For Those Who Wish To Be Knowledgeable When It Comes To Being Different With Wheels

[mr shickadance]

THIS IS LONG…..BUT IT WILL ANSWER YOUR QUESTIONS AND WILL BE A BETTER PERSON AFTER READING IT
Introduction/ Preface


There seems to be a lot of misinformation about wheels and how to go about wondering if a particular wheel will fit and what needs to be done to make a wheel fit with as little running issues as possible. This guide is here to help complete newbs gain some knowledge on the this topic and not ask the same question over and over. I will do my best to cover all topics regarding wheels and try and answer as many common questions as possible through this guide. That being said, this is not a comprehensive guide or an end all, be all guide for wheels as some fitments may be so aggressive that they lose these concepts altogether. What this is meant for is the average person wondering if their wheel will fit given a certain amount of specifications.


Our wheel bolt pattern is 5x112

Before continuing on I should note that you need to ask yourself one question before you go wheel shopping.

- Am I lowered?

if your answer is no, then stop looking at wheels right now,

save up for a decent suspension (springs are fine and look at the newbie sticky for spring/coilover information and how much drop to expect with different spring/coilover set ups are out there). When members offer advice to lower your car before going to a new wheel is not because it is the proper thing to do (even tho it is). We say this because a 19 inch wheel on a stock suspension creates an illusion of a big amount of wheel gap….you will NOT like the wheel you like on your car because of this and it looks about a silly as 20’s on a minivan…. So please I know wheels are very tempting, but get a drop before you go wheel shopping….who knows you may even like the wheels you have after a drop.



PART 1

Offset (commonly referred to as ET)

Offset is very tough to explain without reference to this picture, offset is measure in millimeters and what I feel is most misinformed and if you don’t know what it is, its hard to search for wheels. Offset is essentially the distance measured from the centerline of the wheel, less the measurement of the back space. Back space is the measurement from the inside wheel rim, to the inside of where the wheel bolts into. Centerline is measured from the inside of the rim of the wheel to the center of the wheel. Confused? Yea, you should be glance at the image for a little while and try to make sense of it. Still confused? That’s ok. Just understand that the lower the positive offset, the further the wheel will stick out.
Here’s a good example, if you are on stock wheels right now your offset is a positive 45mm. if you were to add a 10 mm spacer (covered in the topic below) your offset would be 35mm and your wheel would now stick out further away from the car by 10mm. you do not have to totally understand the concept of offset but just understand that while you can reduce offset by adding a spacer, you cannot add offset by adding a unspacer….because they don’t exist….and that’s impossible….and dumb….
On a note about our b7 cars, a 30-35 offset will sit pretty flush again the fender andis considered an optimal offset, so if your looking at a wheel that has an offset of 50 try and figure out what size spacer you would need to make this work with the fender.

….got it yet?

…correct you would need a 15-20mm spacer to get your offset down to 30-35 and start looking good. Since we are talking about spacers its prolly a good idea to find out what they are, what they do and what’s needed to rock certain spacers
You can even go beyond the 35-30 threshold if you wanted to, the rim of your wheel will now poke outside of your fender….this is commonly referred to as poke. Poking your wheels out may require extra work to not have your wheels rub or cause damage inside the fender. This will be covered later on but for now we must make baby steps young grasshopper

Spacers

Wheel spacers are used on our cars to push the wheel further out of the wheel well in our car. People use spacers for many reasons but the reason why most people use spacers is to make the rim of the wheel as close to being flush with an imaginary line drawn from the fender to the ground. This makes the car look very nice. In some cases people use spacers to push their wheel even farther past this, it is commonly referred to as an aggressive set up and most people think this looks great.
Subcategory - Wheel adapter
Say you are really in love with a wheel and its in the classifieds for dirt cheap and you wanna jump on it? Perfect right….well come to find out the bolt pattern is 5x130 and you hopes and dreams are shattered right? Wrong...well maybe… in addition certain spacers can change the bolt pattern on our cars and let you run different bolt patterns; the caveat is that these adapters are very large and the smallest one I can think of offhand is one made by h&r which is 15 mm and switches to 5X130. Check out their site for more information but to get the general idea understand that different bolt patterns can be done, but a big spacer is require. So an ideal wheel would be something like a 5x130 bolt pattern with an et of 50, something nice and big to play with, something that just won’t work or be very difficult to work with would be something like 5x130 and et of 5. Understand? Good, almost done with spacers DON’T GIVE UP!! Your almost on your way to being knowledgeable with wheels!!! Mom and dad would be so proud….
Spacers effect the offset of a wheel by subtracting the offset, as explained above. Now understand that when you add spacers you are increasing the distance that your lug bolts must screw into. Your lug bolts will not magically grow threads as you add distance (spacers) to your hub. In certain cases you must buy new bolts that have longer threads to get to work properly. Ok so your sitting there and thinking, ok I understand offset (somewhat) and I get that bigger spacers need longer lug bolts…..but now I wonder how much longer do my lug bolts need to be? Well my friend, I have taken care of that in the lug bolt section below. But first, read up a bit on lug bolts….

