[12v_dub]

Saw this new tire from Michelin. Pilot sport A/S 4




https://www.tirerack.com/tires/tires...=935YR1PSAS4XL

[12v_dub]

This size would be the best option to keep the ration same as oem at +/- .3%

255/40/21 F

295/35/21 R

[ga9213]

These are the tires they are putting on the new corvette if I'm not mistaken. Supposedly a quite capable all season.

[M40i017]

These tires are the best!! I love them

[fricfracfrank]

I have no knowledge when it comes to wheel & tire geometry, dimensions, etc. so flame me if need be. But Is there a safe margin in which you can go wider on the tires than the wheel? For instance (and I'm just using random numbers) a 295width wheel with a 300width tire.

[12v_dub]

Originally Posted by fricfracfrank

I have no knowledge when it comes to wheel & tire geometry, dimensions, etc. so flame me if need be. But Is there a safe margin in which you can go wider on the tires than the wheel? For instance (and I'm just using random numbers) a 295width wheel with a 300width tire.

There are member that installed 295 tire on a stock 21" wheel without any issues.

[dmicah]

It's really great to have such a fantastic new option for the 21" wheels. People really seem to struggle with that. Good find!

[fricfracfrank]

Originally Posted by 12v_dub

There are member that installed 295 tire on a stock 21" wheel without any issues.

What's the width of the stock 21s?

[_ink]

Originally Posted by 12v_dub

This size would be the best option to keep the ration same as oem at +/- .3%

255/40/21 F

295/35/21 R

other than Speedo, is there any other reasons we should keep as close to OEM specs?

[12v_dub]

Originally Posted by _ink

other than Speedo, is there any other reasons we should keep as close to OEM specs?

It should to be under 1% ratio front and rear so it doesn't put stress on x-drive system.

[12v_dub]

Originally Posted by fricfracfrank

What's the width of the stock 21s?

8.5" front and 9.5" rear

[spta97]

Good find!

They have the X3MC sizes as well - I linked your post in the F97 forum.

Those who want all seasons (the X3M/C only come with Summer Tires) have used Pirellis. I'm sure this will be well received (except those who bought the Pirellis )

[AcidLotus]

I take it they aren't RFT given how much people seem to dislike their ride and the lack of any readily visible specs saying either way?

[12v_dub]

Tirerack doesn't show 295/35/21 size option anymore. WTF

[TheusBimmer]

Originally Posted by 12v_dub

Tirerack doesn't show 295/35/21 size option anymore. WTF

According to Michelin official website, they never provided the 295 for the 21". It could be very likely that Tirerack had the wrong info up and corrected their error. Sorry guys for being the bearer of bad news. When it comes to tires, I have learned to always check the manufacturer website.

https://www.michelinman.com/tires/hi...8;gclsrc=aw.ds

[Oldguysrule]

Well that sux.

[_ink]

I'll be going the PS4S option very soon..

[mlmetzger]

So, has anyone here changed to the PSAS4?

I currently have the OEM Bridgestone AS (245/50/19) and am scheduled to have these new Michelins installed next week. Interested to hear about other's driving impressions.

I had a positive experience changing from PZero runflats to the AS3 on my F25. While the newer runflats are better, I'm still looking forward to improved ride and handling.

[vrships]

there's a thread somewhere in the X5M or X6M forum, where an owner was voided drivetrain warranty because he swapped a new set of wheels, with 0.3% circumference difference between front and rear.

It doesn't make sense that 2rev/mile will fry the differential but it's always safer to use only wheels with matching circumferences. Even with this, the dealer may still find an excuse saying that every tire and rim has manufacturing tolerance so that any aftermarket combos will void the warranty.

[Razel]

Originally Posted by vrships

there's a thread somewhere in the X5M or X6M forum, where an owner was voided drivetrain warranty because he swapped a new set of wheels, with 0.3% circumference difference between front and rear.

It doesn't make sense that 2rev/mile will fry the differential but it's always safer to use only wheels with matching circumferences. Even with this, the dealer may still find an excuse saying that every tire and rim has manufacturing tolerance so that any aftermarket combos will void the warranty.

My thought process may be screwed up, but how can a wheel circumference affect the drive train? There's a tire on the rim and that tire circumference is what puts the load on the drive train. The tire bead sit on the wheel. The tire tread sits on the road surface. X-drive would be a concern with unusual tires, but if you have, say, Conti's mounted that match the sizing from the factory, I honestly don't see anything to be concerned with.

[vrships]

Originally Posted by Razel

My thought process may be screwed up, but how can a wheel circumference affect the drive train? There's a tire on the rim and that tire circumference is what puts the load on the drive train. The tire bead sit on the wheel. The tire tread sits on the road surface. X-drive would be a concern with unusual tires, but if you have, say, Conti's mounted that match the sizing from the factory, I honestly don't see anything to be concerned with.

By circumference I meant for the entire wheel including the tire.

Basically the owner put on tires that have 0.3% difference in circumference, instead of 0.0% than the OEM. The dealer states that this difference causes the failure. While 0.3% is actually equivalent to only less than 2/32" tread depth.

The question is that how can anyone make sure that their OEM tires never had tread difference > 2/32" throughout their lifetimes?

[Razel]

Okay.
I think, too, we're in agreement. Dealer statements about those kinds of tiny differences causing major malfunctions beyond the control of the manufacturer are absurd.
They need to get to a basic read about differential action.