dscri001

Had a question on the alignment specs for the S4's. I just had new tires put on. Went from oem Bridgestone to Michelin pilot sport 4S. This was done at NTB and had them do an alignment since I was sideswiped not too long ago and wanted to make sure everything was true. Only took it there because of the long lead time at Audi, and one of my tires were leaking from debris.

First question is their report says A4 but they pulled my VIN and I figured they aligned it to factory specs. Just wanted to confirm. Also mine has the sport diff and suspension.

Second question is steering feel. This might be me getting used to the new tires since I only picked the car up yesterday, but I get a slight tug when cornering under acceleration. Almost like torque steer but the tug wants to turn into the direction I'm steering. I'm not sure if my muscle memory is messing with me since these are different tires? Will tires have that much affect on drive feel? I've only ever replaced tires with the same on my other cars.

It drives and tracks fine otherwise. I'm not opposed to taking it to Audi and having it re-aligned, they're just always booked out a couple weeks. I just wanted to see what other opinions were out there. Thanks in advance for any help!

A4Audi4Fun

Don't know what factory specs are but your front toe values are more even now, so IMO that should give you more responsive front steering than before, hence the tug you are getting. The new Sport 4S should also be giving you more grip than your worn Bridgestone.

SMac770

1BU is not the PR code for the S4 anyway, that would be 1BD. The only difference would be the front camber spec. B9 cars all run the same alignment parameter except front camber, which adjusts with ride height.
1BU sedan front camber is -43'±23', same as 1BA since they are the same ride height. 1BD sedan front camber is -1°3'±23'. Or roughly -0.7°±0.4° and -1.05°±0.4°
So your front camber is fine, though the subframe needs to be shifted so both sides are -1.0°. But you'll never get a big box tire shop to do that.

1BU is not even sold in the US that I know of; why would they even have that in the system.

Be a lot easier to read that page if the pic was straight on instead of like reading the opening text for a Star Wars movie.

dscri001

lol sorry about that. Thanks for the info though, that was exactly what I was looking for. As far as the camber goes, is it worth getting it re aligned for that .1 deg? Would they be able to adjust caster as well while the sub frame is loose?

dscri001

Yeah definitely more responsive. Steering is definitely more sensitive under load, like micro adjustments take much less effort. Car just feels snappier, crazy that just tires can have that much of an affect!

SMac770

I don't know if having 0.9 / 1.1 vs 1.0 / 1.0 would be noticeable to the driver or to tire wear. Outside my experience. Caster is not adjustable at all, it's just a byproduct of the camber value in this car's case.