Lug Bolts

our cars are unique with other cars that feature lug bolts in that we do not have threads poking outside the rotor when we removed our wheels; this is a blessing and a curse. The blessing comes in the fact that we can utilize spacers and longer bolts to achieve different offsets (I will cover offset later on) and make different wheels fit on our cars. The curse comes in the fact that putting wheels on our car sometimes can be a PITA Lug bolts come with two different fittings

Conical – which are cone shaped

Ball seat – which have like a ball-like appearence before the threads

(there are other types of lug bolts but these are the two most common
which lug bolts you need may vary depending on wheel manufacturer, this is where a simple phone call to the store that sells the wheels can tell you if you need conical, ball-seat or a different type of lug bolt


Remember in the spacers section I mentioned about longer threads being needed for spacers. Well according to the fine people at Black Forest Industries they say that:
5x112 VW/Audi cars use 14mm diameter lugs

Here are some general recommendations for bolt lengths. Ultimately you are the one responsible for safely installing lugs and wheels on your vehicle. 3mm and 5mm spacers can use stock length bolts

10mm spacers for the front wheels (STOCK WHEELS ONLY) can require 32mm long bolts

16mm spacers for the rear wheels can require 42mm long bolts

20mm and 25mm spacers for the rear wheels can require 50mm long bolts, however in some instances with 20mm spacers the 50mm will be too long and bottom out.
Please note that these measurements are for stock OEM wheels and your wheels may be thicker in the bolt pattern and require longer lug bolts accordingly. Use discretion and remember that stock length bolts are 27 mm

now, that was according to black forest industries, a general rule of thumb is that you want to be able to make 6-8 complete rotations with your lug bolts into the hub to have a safe set up, it is recommended to torque the bolts down to 85-95ft pounds

So I think that covers it up so far with lugs but now a short quiz…..ok so I just landed some sweet 19 inch bbs lm’s that are 5x112 bolt pattern and an offset of 50….what do I need to rock these wheel and make them work?

If your answer was conical lug bolts with a length of 42mm and a 15mm spacer I’d say your wrong….you didn’t say get a drop first so there….already forgetting step 1…what a nooby…..but close….you’ll get it….moving on

Hub Centric rings and if you need them or not

So if you have ever taken your wheel off you will notice that on the hub, you see a little ring poking out….this is there to help make your wheel get on easier and work wheel…..understand that the ‘bore’ of the ring is 57.1 mm. now take a look at your wheel you just took off, notice on the inside there is an impression of that ring in the wheel, that’s why when you unbolt all your lugs that the wheel simply does not just drop off and crush your big toe. This is important to understand because some aftermarket wheels have nothing there, and therefore a relatively cheap plastic, hub centric ring will need to be purchased so the wheel is not only held on by just the lug bolts. this information will be clearly presented when purchasing a wheel from a shop or online store like tire rack. If it is not clearly listed, call up the people at the store and ask them about it, they will gladly point you in the right direction.
Furthermore, sometimes your looking at wheels and you notice everything is inline in terms of offset, bolt pattern, and ideal width, except the bore is off….well they make adapters for that too and they are just as cheap as hubcentric rings and can be purchased online by googling something similar to this “66.6mm to 57.1 hub centric ring” and it will take you to places that sell adapters….again this to get you up to speed to know what you need to make the wheels you want work.
Steel vs plastic? It doesn’t matter as long as you are not racing so understand that shelling out an extra 10 dollars for steel rings is not that necessary
Now that you have enough information to get your wheels on to your car I think I should spend a few moments on wheels themselves….this is the reason your reading this right??

