What is the advantage to a staggered setup?

What is the advantage to having a staggered setup on your car? All I ever hear is that a staggered setup increases understeer... so why in the world would anyone want this? Why does BMW stagger the tires on the Sport and Performance Packages?

Thanks,
Andy

The advantage is to BMW and their lawyers.

Originally Posted by TD

The advantage is to BMW and their lawyers.

To reduce oversteer?

Originally Posted by Andy

To reduce oversteer?

Yes. Oversteer is why people are scared of BMWs.

Staggered setups help reduce that fear. Plus, people *think* that fast cars have staggered tires, therefore BMW caters.

Originally Posted by Nick325xiT 5spd

Yes. Oversteer is why people are scared of BMWs.

Staggered setups help reduce that fear. Plus, people *think* that fast cars have staggered tires, therefore BMW caters.

With 18" Kumhos I basically have two choices...

1.) 225s all around
2.) 225s in the front and 265s in the rear

With ONLY these two options, it would seem to me that it would be more advantageous to run the staggered setup (option #2) and then play around with the air pressure to help reduce the understeer. More rubber to the ground has got to help, right? 225s all around just seems like too narrow of a tire for all four and seems like I would just end up loosing traction on all four wheels instead of just the front.

Which would be the better option for autocrossing?

Thanks,
Andy

Originally Posted by TD

The advantage is to BMW and their lawyers.

Nah-- if that were the case they'd do it on all their models--- including the non-sport 330s. Its just marketing--looks more "aggressive" w/ wider rear tires. Its like the quad-exhaust on the M3-- to the casual buyer it looks like its all about performance. In reality, it actually detracts from it.

TO the original poster-- the only advantage to a staggered setup would be on a very high power RWD car-- like a Corvette- so that the rear wouldnt lose traction on fast starts. If BMW really cared about that, they'd include an LSD before they even thought about staggered tire sizes.

you think Lotus uses a staggered setup on the Elise because they are afraid of lawyers?

Originally Posted by Andy

With 18" Kumhos I basically have two choices...

1.) 225s all around
2.) 225s in the front and 265s in the rear

With ONLY these two options, it would seem to me that it would be more advantageous to run the staggered setup (option #2) and then play around with the air pressure to help reduce the understeer. More rubber to the ground has got to help, right? 225s all around just seems like too narrow of a tire for all four and seems like I would just end up loosing traction on all four wheels instead of just the front.

Which would be the better option for autocrossing?

Thanks,
Andy

I thought you decided (correctly ) not to get r comps for at least another year.

:sigh: Anyways, you'd be better off with 225's all around.

The advantage of a staggered set of tires is that in a corner you will be accellerating (turning) by generating sideload. The force to maintain your speed or accellerate is delivered by the rear tires which are generating sideload (like the fronts) and providing forward thrust and carrying a slightly greater load due to weight shift from forward accelleration. The more power you have, the more a staggered set up will benefit lap times.

A lot of folks hate the staggered sizes. Remeber the wagons (that a lot of the smart guys own) are more stable, so their answer shouldn't be perfect for you. Also remember how much your car pushed at your first auto cross? Did it push a lot less at your next event with your corner entries more under control? I think a lot of the dislike of staggered setups has more to do with technique and alignment than objective testing to generate lap times.

With all of that said, this is mitigated on BMWs as strut suspensions have a tendency to understeer. So folks have success with even sizes (Bigger in back for the driven wheels+smaller in back to elliminate strut caused push= roughly equal sizes). I don't think anyone serious is advocating a 40mm stagger in sizes on non Ms. that's probably just too much. You may want to consider another brand or use the 225s all around. there are a lot of people having success with that.

Odds are our cars are already over tired at 225/40-18 (most reports are about 225 or 235 17s) in a vanilla street compound. So when you get stickier rubber, your need to go bigger is even further reduced. Finally, stickier rubber is more stable (=more understeer) so if you're going to a killer race tire you'll need less stagger.

Sticky 225s or 235s will probably work great.

.

Originally Posted by SpaceMonkey

I thought you decided (correctly ) not to get r comps for at least another year.

