1990 coupe suspension
 

Hey.... anyone know if the standard 1990 coupe (not the ZR1) would have a standard suspension?? I am trying to pruchase new drilled rotors and they all ask me if I have the heavy duty suspension. I do know that I do not have the FX3 Select Ride Adjustable Selection.

What they are trying to ask is if you have the optional J55 13" brakes that were part of the HD suspension package
If you don't know how to identify , look at the RPO label under the console lid and see if it has J55 listed

Just look at the front brake rotor thickness.
Standard 12" brake rotors are less than 3/4 inch thick or .720
J55 HD 13" brake rotors are more than one inch thick or 1.040.

You have the standard 12" brakes if it is a fx3 and 1990.

The J55 brakes were not available until the 1991 model paired with the fx3 suspension.

In what country?

My 90 had J55, FX3, Z51 etc

Z51 and FX3 with soft springs? I could be wrong but not sure why GM would pair the Z51 with the soft suspension that apparently came on your car.

edit to add, I am wrong GM did offer Z51, crazy though as it did come with the soft springs though so yes you can have the bigger brakes with fx3 in 1990 its the stiff suspension you don't get stock,:smash:

Z51 per say never had " soft" springs
It was the FX3 option that changed the required Z51 package to soft springs

"In '89, Selective Ride (FX3) came only in combination with the Performance Handling Package (Z51), but when you ordered
those two, in a strange twist, the car was downgraded to softer, base springs, stabilizer bars and front lower control arm bushings.
In 1990, FX3 no longer required Z51 but, if you ordered both, again, you got base springs, bars and bushings.
Unfortunately, this downgrade was not widely known.
Many unsuspecting '89/'90 customers, wanting the stiffer springs and bars, ordered Z51 along with FX3 but never knew their cars
had base parts. While there were 83 Corvette Challenge or World Challenge race cars built during those two model years with FX3
and "real" Z51 (a combination known to some as "R9G") they were not available to the general public.
It was not until 1991 when a combination of SRC and the stiffer springs and bars was released. That was RPO Z07, available through 1995".

Thanks to all!
 

Thanks Churchkey and all others for the suspension info. I did measure my 1990 rotors and yes they were about 3/4" thick so the standard suspension was the answer (thanks to all of you cuz I learn alot on this forum).

In a related topic I will be buying new rotors and pads for my 1990 at KNS Brakes. I decided on the Stop Tech Powerslot Rotors and the Hawk Performance Ceramic pads, per Nick that was very knowledgeable and helpful. It was nice to talk over this selection with a corvette guy. Now it's time to save for the brakes. :thumbs:

vetteoz,
If I have the standard bars, shouldn't they be the hollow style and not the solid bars? My '90 has the larger solid bars front and rear along with FX3, Z51, J55 options.

Thanks,
Mick