PART 2

Wheels

Wheels come in all shapes, sizes, designs, colors and widths and which one you want for your car is completely 100% up to you, in the end you should be happy with your wheels and if someone doesn’t like them well they can go fall off a cliff so long as your happy.
Just understand that adding width to your wheel may make you work a little bit to get the wheel to work with your car.
Consider a wheel that carries an offset of 45 and a width of 9.5, should fit no problems right? Well not exactly, when you go to bolt it up you may notice that the inside of the wheel, rubs against the inside of the fender….not good. So if only there was a way to somehow push the wheel further from the inside of the fender to make this work…..if only there was some solution I could rock 9.5’s and look good….ok enough stupid comments a spacer would solve this issue.
How big of a spacer needed to make it work is where a little finesse and research comes into play. A 20 mm spacer would surely create enough spacer between the inner fender….but it may hit the outer fender which is also a problem. No doubt that if your thinking of running a width in between 8-9.5 it has been run before by many people on b7’s….so do a little research and maybe send a PM or look in a signature of another member to see what offset they have…and do your best to mimic it. Example, if someone is running a 9.5 width with an et of 30 then you would try and find a 15 mm spacer to make your wheel work.
There are other factors to consider with this and I promise I will cover them but one thing at a time makes for the most sense
Brake caliper clearance
The last thing to consider with wheels is if your wheel will clear your brake caliper. Our b7 cars feature a larger then average brake caliper and therefore some wheels will not clear it. Are you totally screwed? Not exactly….the addition of a wheel spacer is the easiest way to distance the wheel spokes from the brake calipers (there are other ways to due this like shaving your caliper down but I think that’s a little dangerous personally). Sometimes as little as a 5mm spacer is needed to clear the calipers and other times a larger one is needed. The only way to find out before you buy the wheel is to call the wheel store, or talk to a member who has the same wheels to see if they ran into problems
So you got wheel width down and your running an offset that allows for no rubbing on the inside now lets talk about what happens when you hit a bump




PART 3 (Tires, Stretching, Camber, Fender Rolling/Pulling, and other Misc problems)


Through the course of driving normally you are going to encounter dips in the road, this is unavoidable and that’s why we have a suspension. The higher your car is, the less you need to worry about this section. This is why ideally a coil over suspension is the best choice because you can raise and lower your car to make it work in addition to adding spacers before you have to go ahead and roll your fenders. I say best option because it is the cheapest option to adjust your height without going with air management.
Your coil over choice should be your own problem and will not be discussed in this thread.
So let’s say you are lower than the average stock height and you hit a bump, your wheel and tire will rise up into the wheel well and hopefully there is enough space so the tire/wheel does not hit anything. Again the higher your car, the less you need to worry about this, the lower your are the higher the wheel is going to travel in the wheel well. Understand what I'm getting at?...cool
So how can I go low, run a wide tire and not worry so much about rubbing?
This is really where the guide gets a bit confusing so lets try to understand things before putting them all together

TIRES

Tires come in 5 measurements, lets break down each one assumed a 235/35/19 90-Z tire is being talked about...



235 – is simply a measurement of width in millimeters and is the width of the a tire (the part that has the tread)

35 – is a percentage of the 235 number, and represents the sidewall of the tire (example, 35 % of 235 is 82.25mm and that is the length of the sidewall) this is a proportional number and its very important that you understand the difference that a side wall number is a percentage, and a width number is a direct measurement

`19 – represents the rim size the tire is made for and is measured in inches, (this tire would be used on a 19 inch rim)

90 – is the load rating, not talked about as much as the above 3 are but still important, the load rating measures how much weight each tire can hold. Proper load rating can be determined by a phone call to tire rack…again this is to get the user familiar with what is involved….im not going to spoon feed this you must do some work

Z – is the speed rating. This is measured by a consonant and not a number, each letter dictates the speed that which is safe to drive the tire up to….this should be painfully obvious that if a car is rated to over 160mph that you drive that fast….it just means that the tire will safely run at those speeds and not break down and fall apart

Stretch

(member: geoffafa...notice the stretch)


Now you understand the basics of a tire measurement lets apply this to a wheel. Because I love bbs lm’s so much lets decide to use that wheel as a reference point. Assume the wheel is 9.5x19, and the tire we want to mount is a 235/35/19
You quickly remember from grade school that 9.5 inches converts into 241.3mm and so now your thinking ….well that can’t happen, the width of the wheel and the width of the tire don’t match up this cant happen. Well it can, and when its done you will notice the tire seems to be STRETCHED on the wheel. What happens is that the sidewall of the tire is pulled to the farthest point on the width of the wheel.

