Bought a car with wrong tire size!

[LasVegasMagnum]

Hi guys. My g/f and I bought a 2005 Magnum in December. She really liked the chrome 20" wheels that were on it, and they were probably the major selling point. I had problems with the shifter, so I brought it to the dealer for work. While there, our service tech tells us that the tire size is wrong and if it's true we've put on 15k miles since the last service. It's absolutely impossible that we've driven that far! He goes on to tell me that the tires on the car are a 35 series tire, when it should be a 45 series. I did a little research on the 35 series and it looks like that part is correct. So, I took the car back to the original dealer I'd bought the car from and explain what's going on. The manager says he'll get back to me once he speaks with his "tire manager."

What do you guys think I should expect to happen? I mean, the miles have a significant impact not only on the resale value of the car, but also weigh heavily on the extended service plan I bought with the car!

I think the dealer should AT LEAST pay for new tires on the car, and give me some cash credit towards the warranty that's been eaten up by the misguided mileage.

[Mr. iNCREDIBLE]

I seriously doubt that the tires made that much of a difference...

i think the offset of the speedo is like 1 - 1.5 mph.

so in 10,000 miles you lost what maybe 10 - 15 miles on the ODO...

if the speedo is running fast, and you gained the same if it is running slow...

check the calibration on the speedo... but i'm willing to bet you aren't that far off... not enough to rack up 1000s of miles...

[vinny68]

I think the dealer misplaced the decimal point.

[LasVegasMagnum]

I would agree that this shouldn't come up to 1000's of miles, but there is just no way we drove it that much. In the course of a year, we've NEVER gone over 12k. But to suggest that we topped that by 3k in 2/3 the time? Impossible. Maybe the previous owner put the tires on and tried to have it calibrated, but calibrated it the wrong way?

Maybe they changed it to Kilometers!!! LOL

[dumpster]

its not the worng size, you can put whatever your preference in tire would be

[GasGunR]

If the tires are 35 series instead of 45 series, they are a taller tire with e larger circumference... meaning that for every revolution of the wheel / tire, your car goes farther than your odometer reads.

Lets say the 35 series tire is 30" tall and the 45 series tire is 31' tall, every time the wheel makes a revolution you would be going slightly over 3" FARTHER than the odometer would be reading. I'm not going to do the math but it takes alot of 3 inches to make a mile, and even if it were off, it would be in your favor on the warranty, not the other way around. Therefore you have no complaint IMO. Some people have purposely used 45 series tires on 20" rims as they felt it looked better with the wheel wells filled a bit more and they felt safer driving over the potholes with more tire between the rim and the hole.

[formerice]

If you had 35's and the car is designed for 45's and you speedo reads 107 mph you would only be traveling 100 mph. It wont do any harm except the ride may suffer some and your wheel well gap is gonna be kinda big. Just replace em with 45 series when they wear out. If you have a hand held GPS or can borrow one you can check your speedo. Indicated 53.5=50 mph. You will actually pick up some out of the hole acceleration with the short sidewall tires.

[Cam]

You should be roughly 5MPH off. Regardless, if it were as much as 10 off it'd equate to this.

For every thousand miles you drove, you'd gain one hundred miles in addition to what you actually did. So if you did drive 10,000, it would have only been 11K on the odometer.

And if the dealer tries to pass off some form of BS that this impacts the car in any negitive manner, tell him to blow it out his %^&.

All you did was add miles that didn't exist.

[boggart]

If the tires are 35 series instead of 45 series, they are a taller tire with e larger circumference


Exactly opposite.


Hey LVM, what size tires are on your Magnum?

[GasGunR]

Yep, I hosed this up from the gitgo... I misread the original post and transposed the numbers in mine... I'm a loser:)

Thats what I get for reading and posting while handling a hundred phone calls in my office:)

Sorry!

Don

Exactly opposite.


Hey LVM, what size tires are on your Magnum?

[mojo]

If your tires are taller than the originals then the miles on your odometer would read to low. Since your new tires are 35's they are likely shorter that the originals and the miles on your odometer likely read to high. The stock tires on my SRT8 are 28.7" tall. It really depends on the size of your tire a 265 35 20 is about 27.4". That would make your odometer read about 5% to high.

[boggart]

Yep, I hosed this up from the gitgo... I misread the original post and transposed the numbers in mine... I'm a loser:)

Thats what I get for reading and posting while handling a hundred phone calls in my office:)

Sorry!

