TRAKCAR

I always try to switch side to side.
Michelin was on track with us in Europe and refused to do it because they said the tire has a great risk of failing once you counter rotate after heat cycles.

A way to sell more tires or truth?

On the RS rears last 2-3 days fronts twice as long.

orthojoe

Oh yeah, yes, I do swap tires side to side when doing consecutive days on a ccw course.

I wonder if the wider front tires and a difference in front spring rates account for the wear difference.... It's still bizarre to me that trofeoR rear tires wear faster and cup2 front tires wear faster on the plain gt3

SmokinGTS

I think it comes down to spring rates...We all need to take a closer look at these. I am running race springs up front with a tender spring from H & R. So far wear looks better and my times are faster.

orthojoe

Made the phone call today and left a message. Waiting to hear back.

MaxLTV

My take on ESC and TC - I run mostly with it on. It's very good and does not interfere most of the time. BUT it can do something that I cannot possibly do to save the car if something unexpected happens (blow off, hitting an oil spill etc).

Having said that, I tried ESC, TC only and all off, and here are my observations:

Thunderhill East - same lap time with all three modes. Only caveat is that exiting out of 11 ESC sometimes cuts the power when rear wheels bounce on the rumble strips. That does not happen in TC-only and all-off modes, leading to more consistent lap times. I would go TC-only for a hero lap there. Also, with all-off need to be lift at the top of bypass because any throttle input at the crest results in crazy wheelspin when at speed.

Also, drove T-hill East in pouring rain for a private day, and the fastest times were with TC-only. TC is superb - allows to spin wheels a little, just to remove some traction from the rear, but not do a wet burnout. ESC was very slow in comparison, and all-off was hard to manage unless short-shifting.

T-hill West (with hairpins) - TC off and all off are faster. ESC kills rotation on throttle, which is helpful in thight hairpins. Also, ESC smoothes out throttle release to reduce lift-oversteer, which makes using throttle lift for oversteer less effective. Can be seen on data if you log the throttle position rather than the gas pedal position - when lifting quickly, throttle closes gradually when ESC is on. I'd go TC-only for hero lap and I drive with all-off when I do West days to practice car control.

Laguna - only drove with TC-only for one day, and rest of the days with all on. With TC-only, the car felt better in T3 exit and T4 exit - I was getting oversteer rather than understeer at trackout. Also, felt better in T11. Meaning I could control oversteer better with throttle. Did not see any difference anywhere else. No meaningful difference in lap times in my case, but I think if I gave it more time, I could have been faster in TC-only mode than with all on (ran very low 1:38 laps with TC-only and all-on, but with exhaust permanently plugged, which steals a lot of time on T11-T2 straight).

Sonoma - I'm too chicken to drive it without nannies at full speed, but I've been there probably 5-6 times total, 2 in the rain.

Manifold

^ Interesting observations. You might try changing driving technique to see if you can achieve equal or faster lap times with ESC/TC on and avoid triggering it. For example, I rarely lift to rotate, since trailbraking seems faster to me and it keeps the back of the car stable.

Tracks here on the east coast tend to have plenty of things to hit, but I may try playing with turning off ESC/TC just to see the effects.

MaxLTV

Lifting to rotate is helpful when braking would be too much of speed loss and you want to shift traction forward with minimal slowing down. A good example would be S-es, where partial lift helps initiate the next curve (e.g., between T3 and T4 in Thunderhill East, I'd go full throttle at T3 exit, then go to almost full lift to load the nose and back to full throttle right after the car gets pointed into T4).

Another example is driving through a carousel and using throttle to balance understeer/oversteer. When adding throttle, the response is instanteneous, but when breathing off gas to tighten the arch, the response sometimes is a little rubber band-like, making it seem like the car wants to understeer more than it really does, so it's easy to breathe off more than it would be optimal.

But these are all VERY subtle things. It's a very well-tuned system that rarely interferes.

The only track where I'm definitively faster with all off is Thunderhill West, which is pretty much and oversized autocross track (1st-3rd gear mostly). And there it's not like I'm triggering ESC and it's cutting power and makes me slower. It's rather that I want car to do something intentionally, that I know would be faster, and it would not do it to the extent I want. E.g., let's say the fastest way to exist a corner is 7 degrees of slip in the rear, and the ESC would only allow 5 degrees, so I can drive with 5 degrees, an be a little slower, or try to do 7, engage ESC and be noticeably slower.