^^regular tire^^


^^stretched tire^^

Pause for a minute and notice that a tire that is not stretched on a wheel, and is fit will bulge out, meaning the widest point of your wheel/tire combo will be somewhere in the middle of your sidewall on your tire.
On a wheel/tire set up that has been stretched, understand that the widest part of the wheel will typically be rim of the wheel and not the sidewall.
This is a huge advantage when having a lowered car as the widest part of the tire, is now lower on the tire, thus when you roll over a bump you are less likely to hit your wheel on the fender or rub on the inside of the walls. This is not to say that a stretched tire will not rub at all, this is only said it will reduce the likeliness of a rubbing issue.
A disadvantage to a stretched tire is you are sacrificing potential wheel width, and ride quality. Because you are stretching a tire it means you are not using the widest tire you could go with. Ride quality will also suffer, as a smaller sidewall will make bumps and dips more noticeable in the drive
For this you are sacrificing a certain amount of ride quality to achieve the look you desire. Again this is just for information so what you choose to do is completely up to you.

Camber

Camber is the angle in which your tires rest, meaning if you were to take off your wheel and roll it on the ground you would notice that it makes a perpendicular angle with the ground, a 90 degree angle. Camber involves tilting the wheel on its side, positive camber would be having the wheel tilted away from your car. Negative camber would have the wheel tilted towards the car. Negative camber is primarily what we are dealing with and on our stock cars, you can adjust the rear camber up to -2 degree and the front wheel cannot be adjusted for camber stock. Aftermarket parts are available for the front and they run a little over 500 dollar for upper adjustable control arms that let you dial in a negative camber in the front.
By angling the wheels or tilting them in towards the car you are helping more the tire hit the ground. You will notice that without camber, if you are very low to the ground that the insides of your tires will wear out faster then the outside. Adjusting camber will even out the tire wear and should be considered when trying to go as low as 24.5 inches fender to ground.
In addition the negative camber will help against rubbing by having the wheel tilted and during a bump in the road the wheel/tire will be angled and therefore clear the outside fender easier this way

Fender Rolling/Pulling

Go outside and feel the inside of your fender, you will notice about a half inch very thin piece of metal running the length of your entire fender (your plastic fender liner may be in the way). This part of the car can be folded against the fender and create more space for the wheel/tire to move during a bump. This is known as rolling the fender. The term is derived because you typically use a fender roller that bolts onto your hub and presses against this strip of metal with enough force to bend it. This is a slow process and should you decide to do it yourself know that time is your friend and you better have plenty of it in order to do this right, rolling too fast cant result in paint cracking and that can ruin your day real fast.
There are numerous diy’s out there on fender rolling so I won’t get into that, but fender pulling the exactly same idea, it just involves not stopping once the fenders are rolled, instead you continue to ‘pull’ the fender creating even more space to run a more aggressive tire or tuck a tire
Earlier on I mentioned how if you carry an offset that’s greater then the fender your wheel will ‘poke’ out of the fender. Tucking is the reverse term and it involves tucking the wheel into the fender. some people thinking tucking is good, others bad again this is only an informative thread and im not going to take any sides here

