Mixing tyre types

Much to my surprise space savers on Subaru Impressa AWD are smaller in diameter than the main wheels.

I would like to know why the posters seem to be obsessing about space savers? I know I first brought it up but it is pretty obvious that with an electronic 4WD the space saver should be the same size whereas with many other cars they are not and has been pointed out even an AWD.

It is of course desirable that a space saver should be the same size but remember they are designed for on highway for the lowest common denominator. Maybe Land Rover decided that it was better to take up more space than to face litigation in the USA where some lawyer could "prove" a space saver was to blame.

If you were stuck in the desert with only a second spare say a camper trailer tyre would you care?

Wouldn't you give it a go and maybe pull the ABS fuse if the car complained?

Why has the thread gone off on a space saver tangent when the post is about different size full sized tyres?
I am doing what I posted and I now sign off
Regards Philip A

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Originally Posted by PhilipA

Why has the thread gone off on a space saver tangent when the post is about different size full sized tyres?
I am doing what I posted and I now sign off
Regards Philip A

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Because the use of smaller spacesavers in some vehicles is an extreme example of the use of different diameter wheels and types and highlights that the question of using marginally different size and types of tyres may not be as much an issue as some people think.

On my RRS I drove from Melbourne to Canberra with three 255/60 R18s and one 255/55 R18 (on the back) and had no issues with the systems - only a small difference but nevertheless a difference.

Garry

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Originally Posted by PhilipA

If you were stuck in the desert with only a second spare say a camper trailer tyre would you care?

Wouldn't you give it a go and maybe pull the ABS fuse if the car complained?

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Because the above may be a fair point for a D2, where the centre diff lock is manually activated. But for a D3/D4, the lock will be triggered by the vehicle, moreso if the tyres are of differing rolling diameter. And of course, you can't pull the fuse for the ABS/TC.

So for any wheel (spacesaver or otherwise), it should be approx the same rolling diameter. That's why :angel:

Of course, in an emergency, one will be tempted to try anything.

Cheers,

Gordon

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Originally Posted by wbowner

Hi,
Here is a bit of a dumb question.



Eg
If I changed my standard 19" tyres on my new D4 which are wranglers I believe! with say Hankooks, would it be possible to hang on to one of the wranglers as a second spare which I would use only in an emergency.

I am hoping to swap the wranglers over before picking the car up for coopers or Hankooks. There is a good chance no one will want the originals so I may run with them for awhile and when I go to change them I am thinking of keeping one as my second spare casing only. If I can exchange I could keep a new one. I would only use this tyre in emergencies and until I could replace it, which could be a few days.

Is this a good idea or at least feasible.

Richard

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Good question and one that's been on my mind as I have 2 brand new spares for a trip but the 4 tyres on the vehicle now have done 25,000km. Trip will be another 13-14000km. Will either new spare be a mismatch?! ( identical size and make - Cooper at3 )