Wheel Spacer Help

[stevey83]

Hi, I recently picked up some new alloys for my car (2003 B6 Cabriolet). They were replacing some Audi replica alloys, which were a different fitment. My new alloys are not as wide, and are also sitting closer to the struts. I have some tyres ready to fit but my mechanic has told me they may not fit, even if i sort the spacing out.

Can anyone tell me what size spacers i need. The wheels are as follows:

Original:
8x18 ET 35

New Alloys:
7.5x18 ET 54

https://www.willtheyfit.com/index.p...2=40&wheel_size=18&wheel_width=7-5&offset2=54

This site is telling me there 13mm closer to the strut, and stick out 25mm less.

 

[joinerman]

Rob our wheel guru should be along to help soon.

 

[Charlie Farley]

Greetings chaps, not sure I can be called a Guru but allways happy to try and assist.
Ok the, lets begin.
So assuming your current fitments are aftermarket and to be honest on an ET35 on the B6 platform they most likely are,so you need to get back to the original oem specs from a size point of view .
Even without looking at the wheel specs for your variant it is very unlikely ET54 will go on without any issues as its a big variation from oem , well even from the ones you have on now, even allowing for the reduced rim width.

You are effectively loosing 12mm (6mm each side) in rim width over the 8j but et54 will move the rim more inboard , by 19mm approx. as that's the rim width not factoring in tyre fitment aswell,
That will make the ET54 7.5's , less 6mm = 13mm closer to suspension than your current fitments, not the oem spec as your are already running more offset than oem.
As you can see my calculation as the same as yours , You need adjust the difference between the two sets of alloys to get the correct fitting or as close as you can to make them fit.
That means you have 6mm to find straight away due to the thinner rims, then the 19mm difference in offset to get back to your current spec, so thats approx 25mm to put the 7.5j at the same point in terms of clearance and offset as you have now but the 7.5's will also now still be 6mm further in from the wheel arch lip as you have to work on 6mm both sides which wont be an issue.
Let me see what the oem spec offset is and if there is any differing info to calculate.

back shortly chaps.

 

[Charlie Farley]

You would be looking at spacers approx. 25mm allround to make them fit based on the sizing above and your current spec alloys, not oem spec.

 

[stevey83]

Wow! Thanks for the detailed reply Rob, you definitely are the guru!

I forgot to mention in my first post, there is an OEM alloy in the boot, which im assuming is what came with the car. that wheel is 7x16 et45.

The alloys im adding are OEM but i think they've come from an A3

 

[Charlie Farley]

Back again, as I thought the oem spec is the same as B7 platform so ET43 on an 8j rim.
Working on oem fitting spec as that's factory fitment then you could reduce the spacer size accordingly by approx. 10mm which factors in the original oem offset , so instead of the there being a difference of approx. 19mm between the two rims it is acctaully only 11mm but that's still the offset and you'll need to add the 6mm width of rim reduction to that aswell.
That makes it closer to 17mm now not 25mm , that's working on oem offsets and clearances.

 

[Charlie Farley]

here is the oem alloy wheel listing for 2003 cabs.
https://audi.7zap.com/en/rdw/audi+a4+s4+cabrio+qu/aa4c/2003-273/6/601-601070/
oem is showing 7.5j 17" ET45 so that kinda makes the calculation easier as they are same rim width you are looking to fit now.
your new alloys will be further in by 9mm plus a bit of tyre sidewall , you only need to add that amount back on to get back to oem specs and as we all know oem specs, work.
Well that's in an ideal world but also depends on wheel style aswell as not all wheel fit the same.

 

[Charlie Farley]

Forgot to mention , you need to adjust the tyre sizing and profile aswell based on 17" alloys , as long as you stick to the same overall sizing rules albeit larger diameter rims you will be ok.
going up from a 17" to an 18" will mean coming down a profile size with tyres .

 

[Charlie Farley]

B6 platform is not my area really so hope that has helped a bit.
good luck chap.

 

[Charlie Farley]

Allow a bit more for spacing than 9mm , maybe 12 mm would work well, just make sure you have caliper clearance with the rims you are going to fit., if you were not using spacers then it would be an issue but since spacers are the best option in this instance you should be ok .
B6 and b7 use alloys with a centre bore 57.1 so alloys will need to be this , if larger you'll need spigot rings.

rob

 

[stevey83]

Thanks for your help Rob, they is plenty of caliper clearance, is more the fact that i need to get more clearance from the suspension struts.

Ive ordered some 12mm spacers, ill let you know when i fit them.

 

[Charlie Farley]

hope things go well, just remember the 7.5j's wont sit out as far a your 8j's do at present working on 12mm spacers but you should get the strut clearance.
To get the same sort of poke and strut clearance you'd need at least 25mm spacing per wheel and that is a fair bit to be honest.

 

[stevey83]

Just a quick update, 12mm spacers arrived and have helped, but ive run into a new problem. They fit fine on the front, but on the rear, the hub sits out about 15mm compared to the front which is around 10mm. This meant my spacers wouldnt sit flush on the rear, so ive been advised by the company i bought the from to go up to 15mm spacers on the rear. Theres plenty of room for them to fit and will make the wheels look flush with the arch.

Before

After

 

[Charlie Farley]

If it's anything like the B7 there is a lip on the hub that prevents certain thickness hubcentric spacers fitting flush, normally it's the 8/10/12 mm etc that are the problem, they just don't sit flush .
easy solution is to just grind off the small lip ,but not the raised part as that keep things all snug.
I did it on mine , well ended up doing on rears and fronts.

 

[Charlie Farley]

here, just the first few mm upto the edge of the raised locating section, or if you can go with a bit more width go wider spacer but keep wheel arch gap in mind.
good luck.