Optimal track Tire pressure stock zcp?

[GregSM3]

All stock set-up was wondering what would be optimal tire pressure (20" Michelins) for track when tires heat up? Thanks.

[OhioRiderAaron]

38-42PSI hot. Some will say that is high, but that produced the quickest laps and didnt roll over the sidewalls. I believe I ran all the way down to 35PSI hot and it rolled way too much. Be careful as the stock tires wear fast if driven at a moderate pace.

[GregSM3]

Originally Posted by OhioRiderAaron

38-42PSI hot. Some will say that is high, but that produced the quickest laps and didnt roll over the sidewalls. I believe I ray all the way down to 35PSI hot and it rolled way too much. Be careful as the stock tires wear fast if driven at a moderate pace.

Yes definitely worried about wear on the outside edges of the front tires. So it sounds like you believe that higher pressure helps alleviate some of that?

[OhioRiderAaron]

Originally Posted by GregSM3

Yes definitely worried about wear on the outside edges of the front tires. So it sounds like you believe that higher pressure helps alleviate some of that?

Yeah it probably helped a bit. My objective is to run the fastest laps possible so whatever pressures it takes to accomplish that is what I go with. The MPSS tires wear pretty quickly when hot so they're gonna start to show wear pretty quickly on track whether at low or high pressures. Extra camber upfront helps quite a bit too, so I recommend camber plates to even-out wear upfront.

[michaelalex17]

Originally Posted by OhioRiderAaron

38-42PSI hot. Some will say that is high, but that produced the quickest laps and didnt roll over the sidewalls. I believe I ran all the way down to 35PSI hot and it rolled way too much. Be careful as the stock tires wear fast if driven at a moderate pace.

Would you say the same pressure for the 19's? I'm pretty sure my door jamb says like 33psi

[F3IGHTY]

Originally Posted by michaelalex17

Would you say the same pressure for the 19's? I'm pretty sure my door jamb says like 33psi

The door jam pressures are not for ideal track performance, those are for average street driving.

[michaelalex17]

Originally Posted by F3IGHTY

The door jam pressures are not for ideal track performance, those are for average street driving.

I asked this same question awhile back because they seemed low to me and everyone responded back saying the car handles best at 33 psi. I'll try and find the thread

[OhioRiderAaron]

Originally Posted by michaelalex17

Would you say the same pressure for the 19's? I'm pretty sure my door jamb says like 33psi

Yes. Door jamb values should only be used for daily driving. When I'm not at the track I keep my tires at 33-35PSI as well.

Originally Posted by F3IGHTY

The door jam pressures are not for ideal track performance, those are for average street driving.

Agreed.

Originally Posted by michaelalex17

I asked this same question awhile back because they seemed low to me and everyone responded back saying the car handles best at 33 psi. I'll try and find the thread

I'm just another forum member here (I recommend you take all posts with a grain of salt, and experiment yourself to validate), but I do not agree whoever said that in the past, but it depends on if they were saying hot or cold pressures. 33PSI (hot) is too low, but try it yourself if you'd like.

[steven26]

Originally Posted by OhioRiderAaron

38-42PSI hot. Some will say that is high, but that produced the quickest laps and didnt roll over the sidewalls. I believe I ran all the way down to 35PSI hot and it rolled way too much. Be careful as the stock tires wear fast if driven at a moderate pace.

+1. I also find those pressures are good to prevent roll over on stock ZCP wheels and tires.

I have tried low (hot) pressures as previous members have suggested and had tons of rollover and it did not handle well.

[MaynardZed]

Originally Posted by michaelalex17

Would you say the same pressure for the 19's? I'm pretty sure my door jamb says like 33psi

33 psi for the street IS the same as 38-42 hot.

I run R888R which has a much stiffer sidewall. 26-27 cold / 34-35 hot is where I liked it.

Lots and lots of variables contribute to tire pressure at the track, but the most simplified advice I could give, is to check the pressures immediately when coming off the track and make them all even at that time. Keep your gloves so you don’t burn yourself.

Unless you suspect a leaking tire, Do Not check the pressures again before your next session. They will be uneven, ie the outside front tire will be a few lbs lower than the other ones. That’s fine, they will even out again nice you get heat back into them.

[GregSM3]

Originally Posted by MaynardZed

33 psi for the street IS the same as 38-42 hot.

I run R888R which has a much stiffer sidewall. 26-27 cold / 34-35 hot is where I liked it.

Lots and lots of variables contribute to tire pressure at the track, but the most simplified advice I could give, is to check the pressures immediately when coming off the track and make them all even at that time. Keep your gloves so you don’t burn yourself.

Unless you suspect a leaking tire, Do Not check the pressures again before your next session. They will be uneven, ie the outside front tire will be a few lbs lower than the other ones. That’s fine, they will even out again nice you get heat back into them.

thanks everyone for the input. I went to the track and kept tires at stock levels - cold. It was definitely cool out at mid to low 40's. Also, I am very much a novice but the tires held up well. But probably as much to do with me being not aggressive as it was the tire pressure.

[LVB]

After 5 track days on stock MPSS at 40Psi, lettering disappeared on both fronts.

[Bon F80]

i ran 34 psi when cold all around and the outer edge on the front tires were gone after only 1 track day. will try the recommended 38 - 42 psi when hot next time, hope it helps...

[MPoweRo]

Originally Posted by Pong

i ran 34 psi when cold all around and the outer edge on the front tires were gone after only 1 track day. will try the recommended 38 - 42 psi when hot next time, hope it helps...

Get camber plates mate.

[Racer20]

With the 19's, 36-37psi hot works best. With a freshly checked nominal stock alignment, my tire temps measure within 5degrees of across the whole surface of the tire and I've always had very even tire wear at these pressures. PSS and PS4S seem to be the same. Everybody I know in the suspension development community has found the same thing on various cars with these tires. It's possible the 20's are different, most of the cars in familiar with on Michelin tires use 18's or 19's.

[Inprogress]

Originally Posted by OhioRiderAaron

38-42PSI hot. Some will say that is high, but that produced the quickest laps and didnt roll over the sidewalls. I believe I ran all the way down to 35PSI hot and it rolled way too much. Be careful as the stock tires wear fast if driven at a moderate pace.

What would 38-42psi equate to when cold? I’m a stock ZCP with MPSS, should I aim for 28F/30R cold?

[OhioRiderAaron]

Originally Posted by Inprogress

What would 38-42psi equate to when cold? I’m a stock ZCP with MPSS, should I aim for 28F/30R cold?

I'd start the morning "high" around 33-34psi cold, then see where that lands you coming off the track. You could try 30-32PSI, but I prefer to not have to put air back in the tire if I end up too low. As the day progresses bleed down to 38-42 hot. I was always cautious on the first few laps so I wouldn't put excess wear on the side walls. Either way with no camber the outer edge will be gone quickly.

[NYG]

My experience so far with three diff tires (Super Sport, 4S, NT01) on the CS, the car starts ice skating in the presence of heat and pressures above 35 psi. I've also noticed severe chunking of the tire at pressures near 40 psi. It really depends on your driving style, so you probably just need to find a good starting point and adjust as necessary. I'm pre-abs on all corners and I tend to start letting the rear loose a little bit near the end of the day for fun.

My optimal HOT starting point is Front: 33psi / Rear: 31psi

I usually start 26 cold all around but still tend to bleed a little air out throughout the day.

Your front tires will see the biggest delta because BMW decided brake cooling isn't important for the f8x, so you'll be getting ridiculous amounts of heat from the calipers/rotors.

EDIT: To the people who are trying to negate outside shoulder wear by increasing tire pressure, it will help minimally. You're still going to see uneven wear until you get the right alignment.

[OhioRiderAaron]

Originally Posted by NYG

My experience so far with three diff tires (Super Sport, 4S, NT01) on the CS, the car starts ice skating in the presence of heat and pressures above 35 psi. I've also noticed severe chunking of the tire at pressures near 40 psi. It really depends on your driving style, so you probably just need to find a good starting point and adjust as necessary. I'm pre-abs on all corners and I tend to start letting the rear loose a little bit near the end of the day for fun.

My optimal HOT starting point is Front: 33psi / Rear: 31psi

I usually start 26 cold all around but still tend to bleed a little air out throughout the day.

Your front tires will see the biggest delta because BMW decided brake cooling isn't important for the f8x, so you'll be getting ridiculous amounts of heat from the calipers/rotors.

EDIT: To the people who are trying to negate outside shoulder wear by increasing tire pressure, it will help minimally. You're still going to see uneven wear until you get the right alignment.

My lord, not sure I agree or recommend any of your suggestions. 26PSI with stock ZCP wheels? Maybe hoosiers or a stiff tire, but no way with 90% of street tires..

[jmg]

Originally Posted by NYG

My experience so far with three diff tires (Super Sport, 4S, NT01) on the CS, the car starts ice skating in the presence of heat and pressures above 35 psi. I've also noticed severe chunking of the tire at pressures near 40 psi. It really depends on your driving style, so you probably just need to find a good starting point and adjust as necessary. I'm pre-abs on all corners and I tend to start letting the rear loose a little bit near the end of the day for fun.

My optimal HOT starting point is Front: 33psi / Rear: 31psi

I usually start 26 cold all around but still tend to bleed a little air out throughout the day.

Your front tires will see the biggest delta because BMW decided brake cooling isn't important for the f8x, so you'll be getting ridiculous amounts of heat from the calipers/rotors.

EDIT: To the people who are trying to negate outside shoulder wear by increasing tire pressure, it will help minimally. You're still going to see uneven wear until you get the right alignment.

Just to throw in my experiences with MPSS on the track I dropped down to 29 cold, tires got to almost 40 hot, and you are right, had to bleed off throughout the day to keep it down, shoulders were trashed, and grip was not great although my fastest lap was at the end of the day.

Someone have any advice? Kept my old MP4S4 on my civic F80 at 42 hot and they started to chunk. Should I just keep it at 32-33 cold and accept that these aren't really track tires?

Going for RE-71R's next.

[NYG]

Originally Posted by OhioRiderAaron

My lord, not sure I agree or recommend any of your suggestions. 26PSI with stock ZCP wheels? Maybe hoosiers or a stiff tire, but no way with 90% of street tires..

I said 26 psi cold . That gets me to 32 psi easily after one session in 75 degree weather. Even higher on a hot day.

I've done it plenty of times with super sports. Now I just show up to the track at my standard cold pressure of 34 and bleed them throughout the day.

Originally Posted by jmg

Just to throw in my experiences with MPSS on the track I dropped down to 29 cold, tires got to almost 40 hot, and you are right, had to bleed off throughout the day to keep it down, shoulders were trashed, and grip was not great although my fastest lap was at the end of the day.

Someone have any advice? Kept my old MP4S4 on my civic F80 at 42 hot and they started to chunk. Should I just keep it at 32-33 cold and accept that these aren't really track tires?

Going for RE-71R's next.

Yeah, I'm not sure how my previous post can get misinterpreted lol.

PS4S chunk so badly at 40 psi. I had the best results at 35 psi with those.

I seldom meet anyone in an f8x that runs their pressures at ~40 psi with typical tires we all use but we've all got unique driving styles I guess.

[Powerslide]

Originally Posted by NYG

I said 26 psi cold . That gets me to 32 psi easily after one session in 75 degree weather. Even higher on a hot day.

I've done it plenty of times with super sports. Now I just show up to the track at my standard cold pressure of 34 and bleed them throughout the day.

Yeah, I'm not sure how my previous post can get misinterpreted lol.

PS4S chunk so badly at 40 psi. I had the best results at 35 psi with those.

I seldom meet anyone in an f8x that runs their pressures at ~40 psi with typical tires we all use but we've all got unique driving styles I guess.

For me - When I had the stock MPSS 20" tires - first morning session cold psi was 34. Kept checking and bleeding air throughout the day so that the hot psi stayed around 38-39psi - maintained pretty good control and tires did not get greasy.

Now have RE-71R's on - yeah baby!!!!