Don

No hard feelings I hope. :beerchug: I figured it was something like that, but didn't want anyone to take that to the bank and be confused. It's amazing the number of people that don't know the 35 or 45 or whatever is the height of the sidewall as a % of the tread width.

[LasVegasMagnum]

They're 35's. I know the difference should be marginal at best. Maybe she's been taking the car out without me knowing while I'm at work or something? Hmmm...

If anybody sees me on Judge Judy record it so I can have a copy!!!

[FleshWound]

If you can get the height of the tire and find out which setting the starscan is showing for wheel size calibration, we'll do the math and know the exact variance.
I'm not sure if the starscan will tell the date of change for wheel calibration, that is if it (wheel size) was changed at all with the scan tool.

Are the wheels OEM or added later?

[boggart]

They're 35's. I know the difference should be marginal at best. Maybe she's been taking the car out without me knowing while I'm at work or something? Hmmm...

If anybody sees me on Judge Judy record it so I can have a copy!!!

I'm sorry but "they're 35's" is not a tire size. That's only 1/3 of the equation. Now you already said they are 20's. We need all 3 numbers 355/35r20 to know how tall your tires are. Without all 3, everyone is only guessing whether your tires are taller/shorter than stock. What we need to know now is the tire width.

[Mr. iNCREDIBLE]

I'm sorry but "they're 35's" is not a tire size. That's only 1/3 of the equation. Now you already said they are 20's. We need all 3 numbers 355/35r20 to know how tall your tires are. Without all 3, everyone is only guessing whether your tires are taller/shorter than stock. What we need to know now is the tire width.



true that;

the "35" in the tire number means only one thing. that the tire is 35% high as it is wide.

for example (i'll use round numbers to make it easy to understand)

a tire that is 100/35 R 20.

this means the tire is 100 millimeters wide

the 35 means that the height is 35% of the width so the tire is 35 millimeters high (top and bottom)

the 20 means that the inner lip of the tire fits on a 20 inch rim.


so if you have a 200/35 R 20 tire, it is not the same height as the aforementioned tire even though it is still a 35 series tire, because the tire is twice as wide, therefore 35% of the width would make the tire 70 millimeters high.


if you do the math the stock 300C tires are 225/60 R18

225 millimeters wide or 8.85 inches

135 millimeters high or 5.31 inches (5.31 inches top and 5.31 inches bottom = 10.62 inches total)

on 18 inch rims.

so the total outside diameter of the tire is: 28.62 inches
(18 inches plus 10.62 inches)

so a tire that is

245/45 R20 would be

245 millimeters wide or 9.645 inches

110.25 millimeters high or 4.34 inches (4.34 top and 4.34 bottom = 8.64)

on a 20 inch rim.

and the total outside diameter of that tire is 28.68 inches


which is .06 inches Taller even though the rim is 2 inches bigger.

not much of an odometer loss there, less that .001 of a mile per hour.

if the tire was a

265/35 R 22

then

265 millimeters wide or 10.43 inches

92.75 millimeters high or 3.65 inches (3.65 top and 3.65 bottom = 7.30 inches total)

on a 22 inch rim

that equals a total outside diameter of 29.30 inches or .68 inches larger than stock...

again, not a HUGE difference in the overall performance of the odometer.



ok now someone check my math cause I did that in my head and I'm old and senile...

[Vindes]

Yeah, what Mr. I said above.

My first thought reading this was the stock wheels on your Magnum SXT were 17". Somebody replaced those with 20's before you bought it.

If the tires on there are 265/35/20's I believe the height lines up pretty close to the stock height.

Or if it's a SXT AWD stock was 225/60/18 which would be the 28.7" tire height as Mr. I mentioned. That would line up about exactly the same as a 275/35/20.

In the end, the only thing the odometer/speedometer cares about is overall tire height. (And rpm of course.)

[LasVegasMagnum]

Sorry guys. I work two jobs and haven't been around much.

The full tire size is 255/35 20. I used a calculator on 1010tires.com to see exactly how much off everything is, and it comes out to about 3.5% fast. It's true that there really isn't that much difference. The dealership had told me that there was a danger of brake failure if you change wheel and tire size by more than 3%, and the website had the same info. I've never heard of that before, but I guess it could be true.

At any rate, the dealer said if I call their supplier for tires, they'll give me a set at cost. I called, and they offered a set of Toyo Proxes at $700. Is that a deal or is it lip service?