Blairc

Ok guys, I`ve got a bit of uneven tyre wear going on and as a result the passengetr side front has worn badly on the inside edge while the driver side is still in perfect condition.

My dilemma is that the backs have good tread left and the driver side front still has a good ammount of tread as well. So, I`m wondering could I just change the front passenger tyre (swapping like for like of course) for a new one to do me until I need to change all four?

Thanks,

Chris.

DaveW

Some may disagree, but at a minimum I would buy 2 tyres for the front. If they are anywhere near needing replaced then I'd do all 4.

Remember its a four wheel drive car and the diffs are not really designed to run for any length of time with different sized tyres (new and old on the same axle).

Dave.

s70rjw

iTrader: (2)

Same problem mate and I just replaced all 4 my choice of course...

Scrappy9

I have the same issue, after damaging a tyre following a puncture.

I have read through Subaru hand book, it doesnt state tyres need to be changed in pairs or all 4 together, just says ensure the same diameter of wheel is used all round.

The advice I received on another forum was split between the manufacturers being greedy, different rolling diameters on the wheels could knacker the diff.
But then the point was made that if tyre pressures are out that also changes the rolling diameter.

So I dont know what to do, my tyres are just over half way worn and I dont fancy a £400 plus bill following a puncture.

DaveW

So your saying that it may be OK to only change one tyre because you could have been driving for 10k or so miles without checking your tyre pressures and one could have been out by some margin? Strange way of looking at it.

Its a bit like running on the space saver spare for 10k, not something you do in a performance car.

But its your car, so you choose. I'm sure it will be fine.

Scrappy9

No I dont actually think I said that.

I said the point was made that different tyre pressures also alter the circumference of the tyre, so as people deliberately run different tyre pressures front and rear and check them weekly to ensure they are correct(and different), doesnt that somewhat defeat the arguement about changing all 4 wheels together?


What I actually said was I was unsure what to do, but I appreciate your constructive comment.

I, as I assume did the original poster hoped to benefit from peoples knowledge on here as to whether changing tyres in pairs or all 4 together is based on fact or it is a myth.

Blairc

Scrappy - Thank you for your positive comments, what your saying certainly adds a few more issues into the equation. I`m still really unsure what to do!!!

Any other perople have any views??

Cheers,

Chris.

DaveW

Scrappy9,

Didn't mean to come across so condescending, my apologies. I think until someone proves otherwise I'll stick to what Subaru recommend and keep all my tyres as close to the same size as possible.

Dave.

Scrappy9

Dave W.

No worries, I think you could well be right.

Just grates a bit taking 3 half worn tyres off, be even worse if the wife finds out the cost.

regards Gary

AvalancheS8

I'd go with just replacing the pair on the front. Also, I'd keep the better tyre that comes off in case you damage another half worn tyre.

I've had to buy a pair of tyres after damaging one half worn tyre on three different occasions, and the second and third times I wished I'd kept the undamaged half worn tyre from the previous occasion. The last time it happened I did, so if it happens again, the spare one can go on.

Scooby diffs don't seem to be prone to problems caused by slightly different tyres, and since a 3mm difference in tread depth is about 1% difference in rolling radius, I don't see it being likely to cause a problem.

Putting it into context with 205/50 16s, at 100 mph your wheels are doing about 1380 rpm, or about 23 rev/sec. If you had a difference in tread depth of 3mm between the 2 tyres on one axle, the 2 sides of the diff would be rotating relative to each other at about 13.8 rpm, or around 1 rev every 5 seconds, that really isn't much at all. Even allowing for diff ratios, the sides of the centre diff would still only be rotating about once per second relative to each other - at 100mph.

Blairc

Folks,

Thanks for all your input. The conclusion I`m coming to on this one is tha it`s safer to change the front two (better to be safe than sorry) and to bite the bullet financially - which is difficult cos I`m a tight Scotsman!!LOL!!

Chris.