Hotchkis Sport Sway Bars 2005+ Ford Mustang
05-08-2008, 12:21 AM
#13
2nd Gear Member
Join Date: Dec 2006
Location: Tri Cities, TN
Posts: 452
RE: Hotchkis Sport Sway Bars 2005+ Ford Mustang
Jeez man, who pissed in who's Wheaties? Maybe you're having a bad week, or maybe you just don't like being questioned, but I made no personal references to you, why the personal attack? I was hoping to elevate this thread to a more technical discussion, as in Norm's response, not just a "Sam Strano says..." thread. Get over yourself, man. Your attitude sucks.
You're obviously not a complete moron, but you are a self congratulatingass to the n'th proportion, on your own high horse. Unlike you, I have no agenda here,contrary to your opinion. Oh, and please don't stop posting. Some of these guys really think you're something.
You're obviously not a complete moron, but you are a self congratulatingass to the n'th proportion, on your own high horse. Unlike you, I have no agenda here,contrary to your opinion. Oh, and please don't stop posting. Some of these guys really think you're something.
ORIGINAL: Sam Strano
steelcomp... who pissed in your Wheaties? If you want to think I'm a complete moron, that's fine but it won't stop me from posting.
As for bar comparisons, most folks use 1045 spring steel. The bar has to fit in the stock location and you can see by looking that it clearly does. The front bar has the same endlink position too. While I agree that if a bars shape or length changes in any tangible way it will effect the stiffness, the fact is that doesn't apply to these bars. Further the front bar stock from Ford is hollow, as is the Hotchkis so there are no worries about "one is solid so what about the big of stiffness that adds". And all you have to do is sit down, and do the math. D to the 4th power. Compare what 34 to the 4th is vs. 38 to the 4th and tell me you come up with 20% difference.
And regarding endlink holes or adjustment. Changing lever arm length is no way equivilent to a 4mm change in diameter. Example, two like size bars, one with a 10" arm the other with a 5" arm. The 5" arm will offer you twice the roll stiffness as the 10" bar with the same diameter... but here we aren't talking about cutting the arm in half, nowhere near that. In fact, having just measured a stock bar the lever arm is about 15" long, and the most you can shorten it without the endlinks getting too far from vertical is about 2.5" at best, or about 16-17%. So no I don't buy that the bar is only 20% stiffer than stock on the softest hole.
And what's more, I've played with bars on these cars already. And in fact a hollow 35mm bar with the softest hole about 1/4" further back is indeed stiffer than the stock 34mm bar. How do I know? I've tested it, and the response rate was up in the car, as was at the limit understeer (I tested that front with a stock GT front bar at first, and later wtih a hollow rear bar we're working on of 22mm diameter).
Ford hit the relative bar balance pretty close to on the head with this car. Some whatstiffer, and that's fine, some some more rear bar vs. front, and that's fine, butthey are damnedclose and not at all small bars. I don't really feel this car needs massively differnet bars, and historically I would change bars on a lot of cars, including other Mustangs right away. Not here. If more roll stiffness is warranted, that's fine and it can be used, but you seem to think that 38/25 is not a massive increase, and you're wrong. Further, you seem to think that as long as you look at the bars front to rear and keep their relative increase of roll stiffness the same that the balance will remain the same when it fact it will not due to the fact a solid rear axle acts nothing like the front end dynamically.
To each his own. If I told you the sky was blue you'd say I was lying and tooting my own horn. I can't please everyone, and I'm not going to try. And fwiw, why would I tell folks this considering I sell the very bars in question? You think I'm some sort of snake oil saleman I guess. I could have popped in and said "those bars are perfect, run them" and tried to make theeasy sale you seem to think I'm after by having the nerve to pay to advertise on this site. But in reality.... I don't think those are the right bars, period. And because I sell those bars I'd hope folks would realize I'm saying that becaue that's how I feel, and not because I don't carry the line.
Nothing is absolute. Hotchkis's thing is massive bars. Always has been, pick a car they make bars for and you'll find they are way bigger than anyone else's. That's just their MO. That's fine and I don't know why, nor do I really care because they also think that regular off the shelf Bilstein HD'sare fine for lowering springs, when in fact for years Bilstein own documention saidthere weren't. I guess Bilstein was lying? I guess that nobody could do any better.
