Goodbye Runflats! (Michelin Pilot Sport A/S 3+)
This weekend I am having Michelin Pilot Sport A/S 3+ non runflat all seasons put on. I really do not want to go to dedicated summer and winter tires. 2 year road hazard warranty from TireRack does not hurt either.
I will report back.
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1. Grip. The PS3s have far more grip than the runflats
2. Steering Feel. Night and day. People don’t talk about this enough, but first time with them on you’ll see. It’s such a pleasure to drive now.
3. Ride. Ride is much more supple and doesn’t crash over bumps.
4. Braking distances. Much better. Byproduct of item 1 above.
Only downside is that these PS3s definitely have a bit more road noise than the stock tires.
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Superior to the outgoing continental run flats in absolutely every way imaginable. Steering feels improved, noise reduced and I can hear the exhaust crackling and doing its thing even with the flaps close now.
Coincidentally I got to drive it a few minutes in the dry and then a rainstorm came in and flooded the highway. These tires are unflappable and cut through the water like a boat. I had a grin on my face.
The entire car feels more lively and more sports car like but at the same time all of the harshness that was bugging me is just plain gone. I had an E class loaner for a few hours and well I wouldn’t say this car has as comfortable a ride as that E300, this is a big step in that direction.
It feels like that center zone that sometimes can feel sort of vague when the wheels are turned like less than one degree now is giving me more subtle feedback as I move the wheel. I just feel like I have more control over the car and the car drives better in a rainstorm than it did in the dry with the run flats.
The only regret I have is not doing it sooner. You don’t have to drive it hard the difference is readily apparent in regular driving.
Last edited by Snarfalus; Jun 15, 2019 at 08:55 PM.
I also had Pirelli P7 Cinturado 18 inch tires on a C300 with sport suspension, and it was the same crashy run flat feel.
They used lower pressures than they used for the continentals. The Continentals were always like closer to 40-42. That is per the gas cap placard and door jam.
On these, shop (dealer) only inflated to 32 ish, which I am not sure how they came up with. They test drove 2 miles so must be ok. Alignment was fine on Continentals just had car checked for Service B last week. Nevertheless, I let them do an alignment for the Michelins. Not sure if anything got adjusted but don’t care.
I have tried the runflats at lower pressures. It helps a bit to run them a little lower, but it isn’t transformative like these.
Last edited by Snarfalus; Jun 15, 2019 at 06:36 PM.
I also had Pirelli P7 Cinturado 18 inch tires on a C300 with sport suspension, and it was the same crashy run flat feel.
They used lower pressures than they used for the continentals. The Continentals were always like closer to 40-42. That is per the gas cap placard and door jam.
On these, shop (dealer) only inflated to 32 ish, which I am not sure how they came up with. They test drove 2 miles so must be ok. Alignment was fine on Continentals just had car checked for Service B last week. Nevertheless, I let them do an alignment for the Michelins. Not sure if anything got adjusted but don’t care.
I have tried the runflats at lower pressures. It helps a bit to run them a little lower, but it isn’t transformative like these.
As far as the tire pressures are concerned, on the sedan, we're supposed to run 36 F and 35 R w/ all-season tires equipped. For summer tires, tire pressures of 40+ PSI are used on 18" wheels.
Was always curious what the coupe requires for the 18" setup with all-season tires.
Does anyone know if there is a mathematical calculation based on the tires maximum inflation to determine the optimal inflation?
Does anyone know if there is a mathematical calculation based on the tires maximum inflation to determine the optimal inflation?
Example:
My stock Conti RFTs have the M+S symbol on them. Gas cap on my sedan indicates for M+S-stamped tires: 36 (F); 35 (R).
Checked the gas cap of a C300 sedan, which has the same OEM Conti RFTs as the C43 sedan (when equipped with 18" wheels and all-season tires).
Cold starting PSI recommendation? 36 (F); 35 (R). My tires have worn perfectly using this approach, and the handling/ride has been as good as possible on the RFTs.
My dealer incorrectly had my tires at 41 PSI all around (based off of the door sill, which is the incorrect approach/number) at delivery, and the ride was terrible, the steering wheel was nervous and darty, etc.
I also was a minute or so underway when I checked the pressure meter so I’ll get a cold reading. I seriously doubt if they were under inflated they would’ve felt so sure footed.
I’m going to check up and make sure everything is optimal.
Last edited by Snarfalus; Jun 15, 2019 at 08:52 PM.
I also was a minute or so underway when I checked the pressure meter so I’ll get a cold reading. I seriously doubt if they were under inflated they would’ve felt so sure footed.
I’m going to check up and make sure everything is optimal.
Turns out the tires were constantly underinflated, and that caused a severe case of tire cupping. The ear-piercing, resonant whine from the tires when leaving the shop one day was unreal. Ever since that experience, I've always paid obsessive attention to my pressures. Not only do I want to keep them consistent for best performance, but for even wear to promote life and prevent cupping.
Will/did you get a spare or getting the green goop and a compressor? If you found a spare can you provide any info?
This was also at Costco.
The installer told me that those goop sealants can damage the TPMS and recommended not to use them. But I’m not sure how factual that is.
So I'm sold on the sealant and compressor for emergency tire repair. I previously thought that the sealant would ruin the tire and the sensor - but that's not the case.
I am investigating tire pressures. I got 34 cold when I started up this morning, so I am looking to whether a few more pounds should be added. They do handle really well. I will post more findings at like 500 miles. (two weeks?)
I am investigating tire pressures. I got 34 cold when I started up this morning, so I am looking to whether a few more pounds should be added. They do handle really well. I will post more findings at like 500 miles. (two weeks?)
18" - 42/33 F/R
19" - 36/33 F/R
These pressures are for runflat tires, lightly loaded and measured cold. Cold means 20C or 68F.
After driving a very few miles the tires will warm up regardless of the weather and the pressures will increase. Mercedes certainly knows this and sets their cold recommendations accordingly.
Original equipment vehicle tire size:
Front: 225/45R18/XL 95Y
Rear: 245/40R18/XL 97Y
Recommended Tire Pressure, PSI
Front: 39 / Rear: 45





