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I've bought a 2011 CTS-V and will pick it up in a day or two. It has good tires on it now, and Spring is upon us, so I have time. Or, a flat or road damage could bring a short-term decision on any of us, so we all need to understand what solutions are out there for us when the time comes.

According to TheTireRack.com, the OEM tire sizes for the CTS-V are 225/40R-19 for the front and 285/35R-19 for the rear. The OEM tires are Michelin Pilot Sport PS2 and they are very highly rated. My car has Hankook tires which are also highly rated. TheTireRack offers a good selection in this size pair: Bridgestone Potenza S-04 Pole Position, Continental ExtremeContact DW, Goodyear Eagle F1 Supercar and Asymmetric 2, Hankook Ventus V12 evo K110, Kumho Ecsta LE Sport, Michelin Pilot Sport PS2, Sumimoto HTR Z III, Toyo Proxes 1, Yokohama ADVAN Sport, BF Goodrich g-Force Sport COMP-2, Humho Ecsta SPT, and Perilli P Zero Corsa System. All are rated four stars or better out of five. All are max performance or ultra high performance summer tires except the Pirelli which is listed as a streetable racing tire, which means that they are not recommended for driving on snow or ice.

The only winter tire for this car that I can find on TheTireRack is the Pirelli Winter Carving Edge in the 225/40R-19 size. I'm not sure that the rim width on the rear is the same as the front but TheTireRack recommends this winter tire for both front

and rear, and it should work OK if not be optimal for high performance, which is not the point for a snow tire.

I don't see an all-season tire in these sizes on TheTireRack's web site.

My inclination is simply to take the wife's car when it snows and the streets aren't cleared, or when there is significant risk of being forced to drive on ice or snow. Then I can leave the high performance summer tires on all the time. That's practical here near Philly and in the southern half of the US, but marginal much farther north.

Perhaps those of us who have driven a V series through the winter can share their experiences and opinions with the rest of us.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Hi Jim, congrats on your new Baby! You didn't say if it is a Coupe or Sedan but Coups have 9" rims front and 10" rear, I believe Sedans are 9" F & R. As far as new rubber goes, I can't advise on snow tires (mine doesn't go out unless it's sunny!) but I did upgrade RedRocket's shoes from 255/40's front, 285/35's rear to 265/35's front, 305/30's rear - both with no clearance issues. I also went to Tire Rack (and D3) for advice and went with Pilot Super Sports as opposed to the OEM Pilot PS2's for better wet/dry grip and wear, Super Sports are the next-gen edition of PS2's. You can find out what will fit your car if you have a Sedan by calling D3 Caddy Tuners, they let me know my sizes above would fit with no issues and they were right. One word of caution, you must maintain the overall OEM tire height Front to Rear or you will get stabilatrac computer issues. My OEM tire height F to R had 1/10" difference. The new Super Sports have identical overall height F to R and have worked very well. I have an old post titled "RedRocket with new shoes" if you are interested what wider tires look like on a Coupe. Would like to see some shots of your new V when you get her, plz. post some. RedRocket out...

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Thanks, that's the kind of input we need to have. Mine is a sedan. I'll have photos in about a week. Watch "Jim's 2011 CTS-V" in the "Supporters' Cadillacs" section.

Your point about matching the rolling radius to keep Stabilitrak happy is very important for both safety and lap times. Thank you very much.

Your remark about going up one tire size, front and rear, is well taken. Your recommendation of Michelin Pilot Super Sports is the kind if thing I was expecting. How about comparison of bite/traction/performance for your new setup?

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Tire Rack's data about the Super Sports compared to the PS2's indicate considerable better wear and increased wet/dry grip. It is difficult for me to compare the two due to the larger size of the Super Sports v/s the OEM PS2's, but high speed cornering is, in my opinion, outstanding and predictable. I have an auto (reprogramed) in the RedRocket and if

you progressively lay into the fun pedal, she will readily spin either the PS2' or the two sizes up Super Sports well into 3'rd with all the traction nannys off (not the fastest way to go but LOOKS GOOD!). If you go with new rubber for your V, I would go with the Super Sports.

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We all go for new rubber every couple of years or so. This is good information.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Jim is your v an automatic? I would think it matters on tire choice. I have the Perilli p zero nero on our "11 mustang gt and they get no traction. I have Perilli oem runflats on the v and they work excellent. That p zero tire may be different than what you listed above, I'm not sure, but I would not recommend them for any performance application. Do the cts-v come with a spare and jack?

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Hi Jim, one last thought on the Perilli "race/street" tire (michelin has one also). A common characteristic most "race" tires with tread (meaning not slicks) have is that they are shaved so that the blocks of rubber that make up the tread pattern are not as tall. The shaved tread doesn't deform and move around during extreme cornering as much compared to street tires. Unless you intend to track your V quite a lot you will never notice the added traction that "race" tires will give you. What you will notice is how fast these shaved tires wear.