^^ Wheel Tuck ^^



Misc Problems

Even with all this information and doing the right things sometimes you just simply cannot get a wheel to work and it may be wise to look in a different direction to get it to work out. Also consider the approach to wheels similar to the approach you would take to skiing or snowboarding. Start with a bunny hill and move on to more aggressive trails/wheels/stances.
In some cases the more aggressive your setup, the more things you will have to give up to get it there. This is the idea that form> function and it may be worth it to you to sacrifice ride quality to achieve the look/stance you are going for. Also the more aggressive your set up is, the more careful of the road you will need to be, a pothole can easily ruin a 3,000 dollar rim not to mention blow out a 200 tire. A beefier tire set up and less aggressive method may be able to cruise over that pothole. The point is, be more careful when you have an aggressive setup.
Back to the ski analogy, using a replica wheel set up with a moderate width and an et that pretty tame and a tire that’s pretty meaty would be atkin to going down a green circle, while running a 18x10 3 piece wheels set up with a FTG (fender to ground) of 24, and a stretched tires and cambered wheel would be something like a black diamond where you would need to be more careful of the road and understand that your giving up some turning radius and whatnot.
All in all it comes down to what you really want your car to look like at the end of the day. If something very aggressive is what your after then go for it but understand you may need to be more careful about driving.






Another useful thing would be if people posted up their set ups with the following information
Wheel size (PLEASE POST ONLY YOUR B7 A4 AND PLEASE INCLUDE THE FOLLOWING)

Offset
Spacers (if needed)
Tire size
Fender to ground
A few words on issues (rubbing, rolling, adjustable control arms, camber setting)

[NERO Quattro]

Great write up, this should be added to Quattro's B7 guide...

[Leo14]

Holyyy sh*t what a write up, good job man

[mr shickadance]

Great write up, this should be added to Quattro's B7 guide...

i would agree with you with only one exception....i wanted this to be more then informative which is why im trying to encourage owners of b7's to post pictures of thier cars along with information regarding thier set up so if we adding this to the b7 guide, i dont think we would be able to do that ya know?

[Phillyb7s4]

X2 on the great write up.

[tankdeer]

Nice job, but I don't think this is chatterbox material. It's you know, relevant. I'd petition to move this to the main B7 section as a sticky

[jimrobbington]

Great job Shicky, and I'll go first, since I have THE MOST COMMON SETUP AVAILABLE for the B7.
19 x 8.5 et35
Tires: 245 35
G to F: 24.5"

Imo, tires are too wide, and I have quite a but of rubbing. I will go with 235s next time.

[ryanworth]

Pretty spot on write-up dude! You should talk to Anthony about getting this sticky'd, as this is a common question in the B7 section.

Here's my setup, best shot that shows the stance.



Front:
19x8.5 et32 (5mm spacer)
225/35/19

Rear:
19x9.5 et 29 (No spacer)
235/35/19

FTG: 24"

No issues on rubbing, and decent stretch. Handles just the same

[mr shickadance]

Nice job, but I don't think this is chatterbox material. It's you know, relevant. I'd petition to move this to the main B7 section as a sticky

Pm'd stokes about it and waiting for a respone i posted it in the chatterbox bc it does not strictly deal with b7s

Id be happy to see it stickyd in either one i just dont want to see it lost in thread purgatory

[davis449]

Awesome write up...too bad target audience will never read it. Newbs are incapable of searching or reading sticky'd threads as proved true by the recent car audio thread in the main B7 section.

[pw211]

The most important thing about posting pictures of your setups is to get pictures at an angle, close up to the fender.

[Checho]

i was a little skeptical when you were telling us about your idea, now that I see it complete, damn good job man.

[VWAUDINUT]

Pm'd stokes about it and waiting for a respone i posted it in the chatterbox bc it does not strictly deal with b7s

Id be happy to see it stickyd in either one i just dont want to see it lost in thread purgatory

This should definetely be stickied. Anyone serious about doing anything agressive needs to understand these issues/technicalities.

I agree anyone who puts a more agressive wheel on than stock and does not lower should be shot.

I will be testing a 18x9 et 36 wheel on my b7 with 235 40 tires once my ST Coils arrive, i'll post my results.

[ryanworth]

The most important thing about posting pictures of your setups is to get pictures at an angle, close up to the fender.

True, we also don't need to load it up with pictures of what it looks like in fine detail. A quick profile suits this better as it's both stance and ride height.


Sent from my iPhone using Tapatalk

[mr shickadance]

i was a little skeptical when you were telling us about your idea, now that I see it complete, damn good job man.

thanks!...post up your ride?

[Checho]

ok, 18x10+11 All the way around on 225/35/18's.
Air Ride and Camber is at 3 degrees when riding height, obviously there is more camber as you air out. FENDER WORK REQUIRED to get these wheel sizes to fit.

