Tyre Rotation

[Pugglt Auld Jock]

Speak as you find .
I have fitted all sorts of tyres except large lorries since I started as an apprentice motor mechanic in 1969, the bit I was referring specifically to, was when a friend was starting S/H tyre business in the early 1980s and we noticed that some makes of tyres, possibly textile based were showing serious wear lines in the sidewalls, in line with where the bracing was wound in the manufacturing process originally and were showing visibly in some s/h tyres, this was put down to a change in the direction, that the tyre experienced after running half it's life in one direction and then doing the opposite.

Now that's interesting Mike. I've seen these lines - usually running diagonally up the sidewall - on old aged tyres. I've never thought too hard about it though, just put it down to old rubber perishing and cracking.

Second hand tyres? Have to take exception there, not something I'd ever consider after seeing some of the covers which were rejected for remoulding when I worked at Firestone back in the very late 60s/early 70s.

 

[bugsymike]

Now that's interesting Mike. I've seen these lines - usually running diagonally up the sidewall - on old aged tyres. I've never thought too hard about it though, just put it down to old rubber perishing and cracking.

Second hand tyres? Have to take exception there, not something I'd ever consider after seeing some of the covers which were rejected for remoulding when I worked at Firestone back in the very late 60s/early 70s.

Yes , that is the lines I was referring to, clearly visible diagonal up the sidewalls.
Strangely it was often quality tyres such as Michelin.
In the late sixties there were some terrible crossply remoulds available locally and tread separation was commonplace.
New tyre quality has certainly improved, so false economy buying s/h, though it was commonplace for dodgy car dealers trying to increase their margins, even on quite high performance vehicles.

 

[vexorg]

I dont rotate tyres on a normal car, just change them in pairs on the axle as needed.

The logic of swapping front and back to even the wear must mean that you are getting worse grip as they tyres are now extra worn on areas that wouldn't normally wear in that position. Or more simply, if the front inner edges are worn (as they do), then on the rear those inner edge must have less grip.

It also makes for a more expensive tyre change as you'll need 4 at once. And anyone that uses decent branded tyres knows that's painful experience.

The exception to that, not normal cars, are those with four wheel drive that are continuously conntect and have a viscous coupling. It's essential that they are rotated often to keep the rolling radious the same front and rear.

 

[Pugglt Auld Jock]

You make some interesting points there. In particular the fact that if you routinely rotate your tyres, say at every service, then you end up having to lay out for 4 tyres all at the same time!

Interesting too that you point out that you've noticed front tyres wear on the inner shoulders? I've noticed this too and I've thought about it for years. I've come to the conclusion that it's due to the nature of the soft, sound deadening, and very compliant nature of suspension arm bushes used these days. Watch almost any car which is coming to a rest after braking reasonably hard. You'll notice that just as it stops the front wheel moves forward slightly (sometimes not so slightly) in relation to the wheel arch. This is due to flexion in the bushings. What is also happening is that it's allowing the front wheels to splay outward slightly (toeing out) and it's this which causes the wear on the inner shoulders of the front tyres. As the car, and so bushings, age the effect becomes more pronounced.

I don't routinely rotate my tyres and will run them until the fronts are approaching 2mm when I will renew them. At that time I put the existing rears on the front and new ones to the rear. I find with front wheel drive, as most are now a days, if you don't do this the rears will expire due to aging long before the tread is worn away.

And "permanent" 4 wheel drive couplings Vs uneven tyre wear? Yes a very expensive one to keep on top of! Wouldn't entertain one for my daily transport.

 

[Puntazooo]

So left rear swapped with left front and right rear swapped with right front? That's the way I'd choose to do it.

Yes, exactly.
Left rear goes to left front, right rear to right front. The left front goes to the right rear, and the right front to the left rear.
This way you make sure that they always rotate and not just on one side of the axis.

 

[vexorg]

This way you make sure that they always rotate and not just on one side of the axis.

You cant do that with directional tyres

 

[Pugglt Auld Jock]

You cant do that with directional tyres

I make a point of never buying directional tyres. Asymetric yes but directional never, not for me anyway.