Threesome (2 girls 1 boy).

Hi guys, I want to buy some new 20" wheels on Tuesday but I'm not sure if they will fit.

My car is a 2012 A5 S-line cabriolet, the new alloy wheels offset is 37 but I've been told my car will only allow an offset of up to 35 is that correct?

I'm also a little confused about tire sizes because one company are recommending 255/35/20 and another company are recommending 265/30/20 so which ones do i go for?????

If the wheels do fit i would like them to be flush with the arches so what size spacers would i need because i hate the factory default look/stance?

Like always I'm very grateful for any help, cheers guys.





 

arad85

Registered User
You reduce offset with spacers (yeah, I know that sounds wrong but...) so you can get to the correct offset with, say, a 5mm spacer. The offset is the positive (towards the outside) or negative (towards the inside) from the centre line of the wheel. What is more important is the J size. What are the J sizes of the wheels you want vs the ones on the car? The J size is the depth of the wheel in inches and if it is larger than your current wheel will affect how close to the suspension you will go, which is tied in with the offset.

As to tyres, I'd go with whichever is closest to your current wheel size - you really want to match the circumference of the wheel as closely as possible - see https://tiresize.com/comparison/ for a calculator. Not doing that means your speedo is out. Another factor may well be that 265/30 are likely to be more costly than the 255/35.

Can't help on the spacers needed to get to flush with the arches - although you could work it out based on finding how far inwards they are now and working out the geometry (plenty of guides on the net to explain how wheel sizes work).
 

CHEZ

moderately amusing
Supporter
What width are the wheels?
 

JG51 AUD

Registered User
What are the J sizes of the wheels you want vs the ones on the car?
The new wheels are 9J but im not sure what size my current wheels are but i do know that they are standard stock OEM 18" alloy wheels.

I've added a pic of my car below just in case you or somebody else knows there size/stats.

 

arad85

Registered User
9J will be wider than yours. 18" are normally 8.5J with 245/40 R18's on A5's.... What year is it? See if you can find the brochure for that year. Alternative is to take the wheel off - it will be stamped on the back.
 

JG51 AUD

Registered User
Thanks dude i appreciate the calculator but to be honest I'm even more confused now than i was before after looking at those stats lol (cringe).

My wheels are 19x9j et 33 (genuine), so your car should be able to run these without issues, use these sizes in the wheel calculator on "willtheyfit" website, this should give you a better idea of fitment.

JG
 

CHEZ

moderately amusing
Supporter
I ran 8.5j x 20 et35 with 255/35/20 running 20mm rear spacers and 10mm fronts, and to be honest could have done with more spacing, and I didn't like the height of the car on that profile tyre.
If still had them I would have opted for 20mm rear and 15mm front.
I think that combo would be OK for them.
At the minute I have 9.5j et 25 20'' bbs and run 265/30/20 with 20mm rears and 10mm fronts lowered on eibach springs and love the look, the rears are mega flush.
The tyres and drop of the suspension all make a difference imo
 

DrEskimo

Registered User
I would prefer my 9j X 19 ET33 255/35 to sit about 10mm and 15mm further in at the front and back, so would personally go for a slightly lower offset if there is the option. 25-30. Think the 20" RS5 are 9x20 ET26?

Oh and go with 260/30. Can't get the correct tyre load on 255/30 and 255/35 is too large and be a large deviation from OEM.
 

lfcrule1972

Winter is coming...
Ok so I viewed this thread cos of the title :) Made me lol
 

JG51 AUD

Registered User
I ran 8.5j x 20 et35 with 255/35/20 running 20mm rear spacers and 10mm fronts, and to be honest could have done with more spacing, and I didn't like the height of the car on that profile tyre.
If still had them I would have opted for 20mm rear and 15mm front.
I think that combo would be OK for them.
At the minute I have 9.5j et 25 20'' bbs and run 265/30/20 with 20mm rears and 10mm fronts lowered on eibach springs and love the look, the rears are mega flush.
The tyres and drop of the suspension all make a difference imo

Totally agree @CHEZ

Spacers and a suspension drop is definitely the way to go on an A5. :yes:

JG
 
My wheels are 19x9j et 33 (genuine), so your car should be able to run these without issues, use these sizes in the wheel calculator on "willtheyfit" website, this should give you a better idea of fitment.
Please forgive me but I cant make any sense of that calculator because I'm just not familiar with the terminology and dynamics (sorry).
 

arad85

Registered User
Look at the graphic underneath the calculator. It shows how both wheels fit. You may need to scroll down to see it.
 
