Pcplod

I got another possibly dumb one. Why does the Porsche owner's manual say not to change tires from one side to another??

If the tires are all the same size (which they were originally on my 86, and still are) don't you want to rotate the tires to ensure the most even wear?? Did the 928 come equipped with tires that had tread which only wanted to go one way for maximum water-shedding or adhesion or something of that nature??

Since I still have tires of the same size all the way around and they don't have a preferred direction of rotation: should I just rotate them like I would any other car, should I still avoid swapping from one side of the car to the other and just move front to back and vice-versa, or should I just not move them and see what happens?

Thanks as usual for the input.

Pcplod

Oh come on....nobody??

Ed Scherer

Most of us have staggered sizes front to rear and many of us also have directional tires on each wheel, precluding any rotation at all.

If you have neither, I don't see why you couldn't rotate. But there may still be some reason... I'll be curious what others have to say.

the flyin' scotsman

As Ed said staggered sizes front to back and directional rubber........no swapping at all.

White Lightnin'

Even with staggered sizes and directional tread design... you can still 'rotate': dismount the tire and remount it on the opposite wheel. It's a PITA, but worth the longer life it will give the tires.

Bjbpe

My original Dunlops (25 years ago) on my S4 were set up to turn only one way and also, the front and back were different. After I wore them out I switched to other tires that had no differentiation right to left and I did swap them with no significant difference.

Recently I purchased a set of new Dunlops with the same set up as my orignal tires and I am amazed at how good these tires are. "White Lightning" (above) has a good comment. For the relatively small cost of remounting the tires I would think that would be a good idea.

Jim M.

IIRC BMW also does not recommend tire rotation. Tires wear or take on a set based on what corner they are mounted. Rotating them "can" upset the handling.

Pcplod

Exactly my thoughts Ed. I know that it came with the same size rubber on all four corners, but the book says do not "switch sides".

Ah well, my tires aren't directional and they are all the same size so I am going to be a rebel and ROTATE MY TIRES!! If you guys don't hear from me soon, start searching the bushes to see which one I've stuffed my car into because I have upset the Porsche engineering/manual-editing gods!!

the flyin' scotsman

I asked the Porsche Owners Manual:

Randy V

This.

No 'rotation', only replacement.

GlenL

If they're not wearing well take them in and have them "flipped" on the wheels. Then mount the wheels on the opposite side. Insides become outsides and rotating direction is preserved.

I've read and heard hocus pocus about not having tires turn an opposite direction. Maybe Porsche was thinking about that. Tires have changed in 34 years since the first 928 was shipped.

Podguy

Most radials come with a direction. Once they are run in that direction and can and will explode if run in the opposite direction. This is true as well with non directional radials. Once they are spun in one direct they take on the mold and will disintegrate when rotated in the other direction

Same sized tires can be swapped from front to read and should be done to even out wear.

safulop

I rotated my tires front-back on my old 944 once. The difference in camber front-back on a 944 is so severe that handling was absolutely destroyed, it felt like trying to steer a train off of its track. I promptly rotated them back to where they were and have never rotated a set of tires since.

I would say that rotating tires on these cars is just being very frugal. If you can afford to maintain a 928 you can afford to buy a set of tires for $750 every few years.

-Sean

Pcplod

Well, I just ended up moving the tires front to back like the manual said.

I don't really have a problem with sticking to a side, or even not rotating at all, I just like to know the reasoning behind the actions that I take. I am still trying to figure out why the manual says to not swap sides and the only reason that I can come up with is because the stock rubber was directional, but since I didn't buy this one new, I can't really say - but I thought someone out there would know. I might even end up doing what Sean did with his 944 and swapping them back as soon as I hit the streets with it, but I never will know unless I try...

Anyway thanks for the input and I look forward to meeting a lot of you next week!!

Podguy

with the original P7s they were $1400 a set and if you got a year you were very lucky.