[Achias]

Short question: In terms of performance/grip, is it a problem to have different but very similar tires between the front and back?

Long explanation: Ilsa and I autocross in the summer and occasionally do a track day, so the amount of grip that I get out of a tire is very important to me.

Through lots of research, I've decided that Michelin Pilot Sport tires are the best for me - good traction and 300 tire wear.

Now, there are three different types of Pilot Sports - straight Pilot Sport, Pilot Sport 4, and Pilot Sport 4S (hang on for a different question about this later).

The sizes I want are: Front-275/40/19 and rear 315/35/20.

Michelin reps have told me that in terms of grip; 4S is best, 4 is next, and straight Pilot Sport is worst, but still very good.

4S is available for the front but not the rear, and 4 is available for the rear but not the front.

I asked the Michelin rep about putting 4 on the rear and 4S on the front, and he said they don't recommend using different tires on the front and rear. His recommendation was straight Pilot Sports for both.

So, is this just a sales pitch, or is there a real problem with having Michelin Pilot Sport 4S on the front and 4 on the rear?

And finally, is there really no difference between the three tires other than the designation? Is the 4S the same as the straight PS but made for use on Porches or Ferraris?

What do those in the know have to say about this?

 

[Achias]

P.S. These will be used for autocross, track, and street in summer only.

 

[Stlhotrod]

Was the Michelin person just a sales person or an actual factory tech rep? If it was a tech rep I would listen to what they say. If it was just a sales person I would call the factory and ask for someone in their technical department.

 

[wizzr]

My feeble little brain can not grasp why a slightly different front to back tread pattern or compound would have any significant effect on a vehicles handling as long as both fronts and rears are matched, properly balanced and properly inflated. I mean we're already running completely different front to back sizes anyway. I do understand their may be a difference in grip, but once a driver understands the limits of his tires, does it really matter?

 

[Stlhotrod]

compound will have the most effect on the vehicle over tread pattern. You want the compound the same so you have some similarity for how well the tires are going to stick in relation to front and rear. Keep in mind the front has more weight on it so it will stick more than the rear. The rear is going to be adjusted with tire pressure to hold or give up bite depending on how much traction or slippage you want. For instance they might want less grip in the rear so they can spin the tires more to keep RPMs up in the power band. While some will do this with a controlled spin over all out having the tires out of control. They other thing is with compounds, heat is a factor and when the tires get hotter the compound has a different reaction to their driving habits as well.


Doing the autocross you are on the tires less than at a track day where you are doing laps. The auto cross is going to like a stickier tire with less heat most likely. A stickier tire also wears out much faster so you have to weigh all of this and make the decision on what and where you are willing to give up. I am no expert on this, just what I have learned from helping a friend with his Corvette. I prefer drag racing where we want all the traction we can get on the rear tires and going straight.

 

[xoxoxoBruce]

Keep in mind the front has more weight on it so it will stick more than the rear.

On the front 200 lbs, 100 per tire.

The Michelin Pilot Sport site shows 4 types:

Pilot Sport 4S;
1st in dry laptime.
1st in dry braking.
1st in wet laptime.
1st in wet braking.
(all these claims are against other brands not other Pilot models)
9% better treadlife than the MICHELIN ® Pilot ® Super Sport.

Pilot Super Sport;
Up to 12% better handling than leading competitors
Up to 2x longer lasting than leading competitors
Better braking than leading competitors

Pilot Sport Cup2;
Faster on a dry track - 1.8 seconds per lap
Faster on a wet track - 1.2 seconds per lap
50% more track laps

Pilot Sport A/S 3+;
More dry grip than a leading competitive max performance summer tire.
Shortest braking - wet or dry - of leading competitive all-season ultra-high performance tires.
Exclusive Helio+ Technology that’s built to stick even in the cold.

The 275-40-19 size is available in:
Pilot sport A/S 3+, part #21607
Pilot super sport, part #84944
Pilot sport 4S, part #21747

The 315-35-20 size is available in:
Pilot Super Sport, part #19605 and part #79340

The 275-40-19 size says rim width 9" to 11" giving a section width of 10.9" to 9.5".
The 315-35-20 size says rim width 10.5" to 12.5" giving a section width of 12.6" to 11".

So the Pilot Super Sport is the only one for a front/rear match IF your rims are wide enough.

 

[Achias]

I spoke to two tire dealer salesmen today, and they both thought that the Michelin Pilot Super Sport 4 and 4S were probably the same tire as the straight PSS - just different designations for the target cars (Porsche and Ferrari).

It looks like I'll be going for the straight Pilot Super Sports since they're the only one available in both needed sizes.

Now, I'm looking for a good price.

Dave

P.S. Thanks for the advice

 

[Texasbaehr]

Before you buy Call Michelin directly and ask for Tech Support. Explain what you need and what you are doing and they will provide the best tire recommendation for you.
Don't rely on a tire salesman. They are incentivized to sell certain tires and have little if any specific technical knowledge about the tires.
Michelin Support line 866-866-6605 0:800-20:00 EST M-S
Greg