a genII viper you're looking at? I'm pretty sure there isn't 12 1/2 inches between spring perches even with the suspension fully unloaded. Either that or they changed the design pretty radically in 01 . . .

peace,

 

[Joe Dozzo]

Hey Matt,

None taken - I've definitely been wrong before!

I'm very sure the springs I have are Gen II - they are new car (98 GTS) take-offs. They still have ID tags on them, "203 RR" (printed one above the other) are very prominent and there are two other numbers, 71765 and 04873203 printed in smaller font on the tags. Now, if I could just find the link to the parts guide some one published a few months back...

Unfortunately, I don't have the car at the office with me today or I'd run out and measure the installed / compressed height. I would not be surprised if the installed height of the springs are 8 inches.

 

[GTS Dean]

Joe is right and correctly answered Tom's question. The free length is the bare spring height. Standard (non-ACR) Viper springs are installed with preload on them. This allows full travel without rattling the springs on the retainers at full droop. They are constant rate - uniformly wound coil spacing and constant wire diameter.

 

[MtHam ACR]

OK, my bad, apologies to Joe -- seems I need to check my viper techs info before I go spouting my mouth off.

 

[Tom F&L GoR]

And you may wonder why I asked...

Gen 1 front springs are 14.5" free length. They are supposedly 250 lb/in springs. On my car, they compress to 10" installed. Therefore the spring must see a 1,125 pound load. A 450lb/in spring would compress 2.5 inches under a 1,125 load. If this 450 lb spring were 12.5" free length, it would compress to 10". Therefore, a Gen 2 rear 450lb/in spring could be used on the front of a Gen 1 car and the ride height would be pretty close to the same. (Yes, I know, scale the car, still have to get rear springs, etc.)

Hey, I might seem clever, but I'm cheap, too.

 

[Snake Bitten]

Tom,

I have an extra set of stocker GenII rear springs...free...still look new...just send me your address...