[Lumbergh]

As all of you know, the CTS-V has more HP than tire to handle it. I want to increase my tire size (width, not diameter) to gain some off-the line traction. My plan is to run 275/35/19's on the front using 10x19 wheels and 305/30/19's onthe rear using 11x19 wheels. These sizes yeild about the same OD as the OEM set-up with increased width. My concern is what offset I should use to get the necessary suspension/body clearances and if I can fit them at all.

Has anyone fit similar sized wheels / tire on their CTS, how did it work out for you, and what offset did you end up with?

Thanks for your help

 

[digital1021]

Your kinda in uncharted territory, to my knowledge no one has mounted after market wheels to the V Coupe. The front fitment should be the same for the sedan and the coupe, however you might have some additional options with the rear fitment on the coupe vs the sedan. On the sedan, there is at least one person who has mounted 305's on a widened stock wheel for rear fitment. Up front the largest I recall is a 265, I am not sure if there were issues with going larger though. I am sure others will chime in with there experience.

~ Matt

 

[whisler151]

Sedan owners have mounted 305s on the rear. Your coupe should be good with 305s.

 

[musclesbmf]

Front max rim width will be 9.5 in my opinion. The 11's in the rear will be good. Get with a quality rim manufacturer or forum vendor so you get the right offsets.

Mark

 

[reevlak]

305 will fit perfectly, however i know for a fact if you try to widen to 11 inches you will have to run spacers b/c there is no way of changing the offset of the stock wheels.
IMO go with some light weight 3-piece wheels or a good quality monoblock wheel like HRE. this will also help reduce rotating mass therefore less inertia and faster ET.

 

[wfo]

Your kinda in uncharted territory, to my knowledge no one has mounted after market wheels to the V Coupe. The front fitment should be the same for the sedan and the coupe, however you might have some additional options with the rear fitment on the coupe vs the sedan. On the sedan, there is at least one person who has mounted 305's on a widened stock wheel for rear fitment. Up front the largest I recall is a 265, I am not sure if there were issues with going larger though. I am sure others will chime in with there experience.

~ Matt

On my V Coupe I'm running 20" Monoblocs...255 front and 305 rear. No issues. (OEM' rear will take the 305)

 

[whisler151]

On my V Coupe I'm running 20" Monoblocs...255 front and 305 rear. No issues. (OEM' rear will take the 305)

Do you have pics of said Monoblocs? :drool:

 

[PDQ-V]

I am running Nitto Invo 19 inch 255's on the front and 19 inch 305's on the rear with no fitment issues.

 

[LV_V]

Someone mentioned being able to fit a 12" wide rear wheel on the coupe.. I wonder if its possible and what a 345 245 20 would look like stuffed back there? Should get you a bit of traction!

I won't be getting a coupe for a little while, but I intend to put 20"x9" up front with 275 30 20 Invos and 20"x12" out back with 345 25 20 Invos. After seeing KILLER-V's setup, I may even buy the Vossen CV3's and send the rear wheels out to be widened 1.5"... After "dry" mounting the rear wheels and measuring the available space, of course.

I have too much time on my hands to think about this!!!! LOL

 

[LV_V]

Anyone on the 12" rear wheel on the coupe? Someone has to at least have measured it, let alone tried it by now...

 

[Ste_V_e]

Can you run 305/35/19's on stock coupe rear rims and leave the fronts factory?

 

[Rule12b]

I have a sedan, but I believe what I am running was originally thought out with the coupe in mind. I had my front rims removed and widened from 19x9 to 19x11. Offset remained intact and I run a 305-30-19 now on that rim in the rear. It's positively huge. I then just put my OEM rears on the front. Spacers ARE required (with longer studs) but in my opinion, very well worth it. The tires and fenders line up neatly flush all around. Now, that's with a sedan, and those 19x10's on your rear may be the ones to widen. That's a question for the guys at D3 or elsewhere that are more knowledgeable than me.

 

[LV_V]

I have a sedan, but I believe what I am running was originally thought out with the coupe in mind. I had my front rims removed and widened from 19x9 to 19x11. Offset remained intact and I run a 305-30-19 now on that rim in the rear. It's positively huge. I then just put my OEM rears on the front. Spacers ARE required (with longer studs) but in my opinion, very well worth it. The tires and fenders line up neatly flush all around. Now, that's with a sedan, and those 19x10's on your rear may be the ones to widen. That's a question for the guys at D3 or elsewhere that are more knowledgeable than me.

Can you post some pics from the rear and front along the fender line showing the position of the sidewalls relative to fenders? Do you have spacer thicknesses you can share with us? I was thinking of this exact setup and think others would also GREATLY benefit with these pics and info. Thanks!

 

[Rule12b]

I posted these in another thread, but here are some more. . .

----------

And a few more. .

 

[mberisha]

Wow! That is ALOT of rubber....looks mean!

The City of Akron may not have to file for bankruptcy seeing that much rubber on a tire!

 

[Fireverm]

I posted these in another thread, but here are some more. . .

----------

And a few more. .

How much smaller is the diameter of your rear wheel compared to your front? It looks to be significantly smaller in these pics, on the order of 3 to 4 inches. Also, was it necessary to go to an 11" rim to fit 305s? I thought I read on here that guys were putting the 305s on the stock sedan rear rim.

 

[DrVolkl]

How much smaller is the diameter of your rear wheel compared to your front? It looks to be significantly smaller in these pics, on the order of 3 to 4 inches. Also, was it necessary to go to an 11" rim to fit 305s? I thought I read on here that guys were putting the 305s on the stock sedan rear rim.

Those look like stock rims to me.... do they make wider stock looking ones?

I'd like to know if there's any noticeable traction change... The stock 285's give it up waaaaaay too easy. I can't believe they put such a small tire on a car with this much torque.

 

[Fireverm]

He says in his post that he had the front stock rim widened to 11" so it is definitely not stock. I was asking if that was necessary to fit the 305 tire as I believe others are putting them on the stock sedan rear rim.

 

[Rule12b]

He says in his post that he had the front stock rim widened to 11" so it is definitely not stock. I was asking if that was necessary to fit the 305 tire as I believe others are putting them on the stock sedan rear rim.

It is not necessary. Lots of folks are running them on the stock rears. However, the actual width of your contact patch and the width of the tire itself looks dramatically different on a wider rim. Traction and handling were both dramatically improved. Now, keep in mind, we had to file a tiny bit of the excess stamping on the control arm to eliminate any rubbing so i cant say you just bolt and go, but the modification was swift, easy, and minor.

I don't think there is so much a difference in diameter between front and rear as there is in ride height making it look that way. The D3 lowering kit drops like 2 inches or so in the rear but only about a half up frontwhich I think will do much to kill the illusion. I just haven't done it yet. In person, you don't notice it but in the pics, yes, it definitely looks that way.

 

[Fireverm]

Thanks for all of the info. One of the reasons I'm interested in going with wider tires on the stock rim is to provide a little extra rubber to protect the rims since my wife hasn't found many curbs she doesn't like yet. I am wanting to do 275-35s on the front and 305-30s on the rear. I'm also a little concerned that the wheels might look too small since both of these combos are about .5" smaller diameter than the stock config.