Tire Size Question. New at this. Help appreciated.
 

Hello. Please excuse my terminology as I am a molecular biologist and not an expert with this stuff.

Overview:
I bought a 02 C5 A6 Avant. Excellent vehicle. Tank like. Among Other things I'm learning about are the wheels.
I do not think it has the original wheels on it. I don't know what Audi they are from as everywhere I look, I can't find these 5 spoke sporty looking rims for that year Avant. Coupled with the lower profile tires, I am confused. It is time to upgrade as the car was purchased sitting on bad tires to begin with. There is now 6 inches of snow on the ground.And I'd like to get this resolved as economically and safely as possible.

Now:
I have attached images, (Rims/Wheels and Tire) in the hopes that an experienced Audi fanatics will slap me silly with help.
They are Audi branded. But the tires are lower profile (not fat) are 225/45zr/17 mounted to Audi Rims/Wheels. 2 are 45ZR and the other 2 are 45R.

Questions:
1: Which numbers can I increase to make the tires bigger on THESE rims/wheels? All but the 17? The bigger the number the fatter and wider the tire? (more rubber?)
2. If I elect to purchase let's say Wheels from a 2012 S4 (thinking about it) will they pop right on with those stock wheels and tires?
3. The bolt pattern for my C5 A6 is a probable 5x112? Do I need to know the bore? (Not sure what that even is)
4. IThe S4 Wheels I am looking at are 18" but the same numbers, 225/45zr/18 instead of 17. Would that work?

I am most concerned about spending the money on a private sale, getting them home, and having them not fit. So any help is appreciated.
TYHe first two images (with the Navy Blue Audi being shown are the vehicle with the tires inflated (current tires)
The second 2 are other audi wheels and tires I wish to just "pop on" but many times I cant find what make and model they are from.
Attached are images. Help is greatly appreciated.

Dr. GreenAnoos

Well, since my flex pipe question was answered so quickly with some really great answers, I must assume either I am a fool for not understanding if these wheels will fit my C5 A6, or that they just wont.

Does anyone know if the wheels pictured will pop right onto my C5 A6 Avant? Or where I might be able to find information about what other audi wheels will fit my car? Im almost positive the wheels pictured, (the blue car) that it came with were not the original audi wheels, the have lower profile tires, 225/45zr 17 inch wheels.

I also tried to edit the title, but i'm not sure how to include the fact that this is a 2002 Audi C5 A6 Avant Quattro. If someone knows how to add that information please do. Thanks gang.

Have you taken the wheel off? On the backside of wheel you should find a part number AND a number letter combo like ET33 or ET27. that ET number is the offset off the wheel. As far as tire sizes go, get on Tirerack.com and chat with a tech person, they will give you their recommendations. If you enter the string of numbers/letters for wheel into Google it should tell you model, year, etc for wheels original intended usage.

Doctor, I will attempt to answer some of your questions/concerns.

I always like to defer to the Owner's Manual for all the tire/wheel size combinations the Audi factory may have fitted. This information is detailed and typically at the rear of the book where the tire inflation pressures are. It will also show you the speed rating and the load rating for the tire.

I believe the center bore on the earlier cars, like yours, would be 57.1mm. The center bore for many Audis was increased to 66.6mm - I think this change occurred around 2010. Many wheels, whether old or new, will fit your car. If you found wheels from a much newer car, you may be able to use them if you got the adapter rings to convert from 57.1mm to 66.6mm. (Some people don't like this as a solution.)

Tire Rack, which is considered an excellent reference resource here in the USA, says:

Original tire/ would have been: 215/55/16
Larger sizes would be: 235/45/17 or 235/40/18 or 235/35/19

^^^ This is what they list for a 2002 Audi A6 Avant

Again, you could refer to the Owner's Manual and likely find similar information from Audi. The key piece I believe you are missing is the load rating and the speed classification for the tire itself. A tire fitted to an A4 is not going to have the same load rating/capacity as found on a bigger saloon/estate like an A6, Avant or A8. All of this comes down to safety and how well a tire will be able to handle poor roads along with other factors. So, the tire I would be seeking for your car would carry this information on the sidewall: 235/45R17 XL 97W The "XL" means extra load or reinforced for a heavier vehicle. "97" is the load capacity and "W" is the speed rating

There are also concerns about the wheel's offset, as Steve mentions, and that's a more complicated discussion. A trial fit at the seller's place of business is some assurance against having clearance problems and the tire making contact with susupension components. The design of the Audi suspension often places the tire very close to things that may interfere. This becomes a concern with the actual offset of the wheel. Again, you can go onto Tire Rack's website and sort through 16" and 17" to see what's a typical offset for your Avant. It will give you a good point of reference.

