New tires and allignment for 328-Questions

I think that one reason you have that kind of understeer / twitchy behavior around large radius sweeps at moderate speeds is because you have more tread on the rear, gripping more, which will cause the front end to kind of plow (understeer) some, but you say you've lowered the PSI in the fronts some so they grip more, it should reduce the understeer. I'm not sure but this is what I experienced when I had new tires put on my car / aligned. I think that once the tires get a good set in them that maybe those symptoms will subside a bit. The handling now is a lot different than the first thousand miles or so after getting new tires. It felt kind of "boaty" and floaty / twitchy feeling around turns, but now there's almost none of that.

 

It takes about .75 to 1 ounce to really start to get a wheel out of balance so a few of those little wieghts missing is not a huge deal....BUT, I would take it back, have the wheels rebalanced, and have the wheel properly cleaned with alcohol where the wieghts will be placed. Then, it is usually a good idea to have some sticky take put right over the weights and extending out about 1.25 inches all around. Not sure what type of tape would be best, but have seen it done, and makes sure they don't come off.

 

I recently tracked my 328 for the first time, and while never really going above 7/10, it was obvious the car understeered a bit on the track's one big sweeper. The track was damp with some fallen leaves, so obviously that added to the conditions. What I did seem to notice was that the car seemed nicely balanced overall, with positive handling responses to throttle input.

 

I had my 89 328 GTB aligned right after I bought it with 7K miles on it. It was out quite a ways, probably never aligned. It still had the original GY eagles on it which I got rid of pretty quick because of age. I have S03's on it, and never noticed any understeer, even at tracks, but it's not really tail happy like reviewers in the 80's all seem to say. I have heard from other owners that track their cars that they experienced the same thing. They were cautious about oversteer on the track, but found the car to be pretty neutral instead. I did have an 85 308 GTB that understeered sometimes. You did not say what year your GTB is, the suspension changed mid 88. The only thing I can think is that maybe you are applying more throttle through the sweeper and if the rears now have more grip you may have to dial in more steering as the power comes on. I think this would be normal and I have noticed this with my car if I'm accelerating through a sweeper.
One note about alignments, the manual specifies the car be full of gas and weighted in the front. Not doing this would result in too much negative camber. As for the wheel weights, I would make them do it over and put tape on them. The stock wheels usually require a lot of weights. A flying weight can put nasty dents in your fenders.

PS
I have a list of GTB vin#'s. Do I have yours? Also, my list is available for anyone.

Dave

 

Glad I could help out some, a nice brisk throttle lift usually does the trick too and a rally drivers flick (turn away from the turn, and quickly turn back in). I don't know if you want to be doing any of that in a Ferrari though, hehe. But I think you have the same problem as I had. After I had picked the car up, as I was driving home it felt like they stole my suspension setup, the suspension parts have since been "put back on" with the tires properly broken in.

 

Steeda,

That's exactly what I've been experiencing on my M3. It's got the staggered set-up and the understeer is significant. It bothers me most on long gentle sweepers as described above. I'm a graduate of multiple driving schools and am pretty good at keeping the car balanced, but it feels like the front end is ever so slightly plowing to the outside a bit. My mechanic suggested finding a pair of rears for the front to even out the set-up, which should help a lot (guess BMW went to the staggered set-up because understeer is preferable/safer for the vast majority of drivers). Maybe I should learn to add a touch of left foot brake?

PS - thanks again for the racingflix access; really enjoyed many of those vids

 

Glad you like the racingflix vids . That M3 is a mean machine!

Have you ever thought about adding a few more degrees of positive caster over stock? I have mine at 6* positive caster from the stock settings. It helps it track straighter for sure, and I think it has helped reduce some understeering, I still need to dial in a bit more negative camber. The understeer you're experiencing in the M3 is a pretty common problem for front engine/rwd cars with wide tires on the rear and skinnier up front, just not enough grip up there to point that weight on the front end where you want it to go. I have 275/40/17's all around and the handling seems to be pretty much neutral now with a hint of understeer if I don't correct it. Lowering the front PSI would help a bit I'm sure, but I don't want to round the front tires off too badly

 

Cool - I'll run these by the guys at GT Int'l, thanks

Sending you a PM by the way...

~C

 

Hardtop has a good point about gas in the tank...and to clarify what i think he says about weight in the front, i believe the manual specifies adding weight to the driver's seat. Conclusion would be to load up the driver/passenger with whatever weights you typically drive around with...(how much does a 'hot' babe weigh? how much does a fat cat driver weigh?).

Also, touched on a bit about new tread, there's a world of diff between new tires & 1/2 worn or really worn rubber. This tends to most noticeable when putting new tires on, as one usually goes from bald to fully treaded, along with possibly a suspension alignment.

I think TireRack sells tires shaved as an option, so if you're -really- into handling, i suppose you could throw away some rubber $$ and get 'em 1/2 worn

 

If you have an understeer problem that is outside the range where air pressure adjustments will neutralize the issue, you can raise the ride height at the rear end. An adjustment of 3 mm should be easily felt and the sweetspot might be a close as 0.5-1mm away from where you are currently 'sitting'.