robski

A few posts lately have got me wondering. When driving a 2wd car, you always replace the driving wheel tyres at the same time, and on a fwd car, as long as the rears are similar they dont seem to impact handling. On a 4wd, should you replace all 4 together, since all four drive?

robski

Andrew Dixon

I see what you're getting at, but generally the advice seems to be that as long as you replace tyres in pairs across an axle you'll not impact handling badly. As front and rear tyres wear at different rates anyway, it shouldn't matter if the tread depths are different front to back.

In fact in some European countries it's illegal to replace tyres singly, although whether this is more for the tyre manufacturers benefit I'm not sure!?

It's a good idea though to keep all four tyres of the same type.

Andy

CJ

Not sure this applies to Scoobies (decent 4wd gear) BUT I heard some major problems with 4wd's the center diff being damaged if uneven/mismatched tyres are used. Something to do with one set of wheels travelling further than the other.

I know you would expect the wheels to be travelling at different speeds during slippery driving conditions. But...

Check with a friendly dealer, you may need 4 new tyres anyway.

Orville

In a 4WD it is best to rotate your tyres regually to maintain even tread wear and then replace all 4 when worn. Brand new tyres on one end and worn ones on the other may well put the diff under some extra stress but thats its job. Personally I will replace all 4 at once.

TonyNesta

Gents - I don't want to alarm anyone, but I heard (can't remember where) that you can't have more than 2mm tread depth difference between front and rear on a 4WD car - if you do, it will tear the diffs apart. Thus a pair of shagged out tyres at one end, and brand newies at the other would be A Very Bad Thing. Can anyone confirm/deny this ?

Bob Rawle

The 2 mm criteria specifically applies to 4x4 Vauxhalls. The transfer box in these cars has a viscous coupling and also seven clutch plates so that the rear drive can be disengaged under braking to enable the abs to use the wheel speed sensors instead of the 4x4 drive. It will be prudent to always try and even the wear our on a Scube, swap the wheels front to back say every 4k miles. I have not heard of any transmission failure due to just replacing two tyres but ... anyone out there know different ?

I will quote from my Japanese manual translation

"When changing the tyres always use exactly the same tyres on all four wheels. The 4WD system relies on all 4 wheels being the same size. Should you have a puncture and have to use the emergency tyre, it is advised to repair the original tyre as soon as possible."

The manual also states

"For longer life on your tyres it is advised to rotate your tyres every 5000km"

ie front to back, not diagonaly

Hope this helps

Bob


[This message has been edited by Bob Rawle (edited 29-08-1999).]

[This message has been edited by Bob Rawle (edited 29-08-1999).]

leaskc

My dealer swapped my tyres front to rear at the car's 15k service.

The tyres lasted 23k in total if this helps anyone guage the life I got from the tyres.

Best advice seemed to be to replace all four at once - so Thursday night saw four new S-02 PPs go on the car...

cheers

Cameron