At about 12K mi my tires are ready for replacement.

A few questions for the group:

1 Has anyone been able to get any discounts on new tires from their dealer due to the short lifespan of the tires?

2 My local tire store guy says that going up to a 275 x40 x18 Goodyear F1 GS EMT will fit and run great. Anyone have experience here?

3 Anyone have comments re a plus one set up?

Thanks guys...any feedback will help!

did your dealer say WHY he thinks the wider tires would be better? He did the math right in that the circumference would be close (though not exactly the same), but I would think that there would be clearance issues (though maybe someone can comment more clearly. Also, I would think that you would need wider wheels, plus with the little amount of toe-in that this car has it might wander all over the place with that big a footprint.

Traction is not a problem with the standard wheels, so I see only downside not upside. Others have done some tire experimentation, so maybe they have more to add.....

Doug

My local tire store guy says that going up to a 275 x40 x18 Goodyear F1 GS EMT will fit and run great.

What size is he planning on running up front? Or did he mean 275x40 all the way around... if so, get the fitment guarentee in writing and give it a shot!!

did your dealer say WHY he thinks the wider tires would be better? He did the math right in that the circumference would be close (though not exactly the same), but I would think that there would be clearance issues (though maybe someone can comment more clearly. Also, I would think that you would need wider wheels, plus with the little amount of toe-in that this car has it might wander all over the place with that big a footprint.

Traction is not a problem with the standard wheels, so I see only downside not upside. Others have done some tire experimentation, so maybe they have more to add.....

Doug

I agree almost 100% with Doug. Unless the local tire guy runs a CTS-V with wider tires, I'm not sure he knows jack about how good the combination might be or what it could offer. Regarding wander, the rear toe-in settings continue with the larger tires, which should encourage a straight path.

I would NOT want 275 width tires in front. One thing I still admire about the M5 is the amount of feedback and quick reflexes of the steering. If there is something I'm not fond of of the V it's somewhat vague steering. Part of that is 245 width fronts. Make that 275 and it will feel like your steering a boat.

I am not willing to pay over a thousand for a set of tires. I ordered a set of Falken Azenis ST115 because of good reviews (http://www.carsound.com/review_archive/performance/Falken_AZENIS_ST115.html), tread life (UTQG: 360AA 30-40k miles), price ($792.35), and good rain performance.

I get them installed Thursday.

PHASTEDDIE:
Yes, I complained that my Cadillac had worn out its tires at 14000 and as a consequence I got a new set of GSD3s.
Perhaps some background is in order: I had rotated the original tires properly, and, for whatever its worth, I am not normally a complainer and I get some respect around my area because I've been around cars and technical stuff all my life and have some accumulated knowlege which makes it hard for me to be BSed. So, when I said to the dealer that my tires weren't giving me the tire life I expect, the folks at the dealership at least listened.
Who knows how the V owners on our site really drive; I suspect my tires get as much "punishment" as any, as I try to heat them before taking them to the limit, and I am careful about tire pressure, balance, rotation and alignment. Anyway, when I complained to my servicing dealer here in MD (I bought the car in MO for other reasons) the new tires were installed within the week after being ordered from Goodyear/Cadillac. I also got a four wheel alignment, because things were not right. The rear end was pretty far out and who knows how long it had been set up that way.
Good luck,
Rob Ketcham

My local tire store guy says that going up to a 275 x40 x18 Goodyear F1 GS EMT will fit and run great.

Wow, that is very enticing information!! I would be very interested in running the stock 245s up front and mounting 275s in the rear. As soon as anyone can confirm if this is accurate info, please post. I would however be concerned how the 275s would look on the stock width wheels. You think they would balloon-out a bit?

Wow, that is very enticing information!! I would be very interested in running the stock 245s up front and mounting 275s in the rear. As soon as anyone can confirm if this is accurate info, please post. I would however be concerned how the 275s would look on the stock width wheels. You think they would balloon-out a bit?


Why the staggered setup? Wouldn't that just lead to increased understeer at the limit? M3 guys do all they can to get rid of the stagger that comes from the factory.

Why the staggered setup? Wouldn't that just lead to increased understeer at the limit?

I don't think a 275 up front would do anything to help the CTS-V. Whether it would or wouldn't cause understeer is a debate which (unfortunately) I'm sure will follow. Originally I felt that a 245/275 combo would look hot. However after thinking about it a bit, without a wider wheel in the rear (staying with all 4 factory wheels), I may have to withdraw my statement.

Change out the wheels such as Shane has done, and yes I still believe the larger wheel/tire combo in the rear looks killer.

I would NOT want 275 width tires in front. One thing I still admire about the M5 is the amount of feedback and quick reflexes of the steering. If there is something I'm not fond of of the V it's somewhat vague steering. Part of that is 245 width fronts. Make that 275 and it will feel like your steering a boat.

very humbly disagreeing... Your M5 had feedback and quick reflexes mainly due to a great front suspension and steering setup (power steering boost, etc)... the V has a 'cadillac' steering setup...

The only impact on steering feedback/quickness that the tires have is sidewall height and stiffness/flex... too much height or flex and steering will feel 'delayed' and vague... but tire width is not going to have much of an impact on steering feel.
245/45 and 275/40 have the same sidewall height, so i'd argue steering feel will not change... or you could go to a 275/40 tire with a stiffer sidewall (i.e. PS2)... better yet run a 275 19" tire and steering will feel less vague. And this is all within limits... put 315s in front, and yes you will lose some steering accuracy. All MHO... (based on trying many different wheel/tire combo on multiple cars... 4 different wheel and tire setups on my Z06 alone, trying to find the ultimate handling combination)

I think 275's all the way around on 9.5" rims would be the perfect setup for this car... the handling would be even more amazing then it is now. (Too bad the fronts would stick way out in the breeze :()

Hey guys...just spoke with Gary at Tire Rack. I'm looking to spring for a set of the German Goodyear Eagle F1 GS-D3's in one size wider than stock...i.e., 255/45-18. 1/2" taller and 1/2" wider. I love the factory wheels so I'm looking to stay close to stock. I figured the additional 1/2" in height wouln't matter that much and would only tend to "fill up the wheelwell" a bit. (the slight change in rear gear ratio also wouln't matter that much...the "Maggie" come springtime will take care of that) The additional 1/2" in width would also be cool but Gary suggested I ask around to see if there were any clearance problems...he said things were pretty snug from the factory. I took a look and figure they'll work...but thought I'd ask around. Anyone running 255/45-18's???

I just don't think you improve your handling at all. You're widening your treadwidth but you're also adding sidewall which is going to add squirm. Why bother doing that and going away from the stock size?

Your argument with the Maggie would make much more sense if you were going with 255/40 18 tires. You'd have a wider width, with less sidewall squirm and the Maggie more than compensates the loss of top end.

but thought I'd ask around. Anyone running 255/45-18's???

WhiteLightning ran 255/45 and they rubbed a little front and rear... i have an email from him where he gave me details... i'll try to find it.

WL... you out there??