[pw211]

True, we also don't need to load it up with pictures of what it looks like in fine detail. A quick profile suits this better as it's both stance and ride height.


Sent from my iPhone using Tapatalk

not to argue, but I think the opposite. Honestly its about a close up of the setup with respect to the fender. Profile does little for wheel setups.

[ryanworth]

not to argue, but I think the opposite. Honestly its about a close up of the setup with respect to the fender. Profile does little for wheel setups.

After seeing Sergio's post, I see what you mean. Haha. Wasn't trying to pick a fight either. Love you hunny bun. =P

[pw211]

After seeing Sergio's post, I see what you mean. Haha. Wasn't trying to pick a fight either. Love you hunny bun. =P

<3

I know you weren't dude, I just wanted to clarify cause this could be a super helpful thread for b7 guys who want to know how certain offsets/widths will sit.

[Mc Suly]

Very well done!

[Capt. Obvious]

Fantastic write up! Now if only the noobs would read it...

Since the topic of this thread is wheels and fitment, I'm going to post this here since a common problem with retro/old/custom built wheels is that no one knows what the offsets are. Well, now you can know:

[JEmm]

I posted this in the ftwltbdwictw thread but if you're looking at wheels/tires and have sizing questions, these are great resources that you could use by yourself before even looking on here...

www.tyrestretch.com - pretty self explanatory, can see how different sized tires fit on different sized wheels. Gives height, width, tire width, profile and usually even what tires they are
http://www.1010tires.com/WheelOffsetCalculator.asp - input wheel width and offset currently and what you want to buy, tells you the difference in clearance you will have inside and out
http://www.1010tires.com/tiresizecalculator.asp - put in different sized tires and gives you the difference in rolling diameter and other essential info

[mr shickadance]

I appreciate the positive feedback on this and i really like the extra links.....i just want more people posting up thier cars only bc this could be very effective if we have the guide, as well as pictures of people's stance's and how they got them there

[naiku]

Awesome write up...too bad target audience will never read it. Newbs are incapable of searching or reading sticky'd threads as proved true by the recent car audio thread in the main B7 section.

Sad but true.

I broke rule 1 of this sticky, got new wheels before lowered. In my defense though I needed new tires, and found the wheels I wanted with new tires on them for about the same as I would have paid for tires only. Coils are on the shopping list though.

[co_pa]

....i just want more people posting up thier cars only bc this could be very effective if we have the guide, as well as pictures of people's stance's and how they got them there

seriously, great write-up, man. subscribed.

i'll post up when the g*ddamn winter weather breaks and i can dial in my coils.

[bengtc]

Nice write up, I suggest adding this link for a tire size difference calculator: http://www.miata.net/garage/tirecalc.html to the first post.


18x8.5 +35 wheel size
235/40/18 tire size
eibach springs

[Checho]

just a word of advice, that 8.5+35 is THE MOST COMMON fitment for B7's. It would probably be much more helpful if you posted a shot of the fitment (from the rear/front showcasing the poke/tuck in regards to the fitment of the wheel set up)

side shots don't really do much.

[Vorsprung]

just a word of advice, that 8.5+35 is THE MOST COMMON fitment for B7's. It would probably be much more helpful if you posted a shot of the fitment (from the rear/front showcasing the poke/tuck in regards to the fitment of the wheel set up)

side shots don't really do much.

I agree. Don't remember what my FTG height was but this was fairly low imo.
And as you can see quite a bit of room to push them out farther.

19x8.5 +35 235/35/19

[mr shickadance]

SUPPLEMENT TO THE WRITE UP

Staggered Setups on Quattro

ok, lets talk about one more thing, a frequently asked question that some people have is "Can i run a staggered set up even tho i have AWD" the short answer is yes, but there's more to it then that.



recall from talking about tires that while some numbers on a tire are direct measurements, others are percentages. also consider that running a wheel that has a width of 8.5 in the front and 9.5 in the back will require different tires to make them fit.




lets use an example of running a staggered set up with these measurements, 19x8.5 in the front, and 19x9.5 in the back.




so now you have a wheel set up that is staggered and lets talk about what goes into making this happen



