MPG drop with touring wheels?

I also have changed my stock 15's to touring wheels ... noticed that the mpg dropped by 1-3... my tire pressure is 37/35

 

I get about 75 to 90 around town doing 30-40, in city i get about 47 and highway 50-60

 

I keep my tires at 44/42

 

Falken Ziex ze-912

FYI, the Falken Ziex ze-912 was Consumer Reports' top rated Ultra High Performance all season tire in its January 2008 tests of Ultra High Performance tires. I don't know about its rolling resistance as compared to the Touring's OEM Bridgestone Turenza El400's, but Consumer Reports rated its rolling resistance as "good".

It can be bought at DiscountTire.com in the Touring's OEM 195/55/16 size for $77 each.

 

I could be wrong but I don't believe a tire's maximum rated pressure means it must be used at that pressure.

 

Hey we told you so!

My guess is that in the long run, you'll end up with a 2 to 3 mpg drop -- and not that huge drop that you had posted about initially.

 

Arvind: I just put on Falken 205/55/16 tires, Ziex 325. I use to get 48 mpg and in the first 300 miles on these new tires, I've been averaging around 43 mpg. Of course you have to add another 2% to that number because of the change in tire size. I'll let you know how I do as I break the tires in. Barry

 

Barry: You have some really insightful posts. Very informative. I'm curious about your gas consumption. I need to replace my tires soon, and it looks like the 195/55/16 is a tough size to find. I'm going to jump up to 205's I think. Have you experienced any noticable changes in the way the car drives with the bigger tires? Keep the awesome posts coming. MAX

 

Max: I see you're in LA also. I looked all over for the original 195/55/16 tires and as you also notice the pickings are pretty slim. I hit something last Friday night and my tire was flat within 30 minutes. So I didn't have lots of time to go shopping. And since I had 40,000 miles on my Prius, it was time to change the tires anyway. It was a toss up between Big O Tires and Costo. The Michelins at Costo were in the $150 range and Big O had Falkens closer to $110, both in the 205 size. Big O also had Firestones in the 195 size, at the same price. Since the Falken was a better tire I opted for them. Of course when all was said and done with installation, tax, and a minor front end aligment, it was still $600 by the time I was finished.

At first glance the car is a little quieter on the freeway, and the ride does not seem quite as harsh. And you know how some intersections hump to drain the water, the new tires definitely make a difference there. Its not a jarring when you go over them. The real test will be in the wind and rain. I had some pretty scary moments on the I 5 between LA and San Francisco.

I was averaging around 48 mpg around in town on surface streets and the freeway. Of course it's tough to do more than 50 on the freeway during the day. Remember that heat wave we had a month or so ago. The temperature was over 110 in the Valley and I barely got 39 mpg. But everything went back to normal when the temperature cooled down. But driving to Las Vegas, Phoenix, and San Francisco, I would average anywhere between 42 and 44 mpg. I reset the screen after each fillup so I would know when to refill the tank. At 48 mpg I would refill anywhere between 400 and 430 miles. But on the open road when I average in the low 40's I refill the tank between 350 and 400 miles.

I'll let you know how the mileage changes as I break the tires in.

Here's another web site that calculates the difference in speedometer readings for different size tires. Tire size calculator

Barry

 

I have over 2,000 miles on my new Falken Ziex 325 (205/55/16) tires and my mpg is beginning to settle in back to where it use to be. I'm back averaging around 46 - 48 mpg on each tank around Los Angeles. And I was pleasantly surprised at the increase in mpg on the open road. I use to average 40 - 42 mpg between Los Angeles and Phoenix, which includes climbing a mountain or two and I averaged 44 mpg both ways on my last trip.

 

I do not know about the US Prius but my Ossie Prius has a setting on the MFD for tyres. I can select either 15" or 16" and reset the calibration when new tyres are fitted. I suspect that the Prius continually recalibrates tyre diameter as the miles are clock up to correct distance travelled.

 

simple: touring wheels and tires are bigger and heavier than the standerd 15", hence the drop in MPGs

 

Yup, that's the bottom line. He had an odd tank of 30+ mpg, but that was just that.

Better MPG Tire = Skinny - Hard compound - Low weight
Worse MGP Tire = Fat - Sticky - Higher weight

There is a trade off between performance, and fuel economy. Choose what's best for you.

... Brad