Tyre Wear

[Tim86]

Hi Guys

I have recently purchased two new Kumho 33x12.5xR15's to add to my existing two Kumho 33's that have approx. 60% tread left.
I generally drive my unmodified (except for the front axle shift) '95 Hilux SFA rather sedately in 2wd (rwd) on road.
The question is should I place the two new tyres at the front or the rear in order to match the tread depth of the older pair over time i.e. will the front or rear tyres wear quicker under my conditions?

Colleagues have advised that the new tyres should be placed at the front but these chaps both drive IFS vehicles and I have observed that the IFS setups tend to 'round out' the front tyres over time due to their geometry which generally would appear as quicker wearing. SFA setups tend to keep the tyres more perpendicular to the terrain than IFS.

Any advice would be greatly appreciated!

Cheers

[Mud Dog]

Tim, it is in fact better to put them on the front. They will wear a bit faster there than on the rear because the front is where most of the braking power is as well as that there is a little extra scuffing because they are the steering wheels.

The fractional difference in diameter between the new and older tyres is not a point of concern since your vehicle has no permanent drive to the front as is the case with AWD vehicles, so there is no axle wind-up while on hard surfaces unless you engage 4WD and lock the hubs. In off road scenarios where 4WD is active, there is more than enough slippage to make it a non issue, so no concerns there either.

[Tim86]

Thanks Mud Dog

I would have thought that the rears would possibly wear faster obviously because they are the driving wheels but also due to engine braking as well. I will take your word for it - on the front they go!

[Mud Dog]

One can be forgiven for thinking that, because there is some logic to it, but factor in the "stress" difference between acceleration and braking, you will understand that acceleration is a lot more gradual than braking (unless you're in the habit of spinning the wheels on take-off), and braking is much harsher so there is more wear with braking.

Also, it's generally better to have the new rubber on the front for better braking and steering - just be aware that for the first few weeks / 1000km's, they won't be as good until they've "settled in".

Just to elaborate on a point from your initial post, even though there is no concern about marginally different tyre diameter (caused by wear) between front and rear axles on the SFA, one should try keep the tyre diameters similar between left and right on each axle.

[Lorry]

Hi.
I bought a new set of AT tires last year, since then I have done over 25000 km, at ever 10000km I do a tyre rotation swapping the front to rear on the same side, I did notice that the front tires had a rounded shape due to the steering etc etc than the back which had a more flattened look. At the end of the day with the tire rotation it sorted out the issue or even wear.
It is very important that you keep the tires on the same side of the vehicle so as to not cause a uneven wear on the bite of the Tyre. you don't over use the one side of the nobbles or tread of the Tyre.ie. when a tyre accelerates it uses the bite on the one side, and when you brake it uses the bite of the tread on the other side. If you swap them over from right rear to left front the braking bite will be the same side that was used for the acceleration as the rotation of the tyre has now changed.