18s or 20s, that is the question

[woody80z28]

Now, not even getting into wheel appearance or the look of "rubber band" tires, which would perform better all around?

(4) 20x8.5 with 245/35R20 & 255/35R20
or
(2) 18x8 with 245/40R18 & 18x9.5 with 275/40R18

I need to make a decision quick, too, because free shipping from Coys is over on the 30th. haha

[Roger M]

I'm no expert, but i am pretty sure the 18" wheels and tires will perform much better than 20s. More sidewall willl also give a better ride.

[68Formula]

Two rims of the same weight but different diameters means for torque to overcome the inertia of the larger one. Wider tire patch means (assuming same tires) higher better grip. Sidewall stiffness can be a good thing, but once to an extreme is a detriment by providing poor limit feedback to the driver before losing traction and possibly worsening the contact patch.

20s for show (assuming you like that cr@p) and 18s fo go. Don't bother with 20s unless you have 16" brakes.

[O'Neall]

I'm no expert either, but the slim sidewall will give a rougher ride and you're more likely to damage a wheel on a pothole or some other road irregularity. Plus, 17 or 18 inch UHP tires perform as good or better than anything larger.

[6'9"Witha69]

18s. No question or doubt.

[Boesch]

You'll get better performance (acceleration and stopping) from the 18's due to inertia affects. With 20's it'll take longer to get them spinning and longer to stop them from spinning. It's in the physics.

[woody80z28]

I'm starting to lean towards the 18s. The 20s I have in mind are cheaper, and the overall tire diameter will close up a little bit of fender gap compared to the 18s. My 12" brakes also wont look as tiny in 18s though. haha

The one thing I have against the 18s is the tire height. In order to get the body to sit on the 18s right, I'll need to lower it and lose more ground clearance. I'm already tight at my headers and at my cut outs. Right now with my 15" wheels I have 26/28" tires front/rear and the stance could use to be lowered a little. The 245&275/40R18s will put me at 25.7/26.7". The 20s would be 26.8/27".

Does anyone have a pic of a 2nd gen with 20/20? I know of a few running 18/20, but none all 20.

[Roger M]

I'm starting to lean towards the 18s. The 20s I have in mind are cheaper, and the overall tire diameter will close up a little bit of fender gap compared to the 18s. My 12" brakes also wont look as tiny in 18s though. haha

The one thing I have against the 18s is the tire height. In order to get the body to sit on the 18s right, I'll need to lower it and lose more ground clearance. I'm already tight at my headers and at my cut outs. Right now with my 15" wheels I have 26/28" tires front/rear and the stance could use to be lowered a little. The 245&275/40R18s will put me at 25.7/26.7". The 20s would be 26.8/27".

Does anyone have a pic of a 2nd gen with 20/20? I know of a few running 18/20, but none all 20.


I have 275/40/18s on the back of my buick now and i want to increase the diameter as well. Since i already have 18" wheels, I'm going to go up to a 45 or 50 series tire. That is the cheaper alternative for me, over buying 20" rims and tires.

[Mr.VENGEANCE]

the RS chevelle is running 20s and is a real player... so dont knock 20s my man..

18s is a sure shot but 20s arent a punk tho..

[HILROD]

There are a bunch of taller tires in 18. Look at the plus one sizes for the '05 and up Mustang tires.

[class67]

18s. No question or doubt.

+1, no question!

[BaddestBuick]

how about some 19's and 18's up front

[68Formula]

Tirerack is having a sale on Eagle F1 Supercar tires.

Put a 255/45 on the front and a 285/40 rear and you have a 27" tall tire. Or go to a 245/45 front for 26.5". Remember for each inch you go up in overall diameter, you fill the fender gap .5" and increase ground clearance .5".

http://www.tirerack.com/tires/tires.jsp?tireMake=Goodyear&tireModel=Eagle+F1+Supercar&partnum=84WR8F1SUPERCAR&vehicleSearch=false&fromCompare1=yes&place=3

[woody80z28]

The 275/40R18s are the biggest I can find in my price range. I'm going to call both places today and see the difference in weight between the two.

[woody80z28]

Ok the 20s are 33lbs and the staggered 18s are 29/31.

[TPI Monte SS]

I'd go 18s as well. I noticed a difference in acceleration and braking on my Cherokee by going from the stock 15" wheels with 225/75s to my nice-weather 18"s and 225/60s. Takes longer to stop, and acceleration is off a bit as well.

