[Datka]

Originally Posted by Blubaron79

Thanks for responding! I came in with temps at 78F at a pressure of 38. My front tires showed a tiny bit of sidewall wear after the event. They are RFT's of course.

Is it still worth decreasing pressure? I plan to only track my stock car maybe 3 times a year. (This May change as I get more addicted)

And of course the guy in the Mustang ran off track 3 times. Lol

You don't want less than 38 hot tire pressure. I would recommend street ground control camber plates. They will allow you to adjust front camber for the track and street.
Setting front camber to negative 2.5 or 3 will not only save your tires but will improve the handling dramatically.

[Blubaron79]

Originally Posted by Datka

You don't want less than 38 hot tire pressure. I would recommend street ground control camber plates. They will allow you to adjust front camber for the track and street.
Setting front camber to negative 2.5 or 3 will not only save your tires but will improve the handling dramatically.

I just need to know how much they warm up on the track. I'll monitor them more closely next month.

[JG_Coupe88]

Originally Posted by Blubaron79

I just need to know how much they warm up on the track. I'll monitor them more closely next month.

I coded mine with bimmercode to show tire pressures and Temps on my Idrive. Pretty awesome, I leave the tpm menu up and can keep an eye as they heat up thoughout laps. Just an idea if some of you aren't doing that already!

[nickf30]

Originally Posted by JG_Coupe88

I coded mine with bimmercode to show tire pressures and Temps on my Idrive. Pretty awesome, I leave the tpm menu up and can keep an eye as they heat up thoughout laps. Just an idea if some of you aren't doing that already!

I did the same thing to show Tire Temp / Pressure on mine. However once I measured with an infrared temperature gun ($18 Amazon) the actual reading is about 30F higher than the TPMS display (160F actual vs 129F TPMS) and there are variation on inside vs outside edge.

[JG_Coupe88]

Originally Posted by nickf30

I did the same thing to show Tire Temp / Pressure on mine. However once I measured with an infrared temperature gun ($18 Amazon) the actual reading is about 30F higher than the TPMS display (160F actual vs 129F TPMS) and there are variation on inside vs outside edge.

Woah 30! I need to get me one of those.

[FaRKle!]

Originally Posted by JG_Coupe88

Woah 30! I need to get me one of those.

You should get a pyrometer. Tire surface temp changes very quickly compared to core temp.

I'm using a Longacre combo digital pressure gauge/pyrometer unit.

[JG_Coupe88]

Originally Posted by FaRKle!

You should get a pyrometer. Tire surface temp changes very quickly compared to core temp.

I'm using a Longacre combo digital pressure gauge/pyrometer unit.

Used a similar one that belonged to a buddy a while back. Thank you I'll check those out on Amazon prior to the next track day.

[FastF30]

I read thru the posts and for xdrive yes trail braking or what I like to do is engine braking (major down shifting) which throws the weight on the front and keeps you in the right gear to blast out of the corner... also you hit the apex different than you would in a normal RWD car.... you have AWD .... take advantage of it... here is a good video explaining different lines to take.... all in all it's a lot of fun!

[Insane435]

Here is how both of my front tires look after 3 track days; this is my outer edge. The track is very technical. My rears look pretty good.

All tires are 5/32"



Here is my alignment specs as well. Thoughts? He said he dialed in more negative in the rear due to my lowered suspension (KW V1).

[rphz]

Originally Posted by Insane435

Here is how both of my front tires look after 3 track days; this is my outer edge. The track is very technical. My rears look pretty good.

Your tire wear is a sign of two potential issues: you are over-driving in the corners and your pressures may be too low. With your added power and AWD, it makes this even worse (and easier to do). I can't tell if you are square or staggered with your wheels and tires, but if not squared, additional wear on the front will occur.

In a previous post you asked about a whether a track spec tire would help, and yes, something like the RE-71R would be more predictable and not heat up as fast. I tried out a set of the Firehawk Indy 500s on the track at the beginning of this season and they were horrible due to the same issues (heat and pressure management), and wore as bad as your tires are. They got really hot really quick, and it was impossible to find a sweat spot for tire pressure where they weren't too greasy or completely ruining the shoulders, which I eventually did. Some of this is of course driving too hard in the corners and something I'm still working on as well. However, I switched to the RE-71R (same 255/40-18 tire size on the same 18x8.5 wheels) and it was night and day. Yes, they still warm up and you need to keep and eye on pressures, and eventually they will get too hot and get somewhat greasy (and will also start "melting" a bit) but still to a much lesser degree, much more predictable, and less shoulder wear even when over-driving them. My times in autocross went up significantly and overall I had much better control of the car.

I can't speak to the tires you currently have as I've never run them, but even with a treadwear of 280, you are quite a bit higher than the 200 you get with an RE-71. Note that the lower the treadwear, the quicker they will wear out, and you will be lucky to get a busy season out of a set (but you will have more fun wearing them out) . So consider them a track-day-only tire if that is possible and if you have a square wheel set you can still rotate them front to back.

One last note on using Sport+ - don't. Use DSC off as you can use this to your advantage to steer out of corners as you accelerate. With the amount of power you've got, surely traction control is getting in the way, even with Sport+ and DTC. It's very difficult to lose control with DSC off and xDrive unless you upset the car by abruptly letting off the throttle. You can power through the corner and let the front pull you out, while the back steers around for you. When you get it right, it's a great feeling. Also, comfort mode will give you much more predictable throttle modulation which will allow smoother acceleration out of corners and reduce the amount of understeer if you try to accelerate too much too soon powering out of a corner.

Hope this helps...just sharing some things I've learned this year

[Insane435]

Tons of help man. I am running a staggered setup. I do plan on getting some 18s and throwing on RE-71s next year. Its good to know that 255's square can fit. I can tell I am not doing well in my turns because i am probably putting too much power down when trying to exit and traction is kicking on. I will definitely try comfort mode with traction off.

Also, these tires are going to be replaced before next spring for the street.

[nickf30]

Use chalk to mark the outside edge to sidewall on first 1-2 heat works well for me at autocross. Check the mark and adjust ur tire pressure right away if the wear pattern is not where you expected.

[Insane435]

Originally Posted by nickf30

Use chalk to mark the outside edge to sidewall on first 1-2 heat works well for me at autocross. Check the mark and adjust ur tire pressure right away if the wear pattern is not where you expected.

I do need to do that. If you over inflate/psi rises, does it wear more on the outside or do i have it backwards?

[nickf30]

Originally Posted by Insane435

I do need to do that. If you over inflate/psi rises, does it wear more on the outside or do i have it backwards?

If you overinflated the tire you will see the chalk mark still there at the edge of your sidewall (no grip). Going the other way if you see all the chalk mark disappear you need to increase tire pressure right away (less grip and may destroy your tire). Base on my limited experience, I can find 2 seconds per lap just by adjusting the tire pressure in 2 PSI step.

Here is a quick video on how to read the chalk mark from your tires: