Track - Staggered or Square?

[CanAutM3]

Originally Posted by nicknaz

Agreed other changes will activate euro mdm. But is the factory number or date a calibration point for the different diameters?

doesnt seem like anyone knows for sure

I checked the PSS diameters on the Michelin website and they are 661mm/677mm for the 18" and 661mm/675mm for the 19". So the rolling radius of the rear 18" is only 1mm larger than the rear 19". That is negligible IMO and well within tire wear variation (thread depth is 7mm).

Therefore, I don't believe there is a DSC/MDM calibration difference between the 18" and 19" wheels.

[dawgdog]

[QUOTE=FTS;17853239]

Originally Posted by Gearhead999s

Trailing throttle is all I found that I needed to get the car rotated to the apex.But truthfully I only drove the car twice and probably could use a lot more time in the car before really commenting on a 911's behaviour but that was my impression.

Nice pic

I can understand and appreciate your point of view. However, not trail braking in a 911 is not using its most fundamental advantage, which its dynamic balance. Under braking the weight distribution is almost perfect on both axles, and since you have 325 rears vs. 245 fronts, to get the most out of the car approaching heavy braking zones is to stay off the brakes as much as you can, and extend the braking distance into the corner like no other car can. However, never extend it to the apex, you do need to be on the throttle before or at the apex, so you can use the rear traction and also to rotate the car as the fronts will be just
watching the scenery and not doing much

Still love the 911s

This is my experience tracking a .2 GT3RS for over two years. With trail braking you can brake later, particularly in long sweeper turns. This helps rotate the rear and allows you to get on throttle sooner before the apex. Or if I need to rotate the rear quickly I can lift and then apply throttle to hook up the rear end. Drove the M3 for the first time on track yesterday totally stock. 7 seconds off my RS times from last weekend but I am relearning BMW on track and I lack sticky tires and brakes. Having fun and hope to improve today.

[smh_amg_m4gts]

Originally Posted by nicknaz

How about the tire temperature displayed on the screen under the tire pressure? Any experience with how similar or different the needle type thermometer measurement is vs. the car's reported tire temperature?

EDIT: thanks everyone for the tips on the tire pressure. I used the 30psi cold / 33-35 psi hot for the stock PSS and it was a good recommendation

How did the stock PSS' work out for you? 19s I presume...

[smh_amg_m4gts]

[QUOTE=dawgdog;17881985]

Originally Posted by FTS

This is my experience tracking a .2 GT3RS for over two years. With trail braking you can brake later, particularly in long sweeper turns. This helps rotate the rear and allows you to get on throttle sooner before the apex. Or if I need to rotate the rear quickly I can lift and then apply throttle to hook up the rear end. Drove the M3 for the first time on track yesterday totally stock. 7 seconds off my RS times from last weekend but I am relearning BMW on track and I lack sticky tires and brakes. Having fun and hope to improve today.

This sounds like a different thread...having raced superbikes I'm very familiar with trail braking. But after watching a couple instructional videos, it looks like braking should be done in a straight line and not in the corner.

[gthal]

Originally Posted by stunnaM3

This sounds like a different thread...having raced superbikes I'm very familiar with trail braking. But after watching a couple instructional videos, it looks like braking should be done in a straight line and not in the corner.

Depends on the corner, the car and the driver.

In an M, trail braking on certain corners is the fastest way into and out of the corner. The driver needs to have some experience to do it right. Some corners benefit less or not at all and braking in a straight line is fine.

Likewise, trail braking in a Porsche is less common given where the weight sits on the chassis.

[FTS]

Originally Posted by stunnaM3

This sounds like a different thread...having raced superbikes I'm very familiar with trail braking. But after watching a couple instructional videos, it looks like braking should be done in a straight line and not in the corner.

Like gthal says, it does depend on the corner. First, techniques don't change from car to car, same for BMW and a 911, what changes is how you apply the techniques.

Second, you shouldn't trail brake into high-speed corners as it is more difficult to balance the inputs to be consistent in such corners and recovery exponentially more difficult. In such corners, best of what I found is to brake while mostly straight, than on throttle before turn-in with gradual increase on throttle pressure. However, for slow- to medium-speed corners, trailing the brakes is a must IMO.

[smh_amg_m4gts]

Thanks for the feedback!

[CanAutM3]

Originally Posted by stunnaM3

This sounds like a different thread...having raced superbikes I'm very familiar with trail braking. But after watching a couple instructional videos, it looks like braking should be done in a straight line and not in the corner.

In short, the way I see it is that there is the safe way and the fast way.

I consider trail braking any braking carried past the turn-in point.

The vast majority of schools start by teaching that all the braking has to be done in a straight line. That is to make it safe for beginner/intermediate students. However, if you look at videos/telemetry from any pro racing, you will quickly notice that they keep decelerating all the way to the apex on the vast majority of corners (on corners that require deceleration naturally ).

Mastering braking and brake modulation is already quite complex in a straight line and is often left to later stages of the driver education process. Doing so while the car is turning is even more difficult. A driver has to be quite comfortable with high slip angles and managing yaw with weight transfer to be able to properly master trail braking.

I am far from being a pro but I do carry some level of trail braking in almost every corner to get the car pointing in the right direction. I then use the throttle to catch the rotation. I usually avoid carrying too much trail braking (if at all) in turns where the car can get unsettled (bumps, negative camber, crests, slick spots).

