Swaybar stiffness. Such thing as too stiff?
03-23-2019, 09:21 PM
#1
Thread Starter
Swaybar stiffness. Such thing as too stiff?
Hey guys. Recently been pondering this. I haven’t really seen this being this discussed, so hoping to look for clarification here.
To my understanding, you want to go as stiff as possible for coilover spring-rate, as long as the damping can handle it, and it can still properly absorb bumps. However, is there a limit to how stiff you can go with sway bars? Does going too stiff limit the ability of the coilovers to soak up bumps?
Currently on stock ohlins dfvs, 245 rs4 non-staggered, with Karcepts front bar on medium setting, and 00’ ap1 rear sway (car is an ap2). Car handles great. What got me curious though, it seems like a decent amount of people are running Miata rear sways, and aftermarket options also seem to be low-stiffness.
To my understanding, you want to go as stiff as possible for coilover spring-rate, as long as the damping can handle it, and it can still properly absorb bumps. However, is there a limit to how stiff you can go with sway bars? Does going too stiff limit the ability of the coilovers to soak up bumps?
Currently on stock ohlins dfvs, 245 rs4 non-staggered, with Karcepts front bar on medium setting, and 00’ ap1 rear sway (car is an ap2). Car handles great. What got me curious though, it seems like a decent amount of people are running Miata rear sways, and aftermarket options also seem to be low-stiffness.
03-24-2019, 06:32 AM
#3
At some point you will lose compliance and lift tires off the ground, which is obviously not good for traction. The reason for the stiff front bar normally used on the s2000 is to counteract rear wheel lift and to make the vehicle handle more neutral with a square setup. This is something that the AutoX people use because the B/C street category only allows changing of one bar. People change to the softer Miata bars to combat snap oversteer and again with a square setup would help to make the car more neutral again. You have added front grip by going square and this would cause the car to oversteer worse. I have the Karcepts .25 bar and started on max and really wondered what the heck was up with how badly it handled. It horribly understeered, so I would just throw it into the corners to get rotation and would just end up spinning out. I want to get the Karcepts rear bar to soften it, so I could also soften the front a bit more. Currently have it on the middle setting and seems to handle great now!
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kt411gcn (03-25-2019)
03-24-2019, 09:07 AM
#4
Thread Starter
Setup has been great for me. It is borderline oversteer at mid/low speeds. It is one turn on the ohlins adjustment knob away from being neutral-handling.
03-24-2019, 09:10 AM
#5
Thread Starter
At some point you will lose compliance and lift tires off the ground, which is obviously not good for traction. The reason for the stiff front bar normally used on the s2000 is to counteract rear wheel lift and to make the vehicle handle more neutral with a square setup. This is something that the AutoX people use because the B/C street category only allows changing of one bar. People change to the softer Miata bars to combat snap oversteer and again with a square setup would help to make the car more neutral again. You have added front grip by going square and this would cause the car to oversteer worse. I have the Karcepts .25 bar and started on max and really wondered what the heck was up with how badly it handled. It horribly understeered, so I would just throw it into the corners to get rotation and would just end up spinning out. I want to get the Karcepts rear bar to soften it, so I could also soften the front a bit more. Currently have it on the middle setting and seems to handle great now!
03-24-2019, 10:18 AM
#6
Going square induces far more understeer than stock. Therefore, you want to stiffen the front and soften the rear. You have done so with the front bar. Now, change the rear bar to an '04 or later, and you'll notice the handling shift towards neutral immediately.
03-24-2019, 11:28 AM
#7
Thread Starter
The suspension setup changes you recommended are for a setup that is oversteering.
My setup is borderline oversteer, one click on ohlins away from neutral.
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03-24-2019, 01:10 PM
#8
You didn't say where. On the street? At track days? In Autocrosses? Each has different criteria.