Might I ask that youjump down off you high-horse and if you wish to discuss something to do so inaway thatbetter hides youdisdain for me? If you want to discuss, we can discuss.
steelcomp... who pissed in your Wheaties? If you want to think I'm a complete moron, that's fine but it won't stop me from posting.
As for bar comparisons, most folks use 1045 spring steel. The bar has to fit in the stock location and you can see by looking that it clearly does. The front bar has the same endlink position too. While I agree that if a bars shape or length changes in any tangible way it will effect the stiffness, the fact is that doesn't apply to these bars. Further the front bar stock from Ford is hollow, as is the Hotchkis so there are no worries about "one is solid so what about the big of stiffness that adds". And all you have to do is sit down, and do the math. D to the 4th power. Compare what 34 to the 4th is vs. 38 to the 4th and tell me you come up with 20% difference.
And regarding endlink holes or adjustment. Changing lever arm length is no way equivilent to a 4mm change in diameter. Example, two like size bars, one with a 10" arm the other with a 5" arm. The 5" arm will offer you twice the roll stiffness as the 10" bar with the same diameter... but here we aren't talking about cutting the arm in half, nowhere near that. In fact, having just measured a stock bar the lever arm is about 15" long, and the most you can shorten it without the endlinks getting too far from vertical is about 2.5" at best, or about 16-17%. So no I don't buy that the bar is only 20% stiffer than stock on the softest hole.
And what's more, I've played with bars on these cars already. And in fact a hollow 35mm bar with the softest hole about 1/4" further back is indeed stiffer than the stock 34mm bar. How do I know? I've tested it, and the response rate was up in the car, as was at the limit understeer (I tested that front with a stock GT front bar at first, and later wtih a hollow rear bar we're working on of 22mm diameter).
Ford hit the relative bar balance pretty close to on the head with this car. Some whatstiffer, and that's fine, some some more rear bar vs. front, and that's fine, butthey are damnedclose and not at all small bars. I don't really feel this car needs massively differnet bars, and historically I would change bars on a lot of cars, including other Mustangs right away. Not here. If more roll stiffness is warranted, that's fine and it can be used, but you seem to think that 38/25 is not a massive increase, and you're wrong. Further, you seem to think that as long as you look at the bars front to rear and keep their relative increase of roll stiffness the same that the balance will remain the same when it fact it will not due to the fact a solid rear axle acts nothing like the front end dynamically.
To each his own. If I told you the sky was blue you'd say I was lying and tooting my own horn. I can't please everyone, and I'm not going to try. And fwiw, why would I tell folks this considering I sell the very bars in question? You think I'm some sort of snake oil saleman I guess. I could have popped in and said "those bars are perfect, run them" and tried to make theeasy sale you seem to think I'm after by having the nerve to pay to advertise on this site. But in reality.... I don't think those are the right bars, period. And because I sell those bars I'd hope folks would realize I'm saying that becaue that's how I feel, and not because I don't carry the line.
Nothing is absolute. Hotchkis's thing is massive bars. Always has been, pick a car they make bars for and you'll find they are way bigger than anyone else's. That's just their MO. That's fine and I don't know why, nor do I really care because they also think that regular off the shelf Bilstein HD'sare fine for lowering springs, when in fact for years Bilstein own documention saidthere weren't. I guess Bilstein was lying? I guess that nobody could do any better.
Might I ask that youjump down off you high-horse and if you wish to discuss something to do so inaway thatbetter hides youdisdain for me? If you want to discuss, we can discuss.
05-09-2008, 07:32 AM
#14
2nd Gear Member
Join Date: Jan 2006
Location:
Posts: 184
RE: Hotchkis Sport Sway Bars 2005+ Ford Mustang
Since this has turned into a techincal discussion about sway bars I have a question. Explain why a larger rear bar is often recomended when you start running a staggered wheel set up? To be more specific I am now running 255/45r18 up front and 285/40r18 in rear. I have vogtland gt500 spec springs, koni yellow's, lower control arms, adjustable panhard rod w/ brace. caster camber plates up front. upper rear control arm. The car was feeling good with the stock tires and the front struts set at one turn in from full soft and the rear set at 1.5 turns in from full soft. when I added the new wheel and tires the *** end started to feel different. I do not have a lot of seat time behind the new wheels and tires and I realize that it will take some getting used too. I have read on other posts in the past about rear sway bar recomendations for those doing the staggered wheel thing. If any one can educate me on the this area and make some set up recomendations to me it would be great.Also would I benefit from asteedax5 balljoints and do you have to tun them with a bumbsteer kit?
