question about tires..

[ramhouston]

if one was to run "P rated" tires with less sidewall, would you still feel all road bumps/irregularities more commonly? I am under the impression that a "P rated" tire with less sidewall will always ride better than a "E rated" tire that has more sidewall. i am curious to hear what you folks have to say. TIA!

 

[kdoublep]

Taller sidewall will provide more cushion than a low profile sidewall

 

[Rick3478]

if one was to run "P rated" tires with less sidewall, would you still feel all road bumps/irregularities more commonly? I am under the impression that a "P rated" tire with less sidewall will always ride better than a "E rated" tire that has more sidewall. i am curious to hear what you folks have to say. TIA!

I think I agree with the general concept, though there is a lot of individual variation between tire brands and "models". Also the "low rolling resistance" tires get that way by having very soft sidewall rubber (among other things), at the expense of not lasting as long. And Goodyear, Michelin, and others have tire models with a cushion layer in the belts to soak up little impacts, and they can be quite cushy. As always, you get what you pay for (or at least you never get more than you pay for).

 

[ramhouston]

Taller sidewall will provide more cushion than a low profile sidewall

but in terms of road feedback, what do you think?

 

[Rick3478]

but in terms of road feedback, what do you think?

If you're referring to steering feedback, generally lower profile or stiffer sidewalls feel more "planted". And of course the harder the tire, the more bumps you feel.

 

[ramhouston]

If you're referring to steering feedback, generally lower profile or stiffer sidewalls feel more "planted". And of course the harder the tire, the more bumps you feel.

not referring to steering feedback, but more like feeling every irregularity and bumps on the pavement?

 

[HSKR R/T]

I think I agree with the general concept, though there is a lot of individual variation between tire brands and "models". Also the "low rolling resistance" tires get that way by having very soft sidewall rubber (among other things), at the expense of not lasting as long. And Goodyear, Michelin, and others have tire models with a cushion layer in the belts to soak up little impacts, and they can be quite cushy. As always, you get what you pay for (or at least you never get more than you pay for).

I think you have that backwards in the low rolling resistance thing. To have low resistance, you would need a harder rubber compound with higher tread wear rating, and in turn stiffer sidewalls to prevent flex to keep contact patch smaller.

 

[John Jensen]

ramhouston,
P rated tires have the most flexible sidewalls which give the softest ride and are best at not feeling "all road bumps/irregularities". They are normally car tires, not truck tires. They also have the least load carrying ratings, and are more prone to road hazard damage. You should be looking at tires rated to be safe for whatever load/s you carry. Then, when running empty set the PSI to achieve the best ride.

 

[Rick3478]

I think you have that backwards in the low rolling resistance thing. To have low resistance, you would need a harder rubber compound with higher tread wear rating, and in turn stiffer sidewalls to prevent flex to keep contact patch smaller.

It may seem counter-intuitive, but sidewall flex doesn't have much influence on contact patch area. In fact the upper half of the tire is the part that supports the vehicle with the sidewalls pulling against the carcass and belt structure, which in turn is under tension from inflation pressure.

The contact patch area supports the overall tire structure by inflation pressure keeping the belts stretched tight and pressed against the road. You can reduce contact patch area some by jacking up pressure, and that may reduce rolling resistance a bit but creates other problems. For the same pressure (and therefore same contact patch area), you have to do more work forcing hard rubber to deflect at the edges of the patch, generating more wasted heat, compared to soft rubber that just bends and bounces back. Sidewall flex is part of that story, soft tread and flexy belts help, too.

The tradeoff is that softer rubber doesn't last as long, and it may even be questionable if you save enough fuel to pay for the extra tires you wear out. But it makes the EPA numbers look a little better, so LRR tires are popular with makers, maybe not as useful for users. Though as a side note, they tend to be quieter than hard, long treadwear tires, for similar tread pattern.

That's my take on LRR. I did quite a bit of research before choosing Firestone Fuel Fighters for my Mazda. I don't think I would put them on a truck, though.

 

[ramhouston]

P rated tires have the most flexible sidewalls which give the softest ride and are best at not feeling "all road bumps/irregularities".

i have the same ideology too lol!
maybe i'm just running too much air in my tires??

 

[ramhouston]

Taller sidewall will provide more cushion than a low profile sidewall

would the "more cushion" mean better ride comfort overall or is that subjective to ask?

 

[kdoublep]

One would think

 

[Scram1500]

i have the same ideology too lol!
maybe i'm just running too much air in my tires??

What psi are you using? The door jamb indicates 36 psi for most models

 

[Rick3478]

would the "more cushion" mean better ride comfort overall or is that subjective to ask?

A little, but it's pretty subjective. To take maximum advantage of that cushion you would have to reduce inflation pressure, relative to a low profile tire, to get a similar percentage of sidewall flex.

Also, the taller profile tire, for the same diameter, will have more rubber and less wheel. Since most vehicles have aluminum alloy wheels these days, that means a wheel with the tall profile tire will be heavier than a wheel with a low profile tire. The heavier wheel will absorb more road impact, wheras the lighter wheel will transfer more of the tiny, sharp impacts to the rest of the vehicle and passengers.

And more squishy, flexible rubber makes tall profile tires harder to balance and keep balanced.

If ride comfort is your goal, consider tires with a cushion layer in the belt/tread structure. Goodyear Assurance comes to mind, and I think maybe Continental Comfortred. Those are off the top of my head, I didn't research.