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I never asked whether the car was automatic or manual transmission and will simply take what is there when I get into it. Bruce drove it and would have said something if it was a manual transmission as he knows that a manual would be my first preference, but is not a deal-breaker because manual transmissions are rare on used late model CTS-V cars despite the manual transmission being the standard option. The Cars.com page on this car is down but the dealer's page on it is still up; I looked just now and the transmission isn't mentioned. Since this is a Porsche dealer they might not have thought a manual transmission worth mentioning in either the feature or option list.

My impression of track-intended, street-legal tires is much as REDROCKET says. I have heard that they offer no discernable advantage over ultra or max high performance street tires in legal public driving, motocross, or gymkhanas, they are dangerous in even light rain, and that they wear extremely poorly. I would expect that a car with such tires would travel on a trailer between events. This type of tire is best for people who intend to use the car in competition in which rules demand a street-legal configuration or that the car be driven to the track, but not for daily driver use like my car.

I was originally hoping for an ultra high performance all-season tire. That's what I have been using for over 20 years, first on a Pontiac Grand AM GT with Level II suspension and Quad 4 HO, then my 1997 ETC. I even have them on my wife's 1999 Grand AM GT for when I drive it, and for an extra safety margin for her. But if the CTS-V breaks loose even summer tires with part throttle in the first three gears, the tiny extra margin of traction with summer tires is worth it for safety, performance, and tire wear. Also, the CTS-V has a built-in cornering G meter that a spirited driver will tend to mentally calibrate for the tires and driving conditions, and will see the difference with summer tires. But a second set of winter tires (and possibly wheels) are necessary in the salt belt and in Canada. We won't be seeing many V-series in Cadillac Club Sweden, and for those that we do see, winter tires are going to be a major topic.

In my perusals around the WWW I have noticed that the CTS-V has nine-inch rims both front and rear. The difference in tire size is to add grip in the rear while not increasing unsprung weight in the front. This means a difference of 0.1 inch in ride height, which is calibrated into the Stabilitrak according to a previous post in this topic.

For the geeks among us, the nominal diameter of a tire is, from the wheel size, the aspect width, and the profile height,

Diameter, inches = Wheel diameter in inches + (((width in mm)/25.4 mm/in) X ((aspect ratio as percentage)/100) X 2)

The number of revolutions per mile is

Number of revolutions per mile = ((5280 ft/mi) X (12 in/ft))/(pi X (rolling diameter, inches))

From these formulas, the OEM tire sizes of the supercharged models of the CTS-V are

225/40R-19 => 26.1 in diameter, 773.1 revs/mi

285/35R-19 => 26.85 in diameter, 751 revs/mi

These are theoretical numbers and are based on published tire size numbers, which are close but not exact for every tire. They give about a 3/8 " higher rear axle for the OEM tire sizes.

You can tighten up these numbers by looking at the revolutions per mile in the specifications for a particular tire. You can use this formula to match rolling diameters of up-size tires. For example, I ran these numbers on REDROCKET's upgrades and I got diameters of 26.3" front, 26.2" rear - which are essentially equal and does NOT preserve the 3/8" increase in height of the rear over the front (3/4" in difference in diameter, rear larger, in OEM tire sizes). This may be enough to affect aerodynamic lift above, say, 125 mph so my advice is to watch it on the straightaways until you get a feel of things if you run it on the track with those tire sizes. Using the formula to investigate a better rolling radius for the rear tires, I found that going to 35 profile gives 27.4 inches diameter and 0.55 inches more height in the rear, which is perhaps a better match.