Manifold

Yes, you're right, I was being too simplistic and hit 'Submit Reply' too quickly.

I do lift in the same situations, and I too find that sometimes the back of the car can move too quickly. I think I'm catching it before the car does, but will try ESC/TC off (in a safe location) to see the difference.

skippyBKR

That's interesting....
Like this?

Earlierapex

The 991 ESC is almost completely non-invasive. It's really incredibly well designed. Barring some very bizarre track with very tight corners and lots of bumps, I don't see any reason why you would turn it off.

Some observations:
1) I can rotate the car with trailing throttle or trail braking without the system jumping in.
2) If I come in to a corner too hot and the car starts to rotate too quickly, the system will catch the car just as fast as counter-steering if not faster.
3) When it catches fast-coming over-steer, you don't have to catch the second swing with a second countersteer.
4) The 991 is like a pussycat with oversteer anyway. It's very easy to catch with countersteer when ESC is off, so you really don't need or not need the system (might as well leave it on). This must be the 4WS.

I think I disagree with trackcar. With practice, I think I could use the system to push the turn-in to apex speed and rely on the system as a safety net without being on my counter-steer tiptoes. I'm not recommending this strategy, but I think it could work with practice.

MayorAdamWest

I don't know what that's a picture of above, but not rotating. Doesn't even look like the tires were used.

As for rotating, I think the Michelin comment is interesting. I wondered this myself. Just because the tire can be rotated doesn't mean it will last longer if doing so. I'm really curious now to see a comparison. I can certainly imagine how chunking could occur after swapping directions.

TrackDays247.com

My Kumhos exhibit a tread 'squeeze', ie a directional smearing of the tread that might affect the wear one way or another....rotating on mine didn't make a difference however.

trakmor

They do look to be in good shape...well, except for the obvious. Almost look like they were driven aggressively at low pressures and the tire came off of the wheel?

I basically have over driven into corners on the cup 2's and am now looking at the consequences, a very worn left front with the rest of the tires in pretty good shape. Still getting used to the car...but get to pay a stupid tax (i.e. new tires a little sooner than necessary).

Thanks, just switched fronts and rears left to right and am hoping to get one more additional day after overcooking the left front(see above). Have never done that before so am curious to see if there is much of a difference with the feel...all of the tires have equal heat cycles though. If there are any issues I'll let you guys know.

skippyBKR

Let me elaborate.
This tyre blew out on day 6 of a Tarmac Rally (Targa Tasmania) nearly throwing us off the road and nearly costing us the win.
The 6 days comprised of 2000km of touring and 500km of racing on sealed roads. Some stages were up to 50 km in length.
We are allowed 6 tyres for the event but the GT3 could do it on 4 tyres. We opted to use 3 fronts and 3 rears and rotate them every day.
So, each tyre got about 30 heat cycles and 4 direction changes (if you follow).
The tyre photographed is well trashed because we had no choice but to drive the remaining 7 km's of the stage with a blowout. The rim damage made me cry but it's what we had to do to win.
My ears pricked up with this info from Michelin on not rotating after several heat cycles as there was no obvious puncture in the tyre - it seemed to fail with a bang.
If this is indeed what happened to us, then I think Michelin should be putting this info out a bit better!

Tom Tweed

WTF? When and where did Michelin start saying you can't rotate the Sport Cup 2 tires? Is this only with the N1 version for the RS? There isn't any info I can find on their website about this. They recommend routine rotation in all their manuals. Their technical FAQ says this:

"Tires with directional tread patterns must be mounted so that the primary direction of rotation matches the directional arrows on the tire sidewall. If all four tires are the same size, directional tires can be rotated front to back.
Tires with tread patterns that are both asymmetric and directional require left and right specific tires. Sidewall markings will identify the side of the vehicle and the primary direction of rotation for the tire. If all four tires are the same size, they can be rotated front to back."

There are no directional arrows or L&R side specifications on the MPSC2 that I have seen, just a marking specifying "outside." They don't appear to be asymmetric or directional. I am going to refrain from flipping the tires on the rim as I would with Hoosiers, but I have routinely swapped left and right side tires between events (both front and rear) with my N0 version MPSC2's. If this is dangerous, they should be informing people loudly and unequivocally.

TT