AKrlic

Dave..tire adhesion and torque bias are two very different things, as I'm sure you're well aware.
Now, you can induce oversteer one of two ways... either by running a narrower tire in the rear, or by sending more power to the rear wheels. According to the fundamental principles upon which quattro operates, "torque is sent to the slowest moving wheels." Larger wheels spin slower, so they will always receive a proportionately larger chunk of the torque pie. again, the difference in the rolling circumference might indeed be negligible, but on a torsen-equipped car this might lead to accelerated driveline wear or even adverse driving characteristics. if anyone has any documentation on this phenomenon, please let me know.

if MTM weren't averse to disparate wheel/tire sizes, why should i be?

AntiSocial

Easy install, best thing that happened to the car, handling wise. It drove so neutral with that setup (H&R/Bilstein, 28mm front, 26mm rear), but the big rear bar rubbed ever so slightly against the H&R springs. Rear coilovers will fix this. :-) No biggie, just a squeak every once in a blue and it wiped the powdercoat off the spring.

AntiSocial

It's a conspiracy. =P

Kep

When turbo coming??

TurboJew

...in order to prevent long-term damage to the center diff.

AKrlic

I'm running the same tires [255/35/18] at all four corners. Ok.. so..the wider width of the rear wheels will cause the rear tires to "stretch" to fit, in theory giving me a larger contact area in the rear.. but this same "stretching" [it's not really stretching, but more of a curving] will also leave me with a proportionate decrease in the measured "profile" of the tire. In other words, if you were to look at the car from the side and measure the profile of the tires with a ruler, you might find that the tires in the rear are "lower-profile", even though they are all the same size tire [i haven't done the math, but my logic seems cogent enough]. I believe it's this slight difference in profile which translates to a slightly different rolling circumference [which is where all of the trouble occurs, ostensibly].

Perhaps MTM ran a mismatched combo of wheels because their primary focus was on short-term performance gain.. maybe they knew this would ultimately kill the diff, but did it anyway because they can afford to. in this case, i'm ****ed [well, not really.. my stock wheels/tires are on right now], and i'm forced to sell my wheels at some point in the near future. OR, maybe MTM were enlightened on some higher mathematical **** [a euphemism, of course] and determined that the slight disparity in rolling circumferences were negligible. Who knows?

I've emailed a few people about this today... hope to have some concrete answers by the end of the week.

Thanks for the help, everyone!

urS4guy

Guys

The answers to your questions are as follows. The mounting kit($150) will enable non-bar equipped cars to run this sway bar. For the guy wanting to know the benefit even if you run coil-overs, it comes down to comfort and streetability. Sure, the ultimate would be a track trimmed coil-over set-up but the drive on the street would be very hard(pun intended) to live with. I run 400lb linear Eibach springs at the rear and the feel is firm. I'm also running the bar at the middle, 140lb, setting. When I'm not in a turn, the bar is just along for the ride. Go into a turn and the bar prevents the outside suspension from compressing and the inside from decompressing. You'd need a much stiffer spring to accomplish this same thing and that would make your street driving uncomfortable. The bar also works for stock suspensions in the same way. The design criteria used by the Audi engineers was and is to give us understeer for safety concerns. A rule of thumb in suspension set-up has you going stiffer in the rear vice the front to diminish this understeer. This bar was designed to give us neutral handling at turn-in through apex with mild oversteer at exit and from all the accolades over the last 2 years we've hit it right on the nose. Another benefit is an overall stiffening of the car's feel. BTW we've done about 40 of these bars.

Hap, answerin in Everboost

germantoy

no roll at all
i love it handles just like my rabbits of the past

germantoy

custom machine a bracket?

Don@STaSIS

Curious as to how the cars without the proper subframe fit the bar. I've been poking around at a '93 urS4 for a friend to do a rear bar solution and I suggested the Hap bar and he wants a stock setup. I don't want to swap subframes for him, way too much of a PITA, so wondering how that bar mounts, actually one of his questions as I tried to sell him out of the stock bar and stock subframe swap idea, a real pain in my *** if I have to go that route on that car. All I could see was to add a vertical bracket to the subframe slightly more inboards. Curious how the Hap bar does this, maybe I can sell this guy one so I have something easy to install

Thanks,