Differences between 17” and 18” wheels
#46
If that was the case, all cars would run on the same tire with the same pressure and just adjust the bar (theoretically).
Adjustable bar does a lot to help in moving balance between car's ends. But... there are at lest 4-5 factors - bars, springs, shocks, tire width, tire pressure/sidewal stiffness. Far, far from everything can be solved with adjustable bars. If you consider more esoteric things, like complete difference in behavior in turn-in, and coming out of the turn...
Adjustable bar does a lot to help in moving balance between car's ends. But... there are at lest 4-5 factors - bars, springs, shocks, tire width, tire pressure/sidewal stiffness. Far, far from everything can be solved with adjustable bars. If you consider more esoteric things, like complete difference in behavior in turn-in, and coming out of the turn...
#47
Addict
Rennlist Member
Rennlist Member
I believe that Steve knows more about suspension that most people on the planet and certainly has forgotten more than I ever knew. Having said that.. if you ask Steve directly whether his statement translates into: "you can work out any tire difference with adjustable sway var" he will say: "absolutely not". I truly don't see how "prime tool becomes "Any tire width combination can be compensated for with adjustable sways.". It's one tool. It's, quite probably, the most important tool. But, like any one tool, it will not overcome everything.
Would love to hear from Steve.
Would love to hear from Steve.
#48
Drifting
Great thread
I'm looking at the oz allegerita too for low weight
One factor not in this discussion is the stress on steering components
There seems to be a lot of leaky racks now we're on 18s. My 95 came with 18 solid twists, no brace & now a leaky rack
Does anyone else suspect the extra stress of more grip & weight as prime culprit in rack wear?
I'm looking at the oz allegerita too for low weight
One factor not in this discussion is the stress on steering components
There seems to be a lot of leaky racks now we're on 18s. My 95 came with 18 solid twists, no brace & now a leaky rack
Does anyone else suspect the extra stress of more grip & weight as prime culprit in rack wear?
#49
I believe that Steve knows more about suspension that most people on the planet and certainly has forgotten more than I ever knew. Having said that.. if you ask Steve directly whether his statement translates into: "you can work out any tire difference with adjustable sway var" he will say: "absolutely not". I truly don't see how "prime tool becomes "Any tire width combination can be compensated for with adjustable sways.". It's one tool. It's, quite probably, the most important tool. But, like any one tool, it will not overcome everything.
Would love to hear from Steve.
Would love to hear from Steve.
Ask me how I know.
#50
Rennlist Member
Allow me put a finer point on it. If a car is set up to understeer or oversteer as a result of tire width differences between front and back alone (assuming all other suspension components yield neutral handling), it can be compensated for either direction by tightening or loosening adjustable sway bars. So, a car with a much wider tire in the back will have a tendency to push, and this can very easily be dialed down to neutral or to oversteer by adjustment of sway bars alone.
Ask me how I know.
Ask me how I know.
#51
Addict
Rennlist Member
Rennlist Member
Great thread
I'm looking at the oz allegerita too for low weight
One factor not in this discussion is the stress on steering components
There seems to be a lot of leaky racks now we're on 18s. My 95 came with 18 solid twists, no brace & now a leaky rack
Does anyone else suspect the extra stress of more grip & weight as prime culprit in rack wear?
I'm looking at the oz allegerita too for low weight
One factor not in this discussion is the stress on steering components
There seems to be a lot of leaky racks now we're on 18s. My 95 came with 18 solid twists, no brace & now a leaky rack
Does anyone else suspect the extra stress of more grip & weight as prime culprit in rack wear?
#52
Addict
Rennlist Member
Rennlist Member
Allow me put a finer point on it. If a car is set up to understeer or oversteer as a result of tire width differences between front and back alone (assuming all other suspension components yield neutral handling), it can be compensated for either direction by tightening or loosening adjustable sway bars. So, a car with a much wider tire in the back will have a tendency to push, and this can very easily be dialed down to neutral or to oversteer by adjustment of sway bars alone.
Ask me how I know.
Ask me how I know.
