Thread: OK to fit new tyre only one axle?

AFAIK generally that is fine, provided they're the same size tyres (ie 255/60/R18 front and back, or whatever your tyre size is). The small change in diameter due to tyre wear is negligible.

It is not advisable to run different age or tread pattern tyres from left to right, as this adversely affects handling.

If the front tyres only have 10k km left, it maye be cheaper in the long run to buy 4 now, as you can get deals for four tyres, or get an alignment included for free etc. You could then keep the fronts as spares, or replace your existing spare with one of them.

Cheers

Dan

Providing the tyres you use are exactly the same designated size you won't have a problem. The rolling diameter of a tyre relates to the length of the steel belts and tread depth has very little effect on this.

Thanks guys - the answer I was hoping for! Yes, it's true that there are some good 4 for three offers going but I am expecting to buy on the internet and get them fitted. saved a bundle last time I did this (on the Rodeo). At present the budget is sad hence likley just the two I need. I realise that warranty is tricky when the tyres are not purchased from the fitting shop but touch wood never had a warranty claim on a tyre. My tyres are 235/70 R16. Odd size?

Originally Posted by bee utey

The rolling diameter of a tyre relates to the length of the steel belts and tread depth has very little effect on this.

the diameter (and circumference) will change from a new tyre to one which is worn. I think the OP was considering the extra work the centre diff has to do, but I don't think it's an issue. It has significantly more work to do in bends/turns, than a ~1% difference in front to rear tyre size.

Originally Posted by V8mumble

the diameter (and circumference) will change from a new tyre to one which is worn. I think the OP was considering the extra work the centre diff has to do, but I don't think it's an issue. It has significantly more work to do in bends/turns, than a ~1% difference in front to rear tyre size.

A tyre is a dynamic object and wrapping a tape measure around an inflated tyre off the ground will not give you the rolling diameter. Once again I'll dig out a diagram of a tyre contacting the ground that illustrates the effect.



The steel belts are parallel to the ground and apart from extreme accel/decel conditions the tread rolls forwards at the rate of the belts immediately above it.

Originally Posted by bee utey

A tyre is a dynamic object and wrapping a tape measure around an inflated tyre off the ground will not give you the rolling diameter. Once again I'll dig out a diagram of a tyre contacting the ground that illustrates the effect.



The steel belts are parallel to the ground and apart from extreme accel/decel conditions the tread rolls forwards at the rate of the belts immediately above it.

So this could explain the sometimes noticeable difference between 2 different brand tires with the same size stamped on the side?

"I think the OP was considering the extra work the centre diff has to do, but I don't think it's an issue. It has significantly more work to do in bends/turns, than a ~1% difference in front to rear tyre size."
Yes, that was my concern. Corners are corners but with odd sized tyres front to back the centre diff is working all the time. But not very hard, I guess.

One thing which might become more sensitive is the ABS system so as long as you dont get erratic ABS, TC or EBD behaviour you should be OK.