New Tires = Bad MPG?

[bmcnallen]

Originally Posted by wireless

As a 'licensed' engineer, you of all people should understand the inability to probably provide a root cause analysis without all of the variable and specifications identified

completely agreed

[atirevold]

I had to get new tires on Friday. I hope my mileage doesn't decrease. I had the Michelin MX4V and at 31000 they were completely worn. I had the same tire on my Volvo S40 when I had it and they lasted about the same mileage on it.

[bmcnallen]

Originally Posted by kenny1773

I am going to assume the Michelin Energy's that were OEM were the

Michelin Energy MXV4 S8?? a V-rated tire?




I am thinking you should NOT have put a T rated tire on a car that requires V rated tires

I think I found some more of the problem

I didn't get a chance to look at whether the Michelins were v-rated tires. I guess it was? I simply looked up the Camry on the Discount Tire website and ordered the tire from the choices it brought up. The only BFG tire on that site for the Camry was the T-rated tire. What is the actual difference between the different rated tires? I can still go back and get a different set if needed.

[bmcnallen]

NM.. i read they are speed ratings, but how does this effect the rolling resistance?

[kenny1773]

Originally Posted by bmcnallen

NM.. i read they are speed ratings, but how does this effect the rolling resistance?

I am not an engineer nor probably qualified to answer this question, but just havnig done some similar research myself on tires because going with an H-rated instead of a V-rated would have saved me $100, I came to the conclusion that the lower speed rated tires have a softer sidewall and will have more lateral flex.

In theory, this should only affect handling and possibly braking, but I could imagine a situation where the softer sidewall could affect the contact patch of the tire on the road and cause more reistance.

Purely speculation, and I probably spent more money than I should have to get V-Rated tires


The 2007 XLE camry requires V-Rated tires, much like my 2005 SE does. The LE takes H rated, and I am not sure what would take a T rated. I just think T is too low, where you might get away with H.

I found the tire selectors on a dozen different web sites to give me all kinds of different options on speed ratings when I searched, but I know my car had V rated RE92's on it, so that is what I looked for on replacements.

I could not find an 'official' explanation on exactly what a lower speed rated tire would do, other than it would lower steering response and lower the over all handling of the vehicle. No one mentioned fuel economy.

[bmcnallen]

Just got off the phone with discount, and they have some V rated tires on the way. They rep said they had glitches in their system, and that was one problem he knew of that they were fixing/updating. He confirmed that the T rated tires have a higher rolling resistance. He said, "Yeah we should've put V-rated tires on there." Thanks for narrowing it down and all the help from everyone.

Hopefully this is really help my mileage woes!

[niceguy]

My SE comes with 36 psi on all 4 stock Bridgestone tires. Is it too high? Should I readjust them to 32 psi instead?

[bmcnallen]

Well here's an update on this issue...

After a damaged sensor, stripped lugnut, and alignment, I finally got the V rated tires put on. My mileage is back up to normal.

Thanks for everyones help on pinpointing the culprit. Lesson here: Don't assume that automated systems will match up the correct tire. Double check everything!

[bigkidd]

Right on!!! I put H rated tire on my V8 SHO cutting cost, the gas mileage suffered, the handling was horrible, brakes and ball joints tie rod ends life was shorted. It was like ride on a bowl of Jello.

[RICO8458]

i finally replaced my oem tires after 60,000. got new ones and a 4 wheel alignment too. did you plus size? same rims? same tire size? specs? should not change the mileage output. strange case here.

[njerald]

Originally Posted by bigkidd

Right on!!! I put H rated tire on my V8 SHO cutting cost, the gas mileage suffered, the handling was horrible, brakes and ball joints tie rod ends life was shorted. It was like ride on a bowl of Jello.

What size V8?

[white07cam]

Tauras SHO was a 3.4 I believe

[eddiefromcali]

Originally Posted by njerald

What size V8?

that would be a DOHC 3.4 V8 rated at 240hp

http://www.fordmuscle.com/archives/2...Tell/index.php