Will 18X9.5 fit on my AUDI A4 with OEM sports suspension

[yes4idol]

I have a potential seller for these TSW wheels 5x112 with a 35 offset and are 18x9.5 with a 3 inch lip and are wrapped with a 245/35/18.

1st question, will 18x9.5 35 offset fit on the rear with no problem?

2nd questions, I may be able to get 18x8.5 for the front, with 35 offset, will this setup fit?

I have an B6 A4 Quattro

THANKS!

[kepone]

Yes but be very careful about your tire sizes or you will destroy your transmission.

[Tgr_Clw]

Yes but be very careful about your tire sizes or you will destroy your transmission.

How will 245 tires destroy the tranny???

[kepone]

If the overall tire circumference is more than 5% different between the front and back he will eventually mess up the center diff and possibly the gearbox as well..


He mentioned the rear tire size, not the front..Therefore i warned him to be careful with his tire sizes.

[Tgr_Clw]

Ah I see. I thought he wanted to run same size all around. I suck at reading.
Carry on.

[Audii-Dudii]

If the overall tire circumference is more than 5% different between the front and back he will eventually mess up the center diff and possibly the gearbox as well..

Actually, the threshold is less than 5% (more like 1-2%) but well before the difference in diameters screws up your center diff, it will potentially screw up your car's performance.

This is because the Torsen center diff always splits torque between the front and rear wheels with the maximum amount going to the end of the car with the slower-turning driveshaft. So, depending upon which end of the car has the taller tires (hence the slower-turning driveshaft), you will end up biasing the torque split to the front wheels or the rear wheels, which isn't necessarily optimal unless you compensate for this by tweaking various other aspects of the suspension setup...

[Audii-Dudii]

1st question, will 18x9.5 35 offset fit on the rear with no problem?

Maybe, depending up on the alignments settings and particular brand/model of tire you use, but not with an ET35 offset ... at least not up front, anyway, as you'll need an offset more in the range of ET22-25 to clear the upright, and probably not without pulling the fenders unless you run ridiculous amounts of negative camber.

I'm in the process of setting up my B5 A4 track/play car to use 18x9.5 Corvette wheels with 285/30-18 tires up front and 245/35-18 tires in back (see the photos below) and for grins-n-giggles, I plan to try test-fitting them on my B6 A4 3.0 this weekend. I know the 285/30-18s won't fit under the stock fenders, but suspect the 245/35-18s will be close as that's what I'm presently running on 18x8.5 ET38 wheels. We'll see...







And one of my B6 A4 with the 245/35-18s on 18x8.5 ET38 wheels...

[Capt. Obvious]

Actually, the threshold is less than 5% (more like 1-2%)

Nope, wrong. According to factory Audi tech manuals, it's 5%.

And for someone to adversely affect the performance of their car to the point of being able to actually tell the difference between having 235/35's in the front and 245/35's in the rear, I sure as hell hope you aren't on the public roads I'm driving on. Hell, my car had a tendency to OVERSTEER when I had 255/35's in the rear and 225/40's in the front.

[Audii-Dudii]

Nope, wrong. According to factory Audi tech manuals, it's 5%.

I also recall Audi quoting 2 or 3 % for my '89 200q and '90 90Q, but keep in mind Audi's only referring to temporary use, not long term.

And for someone to adversely affect the performance of their car to the point of being able to actually tell the difference between having 235/35's in the front and 245/35's in the rear, I sure as hell hope you aren't on the public roads I'm driving on. Hell, my car had a tendency to OVERSTEER when I had 255/35's in the rear and 225/40's in the front.

The difference in diameter between a nominal 255/35-18 and a nominal 225/40-18 is ~1.5mm, which works out to ~.2%, so you likely weren't experiencing any tire diameter-induced torque-split anomalies. Remember, a Torsen center diff doesn't differentiate at all until it's splitting torque at its bias-ratio, therefore, whenever it does differentiate -- as it's forced to do when the front and rear driveshafts turn at different speeds because the tires are different diameters or the car is going around a corner -- torque is necessarily split at the bias-ratio and biased toward the end of the car with the slower-turning driveshaft.

That said, my B5 A4 has a tendency to understeer even when it's cornering on three wheels, so I'm not sure what else you did to get yours to oversteer ... slam it so low it was on the bump stops most of the time with a resulting rear spring rate of infinity, perhaps?

[Capt. Obvious]

That said, my B5 A4 has a tendency to understeer even when it's cornering on three wheels, so I'm not sure what else you did to get yours to oversteer ... slam it so low it was on the bump stops most of the time with a resulting rear spring rate of infinity, perhaps?

Haha, no. Never even got close to the bump stops in the rear. I ran a lot of rear camber with those tires, so I contribute it to the reduced contact patch.

[Audii-Dudii]

Haha, no. Never even got close to the bump stops in the rear. I ran a lot of rear camber with those tires, so I contribute it to the reduced contact patch.

Even when cornering? Hitting a bumpstop mid-corner will absolutely cause a car to snap oversteer...