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Re: Mismatched Tyres - How dangerous?

Richard Murphy ( snipped-for-privacy@murphy00.freeserve.co.uk) gurgled happily, sounding much like they were saying :

> Just got back from my MOT, failed, amongst other things due to the 2 >> front tyres being of different types! This surprised me, as I had them >> professionally (?!) fitted about 2 months ago by Hi-Q. Checking myself >> they are :- >> >> Offside - 185/65R14 86T >> Nearside - 185/70R14 88T > Dangerous and illegal > > Does your car still brake and accelerate in a straight line? > if so I would be very surprised.

There's not a huge difference between 185/65 and 185/70 in size - about 9mm in the sidewall height, or only slightly more than the difference between a bald and new tyre of the same type and size.

Many new cars come with a spare that's a different size to those fitted - not just "space saver" spares, either - but virtually anything with alloys and a steel spare.

Even so, it's not a great idea.

Reply to
Adrian
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How would an XM or similar cope with a space saver? - I'm guessing it wouldn't like it much at all.

cheers, clive

Reply to
Clive George

Clive George ( snipped-for-privacy@xxxx-x.fsnet.co.uk) gurgled happily, sounding much like they were saying :

Can't see how it'd be a big problem on a hydraulic Cit.

There's only one height corrector per end, running off the anti-roll bar. That'd have a little bit of a twist in it, same as any "normal" car, but it wouldn't confuse the suspension at all. If anything, it'd cope a bit better than steel sprung, as the amount of fluid in the suspension cylinders would adjust to ensure the same pressure both sides, instead of potentially having one corner slightly lighter than the opposite.

While XM spares are consistent with the main boots, most late CXs came with a slightly smaller spare than the main four - nothing wider than a 185 will fit in the spare wheel holder and allow the bonnet to shut. The spare on a CX turbo would have been a 185/80 14, while those on the alloys were 220/55

390.
Reply to
Adrian

Adrian wrote

That's what I thought today when I had a front tyre puncture, only at low speed, and found a thin nail through the tyre wall just off the thread. :-( It will have to be a proper galvanised repair, and the tyres are only about 8000 miles old.

The sizes are 205/60 x 15 and the spare is 195/60 x 16 (Rated 80mph).

Reply to
Gordon

Gordon wrote

Correction: 205/50 x 16 and spare = 195/60 x 15

Reply to
Gordon

Having dofferent profile tyres when comparing front to rear tyres is not a problem, mainly on high perfomance cars. It is not a good idea to have different profile tyres on the same axle. The space saver argument is invalid, the tyre may be narrower, 195 instead of 205, and 15 inch instead of 16 inch, but it is still a 60 profile. Insurance companies are very wary of these sort of things, if the car were to be in a brake related accident they would use the different profile tyres to argue the non-payment of a claim.

I should check with Hi-Q and get them to replace/reimburse you for what is a very poor mistake.

James

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