[gsrbri]

I know this is somewhat off topic, but I went with a staggered set-up for my track wheels/tires on the F82. 275/35-10 front and 305/35-11 rear in 18" diameter. CCW wheels and Nitto NT-01 tires. I wanted the extra grip in the rear for better throttle management. Putting the power down on track is difficult, especially during corner exit onto the straights (where one can find some significant lap time reductions). I'll have photos and a full review soon. At LRP shortly.

[CanAutM3]

Originally Posted by gsrbri

I know this is somewhat off topic, but I went with a staggered set-up for my track wheels/tires on the F82. 275/35-10 front and 305/35-11 rear in 18" diameter. CCW wheels and Nitto NT-01 tires. I wanted the extra grip in the rear for better throttle management. Putting the power down on track is difficult, especially during corner exit onto the straights (where one can find some significant lap time reductions). I'll have photos and a full review soon. At LRP shortly.

You are actually right on topic

It's the other discussion on trail braking that

Looking forward to your review. The 275-305/35R18 NT01 is a setup I am considering.

[heckyeahbro69]

Originally Posted by gsrbri

I know this is somewhat off topic, but I went with a staggered set-up for my track wheels/tires on the F82. 275/35-10 front and 305/35-11 rear in 18" diameter. CCW wheels and Nitto NT-01 tires. I wanted the extra grip in the rear for better throttle management. Putting the power down on track is difficult, especially during corner exit onto the straights (where one can find some significant lap time reductions). I'll have photos and a full review soon. At LRP shortly.

I'm also considering ditching my 275 square setup for 275/295. Seemed that even on 275 nt01's it would spin on corner exit, though the track conditions may have not been ideal. It was very hot and greasy. We'll see how it works at sebring before i make the decision to ditch the 275 rears.

[evanescent03]

Originally Posted by heckyeahbro69

I'm also considering ditching my 275 square setup for 275/295. Seemed that even on 275 nt01's it would spin on corner exit, though the track conditions may have not been ideal. It was very hot and greasy. We'll see how it works at sebring before i make the decision to ditch the 275 rears.

so far my 275 rear NT01 have been fine. (3 lapping days, one day was very wet so put the PSS back on). all electronics off but maybe not driving as hard as you all... I think later on I'll be adding some wider rears since the car can support it but I'll keep the spares for the front probably at least until the tires are gone....

[smh_amg_m4gts]

http://f80.bimmerpost.com/forums/sho...1#post18163021

Not a bad deal at $200 off and free shipping!

[MaynardZed]

Originally Posted by heckyeahbro69

I'm also considering ditching my 275 square setup for 275/295. Seemed that even on 275 nt01's it would spin on corner exit, though the track conditions may have not been ideal. It was very hot and greasy. We'll see how it works at sebring before i make the decision to ditch the 275 rears.

Bigger rear tire not a bad idea, but check your rear toe settings. Factory settings are only about 1/16 total toe. I added a lot more rear toe in and it definitely helped the tail happiness on corner exit.

[Lojs]

Originally Posted by MaynardZed

Bigger rear tire not a bad idea, but check your rear toe settings. Factory settings are only about 1/16 total toe. I added a lot more rear toe in and it definitely helped the tail happiness on corner exit.

How to?

[heckyeahbro69]

Originally Posted by MaynardZed

Bigger rear tire not a bad idea, but check your rear toe settings. Factory settings are only about 1/16 total toe. I added a lot more rear toe in and it definitely helped the tail happiness on corner exit.

It was just that track. I ran sebring last weekend and I could readily put the power down without the same wheel spin I had at pbir. The car had Pss10's and different rear camber, but the toe was the same. I think the nitto 275s are fine for stock power levels. I have no plans for a tune, the car is plenty fast imo. Toe seems to only make a difference in how the rear end rotatates but not really controlling wheel spin.

[neo871]

I've been going back and forth all day through these track wheels threads and I still can't draw a proper conclusion...to many option out there
If I were to go for a 18" staggered track setup, what tire with/height would be ideal?

[JNoSol]

Originally Posted by neo871

I've been going back and forth all day through these track wheels threads and I still can't draw a proper conclusion...to many option out there
If I were to go for a 18" staggered track setup, what tire with/height would be ideal?

This is my recommendation for 18s staggered: 18x10 ET22 front and 18x11 ET40 rear. 275/35/18 front and 305/35/18 rear.

[neo871]

Thanks!
Wouldn't the 295/35 be a better choice considering it's closer to 275/35 diameter?

[JNoSol]

Originally Posted by neo871

Thanks!
Wouldn't the 295/35 be a better choice considering it's closer to 275/35 diameter?

If you run 295/35, use 18x10.5 ET34. 295 sits 2.2% taller in the rear and 305/35 sits 3.2% taller. OEM is 2.7% taller in the rear. You can't go wrong either way. No MDM issues being under 1% delta. Just pick the less expensive tire option.

[CanAutM3]

Originally Posted by neo871

Thanks!
Wouldn't the 295/35 be a better choice considering it's closer to 275/35 diameter?

Depends what wheel diameter you are talking here, 18" or 19".

For instance, the NT01 305/35R18 has only 0.1" smaller radius than the stock PSS in 275/35R19, effectively negligible. Further, the NT01 is not even available in 295/35R18.

[neo871]

I'm not from the US, so NT01 would be quite hard to get. In fact, I wasn't even thinking of R-comps, but rather RE11, PSC2 or similar.