For example, competitive competition classes have rules, where w2w or not. Street autocross classes can't lower the car, must use OEM springs, can't use offset ball joints limiting front camber to -1.9°. STR limits rims to 9" width, tires to 255. Can't use metal bushings. The negative camber that would be optimal on track would cause excessive tread wear on the street.
For track cars, that is often the most important criteria with enough other cars running to establish what is the best practice.
For street cars, a driver will never be at continuous maximum lateral forces. First, there are few street turns tight enough and fast enough to be at the limit. Second, if you are at the limit all the time, eventually you go past it, with really bad outcomes on the street. Third, on the street there are oncoming cars, pedestrians, police, and the assumption you stay in your own lane. So feel is much more important. The Mazda Miata is widely praised but runs on narrow tires with a fairly soft suspension.
That stiff front bar makes it seem more responsive on the street from my personal experience.
On the track, the combination of springs, bars, and shocks will depend on the track surface, the track shape, speeds involved, and aerodynamics. Generally less stiff adds more mechanical grip and more aero needs stiffer springs. With the short wheelbase, many have found they went to stiffer springs to control pitch (e.g. brake dive) and roll, requiring less from the anti-roll bars.
If you search the threads here you will find cars running competitively in SCCA E/Production and T3, and NASA TT3, TT4, and TT5. In autocross SCCA A/Street (well, there used to be A/Street CRs), B/Street, STR, and DSM (with 315/30 Hoosier A7 tires). Plus large numbers of owners running track days. You could PM them for their specific recommendations.
For example, competitive competition classes have rules, where w2w or not. Street autocross classes can't lower the car, must use OEM springs, can't use offset ball joints limiting front camber to -1.9°. STR limits rims to 9" width, tires to 255. Can't use metal bushings. The negative camber that would be optimal on track would cause excessive tread wear on the street.
For track cars, that is often the most important criteria with enough other cars running to establish what is the best practice.
For street cars, a driver will never be at continuous maximum lateral forces. First, there are few street turns tight enough and fast enough to be at the limit. Second, if you are at the limit all the time, eventually you go past it, with really bad outcomes on the street. Third, on the street there are oncoming cars, pedestrians, police, and the assumption you stay in your own lane. So feel is much more important. The Mazda Miata is widely praised but runs on narrow tires with a fairly soft suspension.
That stiff front bar makes it seem more responsive on the street from my personal experience.
On the track, the combination of springs, bars, and shocks will depend on the track surface, the track shape, speeds involved, and aerodynamics. Generally less stiff adds more mechanical grip and more aero needs stiffer springs. With the short wheelbase, many have found they went to stiffer springs to control pitch (e.g. brake dive) and roll, requiring less from the anti-roll bars.
If you search the threads here you will find cars running competitively in SCCA E/Production and T3, and NASA TT3, TT4, and TT5. In autocross SCCA A/Street (well, there used to be A/Street CRs), B/Street, STR, and DSM (with 315/30 Hoosier A7 tires). Plus large numbers of owners running track days. You could PM them for their specific recommendations.
The following users liked this post:
kt411gcn (03-25-2019)
03-24-2019, 09:50 PM
#9
Thread Starter
You didn't say where. On the street? At track days? In Autocrosses? Each has different criteria.
For example, competitive competition classes have rules, where w2w or not. Street autocross classes can't lower the car, must use OEM springs, can't use offset ball joints limiting front camber to -1.9°. STR limits rims to 9" width, tires to 255. Can't use metal bushings. The negative camber that would be optimal on track would cause excessive tread wear on the street.
For track cars, that is often the most important criteria with enough other cars running to establish what is the best practice.
For street cars, a driver will never be at continuous maximum lateral forces. First, there are few street turns tight enough and fast enough to be at the limit. Second, if you are at the limit all the time, eventually you go past it, with really bad outcomes on the street. Third, on the street there are oncoming cars, pedestrians, police, and the assumption you stay in your own lane. So feel is much more important. The Mazda Miata is widely praised but runs on narrow tires with a fairly soft suspension.
