Mismatched tyres

[starspeed]

MY SL500 (2003 registration, 42,000) is currently being serviced by an MB authorised repairer. They have called to say that the o/s rear tyre is showing signs of uneven wear and proposed to fix the steering geometry. In more or less the same breath they told me that the n/s rear tyre is the wrong size
(225/45, should be 255/45). I reminded them that they had fitted the wrong tyre and suggested that was the cause of the wear on the opposite tyre. I also suspect that the diff could have suffered accelerated wear due to the mismatch.

I would be grateful to learn if that analysis sounds right.

I'm proposing to ask for two replacement tyres (not surprisingly) and geometry re-alignment free of change and a promise to fix the diff if it fails in the next two years or so.

 

[stella1]

i should think so too,when the work is done NAME and SHAME them

 

[Cole@MBS]

225 on the rear of a SL,i have 225,s on the front of my C,class

255 would be the correct size, was it mb who fitted the 225 on it last time!

 

[starspeed]

It was the same dealer who fitted the wrong tyre. They also tried to tell me that the '225' figure was the speed rating. Name and shame under consideration!

 

[television]

255 x 45 x 17 are standard all round on the 2003 SL with the standard wheels

 

[robertjrt]

MY SL500 (2003 registration, 42,000) is currently being serviced by an MB authorised repairer. They have called to say that the o/s rear tyre is showing signs of uneven wear and proposed to fix the steering geometry. In more or less the same breath they told me that the n/s rear tyre is the wrong size
(225/45, should be 255/45). I reminded them that they had fitted the wrong tyre and suggested that was the cause of the wear on the opposite tyre. I also suspect that the diff could have suffered accelerated wear due to the mismatch.

I would be grateful to learn if that analysis sounds right.

I'm proposing to ask for two replacement tyres (not surprisingly) and geometry re-alignment free of change and a promise to fix the diff if it fails in the next two years or so.

My spare tyre changed: size, tread patten, manufacture and diameter, has yours?

 

[starspeed]

The spare is a so-called 'space saver' for temporary use and with a 50 mph speed restriction.

The dealer is now indicating that the wear on the correctly sized tyre is due to slight under inflation, not the fitting of a smaller tyre on the same axle. They also seem to have difficulty understanding that non-spec tyres could lead to the rejection of an insurance claim in the event of an accident.

 

[Miffy]

on my clk I have 225/40 fronts and 255/35 rears

 

[robertjrt]

The spare is a so-called 'space saver' for temporary use and with a 50 mph speed restriction.

The dealer is now indicating that the wear on the correctly sized tyre is due to slight under inflation, not the fitting of a smaller tyre on the same axle. They also seem to have difficulty understanding that non-spec tyres could lead to the rejection of an insurance claim in the event of an accident.

I always understood that tyres should match the opposite. My front wheel van had wider on the front than rear, but, were all the same circumference.

Years ago, many years ago one was not allowed to have cross-ply and radial on the same axle.

The Road traffic Act should have the correct interpretation, or, ask a traffic policeman, if it is "fineable" they will know!

 

[rf065]

The Road traffic Act should have the correct interpretation, or, ask a traffic policeman, if it is "fineable" they will know!

If the law states they must be the same size, then space savers would be illegal

Russ

 

[D1gger5]

You have to have the same profile tyres on each axle (front and rear) to pass the MOT.

My workhorse car has 185/60 on the front (low profile) and 185/70 on the rear.



If the garage/dealer have put on an incorrrect tyre then there is possible handling problems as well.

 

[CL500Wizard]

its not only the profile, but one should have the same make and spec tyres on one axle. having different makes/specs can dramatically change the handling of the car

 

[Miffy]

You have to have the same profile tyres on each axle (front and rear) to pass the MOT.
quote]

agreed, I just read this on the mot info site

http://www.motuk.co.uk/manual_410.htm

 

[rf065]

It would appear that a space saver will fail an MOT if fitted to the car, how can it be legal to drive on the road then?

Russ

 

[robertjrt]

If the law states they must be the same size, then space savers would be illegal

Russ

I think you will find "space savers" are the same diameter as the tyres supplied with the car. The "space saver" is specifically manufactured as a Get You Home/garage and is speed restricted, 50 mph?

Having the wrong tyres, different tread (same axial), type, size or damaged covers is a danger. Large heavy cars at speed need first class tyres and brakes. Having once had a "blow out" at speed on the motorway was not a pleasant experience, in the blink of an eye, **** happens, why take the chance?

 

[D1gger5]

I'll never rely on remoulds - FALSE ecoomy on older cars.

Remoulds on my first car lasted three months. One car I bought had a pair on it and a full MOT until it decided to shred its tread between Loughborough and Kegworth at 70 on a dual carriageway. Then again the death chariot (Must have been a well dodgy MOT and DOT didn't car) was crushed well before the MOT expired.

Why pay a premium for super duper sticky rubber that wears like soap. I would rather have a harder compound all round at a reasonable mid range price. Alcohol and computres don't mxi

 

[robertjrt]

I used asymetric tyres on my C180 and the difference was very noticable, they wore very well, good value for a quality tyre.

 

[JEZ.S320L]

It would appear that a space saver will fail an MOT if fitted to the car, how can it be legal to drive on the road then?

Russ

If anyone were stupid enough to submit their car for an MOT with a Space Saver tyre fitted, then they deserve to have it fail. Not only that - but they should be forced to have the 'fail' notice pushed slowly up their rear end with a red-hot poker!!

You can never regulate for fcukwits.

 

[rf065]

I think you will find "space savers" are the same diameter as the tyres supplied with the car.

They may be, but they are not the same width, which is how this post started.

Russ

 

[ncooper]

(225/45, should be 255/45). I reminded them that they had fitted the wrong tyre and suggested that was the cause of the wear on the opposite tyre. I also suspect that the diff could have suffered accelerated wear due to the mismatch.

I would be grateful to learn if that analysis sounds right.

I'm proposing to ask for two replacement tyres (not surprisingly) and geometry re-alignment free of change and a promise to fix the diff if it fails in the next two years or so.

Hello,

Although the tyres are mismatched,the difference is only the width,not the circumference,so there will have been no effect at all on the differential.

The whole purpose of a differential is to allow the driven wheels to rotate at different speeds,so even if there had been a difference in the circumference,it would have coped with it.

At the risk of offering an egg sucking lesson,tyre sizes are as follows,using one of mine as an example.

195/70/R14

Width of the tread(mm)/cross section of the tyre(mm)ie the distance from the rim to the tread/rim diameter(inches)

Regards,
Nick.