:sigh: Anyways, you'd be better off with 225's all around.

I had every intention of holding off on the R comps until last Sunday after the event. I was standing there waiting for my trophy, next to Victor, the guy who drove the E36 M3 that finished in 3rd .18 seconds ahead of me. He turns to me and says, "This is your second autocross ever, right?". "Yes", I replied. He goes on to say, "If you finished that well on street tires, I'm going to be scared to death when you get yourself a set of Kumhos!".

That made me feel pretty good, but as you can tell it made me want to get a set of Kumho tires even 10x worse!! I was talking to a different guy earlier on in the day that had been autocrossing for years, we got on the subject of tires and he told me that on a course like this, that a set of R comp tires would easily shave 2 seconds of your time, if not more. If my time would have been 2 seconds faster that day, I would have been running times as fast as the guy who won my class!! Now, granted you can always play the "what if" game, but needless to say my desire to run on a set of real tires has increased by 10 fold. Come on, put yourself in my shoes (no pun intended ), wouldn't you want to go out and buy a set of R comps if you were me?

Question:
Will 225s fit on an 8.5" wheel? If not, I'm not going to be able to run 225s all around and will either have to go staggered or go with a different brand of tire (which I don't really want to do).

Thanks,
Andy

Originally Posted by Andy

Question:
Will 225s fit on an 8.5" wheel? If not, I'm not going to be able to run 225s all around and will either have to go staggered or go with a different brand of tire (which I don't really want to do).

Thanks,
Andy

Yes, 225's will mount on an 8.5" wheel. The recommended rim width range given by the tire manufacturers on most 225/40R18's is up to 9".

Originally Posted by Andy

I had every intention of holding off on the R comps until last Sunday after the event. I was standing there waiting for my trophy, next to Victor, the guy who drove the E36 M3 that finished in 3rd .18 seconds ahead of me. He turns to me and says, "This is your second autocross ever, right?". "Yes", I replied. He goes on to say, "If you finished that well on street tires, I'm going to be scared to death when you get yourself a set of Kumhos!".

That made me feel pretty good, but as you can tell it made me want to get a set of Kumho tires even 10x worse!! I was talking to a different guy earlier on in the day that had been autocrossing for years, we got on the subject of tires and he told me that on a course like this, that a set of R comp tires would easily shave 2 seconds of your time, if not more. If my time would have been 2 seconds faster that day, I would have been running times as fast as the guy who won my class!! Now, granted you can always play the "what if" game, but needless to say my desire to run on a set of real tires has increased by 10 fold. Come on, put yourself in my shoes (no pun intended ), wouldn't you want to go out and buy a set of R comps if you were me?

Nope. And I am in a similar situation. This is my first year autocrossing, and I've been to about 6 autocrosses. Perhaps I haven't done as well as you initially, but I'm starting to get competitive.

Yet I know there's a lot more things I could be doing better. I just think R comps will mask bad driving habits. And personally I think it would be better to learn as much as possible on street tires before making the leap to r comps.

R comps may shave time off your runs, but as a novice, they may not. You CAN overcook R comps, and they are not very forgiving.

As for staggered sizes, with enough power or funny wieght distribution (think P car) you need the staggered sizes to keep things under control on corner exit.

So staggered sizes show up on P cars, V cars (Viper), C cars (Corvettes) due to weight and/or power. So they make the car LOOK like it is higher performance. So people do it to other cars.

But it can help on some cars, it can hurt on some cars.

Originally Posted by Andy

With 18" Kumhos I basically have two choices...

1.) 225s all around
2.) 225s in the front and 265s in the rear

With ONLY these two options, it would seem to me that it would be more advantageous to run the staggered setup (option #2) and then play around with the air pressure to help reduce the understeer. More rubber to the ground has got to help, right? 225s all around just seems like too narrow of a tire for all four and seems like I would just end up loosing traction on all four wheels instead of just the front.

Which would be the better option for autocrossing?