05-09-2008, 08:14 AM
#15
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
RE: Hotchkis Sport Sway Bars 2005+ Ford Mustang
What you're trying to do is re-balance the slip angles (which is adefinition of either understeer or oversteer that can actually have a number attached to it - in vehicle dynamics there is something called "understeer budget" that slip angles are one component of).
When you put larger tires on the rear the usual effect is that the rear tires will now need less slip angle during any given corner. Meanwhile the front tire slip anglesremain unchanged. More slip angle up front relative to the rear (or less slip angle in the rear relative to the front in this case) means that the front wants to run wide more than the rear does, which is an understeer effect. So you want to make the rear a little "looser" to put the balance back where it was. One way to do this is by making more of the lateral load transfer happen out back, because the more unequally either pair of tires are loaded the less total grip they have - and since this is true at any slip angle, the rears will always slip a little more with the larger bar in place.
You do have to be a little careful with this sort of tuning- all the usual caveats about "everything else remains the same" apply. It's most applicable when the larger rear tires are simply wider sizes in the same tire make/model as before (which were hopefully the same make/model as the fronts). And when the wider tires are mounted on comparably wider wheels.
It may demand more from the driver, since the extra lateral load transfer that helps your steady-state cornering means that you won't be able to add throttle on corner exit quite as soon or quite as fast as you might have been able to with the smaller bar. IOW, faster but less forgiving up around the limits.
Norm
When you put larger tires on the rear the usual effect is that the rear tires will now need less slip angle during any given corner. Meanwhile the front tire slip anglesremain unchanged. More slip angle up front relative to the rear (or less slip angle in the rear relative to the front in this case) means that the front wants to run wide more than the rear does, which is an understeer effect. So you want to make the rear a little "looser" to put the balance back where it was. One way to do this is by making more of the lateral load transfer happen out back, because the more unequally either pair of tires are loaded the less total grip they have - and since this is true at any slip angle, the rears will always slip a little more with the larger bar in place.
You do have to be a little careful with this sort of tuning- all the usual caveats about "everything else remains the same" apply. It's most applicable when the larger rear tires are simply wider sizes in the same tire make/model as before (which were hopefully the same make/model as the fronts). And when the wider tires are mounted on comparably wider wheels.
It may demand more from the driver, since the extra lateral load transfer that helps your steady-state cornering means that you won't be able to add throttle on corner exit quite as soon or quite as fast as you might have been able to with the smaller bar. IOW, faster but less forgiving up around the limits.
Norm
05-09-2008, 10:35 AM
#17
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
RE: Hotchkis Sport Sway Bars 2005+ Ford Mustang
Can't make any specific suggestions until I have some measurements. For a guess, I'd say whatever amount more bar gives additional wheel rate equal to about what 10% of the rear spring rate would do and go from there.
Right about here I'll grumble a bit about most S197 sta-bar adjustabilities being on the front bars only, as it just isn't as logical to tweak the bar that's primarily responsible for limiting roll for balance while leaving the rear bar that's on there for balancing the roll couple in the first place alone. I'd like to see an infinitely-adjustable rear bar, but that's probably a separate rant.
Missed the X-5 balljoint item earlier - anything you do to a strut suspension that affects the inclination of the LCAs relative to the tierods means that the bumpsteer will be affected, so yes.
Norm
Right about here I'll grumble a bit about most S197 sta-bar adjustabilities being on the front bars only, as it just isn't as logical to tweak the bar that's primarily responsible for limiting roll for balance while leaving the rear bar that's on there for balancing the roll couple in the first place alone. I'd like to see an infinitely-adjustable rear bar, but that's probably a separate rant.
Missed the X-5 balljoint item earlier - anything you do to a strut suspension that affects the inclination of the LCAs relative to the tierods means that the bumpsteer will be affected, so yes.
Norm
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