Tire mismatch

[DunnInn]

We’ve had this rv for about 7 years and just noticed that the front tires are different sizes. It’s a 41 foot Newmar Dutch Star. Drivers side tire is 275/70, passenger side is 275/80. All others are 275/70. This seems like it should be a problem. Any ideas?

[wolfe10]

naturist wrote:
I agree about replacing all due to age alone. On an undriven axle, only handling would be the performance issue. Put that mismatch on a driven axle and watch the differential explode in flames within 30 miles at highway speeds. Don’t ask how I know that.

Brake performance would also be effected. And if ABS brakes, it would likely throw a code.

[naturist]

I agree about replacing all due to age alone. On an undriven axle, only handling would be the performance issue. Put that mismatch on a driven axle and watch the differential explode in flames within 30 miles at highway speeds. Don’t ask how I know that.

[wolfe10]

DunnInn wrote:
We’ve had this rv for about 7 years and just noticed that the front tires are different sizes.

This says it all-- the mismatched tires are at least 7 years old.

Replace with the proper size and load range per your GVWR plaque.

[wa8yxm]

Sounds like the prior owner had a flat and put on a wrong size replacement.

For short term use it's ok to have an odd size tire. Short term is "Driving to tire store" but for long term use each axle should have same size and same age tires. (Or nearly same age) at least on every ride i've had

having different size tires on the front affects handling.

[CA_Traveler]

Don't you have a ID tag that gives you the tire size? What is the tire DOT date for each tire? At 7+ years it's time for new tires regardless of tread etc.