ricke666

Hi,

I'll ask here if a certain wheel would fit an Audi A4 2002, with bolt pattern 5x12. The answer is not that important (of course it is in case they fit!) but I would really like to understand how to determine myself if a certain kit can fit or not.

In this example, I'd like to know also if the tires would be too large and rub in the fenders, and HOW DID YOU DETERMINE THIS

Car : Audi A4 2002 Quattro
Wheels : 18 X 8.5 offset +45 5x112 & 5x114.3
Tires FRONT : Pirelli PZero (for racing) 225/35/ZR18
Tires BACK : Pirelli ZPero (for racing) 255/35/ZR18

I took a weird example, I know, it's just to better understand.

Thanks for a quick 101

P.S. (yeah, I did my wiki homeworks before, but it'a s shame I don't get it quite well)

ricke666

Just a quick crash course could do the trick.

I'm a learner, fill my lack of knowledge please

Stevelev

Define fit ! Some do not like having the wheels pushed out to sit flush with the fenders (not sure why??!?) so I'll assume rubbing is a sign of poor fit. Common causes of rubbing are wider wheels, wider tires, agressive wheel offsets and low ride height. I assume you have seen what the difference between lower and higher offset wheels look - here's a couple of pics with 8 mm spacers on the front and 15 mm spacers on the rear of my B6.




Obviously, wheel dimensions (incl tires) is important but so is ride height - a higher OEM ride height (ie: not aftermarket suspension) provides more leeway to what will "fit". Something else to make life difficult is that not all tires measure the same width even though their specs are the same: When I swapped out my worn Toyos (235/40/18's), I experienced some rubbing with the replacement Good Year F1's (also 235/40/18's) - Toyos are known to run narrow, GY is known to run wide and due to being lowered, I was close to rubbing to begin with (see above pics).

A wider wheel will take up more space inside a wheel well (both in towards suspension and steering components as well as out towards the fender). A wheel with a lower offset (or with spacers) will be "pushed out" and closer to flush with the fenders compared to the same size wheel with a higher offset. Where you get into some fun is when trying to fit wider wheels/ tires to what was there before. Here's a great site to assist you with what I'll say next: Wheel and tire comparer

Knowing what doesnt fit is a good start ... in other words, if you know the limitations based on others having issues with rubbing helps considerably ! Let me use my TTS as an example: OEM wheels are 19 x 9 et 52 with 255/35/19 tires and I've seen pics of the same car with 10 mm spacers which pushes the wheels out effectively making them ET 42 (52-10) and flush with the fenders. When looking at aftermarket wheels, I know I dont want a wheel thats more agressive than 42 UNLESS I were to consider a narrower wheel and/ or tire compared to OEM and likely would have to go with something less agressive IF i lowered my car.


I assume you'll be fine with your weird example if you're at OEM ride height although the wide rear tires could rub if you've got fatties in the rear seats.

Hope this helps. Cheers !

ricke666

Wow, that's detailed answer. But I still have questions. Can you just rephrase what you just said with the specs of the wheel I mentionned earlier?

You can apply it to your car for the example !

Thanks,
Eric

Stevelev

Did you try using your data to pump into the website I provided ... Do you know your OEM wheel and tire specs ? Assuming they are similar to what I had on my B6 USP: 18 x 8 ET 42 with 235/40/18 tires.

New fronts are 1/2 inch wider (1/4 more on either side of centre = 6 mm each way) with 10 mm narrower tire (5 mm each way). Close enough to say "no change"

New rears are 6 mm more each way with add'l 20 mm more tire width (10 mm on either side of centre) making the rears more agressive by 16 mm. At OEM height its unlikely you'll rub as I rubbed ocassionally but was running close to 25" fender to ground compared to OEM which is more than 26.5"

School's out !