Uneven tyre wear MK2 Ambulance

[chrisvmax]

Hi everyone,
I've had my Mk2 twin wheel Ambulance for 7-8 years now and it has always worn its front tyres unevenly. It wears down about a quarter of the width of the tread of the tyre way before the rest of the tread.
I've had the tracking checked several times at various different tyre places and they are all saying the tracking is OK.
One guy said it's because I'm running it with incorrect tyre pressure. I use 48 psi front and 44psi rear as is stated on the plates rivoted to the wheel arches,

Any ideas?

Regards,
Chris

[MrMPuk]

Under pressure would cause the outer and inner edges to wear and over pressure the middle to wear, so if it is only wearing on the outer or inner edges I would say it's the tracking.

[chrisvmax]

MrMPuk,

that's just what I thought, but 3 tyre places have checked the tracking and they are all saying it is OK.
Don't know what else to do.

Regards,
Chris

[MarkM]

Tracking is often just if they are straight in relation to the body the toe in or out settings and camber settings WILL cause bad wear my old Cortina looked as if someone was pushing down on the car if you looked at the front wheels but I had even tyre wear so the wheel camber setting and or the toe setting was quite extreme (as it looked) but perfectly fine for the vehicle.

[MrMPuk]

Do you know what the garages were setting the tracking to?

[chrisvmax]

Do you know what the garages were setting the tracking to?

No. I just asked them to check the tracking and they did and said it was OK.

Is there something else that can be checked, or do I need to ask them to do it differently somehow?

Maybe I need to find a friendly garage man and adjust them by guesswork. They are wearing fast on the outside edge, so do I need to undo the track rod end to move the lower half of the wheel out further?

Regards,
Chris

[Terry]

If your front tyres are wearing ONLY on the outside edges
it will be either tracking (its toeing in) or camber.
If you look at the front of the van do the bottoms of the wheels look like they angle inwards ?, if so this is positive camber and will
wear the outer edges of the tyres. Camber is almost certainly not adjustable, (very few cars let alone vans have adjustable camber)
so you will need to check it. You will need to go to one of the modern
tyre fitting places with the electronic super duper machines and have a full alignment test done, then the results of that will give you an idea of what the problem is.
Another thought as its a camper, is the steering very light ?

[AndyG]

It wears down about a quarter of the width of the tread of the tyre way before the rest of the tread.


Any ideas?

Regards,
Chris

How do you mean outer or inner on both sides isommetrically or the inside edge of one side and the outside edge of the other

[Gunslinger]

hhmmmm, interesting one, we need a little more description on which parts are wearing, for example, is it the inner edges of both front tyres that are wearing, or the outer edges, or both. Also how does it feel on the steering ? (heavy/light/notchy/heavy then easy)

i would seriously doubt the outer for one and the inner for the other for the tyre wear, that would be plain odd !

if they have checked the tracking and say its ok, then i would be questioning what the actual settings are that they are getting,
also the camber/castor angle might be at fault (this could be a number of things including weight distribution, remember as standard an ambulance is light at the rear, and the suspension shocks etc take this into account)

One other thought, and this is more of a problem with front wheel drive vehicles, as you move forward/accelerate the wheels can toe-out slightly, due to a certain amount of give/flex in the suspension system, so set a vehicle at 0 degrees that should be set to 1 degree toe-in and when you move forward and accelerate the wheels toe-out more than they should causing wear on the inside edges of the tyres ..... so if you have something worn in your front end (like spring bushes) then this can produce the same affect and will not be detectable by checking the tracking when stationary.

[AndyG]

i would seriously doubt the outer for one and the inner for the other for the tyre wear, that would be plain odd !

.

Mine does I've suussed it do you wanna go there

[Gunslinger]

i would seriously doubt the outer for one and the inner for the other for the tyre wear, that would be plain odd !

.

Mine does I've suussed it do you wanna go there

go on .... cough it up (this should be interesting)

[AndyG]

i would seriously doubt the outer for one and the inner for the other for the tyre wear, that would be plain odd !

.

Mine does I've suussed it do you wanna go there

go on .... cough it up (this should be interesting)

Firstly I have to point out mine's a MK5. So not sure if this should be posted here. But it is strictly tyre wear.
My original problem was passenger/nearside wear on the outer edge only.
But tracking man insisted on setting it his way (what do I know ).

Now I get, said effect. Wear on inner edge drivers/offside and wear on outer edge passenger/nearside.

It's my conclusion, that the tracking has been set to tow out in order to minimize the wear on the nearside tyre. But while I'm driving along the camber of the road means that the offside tyre is being dragged, hence inner edge wear.
The nearside tyre's outer edge is wearing because of my regular full lock U turns
Can you throw any other light onto this subject

[Gunslinger]

hhmmm interesting ....... regular full lock U turns .... how many are we talking about here and could that have been your original problem ? and yes i agree sounds like they toed it out to compensate, its strange that your original problem was wear on the outside, as that kind of negates worn parts causing one side wear only (unless the camber angle is screwed)

[stevew]

Tracking is an interesting subject!
As I understand it to adjust/check the tracking properly you need to do it with the wheels straight ahead and also at full lock in each direction. When you adjust the tracking you are supposed to adjust it equally on each side so as to maintain the Ackerman angle. Thats what should be checked at full lock. If your tracking has been adjusted on only one side, as ALL places I have been to have tried to do, you'll find that the tires don't wear when going straight but wear a lot when turning. This could explain odd tyre wear.
What do you think?

Steve

[MrMPuk]

Sounds good to me!