[JamesNoBrakes]

Originally Posted by LA_LT1

In my experience, if you are interested in performance, smaller wheels are better since they almost always lighter.
Larger wheels have stiffer sidewalls, but there is a diminishing return as sizes increase.
18in are the sweet spot for most cars in terms of sidewall stiffness. Past 18s its just for show.
I went from a 19in OEM to 18in wheel in my BMW and the ride quality increased (same P4S tires), and the acceleration and fuel economy improved due to less unsprung weight.
My Camaro has 20s... the proportions of the car are such where is does not look goofy, 20s used to be DUBs lol. But the ride isn't great and if it was not a lease I would probably get wider 18 in wheels for the performance and ride quality benefits.

Ultimate proof is race cars basically never go above 18in wheels.

There are some advantages to bigger contact patches, but when they come at the expense of rotating weight or sidewall stiffness, then it generally hurts performance. In the dry, a good hard sidewall low-profile tire will work well on say a 19", that results in great cornering and the tire not collapsing or rolling over, excellent for handling. But put an 18" on there and run the same diameter with different profile 18" tires (so it works out to the same as before) and your sidewall is no longer as stiff and will roll-over more during hard aggressive driving. On the other hand, if you can go 18 and lower profile and not give up your contact patch...well you might be getting ahead again. To top it off, testing in wet conditions shows that a little more sidewall, like an 18" with a 255/40 profile, is better at cornering and handling in the wet than the same wheel with a 30 profile tire. That roll and give makes the tire hang on longer and more predictably.

But, for these reasons, I didn't get 19"s for my stinger, I went with some nice 18s from tire-rack and some 255 tires, keep ride quality, possibly give up a little in sidewall stiffness, but much bigger contact patch than OEM and should be better wet handling (I might wet-autoX it). No reason really to go to 19s on that car. Yes, some people love how they look...but when your brakes aren't that big, IMO it just amplifies your small brakes with a bigger wheel.

People have a hard-on for big wheels though, that and lowering cars to the point where they are non-functional as far a suspension. I don't see these things reversing. The trend with auto-makers is to cram the biggest damn wheels and tires you can in there for aesthetics. The RS6 Avant has something like 22"s...wth?

The 19" winter wheels on my Camaro make a difference for acceleration that I can feel.

[kropscamaro16]

my buddy has a set of 18s and 19s with same tires for his 1le next auto x he does he is going to do some tests to see which hes faster on but he doesnt think there will be much difference if any...

[JamesNoBrakes]

Originally Posted by kropscamaro16

my buddy has a set of 18s and 19s with same tires for his 1le next auto x he does he is going to do some tests to see which hes faster on but he doesnt think there will be much difference if any...

Yeah, I'd look for a lot more difference between say 18 and 20.

[s2mikey]

I certainly went with the black 20's on my recent 2022 Camaro order mostly for looks. If I could have got black rims in 18" I would have though. But, a little extra contact patch in cornering has to help, right?

[Malbjey]

Originally Posted by s2mikey

I certainly went with the black 20's on my recent 2022 Camaro order mostly for looks. If I could have got black rims in 18" I would have though. But, a little extra contact patch in cornering has to help, right?

The 18s and the 20s have the exact same tire width on the V6 model. So unfortunately you aren't getting much handling advantage (if any) out of the 20s, besides them having a stiffer sidewall.



The disadvantages of the 20s is that they are heavier, the tires are more expensive and a harsher ride. They do look better than the 18s, though.

[Rock-It Man]

Bigger wheels=more weight.

For handling, more unsprung weight=less traction when cornering on bumpy roads.

At the strip, wheel weight=2 to 3 times the inertia of non-rotating parts.

Unless you need the bigger wheels to clear large brakes, don't switch.

[Seniorrs]

The run flats on 18" wheel weigh 36 lbs.Run flats on 20" weigh 31lbs.Boh good year all season.After 13k miles my rs tires are handling much better.My replacement will be non run flat,26-28lbs or 18"×8.5" wheel 21.4 lbs ,18" tire weight same as 20".

