265/35/19 PS4S ruined my CS

[Maitre_Absolut]

Originally Posted by CanAutM3

Depends... CS with PSC2 have 265, however those fitted with PSS have 255 in front. If your CS came with PSS, you have 255

Read post above regarding imapact of changing tire size and/or tire brand.

Correct. Lots of good info in this thread.

Originally Posted by DS_BMW

I went back to PSS. I would have gone SC2 but weather is always crappy here. Its night and day difference in how they feel compared to PS4 sadly.

Thats unfortunate to hear. I have a set of PS4S with the 265 fronts waiting to go on once the stock PSS are done (last summer). I would not daily drive PSC2. Guess stock is the way to go, maybe I'll sell these before trying them.

[icegrill]

Seems a like kind of a dramatic title🙄

[M3SQRD]

I agree with the above...I have a set of 265/35-19 and 305/30-19 PS4S installed on my M4. I also have a 265/35-19 and 305/30-19 PSC2 setup. In addition, I have a MCS 2WR suspension with 600/900 rates and Essex/AP 9668/9449 brake setup installed. Before my driving ability gets called into question, I have 30 years of track experience, have helped develop suspension setups/packages, and have had multiple pro drivers ride with me. Although there’s a clear difference in overall grip between the two tires, swapping to the PS4S setup doesn’t even remotely come close to the OP “ruined” my M4. I find the PS4S to be a great all around street tire and an improvement over the PSS (which are installed on my e92 M3 and f22 240ix). However, I do have to run higher cold pressures in the PS4S to help support the softer sidewall but that’s it. I may not have a CS but there’s no way the PS4S has “ruined” my car and, I highly doubt, they’ve “ruined” your car. When you created this post, how many miles had you put on the tires? It takes 200-400+ miles to completely remove the mold release from the tread, depending on the type of driving during this period, and the performance and predictably of the tire is affected during this time.

[DS_BMW]

Originally Posted by M3SQRD

I agree with the above...I have a set of 265/35-19 and 305/30-19 PS4S installed on my M4. I also have a 265/35-19 and 305/30-19 PSC2 setup. In addition, I have a MCS 2WR suspension with 600/900 rates and Essex/AP 9668/9449 brake setup installed. Before my driving ability gets called into question, I have 30 years of track experience, have helped develop suspension setups/packages, and have had multiple pro drivers ride with me. Although there’s a clear difference in overall grip between the two tires, swapping to the PS4S setup doesn’t even remotely come close to the OP “ruined” my M4. I find the PS4S to be a great all around street tire and an improvement over the PSS (which are installed on my e92 M3 and f22 240ix). However, I do have to run higher cold pressures in the PS4S to help support the softer sidewall but that’s it. I may not have a CS but there’s no way the PS4S has “ruined” my car and, I highly doubt, they’ve “ruined” your car. When you created this post, how many miles had you put on the tires? It takes 200-400+ miles to completely remove the mold release from the tread, depending on the type of driving during this period, and the performance and predictably of the tire is affected during this time.

I guess everyone feels things differently. I put almost 1k miles on the PS4S and they did not improve. As soon as PSS are back on car feels normal again to me.

[M3SQRD]

Originally Posted by DS_BMW

I guess everyone feels things differently. I put almost 1k miles on the PS4S and they did not improve. As soon as PSS are back on car feels normal again to me.

What tire pressures did you run? I originally felt there was a loss of performance when I switched to the PS4S but the car was also porpoising on the front (dampers can control vertical motion caused by a tire). I played around with tire pressures and found I had to run 42 psi cold on the front. Once I sorted this out, I now had complete confidence in the handling and predictability of the PS4S. The PSS sidewall is definitely stiffer than the PS4S sidewall.

[CanAutM3]

Originally Posted by M3SQRD

What tire pressures did you run? I originally felt there was a loss of performance when I switched to the PS4S but the car was also porpoising on the front (dampers can control vertical motion caused by a tire). I played around with tire pressures and found I had to run 42 psi cold on the front. Once I sorted this out, I now had complete confidence in the handling and predictability of the PS4S. The PSS sidewall is definitely stiffer than the PS4S sidewall.

Interesting. That's a lot of pressure for street driving though. Not everyone will be inclined to try running that high. Thanks this insight for sharing though

[M3SQRD]

Originally Posted by CanAutM3

Interesting. That's a lot of pressure for street driving though. Not everyone will be inclined to try running that high. Thanks this insight for sharing though

I know. I was surprised. However, I just picked up a G20 330ix M sport for my DD and BMW has the rear MP4S 255 tires set to 44 psi (non-runflat, up to 100 mph). The front 225 is set to 38 psi. These pressures seem to fall in line with my MP4S experience on the M4.

