305 rear tires???

[BlackinBlack]

Originally Posted by Brian 1LE SS

Since I have no idea what havoc is happening to a car running 315's on the front, what should I be looking for? They have been on my Camaro for the last 6 years. BTW Tirerack didnt want to sell me 315's for the front or rear because they said they wouldnt fit, but hey what do I know.

It looks like you race the car. The interesting thing would be to put a smaller tire on the car. There is a balance between grip, unsprung weight (big tires and rims weigh more), rolling resistance, and aero drag. It could be that running a 275 on your car it could have more top speed, faster acceleration and better cornering. (Note I said "could") Like anything else setup is important and each car is different.

My point in this thread is that GM spent a ton of time building the 1LE package for handling. The car is a 1G car out of the box. (Which is amazing) It is going to be hard to make it noticeably better without spending a bunch of $$$. Again I could be wrong and I am very interested with people's results as they make drastic changes to the car's setup. (305's on the back is a big change.) If you bought the car for looks not handling then I guess that change will not matter much but for those that want to drive the car hard into a turn it could result in a negative result.

Just my opinion and it is worth what it costs to post it here.

[Synner]

There's so much paranoia in this thread. The tires were meant to make the car mostly neutral as an OEM car. No manufacturer makes a car that will oversteer because of morons who don't know how to drive it killing themselves. Thats why most reviews say understeer is still present but lessened. An OEM designed car and a race car optimized for the track are vastly different. The more tire you can get in a balanced or mild oversteer situation depending on preference is best for racing. You can only brake as fast as your tire will let you. You can only pull as many g's as your tires will let you. If everyone is so scared to mod a car then leave it stock and don't race it because you'll be breaking stuff. And then you'll put a stock part back on versus upgrade to a better than OEM part not designed by an OEM engineer for a mass produced car at a mass produced price? I can power steer way faster through a turn than a car maintaining a mild understeer can, give me more tire and I will do it faster still.

For many people the 1LE will be more car than they'll ever use and stock is fine. For a few people the answer to the question of how fast do you want to go will always be faster. Those people don't rely on OEM engineers to make their mod decisions. Why pull 1g when you can pull 1.2? Or 1.4? Put slicks in 285 size and you can easily do 1.2 or more. Put 305 slicks on and you can brake that much later, that much harder, carry speed better through a turn, and greatly increase exit speed. The stock brembos can lock up the wheels when braking hard. Using track pads will make it even easier, you fix that with wider or stickier tires. You can buy wheels that can shave almost double digit poundage off each corner. You're driving a big V8, power is not the issue. Traction is. Yes a wider tire increases drag. Bad for gas mileage and would probably tip the car into gas guzzler tax territory because OEM's needs to use cheaper mass produced wheels, deal with mileage ratings, and therefore can't reduce the weight to make up for it. Bad for commuters but great for the track.

Listening to an OEM engineer for whats best for a race car is like listening to a politician for whats best for the country. What you get is a deeply twisted perspective based upon whats best for them and their situation. Sorry if I offend anyone but use a little independent thinking and do some research on race suspensions.

[Synner]

Originally Posted by So Cal Camaro

I am happy all you guys or girls are happy with your stock Camaro, but to quote Jesse James, "stock sucks"

+1

[Norm Peterson]

Originally Posted by So Cal Camaro

No, if they really wanted a square set up done right, they should have used 10" wheels all around, the 285 stretched across the 11" wheel looks awful and looks like it is going to wear the tire quickly...I'll get the ZL1 Pedders or Pfadt rear sway bar, it'll be good when I'm done with it...

I'd do the "square" setup the other way - 285's on 11" wheels all around.

The reason is cornering stiffness and turn-in response, which are characteristics you want to favor in a hardcore handling machine. So if you're an OE engineer, you pick a wheel width out toward or at the max recommended width for whatever size tire you end up with. Having the rear package a little stiffer than the front ought to make the car just a little more predictable at the (rather high) limit.

