Mixing tyres front/rear on a 570s

[vantager]

I am thinking of using Michelin ps4s on the rear (they need replacing soon). As the fronts dont need replacing, I could leave the Pirellis on (I dont really like mixing tyres like this) or just change the fronts early - so I'd have michelins all round. Anyone mixed these tyres front/rear?

[anonymous-user]

Wouldnt mix tyres personally.
The only thing keeping your precious supercar on the road is 4 patches of rubber so cant understand anyone scrimping on tyres.
I change mine b4 3mm as performance is dramatically compromised after that especially in wet

[Rocketreid]

vantager said:

I am thinking of using Michelin ps4s on the rear (they need replacing soon). As the fronts dont need replacing, I could leave the Pirellis on (I dont really like mixing tyres like this) or just change the fronts early - so I'd have michelins all round. Anyone mixed these tyres front/rear?

Unless you really push on, on the road I would not worry unduly

In a McLaren it’s the rears which are important and the PS4S are better than the fronts.

On track different proposition though and I would not recommend that

[ANOpax]

How old are the Pirellis?

Chances are that they're close to being time expired anyway so you might as well replace them.

Edited by ANOpax on Monday 11th April 14:55

[12pack]

In the same situation I changed all four and sold the fronts for £100 on eBay. They went to a nice home on a Seat Cupra R

[David W.]

I remember a well respected car man saying what we ask a tyre to do at each end of the car is way more different than the difference between 2 tyre compounds so it doesn’t matter too much. That made sense to me. Clearly both ends need reasonable tread depth though and we are talking about road driving not 10/10s on a track.

[ANOpax]

David W. said:

I remember a well respected car man saying what we ask a tyre to do at each end of the car is way more different than the difference between 2 tyre compounds so it doesn’t matter too much. That made sense to me. Clearly both ends need reasonable tread depth though and we are talking about road driving not 10/10s on a track.

But we aren't just talking about different tyre compounds here are we? We're talking about completely mismatched tread, sidewall, compound and construction details.
However, your 'well respected car man' makes a very good point but not the one he intended.
If you read posts by tyre testing engineers, you'll find that minor differences in design parameters within the same family of tyre can have a huge effect on handling balance. This is why not all MPS4S, for example, are created equal and why there are matched sets for Mercedes, Ferrari, Porsche and BMW. The irony is that they may not be identical in tread, sidewall or compound but the critical point is that they have been designed to work together. (In fact, my Michelin Alpins have very different front and rear treads but, again, they have been designed to work together). Even Porsche and Ferrari have two separate tyre designations within a single MPS4S tyre size for different car models.

Here's a comment online from a Michelin tyre test engineer;

"But trust me, today again I was doing some development for a future rwd BMW and even with the same tread compounds, same size, tyreline, etc... the slight changes made to the internals of the different sets I drove where sometimes just day and night ! Some had a very strong rear, oversteering just a bit on hard maneuvers at high Speed, and others, for the same maneuvers, were just going sideway as hell with heavy countersteer. Some sweaty moments."

The OP is planning to run mismatched tyres on a £100k high performance car, either out of ignorance or thriftiness.

Just don't do it.

Edited by ANOpax on Tuesday 12th April 09:33

[deeps]

vantager said:

I am thinking of using Michelin ps4s on the rear (they need replacing soon). As the fronts dont need replacing, I could leave the Pirellis on (I dont really like mixing tyres like this) or just change the fronts early - so I'd have michelins all round. Anyone mixed these tyres front/rear?

If you're not hooning flat out they will be fine. As a driver we feel the car and adapt to it.

I once drove a Nissan Gtr with summer runflats on the rears and winter on the front, was interesting but you feel the car and adapt to it.

I was at a McLaren dealership last month and they quoted to replace my original front tyres as they were 5 years old. They still have 5mm of tread and are fine for normal driving, despite the out of date 'deterioration'. Double the realistic price, but I assume most customers just pay it.

[Streetbeat]

ANOpax said:

This is why not all MPS4S, for example, are created equal and why there are matched sets for Mercedes, Ferrari, Porsche and BMW.

Could you please explain this, are you saying there is a different construction process for "matched sets"

[samjlevy]

Streetbeat said:

Could you please explain this, are you saying there is a different construction process for "matched sets"

He’s stating that a Porsche OEM PS4S will be different to Mercedes PS4S for instance, which is true. Tyre companies work with manufactures to customise the tyre to their specific specs.

[Streetbeat]

So what will the differences be?

[markiii]

whatever the manufacturer decided they wanted

[samjlevy]

Streetbeat said:

So what will the differences be?

Could be different compound for instance.

Have a look at this:

https://www.youtube.com/watch?v=COA630Juf_U

[TrotCanterGallopCharge]

My 2p

For this type of car, will there be any non compliance with Insurance if tyres mixed?

For the value of the car, seems odd to mix tyres. I've mixed tyres, but only on low powered stuff.

Tyres are consumables. Sell the ones that don't match if you want some money back, & put towards a matching set. If you buy 4 (or 5 if you have a spare), you may get a discount anyway.

[Longy00000]

I believe they can fine tune almost every aspect of the same tyre to fit with the expectation of the car manufacturer they are pairing with. Even things like the beading, the thickness and tensile rating of the wire reinforcement, compounds etc (especially dual or multi compound tyres)
Each part will inhibit or amplify a particular handling trait as per the car manufacturer instructions.

[xcentric]

TrotCanterGallopCharge said:

My 2p

For this type of car, will there be any non compliance with Insurance if tyres mixed?

Doubt it - as long as it has an MOT (and insurance, and driven by an appropriate person) then it's fine to be on the roads.

But whether it's really sensible or not is another question. If the rears are worn out, then the fronts are probably not too far off now, and on a £100k car, finding a ditch is expensive.

TrotCanterGallopCharge said:

For the value of the car, seems odd to mix tyres. I've mixed tyres, but only on low powered stuff.

Tyres are consumables. Sell the ones that don't match if you want some money back, & put towards a matching set. If you buy 4 (or 5 if you have a spare), you may get a discount anyway.

I tend to agree with this. Seems like time to buy 4 new ones. Perhaps have one of the old fronts as a spare if it's better than the spare, but probably best to sell them or junk them.....

[ANOpax]

TrotCanterGallopCharge said:

My 2p

For this type of car, will there be any non compliance with Insurance if tyres mixed?

No. The only insurance requirement is that the tyres are legal. That would pertain to correct load rating, speed rating and minimum tread depth.

[TrotCanterGallopCharge]

ANOpax said:

TrotCanterGallopCharge said:

My 2p

For this type of car, will there be any non compliance with Insurance if tyres mixed?

No. The only insurance requirement is that the tyres are legal. That would pertain to correct load rating, speed rating and minimum tread depth.

Ok.
I was also thinking if McLaren recommended a single brand/tyre, as they had developed the car with that (like when BMW had their run flats years ago), could the Insurance Co not pay out if the owner had used a different brand/type, even though they maybe legal?

[aka_kerrly]

12pack said:

In the same situation I changed all four and sold the fronts for £100 on eBay.

This, whip the fronts off an bang them on ebay/gumtree collection only. I am constantly surprised how much people will pay for used tyres.

[David W.]

aka_kerrly said:

This, whip the fronts off an bang them on ebay/gumtree collection only. I am constantly surprised how much people will pay for used tyres.

This opens a whole new can of worms. Who’d purchase 2nd hand tyres off eBay to put on a road car unless you have total confidence in your tyre company to check them and give them a clean bill of health which they may be reluctant to do.