[Elganja]

I know there are several threads talking about tire pressure -- but most reference just 1 pressure which I assume is overall

I have been running 2psi less in my rear (both cold and hot):

Starting:
- 28psi front
- 26psi rear

Hot Pressure:
- 34psi front
- 32psi rear

Was curious what others were doing -- the hot pressures in the front gets me right at the △ on the tires, with the rears close to it (rears and lower than 32 hot, the balance is thrown off too much for my driving style)

[///MPhatic]

For the street I always run 1-2 psi more in the tires under the engine. In the M2 that looks like 33/32 cold (I rarely drive on the highway).

For the strip I shoot for a hot pressure of 30 on the rears. Our dragstrip is 30 miles away, mostly interstate, so I start with 33/29 and lower the rears to 30 as soon as I get to the track.

[medphysdave]

It's likely track dependent due to the turn directions and how much your leaning on any one tire and braking. After a run my track connect app recommended the following pressures on my cup 2 connects if returning to the track within 30min of the readings.

LF36
RF37
LR36
RR38

On the street I've found that reducing my LF by .5 to 1psi has them equal all around when up to temp on highway.

[Elganja]

Originally Posted by medphysdave

It's likely track dependent due to the turn directions and how much your leaning on any one tire and braking. After a run my track connect app recommended the following pressures on my cup 2 connects if returning to the track within 30min of the readings.

LF36
RF37
LR36
RR38

On the street I've found that reducing my LF by .5 to 1psi has them equal all around when up to temp on highway.

that is a good point too

[Noel911]

I've been running RE71R for several years and just got RE71RS. I like the RS and hope they wear as well as the R's. The R's liked 28-29psi hot and I've liked the RS closer to 30-31psi hot. I run 265s all around so same at each corner. I find the lower pressure wears more evenly across the tread, doesn't eat up too much sidewall and just feels better, which is THE most important gauge IMO.
BTW, I'm been tracking cars for >24 years.

[medphysdave]

Originally Posted by Noel911

I've been running RE71R for several years and just got RE71RS. I like the RS and hope they wear as well as the R's. The R's liked 28-29psi hot and I've liked the RS closer to 30-31psi hot. I run 265s all around so same at each corner. I find the lower pressure wears more evenly across the tread, doesn't eat up too much sidewall and just feels better, which is THE most important gauge IMO.
BTW, I'm been tracking cars for >24 years.

Good to know as I think this is my next tire.

[Elganja]

Originally Posted by Noel911

I've been running RE71R for several years and just got RE71RS. I like the RS and hope they wear as well as the R's. The R's liked 28-29psi hot and I've liked the RS closer to 30-31psi hot. I run 265s all around so same at each corner. I find the lower pressure wears more evenly across the tread, doesn't eat up too much sidewall and just feels better, which is THE most important gauge IMO.
BTW, I'm been tracking cars for >24 years.

that’s crazy how low — if i ran that low i would be well over the triangle, into the sidewall. my home track is very hard on the drivers front tire (summit point main circuit). camber is -3.2/-2.1

e.g here is my drivers side (after 4 days on the track, 80-90 min each day, swapping left to right each day)

[medphysdave]

Originally Posted by Noel911

I've been running RE71R for several years and just got RE71RS. I like the RS and hope they wear as well as the R's. The R's liked 28-29psi hot and I've liked the RS closer to 30-31psi hot. I run 265s all around so same at each corner. I find the lower pressure wears more evenly across the tread, doesn't eat up too much sidewall and just feels better, which is THE most important gauge IMO.
BTW, I'm been tracking cars for >24 years.

How much camber are you running?

[ThreeStripes]

30psi hot would mean going out on 22psi cold for me. I’m confident I’d trash my fronts getting them up to temp/pressure going out that low.

[M1500Z]

Originally Posted by Elganja

I know there are several threads talking about tire pressure -- but most reference just 1 pressure which I assume is overall

I have been running 2psi less in my rear (both cold and hot):

Starting:
- 28psi front
- 26psi rear

Hot Pressure:
- 34psi front
- 32psi rear

Was curious what others were doing -- the hot pressures in the front gets me right at the △ on the tires, with the rears close to it (rears and lower than 32 hot, the balance is thrown off too much for my driving style)

My experience on this tire has led me to believe that 35-36psi hot is a good target, but it's possible it may be slightly higher or lower depending on vehicle load and suspension settings. Adjusting tire pressures to achieve a certain handling characteristic should be a last resort—after exhausting the other tuning methods that may be available to you. If you don't have any adjustments other than tire pressure, so be it, but you really don't want to go too far off the tire's ideal pressure either.

BTW, our camber settings are very similar—I run -3.2º front / -2.3º rear. I wish I'd taken photos of my last set when they came off the car.

This post has some good general info on tires—especially the attached docs from Michelin.

Originally Posted by Noel911

I've been running RE71R for several years and just got RE71RS. I like the RS and hope they wear as well as the R's. The R's liked 28-29psi hot and I've liked the RS closer to 30-31psi hot. I run 265s all around so same at each corner. I find the lower pressure wears more evenly across the tread, doesn't eat up too much sidewall and just feels better, which is THE most important gauge IMO.
BTW, I'm been tracking cars for >24 years.

I disagree with this from my personal experience. I also feel that if you're targeting 30 psi hot, that's a starting pressure of 22-23psi which is very low for a car of this weight and could result in poor wear or damage to the tire. See that post above that shows the RE-71RS having wear issues due to lack of camber and too low cold pressures.

[Elganja]

M2 Comp on stock suspension plus caster and camber plates

i’m not opposed to trying a higher pressure, but all my research says a lower pressure, lol

i start my first session at 28/26 but end up way over 34/32– but bleed at the end of the session to 34/32 (and every subsequent one)

If i had to guess i would imagine i am closer to 35/33 regularly as the day goes on and it gets hotter— but fairly close to my target within a psi

I may try 35/35 ** (aim hot) this weekend when i’m a summit point shenandoah and see how it goes. will measure with a pyrometer too 3

are you in an OGm2 or m2c?

[MustRunFlatOut]

Guys, I'd like to give my endorsement for the Bridgestone Potenza RE71RS tires as well. I ran a 3-day event this past weekend (25-27 August) at Watkins Glen with these tires (new) with Motul 600 brake fluid and PFC 08 brake pads on stock rotors and wheels in my 2018 M2. No other suspension or engine mods at all. However, I am running 255/35 front; 275/35 rear--10 mm larger than stock tire size with no fitment issues.

While I am only an intermediate level driver running solo in full track mode (No DSC or Traction Control), I started each track session at 29-30 psi at each corner. The highest air temp those days was in the high 70's, so rather comfortable for track driving. By the end of each 20-minute session, the front tires were showing 39-43 psi; rears 36-38 depending on air temp and session conditions. That may seem like a lot of pressure, but they held up well even until the end of the session. No lack of traction noticed, and WGI is noted for its several hard braking zones and tight corners.

So, I tend to think starting at 22 PSI, for me, and the tracks I run at (WGI, VIR, NJMP), would be too low. But, as they say... your results may differ. Just my 2 cents.