- rolling diameter,
- tolerance of quattro,
- percentage difference in rolling diameter



Lets discuss rolling diameter first since it needs to be understood before anything else. rolling diameter is defined as the FINAL measurement, of a wheel and a tire from top to bottom assuming the tire is mounted on the wheel.....got it? here's an easier way to explaining it, take a measuring tape, measure from the top of your tire, to the bottom of your tire ....bingo, that is your rolling diameter (only please reference this as an easy way to explain it and it is NOT the proper way to measure rolling diameter bc other factors such as human error, tread wear, and the weight of your car on the tire makes the bottom smaller then the top)



there is an online tool that can help you find rolling diameter on any tire and i will explain that at the bottom but for now, understand that rolling diameter is a direct measurement with the wheel and tire mounted on (example: a 235/35/19 tire has a rolling diameter of 25.5 inches)



now lets talk about tolerance of quattro
consider that a wheel that has a diameter of 6 inches, and a wheel that has a diameter of 12 inches (for example purposes only) when you roll the 6 inch wheel about 15 feet.... it would make 25 revolutions (i made that number up). now roll the 12 inch wheel the same 15 foot length....it will complete 15 revolutions (again made up number, i dont have all day to sit around rolling wheels for you people) but understand that it takes more revolutions to go the same distance for the smaller wheel



now when you have an awd system, power goes to all 4 wheels, so imagine if we had a 6 inch diameter wheels up front, and 12 inch diameter wheels in the back on an awd system. the backs would complete revolutions at a much smaller rate then the front wheels right?



this creates massive strain on the awd system and can blow your differentials to pieces and make you look like an idiot on the side of the road.....so now your thinking ok, well based on what you said its impossible to run a staggered set up for this reason.....read on grasshopper.....read on...



engineers understood that its impossible to get perfect rolling diameters on all 4 tires, so they made the quattro system with certain amount of tolerance before they put it into production. they limit the tolerance to 3-4% of difference between rolling diameters....the closer to 0 you can get, they better it is for the system, but at around 3-4% is the limit at which the quattro system cannot keep up and damage starts to happen too your differentials.


well that's great and dandy and all but before you were talking about rolling diameters, and now your talking about percentages? you lost me buddy



hang in there, cause here is where it all ties together.


understand that since sidewall is a percentage of the width, when you go to a narrower tire, the result is also a shorter sidewall. so a 235/35/19 tire may have a rolling diameter of 25.5 and a 225/35/19 tire has a diameter of 25.1 because the sidewall is a percentage of width therefore, narrower width = narrower sidewall is the sidewall percentage stays constant.

if you were to divide the 25.5 by 25.1 you would end up with you rolling diameter percentage....it would be 1.1% which is clearly falls under the safe threshold of a quattro tolerance

now lets pretend that you had a 235/35/19 tire and a 205/35/19 tire, well we know that the rolling diameter is 25.5 for the 235 but for the 205 the rolling diameter is 24.6, which translates into a 3.6% percentage difference.....which really is on the high side of the threshold and personally i would not feel comfortable running this because there are so many other tires out there that can get a lower percentage difference

ok but you really had your heart set on some 205/35/19's for the fronts.....well if you ran a 235/30/19 tire in the back the diameter of that would be 24.6 and the percentage difference would be .4% and that's extremely good


so now you know that you can fool around with tire sizes and get the diameters pretty close together, and thats done by a series of calculations comparing the sidewalls and other types of measurements



recall that we tried to use the same tire size on wheels which featured two different widths....the stretching of the tire onto the wider wheel decreased its rolling diameter compared to the 8.5 width wheel


so what if we kept the sidewall at 35 and just got a narrower tire for the narrower wheel? that way we would have stretch on the front wheels, and the back wheels so maybe that would make the rolling diameter closer?....so 9.5 translates into 241mm (roughly) and 8.5 translates into 216mm and a 235 tire is stretched by 6mm on a 9.5 tire so a 210 tire should be perfect for an 8.5 tire as long as we keep the side walls constant at 35 but oh wait sidewall is a percentage of width of the tire so those numbers are not going to be constant and omfg i give up this is impossible and not worth it and i hate life and everyone who has staggered setups can go die.....