The load range is also important in tires. Small high-performance cars sometimes use tire sizes that are also used on larger cars, but with a lower load range. For example, the 225/60R-16 tires that are OEM on my Eldorado and an optional size on my wife's Grand AM GT (225/50R-16 is the OEM size), but the load range for the Eldorado is 98 (1653 lbs/tire) while the load range for the Grand AM is 92 (1389 lbs/tire). You can exceed the load range with weight transfer on acceleration. braking or cornering, but not at sustained very high speeds as this is part of the speed rating of the tire. A little margin is good, but too much is wasteful and may increase unsprung weight. The correct load range is one more reason to order tires by vehicle and not by size.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Hi Jim, FYI, I also went from a 1998 Eldo ETC to my RedRocket and you may find, as I did, that while I would drive the ETC in winter conditions, not so in the V (just me, mayby). Anywhoo, when I spoke of maintaining the overall front to rear tire height the same for stabilitrac computer issues, whatever tire height you chooze is OK (doesn't have to match OEM height) as long as the front to rear height stays equal. The only thing that changing to a different overall height will do is make your speedo inaccurate (no big deal, that can be reprogramed with a laptop as I had done). Stabilatrac reads front to rear rotation speeds (among other data) to determint wheelspin. If your front and rear wheels are traveling at different speeds due to overall height differences you likely will get a code problem with the computer. Bottom line: change to whatever tire height you like but keep F to R height equal (no more than 1/10" different). Also, when my RedRocket was stock it was quick and would readily spin the tires, but not much in 2'd and difinately not 3'rd. If you plan to leave yours stock (or mostly so) in my humble opinion, you won't do better than the aforementioned Mich Super Sports. I would contact the folks @ D3 to see what is the largest size that will fit (for 9" rims probably 285's in the rear) and size the fronts to an overall height to match the rear. I mention D3 because they have done all this before and do give good advice freely. As for Da RedRocket, I have done some bolt-ons to increase power (cold air intake kit and exhaust upgrades from KPE) but what REALLY made the difference is finding a tuner to reporgram the engine/trans. My advice is don't go with a "plug-in" chip type of generic reprograming, try to find a tuner that specializes in the LSA motor that will reprogram by driving the vehicle with a laptop ("Dr. Phil" took about 80 miles and an entire morning with the RedRocket), adding 40 to 45 HP (with all included now about 630hp) to the engine but most importantly reprogramming the trans shift characteristics. Keep the shifter in "regular" mode and the car shifts like stock. Place it in "sport" by moving lever to the manual mode but don't shift (allowing trans to auto shift but in sporty mode) and the shifts progressivly get snappier (up to neck snapping) then she starts burning the skins in 1 - 3 as mentioned. You can get rubber in 3'rd at just over half throtle, you don't need to mash the pedal. I found Dr. Phil thru a friend that I met at the Detroit Gran Prix, George AKA Torxila. He has a sedan V with significant mods in the mid 700hp range. For traction Geo. goes with a set of drag radials on the rear (something you and I don't need) which, he said, is the only way his car hooks up (and boy, does it!). I'm getting off topic here(sorry, bloviating too much), but to one more point you raised above - don't worry about unsprung weight when going to larger front tires. My advice: go as wide as the rims and wheelwells will allow, front and rear. The magnetic suspension will take care of the rest! If you have any more questions I will do my best to answer and can probably steer you to those that can when I can't (lots of folks on this blog can too)

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Red Rocket...

What software do you use on your laptop??

I use EFI Live on mine...

I tend to agree about the trans reprogramming.

My big ol' DTS is so much more responsive and much more FUN to drive after being reprogramed.

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Hi TJ, long time no blog to... As far as the laptop program, I have no Idea what Dr. Phil uses. It's good to know one's limitations, and mine is using computers on engines. Phil used to work for Lockheed and GM and has an extensive engineering and computer background. Now he is a full time tuner specializing in LSA's and Vettes. I do know he reporgramed the speedo to match the new rubber via GPS, too many varables such as tire squish (for lack of a better term) due to weight of vehicle on tires etc. to rely on advertized sizes. For $275 ( $300 and he will supply a dino sheet to document the increases, but that is rear wheel HP so I opted not to) he transformed the RedRocket, best $ I EVAH spent! Any more thoughts on a Motor City Road Trip for the Woodward Cruise? Would be a great time, just sayin... D.

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In 1998 the dealer "reprogrammed my PCM" after I asked repeatedly about a performance chip for my 1997 ETC. I don't know what they did but I think it was the spark advance vacuum/rpm map. At any rate, I could feel the engine hum in the steering wheel after that and it has noticeably better snap off the line than it did before. I've never timed mine or put a performance meter on it.

So, I can have my CTS-V PCM psychoanalyzed and its personality adjusted for $275? Is this service available anywhere near the Philly area?

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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In 1998 the dealer "reprogrammed my PCM" after I asked repeatedly about a performance chip for my 1997 ETC. I don't know what they did but I think it was the spark advance vacuum/rpm map. At any rate, I could feel the engine hum in the steering wheel after that and it has noticeably better snap off the line than it did before. I've never timed mine or put a performance meter on it.

So, I can have my CTS-V PCM psychoanalyzed and its personality adjusted for $275? Is this service available anywhere near the Philly area?

The guy that did mine is going to be in Bridgewater NJ the weekend of April 6th.

He travels all over the country tuning GM vehicles.

http://www.truckmodcentral.com/forums/f47/black-bear-performance-tune-bridgewater-nj-%96-april-6th-wknd-2013-a-26675/

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Whoooa, Nellie. This is going to be fun. I'll check with him when I get back.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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