I changed my tires on my cayenne , the old ones are 275 40 20 , and I had new ones installed 275 45 20 since roads her in jordan are bad... They fit perfectly , at the dealer they told me its not good for the car and some other BS , ..
Need ur opinion guys ...

 

I did the same: I have 245/60/18 on OEM 'turbo' wheels on my 2005. Almost 10,000 miles and no problems.

 

I have 275/45/20 on mine as well. Looks a bit fuller than the 40 series. Been to the dealership no issues.

 

so great in the snow!

 

Hi Guys

I have had a Cayenne 2006 V6, for about 8 months and had no problems apart from having to put some coolant once. I now would like to take the car for a servicing, can anyone tell me what exactly needs to be checked to keep it in a good condition? I live in a very hot country (Saudi Desert).

 

Is there a reason you asked this in the middle of a thread on tires?

You can start a NEW thread to ask your question, which would probably be a good idea since very few people are inclined to reply to random off-topic questions in the middle of someone elses thread.

 

The 40 series tire is about 28.7 inches in diameter while the 45 series tire is about 29.8 inches in diameter. I would definately not recommend changing tire diameters by over an inch as it will adversely affect a number of things like, speedometer reading, acceleration, handling, possibly the traction/stability control or ABS functions. Unsprung weight is probably increased too but I don't know the specs on your old and new tires. An increase in unsprung weight is bad too for a lot of reasons. A slight deviation in diameter is ok but over an inch is too much in my opinion. If you want more sidewall then I would suggest moving to an 18 or 19 inch wheel.

 

I went from an 18 to a 20" tire. When calculated there was a 1/3" difference between the two. Sorry should have mentioned that earlier. BTW if you reserach specific tires you will find that they dont measure EXACTLY what it says on the sidewall. I also own a 2008 Jeep Wrangler 4 door and there could be up to an inch difference between two brands of the same "size" tire. The wider tire fills in the well wheel better

 

Yes, I've owned 2 JK wranglers over the past few years, one with a 2 inch spacer lift and one with a 3 inch full suspension lift and larger "flotation" tires. The flotation tires do vary a bit in true size from one brand to the next (i.e. a 33 12.50 17 from one company can be a bit different than a 33 12.50 17 from another) but I've not seen that much variation in true diameter from performance metric size tires like a 275 40 20. The TireRack as well as each manufacturer's own websits have great detailed info on their published measurements including the weight of each tire. I would recommend creating a spreadsheet for the tires you're considering and puting the width, diameter, weight, etc. all side by side for easy comparison. I did that and was able to fit 285 40 18 tires on the rear of my 69 Mach 1 without rolling the fenders or doing any modifications but I did a lot of careful measuring and had wheels made with custom backspacing for it. The JK wrangler does have some "advanced" computer modules for ESP etc, but its suspension design is rudimentary compared to what is under the Cayenne allowing the JK to accommodate lots of different tire diameters (some even suggest the JK was designed in anticipation of customers changing wheels and tire sizes) and its just my personal opinion but I wouldn't stray too far from the original tire sizes recommended by Porsche for the Cayenne (they offer them for 18 through 21 inch wheels). Again, just my opinion on the items that may (or may not) be impacted by a change of over 1 inch but thats whats great about our country, each of us can choose our own path. So, with the Cayenne, to me its more than just will the tire fit without rubbing and fill the wheel well. Hope that helps.

 

Running identical size for over a year now - no issues, no regrets.