I don't know what country you are writing from, Doctor, so I don't know if you have wide access to all Audi models like we do in the USA. However, to find an appropriate tire/wheel combination, I would be looking at older A6 and A8 cars, not A4/S4 cars. Good luck.

Doctor, personally, I would just buy the correct tire 17" for the car and move on unless there is a known problem with the wheels (bend, etc.): 235/45R17 XL 97W

This is likely to be the most economical solution and give the car back its appopriate ratings for this 17" wheel. It is also likely to minimize further aggravation and worry for you.

I haven't taken the wheel off, but this information about the CodeCombo on the back of the wheel is very helpful to know. THank you so much. I will try this once the snow is gone. I think, and am almost positive these are not the original wheels or tires, because everywhere I search, the options for the tire and the wheel/rims don't show up.

Thank you so much for your detailed response. The owners manual doesn't even mention this particular (currently on the car) size wheel or tire. That's why I'm almost positive whoever had the car before put these wheels/tires from another Audi on it. I'll have to try the above mentioned and pop the tire off and look at the combo code on the rear of the wheel once the snow is gone. Thank you again for the extended information. When I logged onto TireRack, the options that are on the car didnt even show up. I tried different sizes too. Maybe that's why the car corners so well but is super stiff where I can feel the bumps in the back of my brain and eyes almost like mini concussions or flash KO's. lol. I'm from New York, currently in the Jersey area hastily writing this, covered in snow. The tires on there now are 225/45ZR/17 - from what I've been told these are lower profile performance tires, on 17 inch Audi wheels/rims. I'm a drugs engineer, I deal in molecules, so all this tire stuff is new and confusing to me, because I've decided I want to do it myself and learn. I'm not so much as interested in the appropriate combination, just a combination that will offer all season, good looks, and not be a pain in the ass and be expensive, like these low profiles are. They constantly end up with issues. And they are Goodyear Eagles. Although, to be fair, I don't know how old they are. I purchased the car for $3800 bucks and it's near mint except for the tires and the little LED display in the dash cluster.

I was also told that if I do get newer tires, say 18s or 19s from an ultrasport a4, like a 2010 or newer, I would need spacers to match the bolt pattern or something. Someone sent me a link titled: "Hub Centric Rings 66.6 / 66.56 Wheel Bore to 57.1 Car for Audi" So i think your numbers are correct. I think I would just have to get the wheels and tires, if I go newer and then buy those $10 spacers and then just pop them on? That's what it seems like to me but I could be wrong. I could also just get all season, fatter tires with the rims/wheels that are on there now. I've seen sets of 4 for around $240-280. Sound about right? Thanks again for your commitment to typing out any information. It is greatly appreciated as I ramble my way into rush hour traffic out the door. Thank you once more.

Thank you so much for your detailed response. The owners manual doesn't even mention this particular (currently on the car) size wheel or tire. That's why I'm almost positive whoever had the car before put these wheels/tires from another Audi on it. I'll have to try the above mentioned and pop the tire off and look at the combo code on the rear of the wheel once the snow is gone. Thank you again for the extended information. When I logged onto TireRack, the options that are on the car didnt even show up. I tried different sizes too. Maybe that's why the car corners so well but is super stiff where I can feel the bumps in the back of my brain and eyes almost like mini concussions or flash KO's. lol. I'm from New York, currently in the Jersey area hastily writing this, covered in snow. The tires on there now are 225/45ZR/17 - from what I've been told these are lower profile performance tires, on 17 inch Audi wheels/rims. I'm a drugs engineer, I deal in molecules, so all this tire stuff is new and confusing to me, because I've decided I want to do it myself and learn. I'm not so much as interested in the appropriate combination, just a combination that will offer all season, good looks, and not be a pain in the ass and be expensive, like these low profiles are. They constantly end up with issues. And they are Goodyear Eagles. Although, to be fair, I don't know how old they are. I purchased the car for $3800 bucks and it's near mint except for the tires and the little LED display in the dash cluster.

I was also told that if I do get newer tires, say 18s or 19s from an ultrasport a4, like a 2010 or newer, I would need spacers to match the bolt pattern or something. Someone sent me a link titled: "Hub Centric Rings 66.6 / 66.56 Wheel Bore to 57.1 Car for Audi" So i think your numbers are correct. I think I would just have to get the wheels and tires, if I go newer and then buy those $10 spacers and then just pop them on? That's what it seems like to me but I could be wrong. I could also just get all season, fatter tires with the rims/wheels that are on there now. I've seen sets of 4 for around $240-280. Sound about right? Thanks again for your commitment to typing out any information. It is greatly appreciated as I ramble my way into rush hour traffic out the door. Thank you once more.

The tires and wheels you have are from an Audi A4.