[BM dnobagaV]

Rather simple. Give the type of wheels/tires you got on & the tire pressure you run at.

I'm asking because my AMG finally arrived from the shop. Driving the last few days, I could literally feel every bump even in comfort mode. Stock PSI suggested is 51. Seriously, 51.

That's fully loaded, up to 186mph, with 4 passengers. Why would I ever be in that scenario? I assume it would be better for daily driving in CA(land of bad roads) if I let them to ~40psi?

Stock at 33 in my 528i and the car is an absolute dream. Like on a cloud.

[G35POPPEDMYCHERRY]

I have a slightly on-topic question. My cold PSI on my F80 is ~32 in 40 degree weather. 33 in 50 degree weather. and shit when its 80 outside and car has been baking PSI rises to 36-37. Sometimes after highway close to 40psi. I would say average 35-36psi when checking. Should I bleed air? Door says 32

[rcracin]

pressure goes up with higher temps. normal. hence the cold pressure recommendation.

51 is high regardless. Unless it's some specially designed tired, 51psi will wear out the insides of the tires faster that the outers. It seems perfectly reasonable that AMG would have a special tire though. Might as well stick with the door recommendation and monitor tire wear.

[eatsleepboost]

Originally Posted by BM dnobagaV

Rather simple. Give the type of wheels/tires you got on & the tire pressure you run at.

I'm asking because my AMG finally arrived from the shop. Driving the last few days, I could literally feel every bump even in comfort mode. Stock PSI suggested is 51. Seriously, 51.

That's fully loaded, up to 186mph, with 4 passengers. Why would I ever be in that scenario? I assume it would be better for daily driving in CA(land of bad roads) if I let them to ~40psi?

Stock at 33 in my 528i and the car is an absolute dream. Like on a cloud.

Yea 51 sounds very high. You can't go wrong sticking with factory door specs but many tires cannot handle that much pressure. If you read right on the tire many say max pressure 44 or around there. I'm curious as to what these tires say on them if you can check and reply. Also what brand and tire type are they?

[cxp213]

Originally Posted by BM dnobagaV

Rather simple. Give the type of wheels/tires you got on & the tire pressure you run at.

I'm asking because my AMG finally arrived from the shop. Driving the last few days, I could literally feel every bump even in comfort mode. Stock PSI suggested is 51. Seriously, 51.

That's fully loaded, up to 186mph, with 4 passengers. Why would I ever be in that scenario? I assume it would be better for daily driving in CA(land of bad roads) if I let them to ~40psi?

Stock at 33 in my 528i and the car is an absolute dream. Like on a cloud.

I literally searched for "Mercedes-Benz CLS63 tire pressure" in Google and this was the 3rd result:
https://mbworld.org/forums/w218/4249...-12-cls63.html

Originally Posted by G35POPPEDMYCHERRY

I have a slightly on-topic question. My cold PSI on my F80 is ~32 in 40 degree weather. 33 in 50 degree weather. and shit when its 80 outside and car has been baking PSI rises to 36-37. Sometimes after highway close to 40psi. I would say average 35-36psi when checking. Should I bleed air? Door says 32

I'm a bit afraid that you're even asking this.
My advice is that you keep it as simple as possible: check your tire pressure monthly before doing any driving and then adjust the pressure according to your manual/doorjamb while the tires are cold.

[G35POPPEDMYCHERRY]

Originally Posted by cxp213

I literally searched for "Mercedes-Benz CLS63 tire pressure" in Google and this was the 3rd result:
https://mbworld.org/forums/w218/4249...-12-cls63.html


I'm a bit afraid that you're even asking this.
My advice is that you keep it as simple as possible: check your tire pressure monthly before doing any driving and then adjust the pressure according to your manual/doorjamb while the tires are cold.

lol define cold. temperature fluctuates drastically throughout the day

[cxp213]

Originally Posted by G35POPPEDMYCHERRY

lol define cold. temperature fluctuates drastically throughout the day

When people refer to "cold" tire pressures, they're not talking about a specific temperature threshold (not for the tire, not your climate) but a tire that hasn't been driven on in a few hours.

Driving on the tires cause the temps and pressure to rise due to the friction between the tire and the road, so at that point, the tire pressures are referred to as "hot" tire pressure.

Climate changes will certainly affect tire pressure but not enough to worry, and certainly not as much as adjusting your tire pressures when they're "hot."

I'll try to simplify even more: check in the mornings and keep note that I said to check monthly (weather tends to change so a monthly schedule is most reasonable).

[Ickdeep]

I'm currently about 36 psi on "Cold" tires. I also fill my tires with nitrogen so I don't get affected from the weather that much (temperature goes from 34 to 70 in a day sometimes).

[BMW11]

Checking the tire inflation pressure
Check the tire inflation pressure regularly
Regularly check the tire inflation pres‐ sure, and correct it as needed: at least twice a month and before a long trip. If you fail to ob‐ serve this precaution, you may be driving on tires with incorrect tire pressures, a condition that may not only compromise your vehicle's driving stability, but also lead to tire damage and the risk of an accident.◀
Tires have a natural, consistent loss of tire in‐ flation pressure.
Tires heat up while driving, and the tire infla‐ tion pressure increases along with the tire's temperature. The tire inflation pressure speci‐ fications relate to cold tires or tires with the ambient temperature.
Only check the tire inflation pressure when the tires are cold. This means after driving no more than 1.25 miles/2 km or when the vehicle has been parked for at least 2 hours.
The displays of inflation devices may under- read by up to 1.45 psi/0.1 bar.
For Flat Tire Monitor: after correcting the tire inflation pressure, reinitialize the Flat Tire Monitor.
For Tire Pressure Monitor: after correcting the tire inflation pressure, reset the Tire Pressure Monitor.
Tire inflation pressure specifications
The tire inflation pressure table, refer to
page 190, contains all tire inflation pressure specifications for the specified tire sizes at the ambient temperature. Tire inflation pressure specifications apply to approved tire sizes and recommended tire brands. This information can be obtained from your service center.
To identify the correct tire inflation pressure, please note the following:
▷ Tire sizes of your vehicle.
▷ Maximum permitted driving speed.