You can't look at a wide wheel setup like the old days where you had tall profile tires that bulged/bellied way out past the wheel flanges - that to me is the picture of soft cornering response, noisy cornering at only moderate g-levels, and heavy outside shoulder wear.

Tire wear with the 11" wheels won't be anywhere near as bad as you seem to think. Generally on the more hardcore performance cars I've owned, I've been running tires at to about half an inch past max recommended for about 40 years. (I'm an engineer, just not in the automotive sector, and I can give myself a little more leeway if I can legitimately justify it to myself. Been good so far . . .) At any rate, I've always gotten very close to dead even wear except for the time I didn't pay enough attention to the inflation pressure and wore out the shoulders. All four of the OE all-season tires that my '08 Mustang came with were wearing within no more than 0.02" across the tread when I took them off last spring (I just put them back on today, for the winter). Matching the inflation pressures and alignment to your driving is rather important.

The reason that the ZL1 uses a staggered setup is because of the significantly greater power and torque available, which would tend to be a little too "unbalanced" on-throttle on corner exit otherwise, Ford went through the same sort of thing with the 2008-era GT500 with the 18" wheel & tire package (reportedly they tried but couldn't make a square setup satisfy corporate handling requirements, so they staggered the tire size but not the wheel width).

I hope Chevy doesn't pay much attention to people staggering the tires on the 1LE just for the sake of appearance, as the risk is spoiling the car for the hardcore handling guys.

I guess you just have to be able to appreciate an appearance that runs contrary to popular opinion. That the subjective appearance in this matter should be kept secondary to the intended [handling] performance instead of the other way around.


Norm

[So Cal Camaro]

This isn't my first venture into driving cars and setting them up the way I want them, I don't care for the stretched tire and given the way I set this up with the Nitto's, it'll be the way I want it...stop worrying about what I'm doing...and worry about your own car's set up....

[white1LE]

Fellas fellas!!! This isn't meant to piss anyone off. So, do you guys think most of these cars are gonna see the track like the video of a professional driver cranking it around Virginia Raceway? Which is a killer video by the way. In my opinion, if you can drive at that level, you will surely feel the difference having a 1 inch narrower or wider tire. But for the guys running an autocross track in a Wal-Mart parking lot around 50 orange cones, I highly doubt you will notice. Kudos to the guys that can feel the difference from a 1 inch narrower or wider tire! That takes a ton of seat time and homework. Mine will eventually see a lap or 2 around Elkhart Lake or Joliet, but for this daily driver, speeds around corners will be conservative cause just because the car can do it doesn't mean I can. So 305's it is for me.

[ssummit camaro]

I plan on putting the 305's on mine. Do you all think I will have to recalibrate the computer for this. Height according to tire rack is 305's- 28.4. and the 285's at 27.9

[white1LE]

Originally Posted by ssummit camaro

I plan on putting the 305's on mine. Do you all think I will have to recalibrate the computer for this. Height according to tire rack is 305's- 28.4. and the 285's at 27.9

If and when you have the car tuned, the tuner can adjust it then. Not for sure if it will make a difference or not.

[Mgizzle]

Originally Posted by Synner

+1

I don't think anyone is saying stay stock, most of us don't and that is because we have different needs and wants from a car.

But to say stock sucks without having any basis, data, experience with it prior to your modifications. It is like saying brownies taste bad and should be out of vanilla when you never tried one in the first place.

If so cal went with his new 1le to his local track and said I pulled a 1 min lap, after which I swapped to the other set of wheels and shaved 2 seconds off, then we couldn't disagree with him making the right choice. The question then would be was it the nitto compound or the width or his driving style?

This is why vehicle dynamics is so exciting, there is never one right answer in the real world.

To the op's question, GM sort of stated they reduced the rear width to make the 1le more neutral and faster around the track => less under steer

They also stated they put heavy duty hubs to handle higher loads. Going more grip by either Tire size or compound could wreck havoc on other parts.

