1960 Valiant- road race torsion bars

The necessary wheel rate depends on a lot of different things. Weight is definitely part of that, but so is tire compound and size. F/R weight balance will also have a component in the F/R wheel rates, but so will ride height, any front to rear rake, and any kind of tire size stagger. And of course, road or track conditions make a huge difference. If you’re running on smooth pavement with sticky tires, your wheel rates will need to be a lot higher than if you’re running on the street with all season hockey pucks. Even shock choice can have an effect, if your cheap shocks are overdampening your suspension you can get a situation where your wheel rate isn’t too high but your shocks are keeping you from using the available travel when it’s needed.

The goal is to run the softest wheel rates that keep you from hammering your bump stops to death. Or, put another way, the highest wheel rates that still allow you to use your entire range of available suspension travel.

Now, I realize my Duster is heavier than a ‘60 Valiant by probably close to 600 lbs. But I run 1.12” (300 lb/in) torsion bars up front with a 1.25” sway bar and 120 lb/in springs with a 7/8” rear sway bar with 275/35/18’s and 295/40/18’s in a 200 treadwear tire. And I use every bit of suspension travel that I have. My car is lowered, but I still maintain about 5” to 5.5” of suspension travel in the front which is basically the factory range. Even though my car is basically a daily driver I’ve considered going a little higher on the front wheel rate.

You say your car is going to be set up for the track, what kind of wheels and tires will you be running? Because honestly, I always start there. Tires are the biggest variable by far. Sure, the weight matters, but that typically stays constant. You can change everything about how the car handles just by changing the tire compound. If you’re going to run 225’s and BFG T/A’s you probably don’t need to go much above 1” for the bars. If you’re going to run 275’s in a 100 treadwear track only tire you might need 1.18’s.