[ShocknAwe]

Keep the cold pressure at the door label specs. I adjust pressure whenever outside temps vary by more than 10 degrees for more than a couple days.

Another tip is that if the car sits outside, adjust your pressures in the morning so you aren't adding air to cold tires on one side, and hot tires on the other due to the sun in the summer.

Don't overthink it unless you're tracking.

[xQx]

OP - I agree. Every car I've had prior to the E88 recommended somewhere around 30-32psi for normal use. I used to run 42PSI all-round on my subaru, higher pressures give more direct handling - a the expense of accelerated shoulder-wear - and less overall grip when you get "over-inflated".

My E88 recommends 48/51PSI for a fully loaded car. I'm assuming that's because it came with runflats.

Since I'm running vastly different tires than the car was expecting (non-runflat MPS4's 225/40 & 255/35) my tire sizes aren't even listed on the plaque.

I had tried running at 48/51PSI and it's just as you say - pretty harsh. ..

So now I run what the tire shop wrote on the book when they sold me the tires - 36PSI at the front, 34PSI at the rear.

Handling, Grip and ride-comfort all seem better than with the ridiculous pressures recommended by BMW.

I'd say you can't go wrong with the factory specs if you're running factory tires; but once you change from factory tires & rims to something else - play with the pressure and see what feels right.

Also - most cars have different pressures for unloaded (driver only) vs fully-loaded (4 passengers+suitcases) car. If it feels harsh on the fully-loaded pressures, check what your unloaded car pressures are, and run them for a while.

[yco]

35psi all around..

[BM dnobagaV]

Originally Posted by cxp213

I literally searched for "Mercedes-Benz CLS63 tire pressure" in Google and this was the 3rd result:
https://mbworld.org/forums/w218/4249...-12-cls63.html

Yeah I saw that thread. Mechanic pointed out that with these super wide tires & wheelbase, that if you lower it too much, the outsides will wear far quicker. We agreed to just work with it for awhile, if not, then eventually let some air out.

Believe I'm running Pilots w/ nitrogen, but not exactly sure. Will check the tire wall to see if they have a personally recommended pressure.

[xQx]

Originally Posted by BM dnobagaV

Believe I'm running Pilots w/ nitrogen.

LOL!

They're either filled with a blend of roughly 78% nitrogen, 20% oxygen; or your previous owner was relieved of some cash by a snake-oil salesman.

This article is actually far more balanced than my view, which is that nitrogen filled tires are an outright scam.

[0w40X1]

Originally Posted by ShocknAwe

Keep the cold pressure at the door label specs. I adjust pressure whenever outside temps vary by more than 10 degrees for more than a couple days.

Another tip is that if the car sits outside, adjust your pressures in the morning so you aren't adding air to cold tires on one side, and hot tires on the other due to the sun in the summer.

Don't overthink it unless you're tracking.

That's right! Use base door jamb sticker pressure.

The high speed and loaded pressures are what you'd put after driving and tires are hot, but they don't say that, and shouldn't be set at that cold.

Driving hard can raise psi easily 6 psi anyway.

[ShocknAwe]

Originally Posted by 0w40X1

The high speed and loaded pressures are what you'd put after driving and tires are hot, but they don't say that, and shouldn't be set at that cold.

For some reason I always thought the high speed pressure rating was for cold fill if driving consistently over 100mph. Disregarded it as nonsense since there's nowhere to do that in the US.

[Red Bread]

Originally Posted by ShocknAwe

For some reason I always thought the high speed pressure rating was for cold fill if driving consistently over 100mph.

They are cold, not sure why the previous post speculated loaded or high speed would be warm.

[uniqueMR]

I have:
275/30R20
295/30R20

set up on M4 Competition. I run between 38-40 psi all around..

[Bt12]

38-40 for me as well

[allinon72]

36psi. Can't imagine what 51psi rides like even in comfort mode. Must feel like Oregon Trail.

[c1pher]

Originally Posted by G35POPPEDMYCHERRY

I have a slightly on-topic question. My cold PSI on my F80 is ~32 in 40 degree weather. 33 in 50 degree weather. and shit when its 80 outside and car has been baking PSI rises to 36-37. Sometimes after highway close to 40psi. I would say average 35-36psi when checking. Should I bleed air? Door says 32

You’re supposed to go by cold tire psi measurements. They account for the pressure increasing with heat. Don’t worry so much if they are higher than the door label says when warm/hot. Worry if you check and the pressure is less than the door label when they are hot.

With that said, I go 2psi above what the door says on my 135. I feel it gives me the best ride, wear and grip.

[david in germany]

I run mine exactly as reccomended on the door jam. I have noticed that BMW sometimes tries to update that fresh feel sometimes after a service by putting a bit more in each tire. By doing so the car feels a bit more nimble and I can feel it right away. I get home and once the car cools I drop back to the original pressure.