The donut spare tire is significantly smaller in diameter than the regular tire by roughly 3 inches.
Especially on AWD vehicles, but also for FWD vehicles when the spare is mounted in the front, there is a significant difference between the spare and the other wheel on the same axle.
I always thought that even a small difference could cause drivetrain damage. But, here the difference is huge.
The manual says to not drive faster than 50 MPH, but it seems it is mostly for safety reasons. It only lists avoiding obstacles and car washes. No other restriction.
I'd imagine that any damage which can occur driving 70 MPH on such uneven tires on dry roads will happen at 50 MPH as well. However, it is obviously designed for that.
Does it mean that fitting any size tire, which is about the same as the tire on the other axle is safe for the drivetrain (of course, it could be unsafe for keeping traction. Here I am talking only on the drivetrain)?
Especially on AWD vehicles, but also for FWD vehicles when the spare is mounted in the front, there is a significant difference between the spare and the other wheel on the same axle.
I always thought that even a small difference could cause drivetrain damage. But, here the difference is huge.
The manual says to not drive faster than 50 MPH, but it seems it is mostly for safety reasons. It only lists avoiding obstacles and car washes. No other restriction.
I'd imagine that any damage which can occur driving 70 MPH on such uneven tires on dry roads will happen at 50 MPH as well. However, it is obviously designed for that.
Does it mean that fitting any size tire, which is about the same as the tire on the other axle is safe for the drivetrain (of course, it could be unsafe for keeping traction. Here I am talking only on the drivetrain)?