Higher tire pressure -> lower MPG??

[cyclopathic]

Just switch from Dunlop Enasaves A/S to General RT-43(H), and looks like there is 5-10% MPG penalty. There are other factors in play, such as break in, lower ambient temperatures, stations switching to winter gas mix, etc, but subjectively car does not roll as well as it was on LRR Enasaves.

The only thing I found out of order is that RT43s were overinflated to 49psi.

General wisdom of ecomodder says higher pressure = to better MPG, but the question I am contemplating, is there such thing as too much? RT43s are non-LRR tire, but they were designed with "Low surface abrasion technology (LSA®)" belts to reduce wear/friction. Would this also mean that at some point higher pressure will change the shape of the contact patch and increase the abrasion?

[25Plus]

If tire pressure is too high, the middle of the tread will have more abrasion than the outside, if pressure ist too low, the sides will have more abrasion - granted that you don´t drive like a racer and the alingment is ok.

New tires are not as hard as older tires and therefore rolling resistance is slightly higher. But mostly, rolling resistance is depending on the tire and the tire pressure. If you have bad tires, fuel consumption can raise 10 %, no matter how much the tires are inflated. Of course mpg will get even worse with lower pressure.

[Cani Lupine]

I keep mine at 50 PSI. They don't roll as well as the EnaSaves, but they definitely grip and handle better, and that's worth the tradeoff for me. I can't stand how the EnaSaves feel like they're going to roll out from under me when I turn a tight corner.

[laceygirl]

That was the great thing about the LS here in Australia... They automatically come with Bridgestone Potenzas... Brilliant tyres...

[cyclopathic]

I keep mine at 50 PSI. They don't roll as well as the EnaSaves, but they definitely grip and handle better, and that's worth the tradeoff for me. I can't stand how the EnaSaves feel like they're going to roll out from under me when I turn a tight corner.

I've tried lower pressure (40/38, f/r), and they seem to roll better and quieter and grip better too.

Agree grip is worth lost MPG. We still have to wait 2 weeks until coilovers come to get it corner.

[cinder]

They need time to break in . The sipes go close to the base of the tire for both the H + T . That could impact F.E. a bit . Consumer Reports rates the Ts' and H better than average for rolling resistance in the November issue . Here's the sipes of the T and H .

[cyclopathic]

Do you remember how they rated them vs LRR tires? any commonly used tires such as Michelin Energy Saver? Need a point of reference, thx

[cyclopathic]

Update:

after putting ~4,000mi on RT-43s we pumped them up to 48psi and this seems to improve coast down distance. It looks like the issue was with the break in. The higher pressure must have resulted in stiffer sipe edges, which had negatively impacted fuel economy.

BTW after 4k they look like they only have a hundred miles or so. Mirage is really light so they will last very very long.

H-rated 185/60R14 have max pressure 51psi, and running 48psi is safe. It improves MPG and handling

[inuvik]

Update:

BTW after 4k they look like they only have a hundred miles or so. Mirage is really light so they will last very very long.

I had a set of Federal H-Rated 185/60R14's on my 4 door Metro and they lasted forever due to such low vehicle weight. I did take a mileage hit running them though.

[cyclopathic]

I had a set of Federal H-Rated 185/60R14's on my 4 door Metro and they lasted forever due to such low vehicle weight. I did take a mileage hit running them though.

RT43s seems to be much better MPG-wise, we're still getting 48.2 MPG even in rain. The only complain it took forever to break in.

The sidewalls very soft, so to get squirm out we had to pump them up to 48 psi, otherwise grip is good for A/S tire