[6'9"Witha69]

But that more weight, no matter how marginal, is further out from the center of the hub. MOI is a bitch when you f&*^ with her. I know you want to "fill in" the wheel well but don't get too caught up in form over function.

[Tony_SS]

18's. 20's will look out of proportion on the car IMO. And like said, the brakes and accel. will work in your favor vs. 20's

[chevella]

the RS chevelle is running 20s and is a real player... so dont knock 20s my man..

18s is a sure shot but 20s arent a punk tho..
Pretty sure the RS chevelle is running 18's. Intro's if I remember correctly. Definately a player!

[Mr.VENGEANCE]

nope.. 19s and 20s my friend.. got the mag issue in front of me.. you dont remember correctly. LOL

indeed a player..

[chevella]

nope.. 19s and 20s my friend.. got the mag issue in front of me.. you dont remember correctly. LOL

indeed a player..

yep....18s my friend...if we are talking about the same car. Obviously we're not. At first I thought you were referring to the blue 70 chevelle RS give away car which did have 18s. I now see that you must be referring to the Roadster Shop 66 chevelle. Not that it matters either way. LOL!!:box:

[68Formula]

nope.. 19s and 20s my friend.. got the mag issue in front of me.. you dont remember correctly. LOL

indeed a player..

Now imagine what it could do with 18s. :naughty:

[Mr.VENGEANCE]

yes the 66 chevelle, playboy..

and if i remember correctly on the skidpad that 70 wasnt that big of a player.. hahahah

and imagining has nothing to do with anything.. that car already performed WITH 20s..

[MrQuick]

Yes, the yellow and flat black striped one is running 20's. If you are going to use 20's for a performance car you will have to tune the suspension for it. They can be made to perform quite well.

https://static1.pt-content.com/images/noimg.gif

[woody80z28]

Anything will handle better than the 275/60R15s on 15x7s I have right now.

I took measurements tonight and I have 6" everywhere except the cutouts which are at 5". Thre are quite a few guys in the 3.5-5.5" range at the k-frame without much grief so I have more room to lower than I thought.

Here's a Z with the wheels/tires I'm looking at.
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

[rocketman]

A 18/20 split would look good

[jknight16]

I know this is a first gen but here are 18's all around on my car

https://static1.pt-content.com/images/pt/2007/09/JeffsCamaroSept07Flagstaff-1.jpg

Rear tires are a 295...

https://static1.pt-content.com/images/pt/2007/09/JeffscarinFlagstaffset2007-1.jpg

[woody80z28]

A 18/20 split would look good
That's what got me wondering about 20s. Here are a couple 2nd gens with 18/20.

https://static1.pt-content.com/images/noimg.gif

https://static1.pt-content.com/images/noimg.gif

[impalatpi66]

i would suggest investing in air ride and get the car as low as you can get it and put on 20s all the way around.

[1FstChevy]

I'll admit that 20's look okay on some Chevelles and other big body cars, but from a performance standpoint its ridiculous to consider 20's.

Of course they only detract from performance minimally with the increase in rotating mass or inertia, but there deffinitly isn't an increase in performance over 18's, not to mention on cars like our 2nd gens it limits how low you can get your center of gravity without some significant modifications to the wheel wells, since the outer diameter of a 20" with even the lowest profile tire is going to be larger than an 18" with a 40 side wall ratio.

& besides increased cost for 20" tires, including the limited availabilty of performance tires in that size should do it for you. I don't think you'd ever see a 20" wheel on a C6R??? :) :) :) Don't get me wrong, I'm all for big wheels and tires (18"s!) but I'd prefer more go, as opposed to all show!

[Zedzag]

I recognize that car. I chose the 18s for a performance standpoint. They definitally are harder to stop and accelerate than the factory 15s. Big brakes are a must with large wheels.
Anything will handle better than the 275/60R15s on 15x7s I have right now.

I took measurements tonight and I have 6" everywhere except the cutouts which are at 5". Thre are quite a few guys in the 3.5-5.5" range at the k-frame without much grief so I have more room to lower than I thought.

Here's a Z with the wheels/tires I'm looking at.
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

[68Formula]

jknight16 please check your pms. Sorry for the thread hijack. Back to topic.