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We have a 2003 Mini Cooper on 17 inch wheels with run-flat tyres.

The ride is firm, to say the least.

The rear tyres will wear out before the front.

Is it wise to fit normal tyres to one end of the car until the other two run-flats wear out, and to purchase a space saver spare?

Scott

From the "Ask Jack" archives - 14 December, 2009

This is a very interesting question and I'm not sure I have the correct answer.

My understanding is that a rule was recently introduced to the affect that cars registered after Oct 2002 must have tyres of the same construction fitted to both front and rear axles.

Tyres with different size designation can be fitted but they must be identical on each axle. For example some high performance cars have a larger tyre on the rear than the front.

A tyres construction refers to its ply orientation, ply rating and load index.

The question is then, does the run flat tyre have the same construction characteristics (as above) to that of a standard tyre?

My understanding is the run flat tyre has a much different side wall construction than a conventional tyre (much thicker).

Does this change the ply rating?

May sound a little pedantic, but fitting different tyres front to rear may change the handling characteristics of the car completely and could make it unsafe or in an unwarrantable condition.

I suggest you go to a tyre supplier (same as the brand of tyres currently fitted) and ask the same question. You may need to ask them to pass the question onto their head office technical staff.

Interesting to read the rears are wearing faster than the front. Is there a wheel alignment concern here as well?

NOTE: A follow up conversation with the technical staff at South Pacific Tyres confirms my thoughts.

They actually go a step further and say it is strongly recommended not to mix these tyres.