What I am saying is that 205/255 tire combination, in concert with other 993 stick components, leads to understeer. If a person is changing wheels and tires, it makes sense to try to bring the car a little close to neutral behavior with choosing 225/255 combination instead of insisting on 205/255 and fighting it elsewhere, hoping that there will be enough adjustment and that that adjustment will not result in other undesirable behavior.
#53
While it's hardly my point that sway bars are "the final arbiter of set-up," it is obvious that once an alignment and corner balance have been completed, there are two FINAL tools for changing the over/understeer: tire/wheel selection and sway bar adjustment. Cracking open the suspension and altering the alignment on a frequent basis is costly and time-consuming, and not practical for most of us who aren't pro racers with an open checkbook. If you are cool with redoing the alignment, yes, spring selection, for example, is just as influential to over/understeer as sways. Sways, however, are only used to modulate lateral cornering forces. You with me so far? Good. I knew you would be, Ken.
The reason sways are so useful is that you can make adjustment to front and rear independently without affecting other suspension settings. Stiffer settings will reduce body roll, while softer settings will increase body roll. Softer settings will make weight transfer more gradual, with less abrupt loading. The relationship between the front and rear sway settings have a direct effect on the handling/balance of the car, referred to as roll coupling. Yes, the difference between loading of the front and rear contact patches directly affects whether a car will oversteer or understeer. Yes, to the same degree as springs. But changing springs all the time is simply not practical.
I must assume you're playing devil's advocate with me here, Ken. You're not only much more knowledgeable about this stuff than I am, you're a flipping lawyer.
Last edited by callipygian 911; 09-12-2014 at 12:42 AM.
#54
What I am saying is that 205/255 tire combination, in concert with other 993 stick components, leads to understeer. If a person is changing wheels and tires, it makes sense to try to bring the car a little close to neutral behavior with choosing 225/255 combination instead of insisting on 205/255 and fighting it elsewhere, hoping that there will be enough adjustment and that that adjustment will not result in other undesirable behavior.
#57
Addict
Rennlist Member
Rennlist Member
Thank you for being polite. Can you tell us, please, if you've actually seen an adjustable sway bar and at least know how many "adjustments" you can make with on? Just so we understand the value here.
#59
Okay, I can't resist. Scotch makes me irascible in the face of Philistines.
You say stuff. A lot of stuff. Over 6000 posts in a decade. Sometimes what you say is peppered with things that make sense, but other times ... not so much. Like here:
What the? Your logics are out of calibration. This if/then conditional statement makes about as much sense as "if salami then I poop dinosaur rocket." Congratulations. You broke the operator. If there is a god of rationality, he is openly weeping right this instant.
Never said nor implied this. Neither did the quote I'd posted. Thanks, though, for setting up the pretty straw man argument. Its fun to knock things down. Wheee!
If you mean difference in tire width, as I explicitly stated, you might be surprised. I spoke with him at length on the matter but, far be it from me to speak for someone else or put words in his mouth. You seem to have a talent for that, though...
What you say here makes sense and I agree. I'm just surprised you have the gall to pretend this was the point you were trying to make with me all along because...well, I very much doubt you poop dinosaur rockets every time a loose woman dangles salami in your face! Ha! However, I have been known to be wrong on occasion... hmmm...
I shouldn't bother acknowledging such primitive baiting; this variety of low-hanging fruit is too easy. I hope you could come up with better ways to undermine an argument, though. Please research this between your thousands of Rennlist posts.
Cheers!
You say stuff. A lot of stuff. Over 6000 posts in a decade. Sometimes what you say is peppered with things that make sense, but other times ... not so much. Like here:
Never said nor implied this. Neither did the quote I'd posted. Thanks, though, for setting up the pretty straw man argument. Its fun to knock things down. Wheee!
What I am saying is that 205/255 tire combination, in concert with other 993 stick components, leads to understeer. If a person is changing wheels and tires, it makes sense to try to bring the car a little close to neutral behavior with choosing 225/255 combination instead of insisting on 205/255 and fighting it elsewhere, hoping that there will be enough adjustment and that that adjustment will not result in other undesirable behavior.
Cheers!
#60