New tires hope I didn't make a mistake

justjoan195 · 06-12-2008, 10:32 PM

I bought my Prius 3 months ago and the tires really needed to be replaced. I was going to replace them with the tires that were on the car (Goodyear Intergity) but was told the Goodyear Assurance Comfort would last longer and were a better tire. I've just had them on for a day, but have really noticed a reduction in MPG on the ride home. Now I've read some old posts and am not sure I made the right choice. The tire place also advised me not to increase the pressure to 40/38. I love this car! I was getting 52-55 MPG. Thanks for any thoughts on the subject.

tumbleweed · 06-12-2008, 10:54 PM

The tire place was wrong about the pressures. 40/38 is fine or even higher, just don't exceed the maximum pressure on the sidewall, 44 psi for your tires I think. They will be fine.

b11101100 · 06-12-2008, 11:39 PM

I'm not familiar with those tires, but all tires have a break in period. You'll see slight increases in fuel economy for the first few thousand miles.

jjksutton · 06-13-2008, 07:35 AM

I wouldn't jump to any conclusions based on the ride home. There could be several factors at play. I don't know anything about the tire you bought, but as long as it was the same size as the previous tires, I would think you'll get similar fuel mileage. I think you should give them some time and then see what you have.

justjoan195 · 06-14-2008, 08:38 AM

Increased my tire pressure yesterday to 42/40 and will see. I love this forum and have learned so much from it. Thank you

PriusSport · 06-14-2008, 10:27 AM

New tires sometimes take up to 800 miles to break in. There are curing agents and other additives in the tire that need to come out. Sometimes they might be noisy for awhile.

I considered a swap of new Integritys at the Goodyear dealer. But I really wanted a wider tire, and they wouldn't change sizes because of the Toyota spec. At the same size, the Goodyear manager said it would not be worth it unless I drove a lot of miles. He said the Integritys were a good OE tire on a lot of new cars, but not a high mileage tire.

justjoan195 · 06-18-2008, 09:31 PM

I increased the tire pressure to 42/40 and had an oil change (also changed the filter). Now MPG seems to be getting better, not as good as it was though.

Devil's Advocate · 06-19-2008, 01:02 PM

It will be 1 to 2 MPG less. I lost 2 mpg but I also went up one size to 195s.

Kaos1 · 06-19-2008, 10:59 PM

A new tire also has fewer revs per mile. That means that when you travel a mile it makes fewer revolutions. As the tire wears, the revs per mile increase. It turns more times per mile. So when our tires are almost worn out, they are spinning faster at any given speed. This makes the electronics "think" that the car has traveled farther than it did when the tires were new. If you use the same amount of gas to travel a given distance in both cases, the indicated and calculated mpgs will be higher on worn tires.

Food for thought.

I replaced my Integrities at 50K with Primacies. I also realized a cut in mpg. Now with 10K on them, I'm getting better mileage than ever. Oh, by the way, I'm running 50/50. A hard ride but the car does roll on and on and on. I'm averaging 63mpg though I'm a conservative driver on and off the highways.

Tires are but one factor of a multi-complex equation for high mpg.

Kaos1

mrblaise · 06-19-2008, 11:38 PM

How do you like the Primacies Kaos? Those are the Michelins... right?

Quote:

Originally Posted by Kaos1

A new tire also has fewer revs per mile. That means that when you travel a mile it makes fewer revolutions. As the tire wears, the revs per mile increase. It turns more times per mile. So when our tires are almost worn out, they are spinning faster at any given speed. This makes the electronics "think" that the car has traveled farther than it did when the tires were new. If you use the same amount of gas to travel a given distance in both cases, the indicated and calculated mpgs will be higher on worn tires.

Food for thought.

I replaced my Integrities at 50K with Primacies. I also realized a cut in mpg. Now with 10K on them, I'm getting better mileage than ever. Oh, by the way, I'm running 50/50. A hard ride but the car does roll on and on and on. I'm averaging 63mpg though I'm a conservative driver on and off the highways.

Tires are but one factor of a multi-complex equation for high mpg.

Kaos1

06-12-2008, 10:32 PM	#1
justjoan195 Junior Member Join Date: Jun 2008 Location: Rhode Island Posts: 3 My Car: 2006 Prius Model: Package: #6 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	New tires hope I didn't make a mistake I bought my Prius 3 months ago and the tires really needed to be replaced. I was going to replace them with the tires that were on the car (Goodyear Intergity) but was told the Goodyear Assurance Comfort would last longer and were a better tire. I've just had them on for a day, but have really noticed a reduction in MPG on the ride home. Now I've read some old posts and am not sure I made the right choice. The tire place also advised me not to increase the pressure to 40/38. I love this car! I was getting 52-55 MPG. Thanks for any thoughts on the subject.

