S3 wide tires 18x8.5 and 18x9.5

[scott_159]

hi guys

i have a set of these BBS ch reps, im looking to fit the widest tires possible to fit to these wheels 18x8.5 front and 18x9.5 rear.

whats everyones thoughts on this? what are you running? any pictures of your set up?

im going to be looking to keep with the standard suspension (no coilover) set up, looking to install new shocks and -30mm springs. so will need to bear in mind clearance

cheers guys

 

[superkarl]

8.5 will require a 235mm tyre whilst the 9.5 rim will require a 255.

Unsure what profile, there is calculators online that let you compare profile sizes to match the circumference of the OEM wheels/tyres so your speedo is still correct and it doesn't look stupid

 

[scott_159]

cheers i am half thinking 235/40/18 and 255 or 265/40/18 although a 35 may be needed just trying to find some info on what others have used.

cheers!

 

[Jenno007]

make sure the rolling radius is very close between the front and rear axle, your haldex will thank you for it

 

[superkarl]

make sure the rolling radius is very close between the front and rear axle, your haldex will thank you for it

The haldex is a viscous coupling it will take care of itself. That's its job

 

[Jenno007]

The haldex is a viscous coupling it will take care of itself. That's its job

I have read many times before that the rolling radius between the front and the rear axle must be within 5%, otherwise it will cause issues.

Quick google and the top two links:

http://www.audi-sport.net/xf/thread...g-different-profile-tyres-with-haldex.141078/
http://www.ttforum.co.uk/forum/viewtopic.php?f=2&t=308911

 

[Sam_]

265 will be a breeze on the rear and 235 should be fine on the front. I run 255 with an "aggressive" offset up front and it does catch occasionally even with mega stiff suspension and 3 degrees of camber.

 

[scott_159]

cheers sam, im thinking along the lines of 265 rear now and 245 front?

maybe keep to the same format of ***/40/18? any pictures of your setup?

cheers

 

[Sam_]

You'll want lower profile than that I'd say? You will also want to make sure the rolling radius aren't too different front vs rear. There's loads of calculators on the net.

Don't have any pics of it on 255/40/17s but this was the most recent on the 245/40/17:

 

[Alex C]

The haldex is a viscous coupling it will take care of itself. That's its job

It's a hydraulically operated wet clutch pack isn't it? the torque is transferred through the friction between the friction disks rather than through a viscous fluid

@Sam_ whats the width of your rims? is that a 245tyre on an 8.5J rim?

 

[superkarl]

It's a hydraulically operated wet clutch pack isn't it? the torque is transferred through the friction between the friction disks rather than through a viscous fluid

@Sam_ whats the width of your rims? is that a 245tyre on an 8.5J rim?

I'm not sure what it would class as, a viscous coupling has plates in it. But yeh perhaps the haldex fluid only plays a role of hydraulically operating the plates.
Dunno if you've seen inside a dsg box but it's basically the same as one of those clutches.
To think our crappy haldex Might have played a part in the development of dsg

 

[Sam_]

@Sam_ whats the width of your rims? is that a 245tyre on an 8.5J rim?

They're 17x9". 245s sat better than the 255s I reckon.

 

[jojo]

I'm running 225s on a 9.5" rim! lol

 

[Sam_]

Oh man, the scene points must be epic

 

[superkarl]

I'm running 225s on a 9.5" rim! lol

Another giveaway

 

[Lulinfornoah]

You'll want lower profile than that I'd say? You will also want to make sure the rolling radius aren't too different front vs rear. There's loads of calculators on the net.

Don't have any pics of it on 255/40/17s but this was the most recent on the 245/40/17:

Hi mate! Sorry for old threat but what is the wheel offset? have you got spacers? Thanks!

 

[Sam_]

Hey, the "final" offset is ET15 front, ET20 rear. I do use spacers but you can get the pro race in a range of offsets so I'm sure you can get something that works. I only have to run such high offset on the front to clear the 18Z 6 pot Brembos. If you're running smaller brakes then I'm sure you could run 20 or 25 all round.

 

[Lulinfornoah]

Thanks dude! I appreciate your answer I will choose et15 all around for looks, btw i’m finding a set of BoxsterS/996 Front calipers to match with some 330 brera discs, so not the bigger brakes as you. If I choose 18x9 instead of 17x9 wich tires do you recommend me?

 

[Plake]

They're 17x9". 245s sat better than the 255s I reckon.

I know, zombie thread but just joined the s3 club and desire more tire and less rim. Really digging this set up. No issues with the 17’s clearing the stock brakes? Thanks if ur still out there. Lol

 

[jojo]

I know, zombie thread but just joined the s3 club and desire more tire and less rim. Really digging this set up. No issues with the 17’s clearing the stock brakes? Thanks if ur still out there. Lol

If we are on about stock 312mm brakes, 16s will clear the calipers, it’s the offset and wheel spoke clearance you need to be concerned about, the S3 doesn’t really do dished alloys with the spokes further inwards.