1997 Pontiac Grand Prix GTP: Suspension and 20-Inch Wheels
A Grand Prix GTP owner considering 20-inch wheels asks whether KYB AGX adjustable dampers would be preferable to the shocks included with a spring package. The useful starting point is the complete suspension plan, not wheel diameter alone.
Plan the suspension before the wheel package
Establish intended ride height, spring choice and available suspension travel before finalizing wheels and tires. Those decisions influence clearance and ride behavior. Building around a wheel already purchased can narrow the options and create compromises that a different tire profile or wheel specification might have avoided.
What AGX adjustment actually changes
KYB AGX uses adjustable damping settings, allowing supported applications to be tuned within the unit’s adjustment range. That changes damping response rather than wheel clearance or spring rate. Confirm the exact Grand Prix application before treating an adjustable product family as a fitment recommendation for this particular car.
Keep lowering limits application-specific
For the conventional-spring AGX approach, stay within the retained 1½-inch lowering limit and exclude coil-over arrangements. Confirm the exact damper and spring combination before installation. The drop amount alone does not establish remaining bump-stop clearance or usable damper travel.
Compare the complete spring-and-damper combination
Ask which dampers are included with the proposed spring package and what ride-height change the springs produce. A matched fixed-damping package may be worth comparing with an adjustable alternative. Neither the AGX name nor a 20-inch wheel specification alone establishes which combination will deliver the better ride.
Related reading
Frequently asked questions
Will adjustable shocks prevent wheel rubbing?
No. Wheel offset, tire dimensions, ride height and clearance determine rubbing; damping adjustment does not correct an incompatible wheel package.
Can I use AGX with any lowering spring?
No. Verify the specific damper application, permitted lowering range and spring compatibility before combining parts.
