Tire Rotation - Brakes etc

[jerry33]

I'm going with either "It's a misprint" or "someone took the measurements from Elon's car which has 265s on the rear". Different rim widths will affect slip angle--and you don't want to get that wrong. If the rim widths are in fact different, then you can't rotate them without demounting them because you will always want the wheel with the wider rim width on the rear.

Assuming non-directional tires (and there are a couple of different kinds of "directionality") the rotation pattern doesn't matter. The bit about radial tires can only be rotated one way is FUD left over from when the North American tire manufacturers were trying to ensure radial tires didn't succeed and were spouting all kinds of things about them. Any rotation method can be used, including the one shown in the owner's manual.

 

[PattyChuck]

<snip>Any rotation method can be used, including the one shown in the owner's manual.</snip>

Now that you brought it up, and since you're the tire guru around here, does it make any difference if you do a criss-cross rotation (Rear Right to Font Left, etc) or do it like it's pictured in the Tesla manual? I was always told to criss-cross the rotation, so was a little surprised when I saw Tesla's recommendation.

 

[yobigd20]

Different rim widths will affect slip angle--and you don't want to get that wrong. If the rim widths are in fact different, then you can't rotate them without demounting them because you will always want the wheel with the wider rim width on the rear.

Not necessarily. It is not uncommon for people to actually put wider wheels on the front than the rear. Usually it's for better handling/cornering. So if the car is cornering real hard and you're limited by your front grip, wider rear tires isn't really going to buy you much. Putting wider tires on the front will let the car grip more and corner harder without slipping.

 

[jerry33]

Now that you brought it up, and since you're the tire guru around here, does it make any difference if you do a criss-cross rotation (Rear Right to Font Left, etc) or do it like it's pictured in the Tesla manual? I was always told to criss-cross the rotation, so was a little surprised when I saw Tesla's recommendation.

It really makes zero difference unless the tires preclude it by being tread pattern directional. (If the tires are casing directional, then you have to criss cross because with casing directional tires the directional arrows will point towards each other at the top of the tire on a rear-wheel-drive car).

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Not necessarily. It is not uncommon for people to actually put wider wheels on the front than the rear. Usually it's for better handling/cornering. So if the car is cornering real hard and you're limited by your front grip, wider rear tires isn't really going to buy you much. Putting wider tires on the front will let the car grip more and corner harder without slipping.

I was thinking of normal driving with the average driver. The best situation from the tire's point of view is that the rim width is equal to the tread width (which on the 19" tires is 8 inches as best I can tell).

 

[TXjak]

It really makes zero difference unless the tires preclude it by being tread pattern directional. (If the tires are casing directional, then you have to criss cross because with casing directional tires the directional arrows will point towards each other at the top of the tire on a rear-wheel-drive car).

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I was thinking of normal driving with the average driver. The best situation from the tire's point of view is that the rim width is equal to the tread width (which on the 19" tires is 8 inches as best I can tell).

If the safety manual is to be believed, all four of the 19" tires are Goodyear Eagle RS-A2, P245/45R19 98V. These tires can be mounted on rims from 7.5 to 9 inches wide, according to the Goodyear website.

 

[widodh]

Isn't the torque a misprint as well? 175Nm or torque for the wheelnuts? That is 'nuts'!

My M5 has something like ~110Nm and that is already a lot.

(Still grinning about the fact that's it in metric )

 

[jerry33]

If the safety manual is to be believed, all four of the 19" tires are Goodyear Eagle RS-A2, P245/45R19 98V. These tires can be mounted on rims from 7.5 to 9 inches wide, according to the Goodyear website.

Can be mounted is not the same thing as optimum rim width which are both different from measuring rim width.

The optimum rim width is the rim width where the tire will perform the best in all areas.

The measuring rim width is the width used to match the various government tests and dimensions. That is, it is possible to make two different sized tires using the same mold by changing the markings and the measuring rim width.

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Isn't the torque a misprint as well? 175Nm or torque for the wheelnuts? That is 'nuts'!

No, that's the correct spec. Corvette has an even higher torque.

 

[TXjak]

Can be mounted is not the same thing as optimum rim width which are both different from measuring rim width.

The optimum rim width is the rim width where the tire will perform the best in all areas.

The measuring rim width is the width used to match the various government tests and dimensions. That is, it is possible to make two different sized tires using the same mold by changing the markings and the measuring rim width.

I mentioned it as a possibility, but I'd also be surprised if they are not using 8" wide rims all around and the 9.0J is a typo.

Also it give the torque as 175 Nm (129 lbf.ft), but I've not seen lbf.ft before. Another typo or a new way of stating pound-feet?

 

[stevezzzz]

I mentioned it as a possibility, but I'd also be surprised if they are not using 8" wide rims all around and the 9.0J is a typo.

Also it give the torque as 175 Nm (129 lbf.ft), but I've not seen lbf.ft before. Another typo or a new way of stating pound-feet?

I haven't seen lbf.ft before, either. Maybe lbf stands for 'pound force' as opposed to 'pound mass'?

 

[TXjak]

You're probably right, I sent off an email to my ownership rep anyway. They need to fix something.

My OEA verified that it is indeed a typo. All 19" wheels are 8" wide.

 

[jerry33]

I haven't seen lbf.ft before, either. Maybe lbf stands for 'pound force' as opposed to 'pound mass'?

That's correct. lbf = pound force.

 

[TXjak]

That's correct. lbf = pound force.

Thanks, found it on the IEEE site.