Lower MPG with new tires.

Yes, but only for a short period of time. Real world difference between the Yoko's and Defenders after break in is more like 1-2 mpg less if you get really anal about it. My Defenders have over 40K miles now and about 70% legal tread. The Yokos (remaining 3) were near bald and replaced by this time before. The Energy Savers are reported to get 1-2 mpg better than the Yokos, but are rated for 60K miles vs 90K miles on the Defenders.

 

As frodo said, perfectly normal. New tires are actually a little larger in circumference which affects the MPG calculation. Also the tires are NOT broken in, so the tread is not rolling as easily as a used tire will.

Give them a few tanks of gas and some time, and your MPG should return. The defender is a LRR type tire, but there are better one's out there. But if you are interested in getting GOOD longevity from your tires, then you made the right choice IMO.

Finally, "Welcome To Prius Chat"!

Ron (dorunron)

 

LRR tires from different brands can perform quite differently. A friend put a set of Conti PureContacts with EcoPlus Tech on his 2010 Prius Hatchback. He keeps them at 38/36 front/rear and has lost about 3-5 mpg compared to the old OE Yoks. But they ride really nicely and are very quiet. The car was fairly linear with the old tires, but now it's even better. He has about 5K or a little more on them now, so are broken in. Unfortunately, he had the update done the same day that those new Contis were put on. So this particular tire/MPG comparison may be skewed a tad.

 

We put Michelin Energy? tires on our 13 after the Yokohama tires wore out. We gained 2 MPG by doing so. The rest of the story is that the salesman talked my wife into the Continental Pure Contact tires telling her that they definitely would increase the fuel economy and if she didn't like them then she could return them within 2 weeks and exchange them. They were on the car for 400 miles and the milage dropped by 5MPG. Car went back to the tire shop, Conti's came off and the Michelins went on.

 

Yes, two different categories of tire (standard vs. grand touring). You trade traction, especially wet traction, and handling for fuel economy and a little more comfort. Tires are all about trade offs.

 

Have a look at Michelin's web site, their rolling resistance ratings of several Prius options:

Energy Saver: 10
Premier A/S: 9
Defender: 8

2010 Toyota Prius Base Tires | Michelin Tires

Your mpg will pick up a bit over time, with extra effort on your part may get close to your previous results, but it will be an uphill battle.

 

I went from well worn Toyo Versado eco to the Defenders & initially took a small but noticeable hit. After >20K I'm back to about the same mileage as before. On both the old & new tires I run max pressure on the sidewall (44psi) in all 4 tires. Most of my driving now is with a hitch mounted bicycle rack installed - higher tire pressure helps lots!

 

I also went from Yokahamas to Michilin Defenders. My milage dropped 2 to 3 mph. The Defenders are noticeably quieter and are rated to last much longer than other LLR tires.

 

more than pay for themselves with $2. gas.

 

went from Yokohamas to Michelin Savers A/S and mileage had gone up 2 to 3 mph. The Savers are noticeably quieter, and lasted 70K.

Thread wear on Defender is rated at 820 and on Saver 480, so Defender could potentially last ~120K. Issue is that tires are usually no good after 3 years, so unless you drive 40-60K a year you are unlikely to benefit from it.

 

3 years?my miata tyres were 10 years old!

 

my Spitfire tires are 16 years old and look very good, but they are kept in garage on blocks.

anything driven daily in harsh conditions will start to deteriorate after 3 years. 5 years is the upper limit, YMMV

 

I don't know my tires well enough to say for sure about your tires, but rolling-resistance is a factor in fuel-economy. I don't know if there is a definitive rating-scale for this, but a real-world indicator (besides calculated mpg) is the temperature of the tires after driving. The energy lost to rolling-resistance is converted to heat.

 

i agree it's probably mostly related to climate and use. another thread says that nhtsa claims six years, but no one knows what's going on inside a tyre.

 

this is $450 question (for Prius owners anyways). From unscientific experience looking at discarded tires I suspect safety-wise most will be fine for quite some time past 3-5 year range. But they tend to loose grip and ride quality, so I tend to budget for ~3 years. Doesn't make any sense to buy tire which will last less then 2 years, and no reason to buy ones which will go more than 4; just saying.

If we have rain to clear salt I'd post a pic of ~3y.o. Mich Saver with micro cracks. The OEM Yokos looked very similar in less than 2 years, so it is definitely tire/rubber compound dependent too.