I’m having a problem with my car (like that’s anything new.) My front tired are riding slightly on the inside edge, so they’re wearing faster on that edge. I want to rotate my tires, and I’m wondering wether I should just switch them front-to-back, or should I switch them diagonally?
the tire treads are non-directional, btw…
I don’t suffer from insanity…
I enjoy every minute of it!
Check your owner’s manual if you still have it for the proper method. Just as a general tip though, if you have radial tires (and nearly all tires are radials now) rather than bias ply, you should keep the tires on the same side of the car. It is never recommended to switch the rotational direction of radial tires.
I’ve always wondered about this. I’ve often replaced tires that have started to wear on just the inside or outside edge. Can’t I just periodically have them pulled off the rims and flipped around, so that the edges wear evenly? This would seem to be more effective than just rotating the wheels.
Actually, if your tires are wearing on the inside edges, it most likely means you have an alignment problem. your tires can be leaning in…
(top)
//____\
// \
or they can be pointing out (opposite of pigeon toed)…
(front)
\______//
\ //
causing wear on the inside edges.
FIRST, get an alignment. THEN rotate your tires. The alignment techs use tread wear patterns to diagnose the problem, and if you rotate without aligning, you’ll just ruin your rear tires, too.
Joe Cool
I agree that you should get an alignment but I think what the alignment does is not change the vertical alignment of the tires but rather the convergence of the two tires. If the two tires are not perfectly parallel when the car is in motion, they are trying to run apart from each other or towards each other which they cannot do. Ask at the alignment garage and they will tell you they adjust the convergence.
What in english is called a front end alignment in spanish is called checking for parallel.
Vertical alignment is not such a problem as convergence and that is why it is generally the front end that causes the problems as it is caused by the steering and has to be tuned periodically. A car has much more tolerance for vertical misalignment than for
convergence misalignment. The least convergence misalingment will make the tires wear very fast. I think I remember wear on the outside means diverging tires and wear on the inside means converging tires But I could be mistaken.
I remember reading a very old manual about how this adjustment was done in the early days. Basically geometrically. Get two very long straight edges and align them with the rim of the wheels and check that they are parallel. It then went on to discuss that wheels that are parallel at rest may become slightly divergent in motion and so a slight convergence at rest to compensate may be needed.
If the car has had major damage it could be that parallel cannot be corrected as even if the two wheels are parallel, one could be ahead of the other and the car is still not balanced and will not go straight.
I used to get weird wear too, but since the new ones REQUIRE rotating every 5000 miles in order to keep the blasted guarantee, they wear evenly.
I rotate mine every 5000 miles or so, and my owners manual specifically recommends that the front two should be crossed instead of just front-to-back.
'Course, that didn’t do me a damn bit of good when a brand new tire fell apart last week while my fiance had the car on a trip to Seattle.
You need an alignment. Probably need some new parts too (I’m guessing tie rod ends). Newer cars need thrust-angle (4 wheel) alignment also. Go to private(not a chain) shop. They need your business and are less likely to screw you around. After replacing worn parts, the numbers you are looking for are:
caster = +1/2deg (yes, positive)
camber = -1/4deg (yes, negative)
toe-in = 3/32"
Note: factory specs are fine, but these will be a significant improvement for handling and (IMHO) safety.
Don’t worry about what the numbers mean, just find a shop that will show you the printout before and after the alignment.
If you really want to know what they mean, here they are: (if not, skip this paragraph). Caster is the angle the steering knuckle makes with the vertical (positive is backward from vertical at the top). Camber is the angle of the wheels from vertical when viewed from the front (outward at top is positive). Toe-in is how much closer the leading edges of the tire are than the trailing edges.
Tire manufacturers swear radial construction is now good enough to survive reverse rotation. Most manufacturers (and me) still say to keep them on the same side of the car.
Ursa, swapping rims is fine, but can get expensive ($7/ to rebalance every time), and now your fancy white letters are on the inside where nobody can see them. 
An alignment adjusts the wheels in three dimensions: Toe-in (equivalent to yaw on an airplane), Caster (pitch–the front-to-back angle of the ball joints that hold the wheel in place), and Camber (roll–vertical or side-to-side alignment).
And yes, a slight at-rest convergence is set so that the wheels are parallel when in motion.
Joe Cool