[Norm Peterson]

Originally Posted by Seniorrs

The run flats on 18" wheel weigh 36 lbs.Run flats on 20" weigh 31lbs.Boh good year all season.

Hadn't thought about that before, but it makes sense that having to stiffen taller sidewalls would add weight compared to stiffening shorter sidewalls.

Makes today a good day. Thanks


Norm

[s2mikey]

Originally Posted by Malbjey

The 18s and the 20s have the exact same tire width on the V6 model. So unfortunately you aren't getting much handling advantage (if any) out of the 20s, besides them having a stiffer sidewall.

The disadvantages of the 20s is that they are heavier, the tires are more expensive and a harsher ride. They do look better than the 18s, though.

Ahhh. Damn. Now I wonder if I should have just went with the stock silver 18's(and saved $800 bucks too)and got my own wheel and tire package later on? Love the look of the black rims though. Oh well. Too late now, Im pretty sure.

[Malbjey]

Originally Posted by Seniorrs

The run flats on 18" wheel weigh 36 lbs.Run flats on 20" weigh 31lbs.Boh good year all season.After 13k miles my rs tires are handling much better.My replacement will be non run flat,26-28lbs or 18"×8.5" wheel 21.4 lbs ,18" tire weight same as 20".

Whoah wait, the stock 18s are run flats now? I don't think they were run flats in the past?



That's crazy. I'd still contend the stock 18s are a better wheel choice versus the stock 20s, especially when it comes to buying a new set of tires.

[Malbjey]

Originally Posted by s2mikey

Ahhh. Damn. Now I wonder if I should have just went with the stock silver 18's(and saved $800 bucks too)and got my own wheel and tire package later on? Love the look of the black rims though. Oh well. Too late now, Im pretty sure.

You could always ask the dealer if its truly too late. I'm sure you won't be the first person to request a change on your order.



I know I mentioned it in the other thread, but I'd totally go for the NPP exhaust, especially if you cancel the black 20s. You could always get the silver wheels painted or powder coated if you want.



Ultimately do what makes you happy!

[Seniorrs]

I think a gen 6 has never had a spare tire.I looked on tire rack,a245-50-18 good year run flat weighs 36 lbs.That makes a 20" make sense if you want run flat tires.They cost around $300 each. You can get a 18-8.5 ,21.4 lb. wheel and a tire 26-28 lbs. to fit gen6 for about $1500-$1800 with sensors ,set of 4.Stock 20" wheel 31 lbs.Non run flat 20" tire 26-28 lbs. The only place I would have for spare is back seat ,since trunk I use most of trunk.

[ajsandiego]

Originally Posted by JamesNoBrakes

There are some advantages to bigger contact patches, but when they come at the expense of rotating weight or sidewall stiffness, then it generally hurts performance. In the dry, a good hard sidewall low-profile tire will work well on say a 19", that results in great cornering and the tire not collapsing or rolling over, excellent for handling. But put an 18" on there and run the same diameter with different profile 18" tires (so it works out to the same as before) and your sidewall is no longer as stiff and will roll-over more during hard aggressive driving. On the other hand, if you can go 18 and lower profile and not give up your contact patch...well you might be getting ahead again. To top it off, testing in wet conditions shows that a little more sidewall, like an 18" with a 255/40 profile, is better at cornering and handling in the wet than the same wheel with a 30 profile tire. That roll and give makes the tire hang on longer and more predictably...

Decided to stick with the stock 18s, dip them black in the mean time and get new tires. Swap for wheels come spring. Now its a matter of finding the right tires. Resolved to the possibility I may need a few mm in spacers given for a few months, from what I can tell the stock offset is 32mm. 255/40 for front is where I am but thinking about going wider in the rear slightly.

[gra359]

Originally Posted by arpad_m

Exactly, it's about front to rear difference and not absolute height to keep Stabilitrak and ABS happy.

On the other hand, large changes to the latter can mess up the speedo to an extent best not ignored, so one may want to at least adjust the tune in that case.

This is exactly what I was looking for. As long as I'm 3% or lower between front and rear tire dia., I'm good to go. I will get the car re-tuned to calibrate the MPH.

Gary