Thanks,
Andy

225s all around will work great for autocrossing. The car will understeer a little less with the same size tire all the way around which helps quite a bit in auto-x. The Ecsta V700s in 225 will have far more grip than your stock Bridgestone or Michelin tires in a 255 size.

I've found the Ecsta V700s to be quite forgiving at the limit when compared to other R compound tires, better than a lot of street tires. As a novice, I wouldn't recommend R tires on a racetrack because the speeds are too high, and there are too many things to run into. But for auto-x, you should be fine. Unless you do something crazy, a few dead cones should be the only damage done when you overcook it.

Have fun!

Originally Posted by GregD

I've found the Ecsta V700s to be quite forgiving at the limit when compared to other R compound tires, better than a lot of street tires. As a novice, I wouldn't recommend R tires on a racetrack because the speeds are too high, and there are too many things to run into. But for auto-x, you should be fine. Unless you do something crazy, a few dead cones should be the only damage done when you overcook it.

Have fun!

I'm still not too keen on novices (or relative novices) using R-comps, because the tires do not give much feedback about the car's behavior, and drivers can't learn to react to the car's behavior. With street tires, the driver can learn to hear and feel what the car is doing, and react accordingly. Street tires are a great tool to learn until one becomes more of an advanced driver.

Plus an inexperienced driver can kill a set VERY quickly overcooking turns and scrubbing the tires sideways.

no comment, it wouldn't be listened too anyways

Originally Posted by TeamZ4

no comment, it wouldn't be listened too anyways

Mark,

I'm not sure what you're referring to, were you referring to me? The whole reason I'm on this board and post threads like this is because I AM looking for advise. I would prefer that anyone and everyone that has an opinion on these subjects to please post, whether you believe it or not, I take ALL advise into consideration.

Here is another concern of mine that maybe you guys can shed some light on... I have participated in 2 autocrosses so far and I'm finding that I am really chewing up my tires, Potenzas S03, and those babies aren't cheep. My thinking, is that if I'm going to get some track tires, I need to hurry up and do so, other wise I'm going to eventually need to be buying two sets of tires.

Another thing I don't understand is what you guys mean by "over cooking the tires" when it comes to the R comps. Now, I understand you are referring to chewing up the tires by sliding around the corners, but what I don't understand is how is that different then chewing up my stock tires. Do R comps wear faster or different then the stock tires? Is it possible to damage R comps by "incorrect" wear?

And... I still don't understand why it's better to "learn" on stock tires compared to R comps. I've never driven on R comps so I have no idea how they feel and react compared to stock tires. In my mind, they are just the same as stock tires, but just with more grip and better traction, no?

Thanks,
Andy

Originally Posted by Andy

Here is another concern of mine that maybe you guys can shed some light on... I have participated in 2 autocrosses so far and I'm finding that I am really chewing up my tires, Potenzas S03, and those babies aren't cheep. My thinking, is that if I'm going to get some track tires, I need to hurry up and do so, other wise I'm going to eventually need to be buying two sets of tires.

Are you chewing up your front tires more than your back tires? It's pretty common when you start autocrossing to enter turns too fast. Entering a corner too fast while trying to brake and turn will grind your tires down very quickly, whatever kind of tires they are. Slow in, fast out works on most turns in auto-x.

Another thing I don't understand is what you guys mean by "over cooking the tires" when it comes to the R comps. Now, I understand you are referring to chewing up the tires by sliding around the corners, but what I don't understand is how is that different then chewing up my stock tires. Do R comps wear faster or different then the stock tires? Is it possible to damage R comps by "incorrect" wear?

R type tires are more sensitive to heat than regular tires. As long as you heat cycle them before using them, this shouldn't be much of a concern for an autocross, although it would be a concern for a racetrack (shaving would be recommended). Also, R tires have a softer rubber compound. If you drive the tires well beyond their optimal grip point / slip angle, it's like rubbing an eraser against sandpaper, and they'll wear out very quickly.

And... I still don't understand why it's better to "learn" on stock tires compared to R comps. I've never driven on R comps so I have no idea how they feel and react compared to stock tires. In my mind, they are just the same as stock tires, but just with more grip and better traction, no?

