Pilot Sport 4S

[ferrarif1]

I need to order new summer tires and see that Michelin is now selling PS4S tires in 325/30/21 but not the required 285/35/21 for the front. Has anyone installed the PS4S tires? What sizes did you install?

[Yuille36]

Have you tried looking for a 275/35/21?

[Blue By You]

Originally Posted by ferrarif1

I need to order new summer tires and see that Michelin is now selling PS4S tires in 325/30/21 but not the required 285/35/21 for the front. Has anyone installed the PS4S tires? What sizes did you install?

Any reason why you wouldn't go with the Michelin Pilot Super Sport in OEM sizes?

[silentm]

Originally Posted by Northeastern X5M

Any reason why you wouldn't go with the Michelin Pilot Super Sport in OEM sizes?

Originally Posted by Northeastern X5M

Any reason why you wouldn't go with the Michelin Pilot Super Sport in OEM sizes?

Why make it easy.

If traction is the goal, switch to 20" and get Corsa tires

[Blue By You]

Originally Posted by silentm

Why make it easy.

If traction is the goal, switch to 20" and get Corsa tires

If I remember correctly, they take too much/too long to heat up on the street. If so, they'd be more dangerous for most casual drivers. They even say "extreme street driving."

In my opinion, go with Pilot Super Sport all the way. Pretty much as sticky as you're gonna get as far as I know. And in OEM sizes, no thinking about it.

[silentm]

OP check out a YouTube video on 2021 X5m CP whoop On GT3 on street tires.

It appears that the 2021's are on 4s. Having experience with both tires, I'd have to say 4s are a bit softer and more comfortable. Reminded me of PS2's.

[ferrarif1]

I ended up sticking with the stock PSS tires. I figured if Michelin and BMW developed this tire for this car, why would I try to argue against that?

[ekological]

I would say your instinct to look for the 4s is right as they are better, but it takes time for new sizes to come out and certain sizes never come out.

[silentm]

Originally Posted by ekological

I would say your instinct to look for the 4s is right as they are better, but it takes time for new sizes to come out and certain sizes never come out.

It's so unfortunate that they do that from time to time.

[Blue By You]

Originally Posted by silentm

It's so unfortunate that they do that from time to time.

That the 4S is the successor to the SS, not the other way around. Those look sick, I stand corrected and would like those for replacements when I need them!

[Tightt]

As I will soon be in need of tires I'm going to grab some 295/325 4S's. They should fit the OE wheels just fine. =)

[bmwx5er]

Originally Posted by Tightt

As I will soon be in need of tires I'm going to grab some 295/325 4S's. They should fit the OE wheels just fine. =)

The rotational diameter difference is 1.4% which is outside the conventional wisdom of max. tolerance of 1% for the transfer case. The 275/325 combo is within spec, in fact closer than the OEM combo of 285/325, but haven't seen anyone in the forum run it yet.

[Tightt]

Originally Posted by bmwx5er

The rotational diameter difference is 1.4% which is outside the conventional wisdom of max. tolerance of 1% for the transfer case. The 275/325 combo is within spec, in fact closer than the OEM combo of 285/325, but haven't seen anyone in the forum run it yet.

The conventional wisdom of 1% rotational difference is for cars with matching F to R rotational values (same size F&R) from the factory, which our cars are not. I'll consult my local BMW shop to get their take on it before ordering up the tires. I'd just REALLY like to have some 4S's on the car as they are a great tire!
I'm also nervous that a 275 will look very skinny and stretched.

[bmwx5er]

Originally Posted by Tightt

The conventional wisdom of 1% rotational difference is for cars with matching F to R rotational values (same size F&R) from the factory, which our cars are not. I'll consult my local BMW shop to get their take on it before ordering up the tires. I'd just REALLY like to have some 4S's on the car as they a great tire!

I thought our cars *are* matched for F&R rotational values from factory - I'd be curious to learn more if that's not the case. The 20" OEM sizes (275/315 in F15s and 285/325 in the F85s) are identical in F&R rotational values. The 21" is not, but still within tolerance. Agreed that the 4Ss are a great tire, but there also is the potential risk to the transfer case to consider..

[Tightt]

If F85's come with 285/325 from the factory, I think its safe to say that BMW designed it that way. So, to your point, perhaps a tolerance of zero is in fact not the target. If OE the car comes with a .7 difference, one could argue that going down to zero is just as bad as going up to 1.4

Then again, I'm no engineer! I'll report back with that my shop says.

[bmwx5er]

Originally Posted by Tightt

If F85's come with 285/325 from the factory, I think its safe to say that BMW designed it that way. So, to your point, perhaps a tolerance of zero is in fact not the target. If OE the car comes with a .7 difference, one could argue that going down to zero is just as bad as going up to 1.4

Then again, I'm no engineer! I'll report back with that my shop says.

I can see where you're coming from, but I've not seen any information so far that would suggest that there is a base difference % when shipped from factory, and the max. tolerance is 1% (or whatever) either way from the base value. Looking forward to your shop's opinion.

[silentm]

The more road you grip the more gas you will use, but I am sure most are ok with that.

[Tightt]

Originally Posted by bmwx5er

I can see where you're coming from, but I've not seen any information so far that would suggest that there is a base difference % when shipped from factory, and the max. tolerance is 1% (or whatever) either way from the base value. Looking forward to your shop's opinion.

I'll report back.

Originally Posted by silentm

The more road you grip the more gas you will use, but I am sure most are ok with that.

Give me the grip!!!!

[Tightt]

Originally Posted by bmwx5er

I can see where you're coming from, but I've not seen any information so far that would suggest that there is a base difference % when shipped from factory, and the max. tolerance is 1% (or whatever) either way from the base value. Looking forward to your shop's opinion.

Hey! I wanted to give you an update. I spoke to my guy at Rogue Engineering and he agreed with you....1.4% would be pushing it and may cause issues, both electrically (wheel speed sensors, etc) and mechanically. So, looks like I'll be sticking to the Super Sports. I just wanted to get back to you with the final info.

[bmwx5er]

Originally Posted by Tightt

Hey! I wanted to give you an update. I spoke to my guy at Rogue Engineering and he agreed with you....1.4% would be pushing it and may cause issues, both electrically (wheel speed sensors, etc) and mechanically. So, looks like I'll be sticking to the Super Sports. I just wanted to get back to you with the final info.

Thanks for the follow up, appreciate it! Have you looked at 275/35/21 in PS4 for the fronts? That's well within tolerance and closer than even the stock 21s.

[Tightt]

Originally Posted by bmwx5er

Thanks for the follow up, appreciate it! Have you looked at 275/35/21 in PS4 for the fronts? That's well within tolerance and closer than even the stock 21s.

I'm considering it....but not too keen on the idea of narrowing the front tire...for aesthetics as well as performance reasons.

[DKNewYork]

I'm running non OE spec 4S tires. I was unaware of all this when I got the 4S. I'm coming from an M5 and had no idea. I went with 265/35 on 10.5 and 295/30 on 11.5 on my BC Forged 21's wheels. Drives normal and no issues so far. Even took it roll racing at MPact last year over 120+ mph. When I realized what I've done. I got worried and almost bought PSS OE specs. Someone did the calculations for me in an X5M chat and said it's close to the 1% and I should be fine. So I never changed them and still have them on. Waiting for the 4S in OE sizing or if the tires need replacing, I'll probably go back to OE specs just to be safe. Try it at your own risk.