I ran 8.5j x 20 et35 with 255/35/20 running 20mm rear spacers and 10mm fronts, and to be honest could have done with more spacing, and I didn't like the height of the car on that profile tyre.
If still had them I would have opted for 20mm rear and 15mm front.
I think that combo would be OK for them.
At the minute I have 9.5j et 25 20'' bbs and run 265/30/20 with 20mm rears and 10mm fronts lowered on eibach springs and love the look, the rears are mega flush.
The tyres and drop of the suspension all make a difference imo
The salesman on the phone told me that the maximum offset that would fit my car is ET35 and the new wheels are ET37 so he suggested that i would need a 10mm spacer, is that correct?
 
I would always opt for a correct fitting wheel over the use of spacers.
Yeah i agree if the wheels will only fit with spacers then maybe I'ts not a good idea after all.

Do you know any good websites that sell 20" wheels with the correct fitting?
 

DrEskimo

Registered User
Yeah i agree if the wheels will only fit with spacers then maybe I'ts not a good idea after all.

Do you know any good websites that sell 20" wheels with the correct fitting?

Do they do that wheel with a lower offset?

There's no problem fitting a wheel with a lower offset (to a degree), or did they specifically tell you that wheel with a lower offset would not fit (presumably for clearance with the suspension mount, but at 9j I don't see why that would be a massive deal...hardly an expert tho!)

I stick with OEM so would go with anything off an RS5. Only aftermarket one I think looks good are these Vossens. But that's quite subjective...!

Audi-B8-RS4-Avant-20-inch-Vossen-CVT-Directional-Wheels-©-Vossen-Wheels-2015-1032.jpg
 
Do they do that wheel with a lower offset?
No they said the wheels only come in Offset 37
There's no problem fitting a wheel with a lower offset (to a degree), or did they specifically tell you that wheel with a lower offset would not fit (presumably for clearance with the suspension mount, but at 9j I don't see why that would be a massive deal...hardly an expert tho!)
I cant remember what he said exactly but yeah something along those lines.
I stick with OEM so would go with anything off an RS5. Only aftermarket one I think looks good are these Vossens. But that's quite subjective...!
Yeah they look nice!
 

DrEskimo

Registered User
They will fit without spacers, it just depends how you like the stance. I don't mind the stock S5 set up, but the tears are a little tucked in. If I was buying new I would try and get ones that have a good stance that's flush with the arches. YMMV..

You can see why I recommended 260/30 and not 255/35 tyres though! The circumference increases by nearly 5%!
 
They will fit without spacers, it just depends how you like the stance. I don't mind the stock S5 set up, but the tears are a little tucked in. If I was buying new I would try and get ones that have a good stance that's flush with the arches. YMMV..

You can see why I recommended 260/30 and not 255/35 tyres though! The circumference increases by nearly 5%!
So the higher the Offset number the closer the wheels are to the curb, or is it the other way round lol?
 

CHEZ

moderately amusing
Supporter
So the higher the Offset number the closer the wheels are to the curb, or is it the other way round lol?
Other way round mate
Imagine if your wheels are level with the arch, then that is zero offset, et 60, for example would mean 60mm inside the arches. Etc
That's how I got my head around it lol
 

DrEskimo

Registered User
So the higher the Offset number the closer the wheels are to the curb, or is it the other way round lol?

What Chez says :p

A wheel with an offset of 35 with a 10mm spacer is effectively a wheel with an offset of 25. Might as well just buy a wheel with an offset of 25 and not bother with the spacers!

There is clearance to consider though. The OEM 20" Rotors are 9j X 20 ET26, so that spec should be fine.

As the wheel size increase an inch, you typically drop the profile of the tyre 5%. So it goes 245/40/18 > 255/35/19 > 265/30/20. Thats why I would recommend a 9 - 9.5j width with an offset of about 25-30 and a tyre of 265 (260)/30.

Good luck with the search mate!
 

lfcrule1972

Winter is coming...
Cheers all, I've learnt something here today :)
 

arad85

Registered User
So the higher the Offset number the closer the wheels are to the curb, or is it the other way round lol?

The offset is the distance from the centre of the wheel (i.e. if you were to cut it in half vertically) to the mounting point on the axle. If the mounting point is exactly at the centre plane of the wheel, the offset is 0. An offset of 35mm means the mounting point is 35mm closer to the outside of the wheel. An offset of -35mm means the mounting point is 35mm closer to the inside of the wheel.

