Service bulletin suggests lowering tire pressure

[HallenTi]

In a service bulletin for 1984 Corvette with Z-51 suspension, Chevrolet suggests the following:

"Ride harshness associated with the Z-51 suspension option may be a source of concern to some customers. Ride harshness can be significantly changed by reducing the cold tire inflation pressure from 35 psi to 26 psi. Operation at a tire pressure of 26 psi could result in a slight decrease in fuel economy and a slight increase in tire wear dependent on driving habits."


No other years are listed here. I have the Z-51 suspension, with the FX-3. Although I sometimes kinda like the "taught" feel of the suspension, I was thinking of trying the lower tire pressure to see just how much difference it makes. However, I know that changing the tire pressure from recommended can affect tire wear as well as fuel mileage, and wondered if others have lowered theirs. I'm interested in seeing any long-term ill-effects from lowering from the recommended 35 to something between the suggested 26 and 32 PSI. I do not drive very aggressively, and have the stock Goodyear tires. Thanks, Tim

 

[c4cruiser]

I recall reading where Chevrolet engineers softened the suspension a bit after the 84 model year because of complaints about ride quality but that may have been the base suspension instead of the Z51.

When I first read the text of the service bulletin you quoted, I immediately thought about the Ford/Firestone fiasco with lowering tire pressures :eek !

I have FX3/FE1 in my 92 roadster and I usually run 30-32psi on all 4 tires unless I am going to do any extended freeway traveling and then I raise pressures up to 35psi. I don't think I would go as far down as the 26psi mentioned as at some point I would think that tire wear would increase and overall handling would suffer. Of course, the tire sidewall sizes were much different from the 16" on the earlier C4's to the 17" from 88 on and I would think (but don't know) that tire pressure may have a different impact on the earlier tires thus changing ride quality.

 

[HallenTi]

I may jujst give your 30-32 a try to see how different it feels. I have seem the spring rate chart for the various suspensions but can't remember the difference between the 84 and the 90 that I have...good point and I will recheck. Yes, I thought similarly, as I know that too low a pressure is NOT a good thing! Thanks for the input.