Some R tires are very touchy at the limit with little feedback, and when they let go they take a long time to recover. The Kumho Ecsta V700s aren't like that. The amount of feedback they give through the steering wheel is comparable to a good street tire, and they have a very graceful recovery when you exceed their limits (overcook) them.

Learning on street tires is easier primarily for two reasons, you can hear them howl as they approach their limits, and you're not going as fast. The Kumhos are basically silent until you've substantially exceeded their limits, at which point you'll hear a grinding noise. This is when you're killing your tires. Also, by not going as fast, you have more time to shift, pick out your braking points, and most importantly, concentrate on your line. Since you're pulling more Gs with Rs, you'll also get tossed around a little more inside the car, making it more difficult to stay in a good position to handle the vehicle controls.

That said, if you learn on street tires first, you'll have to retrain yourself when you get some Rs. You have to look farther ahead, brake later, get on the gas earlier, and be smoother.

I think that learning with R compound tires in auto-x is something that depends on the individual driver. For some people, they'll waste all of their time at an auto-x getting adjusted to the difference in grip, and not learn anything about how to drive. Other people will be able to adjust quickly, and take advantage of them.

Many places run the occasional autocross school. This would be a good place to become familiar with Rs since you will have enough runs to adjust to the tires and continue learning. As an alternative, run them on the street for a couple of weeks. This will give you some chance to become accustomed to them, just be careful of puddles of water, Rs will hydroplane easier than regular street tires.

I'm not referring to you Andy, based on my limited experience I already did my best to take you under my wing privately/publicly and provide you the guidance I wish someone had given me when I started doing this:

http://www.bimmerfest.com/forums/showthread.php?t=43295

I'm reading your response and I can only conclude that you completely missed the points given in that advice. You must also be as new to internet forums as you are at autocrossing, because ask a question and you'll get a million opinions that span the entire spectrum. This is what I am referring to in general, not you. Why would someone of my limited experience want to get into an argument by contradicting the experts?

In case you have never seen a 225/40-18 Kumho V700 on an 8.5" wide wheel, the wheelface/lip will extend about 1/2" wider on each side than the treadface with the sidewall angled inward. The 8" OE wheel lip already protrudes out further than the sidewall. So don't let it fall or sit flat on the pavement if you don't want the lip to get all scratched up. You can then go out and slide all around like many other newbies do. It will be fun though.

Your other option is to use 265's on the front 8" wheel too, but again based on my limited experience there is no advantage for a "good" driver. A "bad" driver will find them to be more forgiving of their mistakes. The problem is that a newbie is much less likely to learn the right way of doing things if the equipment selection keeps forgiving their attempts of doing it the wrong way. In both cases a newbie is selling out their long term development for a short term kluge. Your issue is not with the car or it's setup, your issue is with you; the inexperienced driver. You don't become a good driver until gaining the ability to control the vehicle within the available limits. It doesn't matter what those limits are - street tire, DOT-R tire, handling balance, whatever - give a "good" driver an understeering vehicle and not only will they be significantly faster than a "bad" driver, their front tires will last a lot longer too.

BTW, I have a buyer for the tires so this has nothing to do with me trying to pimp them.

peace and good luck.

advice!

This was a great discussion, as I'm making the same decision. I have a ZHP 330i that will be seeing competition starting in the Spring. I'm downsizing from the OEM 18" to 17" (probably); and was pretty much heading for the 235/40x17 option all around, for track shoes. THe other alternative was the popular stagger option - 225/45x17 front, and 245/40x17 rear. But then I thought, "This whole discussion is revolving around SCCA SOlo II style autocross. How do things change for those doing Solo I (open track time trials)?" I know BMWs are reputed to understeer at low speeds, but get more neutral at racetrack (think 50-100mph) speeds.

Do I still want to go same size for high speed autocross?

And, what are people's favorite "8 months of the year plus track time" tire? The final candidates for me are, the Bridgestone S-03 PP, the Falken Azenis, and the Goodrich KD.

Thanks in advance!

