Michelin PS4S tyres have a major problem that tyre tests and tyre reviews don’t tell you. And it’s not just a problem of the PS4S tyres, it’s also the tyre tests.
Tyre Temperature
Tyre reviews never give us the temperature of the tyre when they give us the tyre’s dry braking distance or lap time. This is an omission that makes these reviews almost useless.
Below is an example of a typical tyre review.
While a tyre like the PS4S may have a faster lap time or better dry braking performance than a PS5 for example, if we don’t know the temperature of the tyres when these times were recorded and we don’t know the typical temperature of the tyre in road driving, there is no way to know if these grip numbers are reflected in the real world.
For Example
A tyre like the PS5 is road orientated and also more all season orientated than the PS4S. The PS4S is designed for road and (20%) track use.
And here’s the issue, a tyre with track use in it’s remit will take longer to get up to it’s optimum operating temperature than a road focussed tyre.
Why?
Because it needs to not overheat on track
Road Driving
This factor translates into it’s road performance.
In the same road conditions the PS5 will have a higher temperature than the PS4S.
The temperature of the PS5 tyre may be 42C,in spirited road driving.
In the same conditions, the PS4S may only reach 35C.
This may not sound like a big difference but the performance of the PS5 at 35C versus 42C is massive. It’s like a different tyre.
Temperature Window
So while the PS4S may give more dry grip than the PS5 in the right conditions, if we can’t get it up to temp in street driving, or it takes longer to get up to temp in normal spirited driving, the PS5 will be the faster, grippier tyre more of the time, despite what the tyre review data says.
Track Tyres
It’s the same problem with track focussed tyres like Pilot Sport Cup 2. Sure they give better lap times than both the PS4S and PS5 on track, but on the road it’s going to be harder to get them up to temp. And if we can’t get them up to temperature, it means their out of their performance window which could/probably mean they grip less than a PS5.
A max performance road focussed tyre will be grippier than a Pilot Sport Cup 2 tyre 99% of the time on a road car.
And this is the problem with the PS4S tyre
Fact is, for most road driven cars which don’t go on track, the PS5 will probably be the gripper tyre 99% of the time in dry and wet conditions.
Sure, the times you find “your” road where you can get the PS4S tyre into their temperature window they will be grippier, but is the extra grip something that is noticeable on the road? And is it worth having less grip the other 99% of the time for that 1%?
Obviously that is your call, but for me, where my opportunities to attack a road don’t come that often, I want a tyre that I can turn on in a minute or two maximum, I don’t want to be losing minutes and wasting KMs of road while my tyres come up to temperature.
PS4S Tyre Problem – In Summary
Yes the reviews say the PS4S can be a grippier tyre than the PS5, but they don’t say at what temperature, they don’t say the temperature of the each tyre in normal driving and they don’t say how long it takes to get each tyre into their window when the pace is increased.
Until we get that data, I’m going to have to assume the PS5 is the grippier tyre for the road.