06-12-2008, 10:54 PM	#2
tumbleweed Senior Member Join Date: Oct 2005 Location: Eastern Oregon Posts: 1,692 My Car: 2010 Prius Model: V Package: Adv. Technology Thanks: 33 Thanked 105 Times in 84 Posts Friends: 0	Re: New tires hope I didn't make a mistake The tire place was wrong about the pressures. 40/38 is fine or even higher, just don't exceed the maximum pressure on the sidewall, 44 psi for your tires I think. They will be fine.

06-12-2008, 11:39 PM	#3
b11101100 Spectra Blue Mica Driver Join Date: Apr 2008 Location: Missouri Posts: 56 My Car: 2008 Prius Model: Package: #5 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: New tires hope I didn't make a mistake I'm not familiar with those tires, but all tires have a break in period. You'll see slight increases in fuel economy for the first few thousand miles.

06-13-2008, 07:35 AM	#4
jjksutton Member Join Date: May 2008 Location: Tampa Posts: 97 My Car: 2004 Prius Model: Package: N/A Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: New tires hope I didn't make a mistake I wouldn't jump to any conclusions based on the ride home. There could be several factors at play. I don't know anything about the tire you bought, but as long as it was the same size as the previous tires, I would think you'll get similar fuel mileage. I think you should give them some time and then see what you have.

06-14-2008, 08:38 AM	#5
justjoan195 Junior Member Join Date: Jun 2008 Location: Rhode Island Posts: 3 My Car: 2006 Prius Model: Package: #6 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: New tires hope I didn't make a mistake Increased my tire pressure yesterday to 42/40 and will see. I love this forum and have learned so much from it. Thank you

06-14-2008, 10:27 AM	#6
PriusSport Senior Member Join Date: May 2008 Location: SE PA Posts: 955 My Car: 2008 Prius Model: Package: #2 Thanks: 0 Thanked 13 Times in 12 Posts Friends: 0	Re: New tires hope I didn't make a mistake New tires sometimes take up to 800 miles to break in. There are curing agents and other additives in the tire that need to come out. Sometimes they might be noisy for awhile. I considered a swap of new Integritys at the Goodyear dealer. But I really wanted a wider tire, and they wouldn't change sizes because of the Toyota spec. At the same size, the Goodyear manager said it would not be worth it unless I drove a lot of miles. He said the Integritys were a good OE tire on a lot of new cars, but not a high mileage tire.

06-18-2008, 09:31 PM	#7
justjoan195 Junior Member Join Date: Jun 2008 Location: Rhode Island Posts: 3 My Car: 2006 Prius Model: Package: #6 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: New tires hope I didn't make a mistake I increased the tire pressure to 42/40 and had an oil change (also changed the filter). Now MPG seems to be getting better, not as good as it was though.

06-19-2008, 01:02 PM	#8
Devil's Advocate Senior Member Join Date: Mar 2005 Location: Las Vegas, Nevada Posts: 913 My Car: 2005 Prius Model: Package: #9 Thanks: 0 Thanked 1 Time in 1 Post Friends: 0	Re: New tires hope I didn't make a mistake It will be 1 to 2 MPG less. I lost 2 mpg but I also went up one size to 195s.

06-19-2008, 10:59 PM	#9
Kaos1 Member Join Date: Feb 2006 Location: Mid-Alantic Posts: 40 My Car: 2006 Prius Model: Package: #6 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: New tires hope I didn't make a mistake A new tire also has fewer revs per mile. That means that when you travel a mile it makes fewer revolutions. As the tire wears, the revs per mile increase. It turns more times per mile. So when our tires are almost worn out, they are spinning faster at any given speed. This makes the electronics "think" that the car has traveled farther than it did when the tires were new. If you use the same amount of gas to travel a given distance in both cases, the indicated and calculated mpgs will be higher on worn tires. Food for thought. I replaced my Integrities at 50K with Primacies. I also realized a cut in mpg. Now with 10K on them, I'm getting better mileage than ever. Oh, by the way, I'm running 50/50. A hard ride but the car does roll on and on and on. I'm averaging 63mpg though I'm a conservative driver on and off the highways. Tires are but one factor of a multi-complex equation for high mpg. Kaos1 __________________ May all of your hills be down, your winds be tail, and your days be warm.

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