Ways to decrease rolling resistance with brand new tires?

So I just replaced the ****ty dunlops with 175-64-14 general RT43s. The grip has significantly improved in wet, so is the road noise. However, my MPGs have suffered tremendously. I am down to 34 in city and 38 on hwy, from 39 and 44 (70mph). These are non LRR tires, so obviously mpg wont be as good as with dunlops. I have read brand new tires could hurt the fuel economy upto 20% because of deeper tread block. I have thus raised the tire pressure from 35psi to 37.5 psi in all 4 corners to overcome some of the rolling resistance. Any other ideas?

Increase pressure to sidewall maximum if you want, and break 'em in. Otherwise, enjoy sporty corning.

Lol cornering sucks in this car, too much body roll. I have another full built dual duty sitting in garage for the winter. I bought mirage because of fuel economy lol. Tires are rated to 44psi maximum, is that the max pressure when tires are cold? The ride is already stiffer at 37.5 psi, much like turning up the coilovers

That's what I did with my Enasaves - aired up to sidewall max, based on reading threads here. In fact, I need to check them after my dealer visit.

What did you do with your old Enasaves?

You also have larger diameter tires, so you need to factor that in. You're actually traveling faster than your speedometer reads.

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Thats fascinating actually. I had always wondered why when using a GPS speedometer cars were always 3-4 kmph consistently shy of what the reading on the speedometer was saying. This must be why

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Originally Posted by Eggman

That's what I did with my Enasaves - aired up to sidewall max, based on reading threads here. In fact, I need to check them after my dealer visit.

What did you do with your old Enasaves?

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I'm pretty sure your dealer will air them to recommended 35 PSI. I threw the enassves away, one of them had a sidewall bulge

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Originally Posted by Cani Lupine

You also have larger diameter tires, so you need to factor that in. You're actually traveling faster than your speedometer reads.

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That is indeeed true. However I think the dealer goofed up a little when they reprogrammed the computer for a recall. Even though I should be travelling faster than the speedo, my gps shows I'm going 3% slower than the speedo. 94-95ish kmph when car reads 100. So I will have to get that fixed as well

Keep in mind that nothing has less rolling resistance than a worn out LRR tire. So even if you had replaced your Enasaves with the same tires, you still would have noticed a slight mpg drop because the tires were new.

I agree, I have read the mpg may go down upto 20% with a set of brand new tires. However, the enasaves had 4/32 tread so not exactly bald but I get what you're saying. Explains why the stockers/most LRR tires with good mpgs are **** in wet conditions

I got new tires a couple of weeks ago and after 500 miles they are riding better and I got better mpg on the 2nd tank. I went to Ecopia Plus 185-55-15 tires on a 6.5in wheel. I was getting 41.5 mpg with the Ensaves. The first tank wasn't great wi the larger wheels. I added a bit more air 38psi, and the second tank was at 39.5 mi/gal with the new wheels and tires.

The gas mileage is still pretty bad even after 3000 miles or so. I have been running these tires at 38psi at all corners. I am averaging 33.5 mpg mixed driving (mostly city..down from 39.5), hwy driving took the biggest hit! About 34-35 mpg at 70mph down from 44 mpg. I cant believe tires alone would make this big of a difference! any more ideas?

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Originally Posted by 604_guy

The gas mileage is still pretty bad even after 3000 miles or so.
...I cant believe tires alone would make this big of a difference! any more ideas?

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Well...you picked the absolute worst time of the year to get new tires. :D I think a few things are not helping you right now...

1) Normal (not low rolling resistance) tires
2) Winter-blended gasoline
3) Cold temperatures
4) Has your car ever had an alignment check?

My fuel mileage dropped an easy 10% with winter blended fuel and cold temps. This car really does not like cold air temperatures! :eek: I get my worst mileage every time the temps fall significantly.

Haha you can say so, one of my stock tires had a bulge in them and knowing how bad they are in winter conditions (I'm glad I got the generals, we got lots of snow this winter..super unusual, these tires performed like champ..at the expense of mileage). I actually wasn't aware this car doesn't like cold temperatures, I was thinking cold air is best (dense) when it comes to air fuel ratio mix. Well my coyote (2014 Mustang GT) rips in colder temperatures, but then again I don't think it's fair to compare 520 crank HP to 75 lool. I'm actually losing out on about 16-18% gas mileage, I'm hopefully things might change with summer blend

Good info from a tire rack: https://www.tirerack.com/landing/fuel_efficiency.jsp

Has anyone tried the Bridgestone Potenza RE92?

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