Torsion bars the bigger the better???
I don’t care about stiffness and hard ride I want concise handling if I race
Street manners unimportant
Race only? What kind of tracks are we talking? And what kind of tires?
I’ve been running 1.12” torsion bars on my Duster on the street for close to 30k miles. With the 275/35/18’s, Hotchkis Fox shocks and Hellwig sway they’re still not too stiff for the street. After going to a set of Falken Azeni 615’s I can totally see how on a smooth track in warm weather I could run larger and still not be oversprung. On the street the 300 lb/in wheel rate is stiff but not harsh. I put 70k miles on a set of 1.12” bars on my Challenger, they were 270 lb/in and they weren’t stiff at all. I’ll probably go larger on that car just for the street.
For an aggressive handling street car I’d say 1.08”-1.14” wouldn’t be an issue at all as long as you’re running good tires, like 200-340 on the tread wear as just a general range. And a good set of shocks. I wouldn’t go bigger than that just because of the road conditions and suspension travel for the street.
On a track you could go stiffer even with the same tires depending on the track conditions. And if you’re running track only tires even more so.
It’s all based on the tires and how smooth the track is. If you have the grip you can go stiffer, as long as the track is smooth enough that you don’t need the travel to keep the tires on the ground.
Seems the trend is to get >1.00 at a minimum nowadays.....with a good shock. Not sure why Mopar didn't do this from the start with the B/RB A's if it was such an improvement.... I mean they had million dollar suspension dynos and could probably replicate any torsion bar rate but they stayed with the .8xx for even the big blocks?
Pretty much already covered. The tires were trash, if the tires won’t grip the forces transferred to the suspension won’t be as high. As the tires get better they transfer more force the the suspension and you need higher wheel rates to manage the higher forces. Radials didn’t come out on production mopars until ‘77 I think? Part of why some of the suspension stuff changed for the F bodies.
And part of it was the market at the time, a smooth, floaty ride was the style of the day. What the consumer wanted, even ahead of handling.
If the factory was putting radials on these cars the bars would have been stiffer. If performance handling had been more in vogue instead of straight line speed they would have been stiffer again.