That stiff front bar makes it seem more responsive on the street from my personal experience.
On the track, the combination of springs, bars, and shocks will depend on the track surface, the track shape, speeds involved, and aerodynamics. Generally less stiff adds more mechanical grip and more aero needs stiffer springs. With the short wheelbase, many have found they went to stiffer springs to control pitch (e.g. brake dive) and roll, requiring less from the anti-roll bars.
If you search the threads here you will find cars running competitively in SCCA E/Production and T3, and NASA TT3, TT4, and TT5. In autocross SCCA A/Street (well, there used to be A/Street CRs), B/Street, STR, and DSM (with 315/30 Hoosier A7 tires). Plus large numbers of owners running track days. You could PM them for their specific recommendations.
For example, competitive competition classes have rules, where w2w or not. Street autocross classes can't lower the car, must use OEM springs, can't use offset ball joints limiting front camber to -1.9°. STR limits rims to 9" width, tires to 255. Can't use metal bushings. The negative camber that would be optimal on track would cause excessive tread wear on the street.
For track cars, that is often the most important criteria with enough other cars running to establish what is the best practice.
For street cars, a driver will never be at continuous maximum lateral forces. First, there are few street turns tight enough and fast enough to be at the limit. Second, if you are at the limit all the time, eventually you go past it, with really bad outcomes on the street. Third, on the street there are oncoming cars, pedestrians, police, and the assumption you stay in your own lane. So feel is much more important. The Mazda Miata is widely praised but runs on narrow tires with a fairly soft suspension.
That stiff front bar makes it seem more responsive on the street from my personal experience.
On the track, the combination of springs, bars, and shocks will depend on the track surface, the track shape, speeds involved, and aerodynamics. Generally less stiff adds more mechanical grip and more aero needs stiffer springs. With the short wheelbase, many have found they went to stiffer springs to control pitch (e.g. brake dive) and roll, requiring less from the anti-roll bars.
If you search the threads here you will find cars running competitively in SCCA E/Production and T3, and NASA TT3, TT4, and TT5. In autocross SCCA A/Street (well, there used to be A/Street CRs), B/Street, STR, and DSM (with 315/30 Hoosier A7 tires). Plus large numbers of owners running track days. You could PM them for their specific recommendations.
03-25-2019, 06:22 AM
#10
Hey guys. Recently been pondering this. I haven’t really seen this being this discussed, so hoping to look for clarification here.
To my understanding, you want to go as stiff as possible for coilover spring-rate, as long as the damping can handle it, and it can still properly absorb bumps. However, is there a limit to how stiff you can go with sway bars? Does going too stiff limit the ability of the coilovers to soak up bumps?
Currently on stock ohlins dfvs, 245 rs4 non-staggered, with Karcepts front bar on medium setting, and 00’ ap1 rear sway (car is an ap2). Car handles great. What got me curious though, it seems like a decent amount of people are running Miata rear sways, and aftermarket options also seem to be low-stiffness.
To my understanding, you want to go as stiff as possible for coilover spring-rate, as long as the damping can handle it, and it can still properly absorb bumps. However, is there a limit to how stiff you can go with sway bars? Does going too stiff limit the ability of the coilovers to soak up bumps?
Currently on stock ohlins dfvs, 245 rs4 non-staggered, with Karcepts front bar on medium setting, and 00’ ap1 rear sway (car is an ap2). Car handles great. What got me curious though, it seems like a decent amount of people are running Miata rear sways, and aftermarket options also seem to be low-stiffness.
Yes, you can have too much spring rate in your ASB. Generally speaking you want as little spring rate as possible without running out of travel regardless if it’s from your ASB or coil springs. Caveats are running more spring rate to make your aero function better and most people find it easier to drive a car with a little more spring rate.
ASBs are springs. If you go to stiff you will over power a shock not designed for it just like you would buying a stiffer coil spring.
The following users liked this post:
kt411gcn (03-25-2019)