0Anthony @ LGMotorsports

12" rear is either going to stick out or rub. No way it will fit without body work.

The front tire you have listed is 26.3" tall and the rear would be 25.2" so yes it is going to upset the computer as well.

SuaveZ51

Ops I left out the off set sorry...

Thanks guys for the good feedback...
Ops I left off the off set and noted the wrong rear tire series...

Work Wheels (3 piece Mesh style wheels).

19x8.5 front 56 off set (265/35/19) and 20x12 rear 72 off set (325/25/20).

Michelin Pilot Sport PS2 tires.

Do you guys think I will have issues:
* rubbing in the front or rear?
* Stick out past the fender lips?
* Computer programing issues?
* Others?

Thanks for the heads up

Bill Curlee

0Anthony @ LGMotorsports

That rear tire, 325/25/20 is 26.3" tall....I don't think the computer is going to like that one either. Might be fine for around town driving but the faster you go the more un-happy it is going to be with Active Handling on.

I have yet to see a 12" rear wheel fit under the back of a C6 and not rub or stick out.

///DarkSide\\\

Anthony,

I see many folks here mounting a 265/35-18 Front & 305/30-19 Rear. What's your experience with this size combo re Active Handling issues etc & what's your opinion on these sizes being mounted to the OEM size wheels (18x8.5 & 19x10)?

Thanks in advance

dads toy

I hope the OP listens to you Tony. I love the wheels on the red vette posted above. Getting close to being able to afford a set.

NTMD8R

Let me chime in here too...

I have 265x35x18 on the fronts
and 305x30x19 on the rears.

I run Autox, and HPDE... with "Competition Mode", and "all off".....
No computer issues whatsoever.
So as far as the computer is concerned.... this combination is fine.

As for running on "stock" wheels.....
MOST reputable tire manufacturers/dealers recommend to go no more than 15%
of the tire section width past the wheel width.
A stock wheel of 9" should therefore have no tire wider than (about) 245.
9.5" should be no more than (about) 255.
10" should be no more than (about) 270.

0Anthony @ LGMotorsports

I did the same setup on my C6 with 18x9 fronts and 19x10.5 rears. They would fit better if you went to a wider wheel but height wise I never had an issue with them at speeds up to 135mph....never had a chance to run it with AH on at speeds past that.

///DarkSide\\\

Thanks guys

I've read here many times that the 265/305 combo works just fine - great actually, just wanted to bring it up once again even though I've already made up my mind to go BIG on the stockers

SuaveZ51

Ok now...

Front tire set up stock to what Im looking at is:

Stock Frt Tire - 245/40R18 * Frt - 265/35R19
Section Width: 9.64 inches * Section Width: 10.43 inches

Rim Diameter: 18 inches * Rim Diameter: 19 inches

Rim Width Range: 8 - 9.5 inches * Rim Width Range: 9 - 10.5 inches

Overall Diameter: 25.71 inches * Overall Diameter: 26.30 in

Sidewall Height: 3.85 inches * Sidewall Height: 3.65 inches

Radius: 12.85 inches * Radius: 13.15 inches

Circumference: 80.77 inches * Circumference: 82.62 inches

Revs per Mile: 809.0 * Revs per Mile: 790.8

Actual Speed: 60 mph * Speedometer1: 58.6 mph (59mph with rounding, tolerance here is +/- 2.5 mph from the Mfg).

Speedometer Difference: 2.301% too slow
Diameter Difference: 2.25% 0.59 inches smaller! stock to new.


Rear tire set up stock to what Im looking at is:

Stock Tire - 285/35R19 * Rear - 325/25R20
Section Width: 11.22 inches * Section Width: 12.79 in

Rim Diameter: 19 inches * Rim Diameter: 20 inches

Rim Width Range: 9 - 11 inches * Rim Width Range: 11.5 - 12.5 inches

Overall Diameter: 26.85 inches * Overall Diameter: 26.39 in

Sidewall Height: 3.92 inches * Sidewall Height: 3.19 inches

Radius: 13.42 inches * Radius: 13.19 inches

Circumference: 84.35 inches * Circumference: 82.90 inches

Revs per Mile: 774.6 * Revs per Mile: 788.1

Actual Speed: 60 mph * Speedometer1: 61.0 mph (tolerance
here again is +/- 2.5 mph from the Mfg).

Speedometer Difference: 1.742% too fast
Diameter Difference: 1.72% 0.46 inches smaller! stock to new

======================================== =============
What do these numbers realy mean? % difference acceptable? Does anyone know what this value/ tolerance is? For front to rear?

Active AH (Handling Parameters)? Does anyone know what the target value and tolerance is when its related to tire diameter?

Thanks for all the good feedback. BUT Im going to need a few...



to understand the: impact... data...

MARSC6

My understanding was not to exceed a 3% change from stock front and rear size difference. Your tire choice may be a problem. Taking a chance like that is a pretty expensive gamble.

What about a 265/30/19 front to match the slightly reduced diameter of the rears?

I currently have the 265/35/19s up front but my rear tires are 315/30/20s which are also a slightly larger diameter.

SuaveZ51

Thanks I'll look into that.

Have you had any issues with the AH (Active Handling) system with your slight change in tire diameter? How long have you been running this set up? How about tire rubbing issues? Front or rear?

Thanks in advance

Oh yea TGIF so

SuaveZ51

MARSC6: what front wheel width are you running? Any issues with your front rim bottoming out due tire profile?

Thanks in adance.

MARSC6

I've had this tire combination up to about 140 without any active handling issues.

My wheels are Vossen VVS-087 19x9.5 +58 offset up front and rears are 20x11 +75 offset on a stock ride height Z51. I've only had these wheels on for 300 miles but so far I haven't had any kind of tire rub.

SuaveZ51

Nice!

Last question do your tires stick out the side of your fenders at all?

Thanks in advance

MARSC6

The rears do slightly







The 305s most people use don't stick out but I was going for the most traction I could get with 20" wheels. The only Toyo R888s that would fit are 315s.

SuaveZ51

Alright...

I’m going to custom order this set up tomorrow:

FRONT:
19X9.5 w/ 58 off set and 265/30/19

REAR:
20x12 w/ 72 off set and 325/25/20

Thanks for all the advice guys...

and

SuaveZ51

Ok guys...

After more discussion with the Mfg I've decided to go a different route BUT,,,

I have question I need help with!!!

The wheel surface comes with a clear coat on the aluminum. The Face of the wheel is a brushed finished so here I don’t see an issue but the lip is going to be polished aluminum.

I’m debating going with a clear coat here as well. I hear from the Mfg that this is the new thing and that most wheels that they are making nowadays are clear coated (face and lip area). But they only give a 1 year warranty.

ANY ONE OUT THERE HAVE EXPERIENCE WITH THIS CLEAR COAT TECHNIQUE ON WHEEL SURFACES AND / OR AN UNDERSTANDING OF DURABILITY, CLEANING ISSUES, ETC...

ANY SUGGESTIONS OUT THERE, ADVICE, HELP!!!

Thanks in advance...

Oh yea. The set up I’m going with is:

HRE 790's

FRONT
19x10 with 58 off set and 265/30/19 Pirelli P Zero Nero

REAR
20x12 with 72 off set and 325/25/20 Pirelli P Zero Nero

DUMAN

i am running the same size tires and i have had no issues at all. up to 171 mph closed coarse of coarse

MARSC6

Unless you like spending a lot of time polishing wheels the clear coat is a good thing. With clear you can easily clean the wheels.