Could mis-matched tyres do this?

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Recently had a puncture on the company Golf, a new tyre was put on due to the size of the hole, despite telling the garage that the rears were Dunlops 225/45R17 91W (current one on 4-5mm) they put on a Michelin 225/45 R17 94W.

I noted this at the time but thought it's a Michelin, logically even better quality, it'll be fine! Now at this point I should say on my cars I only ever put tyres on per axle and tend to have the same make/model all round.

Since on two separate occasions the car has let go at the rear quite significantly (ESP cutting in), once was definitely from the rear left where the new tyre was, this hasn't happened before in the two years/50k I've had the car.

Fronts are Goodyear Eagle 225 45R17 91Y, so I now have three different brands!

So the question is could this be the mis-matched tyres that's caused the loss of control?

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BrettMRC said:

Under what conditions is the rear breaking away?

Thanks for the reply.

Admittedly in wet/greasy conditions, but this was on my cross country commute, and I checked the road that evening where the worst one occurred, and all seemed well.

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TwistingMyMelon said:

Have you checked pressures and condition tyres?

Thanks for the reply.

Yep, I don't trust garages so always check when they change tyres etc, I even checked the torque on all the wheel nuts afterwards! Car has TPMS so any drops are alerted to.

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Vintage Racer said:

Are these on the same axle?

Here in France (and most of Europe as far as I know) it is illegal to mix tyres on same axle (they must be identical manufacture/spec/rating etc).

All tyres have their own characteristics, so may be the problem. - Not sure about UK, but worth checking!

Yep, fronts are the Goodyears, rears are the Dunlop and now Michelin too.

I've never heard that about tyres in the UK having to be the same, but happy to be corrected if so.

Thanks for your reply too

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RB Will said:

How recent is the tyre change? a fresh tyre will have less grip than the old one until it has bedded in a bit especially in the wet, other major one to consider would be the pressure in it.
Either of those is more likely than the mismatch as even mismatched tyres should not have significantly less grip than your old matching pair

Agreed, I was always cautious on my bikes due to the chemicals they use to seal the tyres and you needing to wear it off/the tyre bed in. First time was about 70 miles afterwards, second was hundred of miles later.

Pressures have been checked, never trust a garage!

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TooMany2cvs said:

Unlikely. A mismatch is most likely to give you a difference under hard braking or (on the driven wheels) acceleration.

Cornering, there's a huge mismatch between sides, so a mismatch between quality brands is going to be fairly irrelevant. A mismatch side-to-side is most likely to reveal itself in RH corners behaving a bit differently to LH.

Stupid question - it's not been put on the rim with the inside on the outside, or wrong-rotation...?

Despite 20+ years of driving I don't think I've ever had mis matched tyres, not something I'd do on my own cars.

I guess that first time it let go & the ESP cut in was on a right hand bend, so the new tyre being on the left rear was working harder obviously. It's just that you don't expect a front wheel driver to seemingly oversteer!

I'd wondered that too, and did check, fair point though!

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Debaser said:

Mismatched tyres can definitely cause unusual handling characteristics. I spent some time in a car with mismatched premium tyres front to rear, during high speed cornering in the dry above about 0.6g the front would react much more than the rear, to the extent the stability control would begin to cut in.

As soon as I swapped them for matching tyres all round it was fine.

Clearly some differing views....as mentioned I can't recall ever doing this before so unsure. Being an ex biker I'm so aware of the importance of the contact patch so tyre make/condition etc is crucial to me, as I'm sure it is to most on PH!