A higher positive number means the inside of the wheel is closer to the suspension (for the same J size), so you end up having to worry about clearance from the rest of the axle. A lower number pushes the outside edge closer to the kerb, meaning you have to worry about rubbing on the bodywork.
 
You can see why I recommended 260/30 and not 255/35 tyres though! The circumference increases by nearly 5%!

Sorry to be a pain in the bum but what does that mean? The salesman on the phone recommended i buy the 255/35 tires because their thicker and more durable plus of the bad condition of our UK streets (pot holes etc) and another company recommended the 260/30 tires because they will look a lot better so I'm completely Confused.com which ones to buy.

I don't want the wheels to look like fat tractor tires but at the same time i don't want them to be to thin so they are easily damaged.

If i go for the 255/35 tires will they fit properly once i put the spacers on to bring them flush with the arches?

Do you have any pics so i could physically see the difference?
 
Other way round mate
Imagine if your wheels are level with the arch, then that is zero offset, et 60, for example would mean 60mm inside the arches. Etc
That's how I got my head around it lol
So if the my car Offset is 29 and the new wheel Offset is 37 what size and type of spacers do i need to bring the wheels flush with the arches?
 

CHEZ

moderately amusing
Supporter
So if the my car Offset is 29 and the new wheel Offset is 37 what size and type of spacers do i need to bring the wheels flush with the arches?

I would go 25mm rear + 20mm front at a guess, (maybe more lol)

Personally, I would buy 1pair of 20mm, and trial fit them both to one side first and see how you like them (1 on the front and 1 on the rear)
 
Last edited:

DrEskimo

Registered User
Sorry to be a pain in the bum but what does that mean? The salesman on the phone recommended i buy the 255/35 tires because their thicker and more durable plus of the bad condition of our UK streets (pot holes etc) and another company recommended the 260/30 tires because they will look a lot better so I'm completely Confused.com which ones to buy.

I don't want the wheels to look like fat tractor tires but at the same time i don't want them to be to thin so they are easily damaged.

If i go for the 255/35 tires will they fit properly once i put the spacers on to bring them flush with the arches?

Do you have any pics so i could physically see the difference?

As the diameter of the wheel increases you need to decrease the size of the tyre to maintain a similar overall wheel circumference.

The 255/35 will give you a thicker tyre, but with the bigger 20" wheels it will increase the overall circumference by nearly 5%. Most people will say don't increase this more than 2%. Your speedo will overestimate your speed (so your speedo will say 70 but you're actually doing 65) and others argue other components like the gearbox and ABS are affected as they are not calibrated for that size.

It's up to you but I would personally stick with OEM spec tyres. There is also insurance to consider. If you have a blow out and cause an accident and are found to have tyres out of spec ,that don't have the correct load rating for example...well....why even risk it?!
 
As the diameter of the wheel increases you need to decrease the size of the tyre to maintain a similar overall wheel circumference.

The 255/35 will give you a thicker tyre, but with the bigger 20" wheels it will increase the overall circumference by nearly 5%. Most people will say don't increase this more than 2%. Your speedo will overestimate your speed (so your speedo will say 70 but you're actually doing 65) and others argue other components like the gearbox and ABS are affected as they are not calibrated for that size.

It's up to you but I would personally stick with OEM spec tyres. There is also insurance to consider. If you have a blow out and cause an accident and are found to have tyres out of spec ,that don't have the correct load rating for example...well....why even risk it?!
OK i completely understand now sorry for being a NooB :grimacing:
 

CHEZ

moderately amusing
Supporter
Thanks! Do you know the cheapest place to buy them from because their a little pricey?

I just Google searched and went with the cheapest and can't really remember who from tbh lol.
The H +R 20mm are trax plus, so they bolt into hub, and the wheel bolts into them.
The H +R 10mm I got are just regular spacers so these required 10mm longer bolts.
It is worth finding out what kind of wheel bolt seats are on the new wheels too, as oem audi wheels use radius seat bolts and most after market wheels use tapered seat bolts, NEVER EVER USE THE WRONG TYPE OF BOLT, you will damage the wheels, always use the correct type, I cannot stress this enough.
Also, do as Eskimo suggests and go for a lower profile tyre, as that size does not really suit the A5, it makes it a bit 4x4 looking with loads of ground clearance too.
Good luck
 
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