[CanAutM3]

Originally Posted by M3SQRD

I know. I was surprised. However, I just picked up a G20 330ix M sport for my DD and BMW has the rear MP4S 255 tires set to 44 psi (non-runflat, up to 100 mph). The front 225 is set to 38 psi. These pressures seem to fall in line with my MP4S experience on the M4.

So, it seems the PS4S are designed to run higher pressures.

[M3SQRD]

Originally Posted by CanAutM3

So, it seems the PS4S are designed to run higher pressures.

Yes. That’s what I determined on my own and it’s clear BMW is using very high pressures in the MP4S as well. BMW for speeds > 100 mph has the 330i/ix rear MP4S 255/35-19 set to 49 psi and the front 225/35-19 to 45 psi.

I tried running lower pressures on the G20 330 and the handling became horrible. It understeered badly on entry and then would oversteer mid-corner (DSC is very lenient ). With BMW’s pressures, slight understeer on entry but no oversteer mid-corner. The G20 330 M sport handling (and damping) is a huge improvement over the F series (e.g., F22 M240ix, stock F82 M4). Surprisingly, the G20 330ix M sport reminds me of my ‘03 e46 M3 (which became a dedicated track car by ‘05) although slightly underpowered. I miss my e46 M3.

[jfritz27]

Originally Posted by M3SQRD

I know. I was surprised. However, I just picked up a G20 330ix M sport for my DD and BMW has the rear MP4S 255 tires set to 44 psi (non-runflat, up to 100 mph). The front 225 is set to 38 psi. These pressures seem to fall in line with my MP4S experience on the M4.

Interesting... but I presume that doesn't jibe with the official recs on the door jamb?

Thx

[M3SQRD]

Originally Posted by jfritz27

Interesting... but I presume that doesn't jibe with the official recs on the door jamb?

Thx

The 44 psi R and 38 psi F are the official BMW recommended tire pressures for speeds < 100 mph, and 49 psi R and 45 psi F for speeds > 100 mph.

[anurak]

I had the same issue as well, feels like the car behaves badly and I was so disappointed switching from CUP2 to PS4S. I wish I never made the decision, true that PS4S will last longer and better in rain but it feels like a totally different car. On CUP2 my M4CS feels direct, sharp, and traction is great, but in PS4S the car feels indirect and imbalance when cornering. I'm running 265/35 (F) 285/30 (R) on PS4S and I'm thinking of upsizing the rear to 295/30 will solve this unbalance feels?

[Billy_BMW]

Try higher pressures, 45psi front and rear and see if there’s a difference.

[aboulfad]

Originally Posted by M3SQRD

The 44 psi R and 38 psi F are the official BMW recommended tire pressures for speeds < 100 mph, and 49 psi R and 45 psi F for speeds > 100 mph.

Official BMW as in the owners guide? Neither the M4 or M4CS have such high psi even for speeds > 100mh. Beginning at page 225 of the owners guide.

I personally tried 35psi then 32psi all around on the MPS4S (265/285R19) on my M4 and it felt ok, but I am not an expert or a sensitive driver. I wonder how people feel or perceive difference in steering in day to day driving respecting public road safety?

[JRV-F82-M4]

Originally Posted by Maitre_Absolut

Correct. Lots of good info in this thread.



Thats unfortunate to hear. I have a set of PS4S with the 265 fronts waiting to go on once the stock PSS are done (last summer). I would not daily drive PSC2. Guess stock is the way to go, maybe I'll sell these before trying them.

I would be interested in your PS4S 265/35/19s if you decide to sell them. I am looking for tires for my 19" FI-Rs (Frts 9.5" and Rrs 10.5") and I am about to buy PS4S 265/35 & 285/35s new from TR. I don't track...hence the wimpy rears.

[M3SQRD]

Originally Posted by aboulfad

Official BMW as in the owners guide? Neither the M4 or M4CS have such high psi even for speeds > 100mh. Beginning at page 225 of the owners guide.

I personally tried 35psi then 32psi all around on the MPS4S (265/285R19) on my M4 and it felt ok, but I am not an expert or a sensitive driver. I wonder how people feel or perceive difference in steering in day to day driving respecting public road safety?

