Does air pressure trump speed rating for ride quality?

[Nayov]

Will a soft cheap tire, maybe something like Walmart's bottom feeder line, Douglas, offer a softer ride, or does the air pressure rule when it comes to ride quality?

If you do the very unscientific squash test (sitting on a tire, unmounted) the Douglas collapses but the Falken Ziex on the car now (tested off rim), almost holds my weight; does my so-called test have any validity?

 

[bullwinkle]

Ride quality & Douglas are mutually exclusive, plus they are horrible in any adverse conditions. The Falken Ziex isn't much better. Softer sidewalls seem to mean softer ride, but there's more to it than that.

 

[CapriRacer]

First, be careful. Many people define ride quality as vibration (or vibration-free). I think the word you are looking for is ride harshness.

When it comes to ride harshness, inflation pressure rules. Yes, you can feel the difference between tires at the same pressure, but the effect pressure has is greater. Now that doesn't mean you shouldn't try to select a tire for a better ride. The problem here is that there isn't a way to be sure of the relative ride harshness without actually riding on them. That's where testing and reviews are valuable.

And as a general rule, higher speed rating means a stiffer ride - BUT _ this isn't a universal thing, since the thing that controls ride harshness (sidewall stiffness) is not the thing that controls speed rating (cap plies).

Your test? Probably as rigorous as the test setup - as in not very. But if that's the only thing you have ......

 

[CharBaby]

I stay within the PSI placard listed on the door jamb or glovebox, wherever your tire placard is.
Meaning, +/- 1-2 psi depending on several different factors.

If we're only going out to dinner with friends(sitting in the rear of my car), I don't do anything different.
If we're going to the BIG BOX STORE for a large item, I don't do anything different there either.
However, when moving much of my(RIP) FIL stuff in my car from Tampa, FL to Rochester, NY, yeah, I changed > the PSI.

Generally, my 5 passenger car only has a driver or driver/passenger. So, I keep the F at spec(F:33 & R:33) and the R about 1-2 PSI < because I don't like the feeling of sharp bumps from the rear and that 1-2 PSI takes care of that sharpness or crashing feeling.

 

[barryh]

I wonder if there is a relationship between tyre stiffness and required air pressure. Some 10 years ago or more I drove an old car that had remoulds fitted all round. I was told they were quality Michelin carcasses and a reputable remould but the effect on ride harshness at standard pressures was beyond belief. I presume the remould process had stiffened the tires considerably. The owner had tried reducing the air pressure substantially to get any semblance of ride quality back. This was a car that was for sale so perhaps an understandable motive but possibly dangerous. This was a lesson to me never under any circumstances buy a car with remoulds fitted or consider fitting remoulds to my own car. The other obvious lesson was stiffer tyres ruin ride quality unless lower air pressures are permissible and I somehow doubt they are.

The other example is in the opposite direction of less stiff tyres is my 44 year old motorcycle. The standard handbook air pressures are extremely low by modern standards at 27 psi front on a 3.25 x 18 and 26 psi rear on a 4.00 x18. No one I know of runs anywhere near those pressures on modern tires even though they are the same size and basic construction. They have to be increased by 20% - 25% to get the bikes to handle safely. I presume that's the result of modern tyres being much less stiff than they were over 40 years ago.

 

[BMWTurboDzl]

Will a soft cheap tire, maybe something like Walmart's bottom feeder line, Douglas, offer a softer ride, or does the air pressure rule when it comes to ride quality?

If you do the very unscientific squash test (sitting on a tire, unmounted) the Douglas collapses but the Falken Ziex on the car now (tested off rim), almost holds my weight; does my so-called test have any validity?

Sidewall height: Taller = softer.
Load rating.: Higher = stiffer.

Basically the tallest tire with the lowest load rating allowed for your vehicle will give you the softest ride vs a tire with a higher load rating and lower sidewall.

However the suspension set up will be the biggest contributor.