In theory on a flat road and no camber wider is better for grip. Now add camber, suspension geometry, tire optimal operating temps, various torques acting on center of tire vs. corner design and going wider, wheel mass etc. and wider is a waste of tire that creates significant disadvantages. Hence if Brian ran that bad boy camaro of his with 275s and the same tire compound at 315 with 2 sec a lap better I would say heck yeah! But if he ran same or worst I would say go lower width and play with something else.

[So Cal Camaro]

Originally Posted by Mgizzle

I don't think anyone is saying stay stock, most of us don't and that is because we have different needs and wants from a car.

But to say stock sucks without having any basis, data, experience with it prior to your modifications. It is like saying brownies taste bad and should be out of vanilla when you never tried one in the first place.

If so cal went with his new 1le to his local track and said I pulled a 1 min lap, after which I swapped to the other set of wheels and shaved 2 seconds off, then we couldn't disagree with him making the right choice. The question then would be was it the nitto compound or the width or his driving style?

This is why vehicle dynamics is so exciting, there is never one right answer in the real world.

To the op's question, GM sort of stated they reduced the rear width to make the 1le more neutral and faster around the track => less under steer

They also stated they put heavy duty hubs to handle higher loads. Going more grip by either Tire size or compound could wreck havoc on other parts.

In theory on a flat road and no camber wider is better for grip. Now add camber, suspension geometry, tire optimal operating temps, various torques acting on center of tire vs. corner design and going wider, wheel mass etc. and wider is a waste of tire that creates significant disadvantages. Hence if Brian ran that bad boy camaro of his with 275s and the same tire compound at 315 with 2 sec a lap better I would say heck yeah! But if he ran same or worst I would say go lower width and play with something else.

My question is why do you care what someone else does with the car they bought....get over it...

[CrystalRedTintcoat]

Originally Posted by So Cal Camaro

My question is why do you care what someone else does with the car they bought....get over it...

Ummmm ......

Because the subject of this thread it 305 Tires ?????.
Because these threads are about learning from others.

[CrystalRedTintcoat]

I figure it out. So Cal Camaro is a 10/10th's driver. I'm not.

So Cal, that's not a criticism. You probably are more into this than most of us ever will be.

[Norm Peterson]

Originally Posted by So Cal Camaro

This isn't my first venture into driving cars and setting them up the way I want them, I don't care for the stretched tire and given the way I set this up with the Nitto's, it'll be the way I want it...stop worrying about what I'm doing...and worry about your own car's set up....

It wasn't intended as a personal attack on you or your preference in wheel/tire appearance.

Just a suggestion (with a little tech behind it) that running tires on wheels much narrower than the max-recommended width for the tire leaves a little performance potential on the table. And that even if the consensus on the appearance factor strongly favors a certain "look", that still doesn't mean that it's a universal opinion.

You have your priorities in this and mine are somewhat different. Other participants in this thread are entitled to read both and decide for themselves where to go from there.


Norm

[Norm Peterson]

Originally Posted by white1LE

But for the guys running an autocross track in a Wal-Mart parking lot around 50 orange cones, I highly doubt you will notice. Kudos to the guys that can feel the difference from a 1 inch narrower or wider tire!

Don't undervalue what autocrossing demands or what it can make evident simply because of the relatively low speeds involved. It is a VERY intense activity.

You might even notice the 1" more at auto-X, because that form of motorsports is much more about transient handling (where things like turn-in response matter the most) than running out on the big track is.


FWIW, even in fairly hard street driving it's possible to notice a 1" wheel width difference with the tire size held constant (or a 20mm difference in tire width on the same wheels) if you have the right sequence and spacing of corners and have some idea what to "feel" for.

Maybe almost 50 years of driving with an acknowledged "corner-carver" mindset really does count as applicable seat time. Maybe the difference in feel doesn't matter as much to everyone.


Norm