The M4CS does not come with PS4S either. As I stated above, this is on my ‘20 330xi M sport with 225/255 PS4S (posts 29 and 31). BMW has spec’d these high pressures on the PS4S on the 330xi DD (38/44 psi < 100 mph, 45/49 psi > 100 mph). I never said it was on a CS and so things are clear my experience with the 265/35-19 PS4S also weren’t on a M4CS.

[Suds]

I’ve driven MP4s on some dry sessions during a wet track 3 day weekend.
They are a bit squirmier than a RE71 or NT01 while cornering but they drive really well at 150mph plus on the straights.
So they aren’t the best dry track day tire but for wet/dry weekend they would be my choice.

[aboulfad]

Originally Posted by M3SQRD

The M4CS does not come with PS4S either. As I stated above, this is on my ‘20 330xi M sport with 225/255 PS4S (posts 29 and 31). BMW has spec’d these high pressures on the PS4S on the 330xi DD (38/44 psi < 100 mph, 45/49 psi > 100 mph). I never said it was on a CS and so things are clear my experience with the 265/35-19 PS4S also weren’t on a M4CS.

Thanks for the clarification. My confusion stems from Post 25 & 27, but now it’s clear that you experimented with PS4S on your M4 and ended up with higher pressures. So a conclusion for PS4S, is that one may need to run higher pressures depending on driving style, comfort,...

For both M4 & CS and for speeds < 100mph, BMW always recommends equal pressure across all 4 tires (not PS4S), I wonder how handling/traction changes if I up it to 35psi or higher. I imagine at 40psi+ for daily commute, tires will be stiffer and may be less comfort?

[M3SQRD]

Originally Posted by aboulfad

Thanks for the clarification. My confusion stems from Post 25 & 27, but now it’s clear that you experimented with PS4S on your M4 and ended up with higher pressures. So a conclusion for PS4S, is that one may need to run higher pressures depending on driving style, comfort,...

For both M4 & CS and for speeds < 100mph, BMW always recommends equal pressure across all 4 tires (not PS4S), I wonder how handling/traction changes if I up it to 35psi or higher. I imagine at 40psi+ for daily commute, tires will be stiffer and may be less comfort?

Correct - ended up with pressures > 40 psi on my M4 to address inconsistent handling issues with the PS4S on the street.

It depends on the sidewall stiffness. Increasing the pressure increases the spring rate of the sidewall. I find my M4 with 19” 265/35 and 305/30 PS4S set to 42/43 psi with MCS 2WR suspension F/R 600/900 lbf/in spring rates more compliant and less harsh than my wife’s 240ix with PSS set to 35 psi F and R. The 330 ix with PS4S set to OEM 38/44 psi F/R also rides better than the 240ix.

[aboulfad]

Originally Posted by M3SQRD

Correct - ended up with pressures > 40 psi on my M4 to address inconsistent handling issues with the PS4S on the street.

It depends on the sidewall stiffness. Increasing the pressure increases the spring rate of the sidewall. I find my M4 with 19” 265/35 and 305/30 PS4S set to 42/43 psi with MCS 2WR suspension F/R 600/900 lbf/in spring rates more compliant and less harsh than my wife’s 240ix with PSS set to 35 psi F and R. The 330 ix with PS4S set to OEM 38/44 psi F/R also rides better than the 240ix.

Very interesting remarks, almost everything you are reporting indicates I should try setting higher pressure on my M4 PS4S, but how high?

My M4 is stock suspension (185/575 lb/in spring rate?, M adaptive) with different rears that yours, 265/285R19. Your MCS Front spring rates seem to be much higher than OEM, I hate physics, but does that make sense and how would that impact me adjusting tire pressure for the PS4S?

[CanAutM3]

Originally Posted by aboulfad

Very interesting remarks, almost everything you are reporting indicates I should try setting higher pressure on my M4 PS4S, but how high?

My M4 is stock suspension (185/575 lb/in spring rate?, M adaptive) with different rears that yours, 265/285R19. Your MCS Front spring rates seem to be much higher than OEM, I hate physics, but does that make sense and how would that impact me adjusting tire pressure for the PS4S?

Don't over think it, just try different pressures until you find a setting you like .

[aboulfad]

Originally Posted by CanAutM3

Don't over think it, just try different pressures until you find a setting you like .

Coming from you that’s shocking, I expected some equations if it ain’t broke don’t fix it, it’s set to 32psi and ok. Once our climate warms up, I’ll experiment a bit.