...is prolly what your thinking right now but alas, there is a much easier way to do this




following this link



TIRE CALCULATOR!!!! you can put in tire sizes, and click the button and figure out all the neat stuff needed to make this easier



lets make this easy follow these instructions


type in "235/35/19" in the first box
and "225/35/19 in the second and click calculate



it will bring you to a page and on the far right it says percentage....and it should say for the top tire, 0.0% and bottom 1.1% (or the other way around)



that tells you the rolling diameter difference is 1.1% which is well under the 3-4% limit that audi has put on us.....now factor in that there will be stretch on the 9.5 and not much stretch if any on the 8.5 buttttt the difference will be so minimal that running that tire set up on those wheels falls under the 3-4% threshold


spend a little time with this calculator if your interested in running a staggered set up and try and get that tire difference as close to 0% as you can


now that you understand that you can, in fact, run a staggered set up you just need to make sure that your rolling diameters are close to each other (read: under 3-4% of difference) you now should feel somewhat comfortable going forward in your quest to look fresh, steezy, hella flush, stanced out, slammed or whatever you young hooligans are calling it nowadays....

[VWAUDINUT]

Damn, i feel like an expert now.

We need to devellop a calculator for this shit I hate reading this much.

[G18]

Excellent post, thanks for taking the time to put this together

[Capt. Obvious]

STRETCHING A TIRE DOES NOT INCREASE NOR DECREASE ITS ROLLING DIAMETER.

The rolling diameter doesn't change when you stretch a tire, nor does it change when you run a meaty tire on a narrow wheel.

[swoardrider]

Note:
While the tire calculator is cool, remember that tire sizes are far from accurate, therefore, choose wisely. For example, lots of street Toyos are known to run narrow, whereas most R-compound tires are known to run very very wide. In fact as much as 1 inch wider than a street tire with the same printed size. My Toyo race tires are a 255 printed width, which are really as wide or even a tad wider than my 265 printed width Toyo street tire. And of corse the width of the wheel will also change the width of the tire too.

[mr shickadance]

STRETCHING A TIRE DOES NOT INCREASE NOR DECREASE ITS ROLLING DIAMETER.

The rolling diameter doesn't change when you stretch a tire, nor does it change when you run a meaty tire on a narrow wheel.

i feel like thats impossible.....if you mounted a 235/35/19 on a 19x9.5 and a 235/35/19 on an 8.5 the rolling diameters would be off, not by much but they would be off as the sidewall on the narrower tire is more vertical, rather on a stretched tire that is diagonal....therefore if its the same length but tilted the overall height would decrease with the stretched tire no? im not saying your wrong just when i thought about it thats how i came to my conclusion....i can edit it if im wrong tho

[Capt. Obvious]

You would be incorrect. When you stretch a tire, the bead rolls/pulls up, maintaining the rolling diameter of the tire, despite the sidewall being angled. Modern radials are steel belted, you're not going to change the diameter of steel belts.

[chrislane31]

And remember Adaptec Speedware is your source for any custom Spacers or adapters or any 3 piece wheel hardware or hub rings or wheel bolts in any seat and length.

[mr shickadance]

You would be incorrect. When you stretch a tire, the bead rolls/pulls up, maintaining the rolling diameter of the tire, despite the sidewall being angled. Modern radials are steel belted, you're not going to change the diameter of steel belts.

word? thanks i'll edit my post

[CoDRoX]

Excellent writeup Mr Shickadance.

Allow me to ask a really stupid question though...in 5x112, what's 112? I assume it's the diameter of the bolts?

[ryanworth]

Updated the stance with some spacers. 10mm front, 5mm rear.

Now my current setup is:
Front: 19x8.5+22 (225/35/19)
Rear: 19x9.5+24 (235/35/19)

Issues: Little rubbing on front, rear lip gets some occasional fender rub.

[.Mad Hatter.]

You would be incorrect. When you stretch a tire, the bead rolls/pulls up, maintaining the rolling diameter of the tire, despite the sidewall being angled. Modern radials are steel belted, you're not going to change the diameter of steel belts.

THIS. I was going to make the same comment, this needs to be changed in the above post as I see it far too often and it's simply not the case; diameter of a stretched tire is the same when not stretched.

example:

http://www.willtheyfit.com/index.php...&Submit=Submit