-Bill/BONTRAK

The STS/STX guys I've spoken to say that the KDs are the ultimate street tire. They're ludicrously expensive, though.

The Azenis Sports (which I have) are the next best thing, but don't take heat well. I've heard that they work very well on the track once they're well worn, but get squirrely when new. I can't really comment, as I've never had them on the track under really hot conditions. With an ambient temperature of ~75F, the Azeni were FANTASTIC on the track. I could outbrake and outcorner my instructor in his 325Ci SP on ContiSports in a 400lbs. heavier car with virtually blown rear shocks. (The shocks were so bad that the car was downright scary in the switchback between turns 6 and 7. The tail would float up in the air and take a second or two to settle back down.) That said, I'd be a little concerned about them at higher temps. On the other hand, at half the price of the KDs and lot less than the S-03s, who cares?

The S-03s are probably the best overall tire of the bunch. They have much better rain traction than the Azenis, and are far quieter. (If you've never tried the Azeni out, you should be aware that they're failed wheel bearing loud...) On the other hand, they have the least amount of dry traction, so if that's your primary concern...

I believe the general consensus is that the E46 is still biased fairly heavily towards understeer, even at higher speeds.

Originally Posted by Nick325xiT 5spd

The STS/STX guys I've spoken to say that the KDs are the ultimate street tire. They're ludicrously expensive, though.

The Azenis Sports (which I have) are the next best thing, but don't take heat well. I've heard that they work very well on the track once they're well worn, but get squirrely when new. I can't really comment, as I've never had them on the track under really hot conditions. With an ambient temperature of ~75F, the Azeni were FANTASTIC on the track. I could outbrake and outcorner my instructor in his 325Ci SP on ContiSports in a 400lbs. heavier car with virtually blown rear shocks. (The shocks were so bad that the car was downright scary in the switchback between turns 6 and 7. The tail would float up in the air and take a second or two to settle back down.) That said, I'd be a little concerned about them at higher temps. On the other hand, at half the price of the KDs and lot less than the S-03s, who cares?

The S-03s are probably the best overall tire of the bunch. They have much better rain traction than the Azenis, and are far quieter. (If you've never tried the Azeni out, you should be aware that they're failed wheel bearing loud...) On the other hand, they have the least amount of dry traction, so if that's your primary concern...

I believe the general consensus is that the E46 is still biased fairly heavily towards understeer, even at higher speeds.

Great feedback! Thanks! I've been running S-03s on my last track car, and was pretty pleased with the tire as a daily driver; it's also a nice, predictable track tire; but looking at my times and talking to other drivers, your positioning of it relative to track performance on a road course against the KDs and the Azenis is dead on.

I forgot one more "candidate." The Pirelli P Zero Nero has gotten excelent reviews from TireRack, and is on sale relatively cheap right now! Have you heard any buzz on the Nero? Maybe I'll run out and buy a set of 235/40x17s right now and store 'em til next spring...

-b.
Bill/BONTRAK

Originally Posted by BWoodson

And, what are people's favorite "8 months of the year plus track time" tire? The final candidates for me are, the Bridgestone S-03 PP, the Falken Azenis, and the Goodrich KD.

Thanks in advance!

-Bill/BONTRAK

Kumho Ecsta V700s.

I've been running R compound tires on my daily driver street cars for almost 15 years now. I've used Yoko A001R, A008R, A008RS, Goodrich R1s, Pirelli P0C, Kumho Victoracers, and Kumho Ecsta V700s. The V700s have proven to match the best of the rest for streetability, and are very competitive with the others on the track.

In my experience with 3 sets of V700s, you can expect 20k to 25k miles with occasional spirited driving but no track time. Put some track time or a few autocrosses in there, and you can easily cut the tire life in half, but that's true of almost any tire.

The biggest negative to the V700s on the street are a distinct tendency to tramline. Also, watch inflation pressures closely, at least once every two weeks. Watch out for hydroplaning as the tires wear down, although there're not too bad when new.

The biggest plus is grip, grip, grip! Stopping distances should go down by 10% or more. Just not spinning and sliding the tires so much can help keep down the wear when compared to regular street tires.