So I finally replaced my aging Toyo's with 225-50-16 Dunlop A2's (excellent tires BTW.)

My mileage took a huge hit as soon as I did the tire swap. Before I was getting approx. 400 miles per tank @ 25-26 mpg. Now I'm lucky to get 360 a tank and that's if I push until the gas light comes on. Tonight I got 360 miles on 16.6 gallons for a 21.7 mpg average. FYI I'm running 34psi front, 32psi rear and not driving any differently. The weather's been the same (90's) since June so temp and/or AC use aren't any different. Haven't checked for codes since I have no drivability issues other than mpg.

I didn't expect a 10-15% drop in my mileage from just a plus-one setup. Has anyone had a similar problem? In the meantime I'm going to try raising the tire pressure to 36psi front and 34psi rear, maybe my rolling resistance will lessen (and also reduce my sidewall flex.) Other ideas?

Thanks,
TOM

 

i just stepped up (well a few weeks ago) to 235/17s.... HUGE difference in mileage from my stock 215/15s. I actaully had forgotten that.. and was wondering why it went down so much. then i thought about it and said it was worth the hit for style and handling i dont know about your situation.. stock size to stock size...

 

Stickier, wider tires = more traction = more rolling resistance = worse gas mileage.

You can try increasing the tire pressure, but don't go overboard. I'd say 36 max front and rear. You may see a slight improvement in mpg, but the bottom line is your mileage is suffering because the new tires are stickier. Just one of the compromises one makes when improving certain aspects of the car, handling/traction in this case.

 

Same here: I switched to 225X50 Potenzas about a year ago and haven't gotten more than ~21 MPG since. Oh well.

IT'S WORTH IT!!!!

 

- I've had 225/50/15 Pirelli P-Zero's up front for the past year and my mileage never changed... It has always sucked.

- Full tank of city driving: 17.5-18.0 mpg
- Full tank of highway driving: 24-15mpg

- This is the same mileage that I've always gotten - including when I had the OEM-recommended 215/60/15 tires. Maybe my new exhaust will help? hee hee - somehow, I don't think so. Vroom Vroom!

 

Yea, I assumed a little bit of a drop in mpg, but the actual decrease surprised me. Ha, I wonder if that means I have 10-15% more traction now! Overall, I'd rather spend another couple of bucks at the pump and have better performance.

I also have to say, the A2's are great tires. They are very grippy, quiet, great in the rain & have decent cornering (although I lost a tiny bit of crispness with the additional sidewall flex). I can literally fling the car into a corner now with no worries about traction. I hope they last as long as my old D60's did on my Contour.

Cheers,
TOM

 

How about...the tire size diference causing the decrease in mileage?
It causes an est. 1.5% diference on the speedometer.

The tire is smaller, the smaller tire rotates more to cover the same distance. Which means more energy or gas used.

Ehh?