F/R S197 Sway-Bar Rates

[Whiskey11]

Yeah, the fronts are very aggressive. They're going to be in the 600-1150 range, depending on position. I will share Monday after I finish the calculations.

I dont suppose BMR is looking for a vocal, tech driven, well built car to represent your new forray into the handling market are you?

 

[BMR Tech]

I am going over some final things, before releasing our new bars.

Just thought I would share some info on our new bars we are releasing here in a few weeks.

SB041 (front sway bar)
Hole 1 - 706
Hole 2 - 788
Hole 3 - 886
Hole 4 - 1002
Hole 5 - 1144

SB042 (Rear Bar)
Hole 1 - 224 (for comparison, Boss LS is 272~)
Hole 2 - 259
Hole 3 - 302
Hole 4 - 356


We felt that the market is saturated with front bars that are all around the same range in stiffness....and the rear, we just completely developed a unique design that should be useful for many people. Of course, the people who want little to no bar out back....will not be fond of the rear having a minimum rate of 224lb/in.

I can finally offer some of my customers what they want. I get asked all the time "do you have a huge front bar that is stiffer than all the other 35mm offerings on the market".....I do now.

 

[Whiskey11]

I am going over some final things, before releasing our new bars.

Just thought I would share some info on our new bars we are releasing here in a few weeks.

SB041 (front sway bar)
Hole 1 - 706
Hole 2 - 788
Hole 3 - 886
Hole 4 - 1002
Hole 5 - 1144

SB042 (Rear Bar)
Hole 1 - 224 (for comparison, Boss LS is 272~)
Hole 2 - 259
Hole 3 - 302
Hole 4 - 356


We felt that the market is saturated with front bars that are all around the same range in stiffness....and the rear, we just completely developed a unique design that should be useful for many people. Of course, the people who want little to no bar out back....will not be fond of the rear having a minimum rate of 224lb/in.

I can finally offer some of my customers what they want. I get asked all the time "do you have a huge front bar that is stiffer than all the other 35mm offerings on the market".....I do now.

The rear bar rates don't "wow" me nearly as much because we lost a good portion of the motion ratio of the bar when you switched from the stock location to just inside the lower control arm mounting points. The rear bar will most likely end up being a "wash" in the rear wheel rate department.

The front bar rate wows me though, that's a lot of bar! Nearly double Sam's bar on the stiffest setting.

 

[BMR Tech]

^ Correct, on the rear bar.

That is why we made the rates higher, to compensate for the inward mounts.

That is also why I am so interested to know the rates of the WL rear bar....due to the method it is mounted to the axle. People rave about it.....so I dunno?

I am going to have a meeting with my product design engineer and see what he has to say about the rates we are publishing, and see if he can provide me with some more data behind the motion ratio loss. As in....how is a 356lb/in in our design, compared to say a 272 rate of the Boss LS.

 

[Whiskey11]

^ Correct, on the rear bar.

That is why we made the rates higher, to compensate for the inward mounts.

That is also why I am so interested to know the rates of the WL rear bar....due to the method it is mounted to the axle. People rave about it.....so I dunno?

I am going to have a meeting with my product design engineer and see what he has to say about the rates we are publishing, and see if he can provide me with some more data behind the motion ratio loss. As in....how is a 356lb/in in our design, compared to say a 272 rate of the Boss LS.

Distance between the center line of the wheels minus the distance between the swaybar mounts should give you the motion ratio of the bar in roll. Or for less tape measure, distance between wheel center line and swaybar mount doubled.

I'd ask though, I think it'll more or less end up being a wash with some of the stiffer bars but I have no math/tech to back it up other than just an observation.

 

[2013DIBGT]

God damn! That IS a hell of a lot of bar out back. Seems like a perfect upgrade for the drift crowd though.

On a serious note, what would a hypothetical suspension configuration look like that would use bars of these rates and actully handle well and be drive able somewhere other than a parking lot? I'm not trying to be funny here, I'm genuinely interested in knowing.

 

[csamsh]

On a serious note, what would a hypothetical suspension configuration look like that would use bars of these rates and actully handle well and be drive able somewhere other than a parking lot? I'm not trying to be funny here, I'm genuinely interested in knowing.

That depends on your dampers, springs, wheels, tires, driving style, and how you like your car setup.

 

[Whiskey11]

God damn! That IS a hell of a lot of bar out back. Seems like a perfect upgrade for the drift crowd though.

On a serious note, what would a hypothetical suspension configuration look like that would use bars of these rates and actully handle well and be drive able somewhere other than a parking lot? I'm not trying to be funny here, I'm genuinely interested in knowing.

Also keep in mind that their rear bar has a different routing, slightly, than factory that changes the rate the contact patch actually sees. It may not be too much more than the LS bar.

 

[EGNARO]

just out of curiosity how is this measured?


i have a buddy that has a steed front sway bar on his car, while i have a stock bar with adjustable end links turned all the way out and i find that my setup is stiffer than his

 

[Whiskey11]

just out of curiosity how is this measured?


i have a buddy that has a steed front sway bar on his car, while i have a stock bar with adjustable end links turned all the way out and i find that my setup is stiffer than his

You need to know the sway bar rate for his chosen location and your stock bar rates then factor in the motion ratio and go from there. Up front you can use the strut's motion ratio for the calculation.

Wheel Rate = Spring Rate x (Motion Ratio)^2

Substitute spring rate for bar rate and you will get a highly simplified version of what is going on. There are other things to factor to make the calculation more accurate but the above will give you a relative comparison to work with.

 

[sheizasosay]

Whut whiskers is tryin' to say is: ain't never gone be no need to worry bout no maff formulas if yuh just pertend ain't no such thang as unicorns.

Let me translate my other self: that swaybar isn't much different than a typical adj rear swaybar in regards to roll stiffness.

 

[EGNARO]

You need to know the sway bar rate for his chosen location and your stock bar rates then factor in the motion ratio and go from there. Up front you can use the strut's motion ratio for the calculation.

Wheel Rate = Spring Rate x (Motion Ratio)^2

Substitute spring rate for bar rate and you will get a highly simplified version of what is going on. There are other things to factor to make the calculation more accurate but the above will give you a relative comparison to work with.

alright cool thanks for the info ill research a bit

 

[BMR Tech]

We got the new front bar up on our site this morning.

http://www.bmrsuspension.com/index.cfm?page=products&productid=1340&superpro=0

Hoping to have the rear bar up soon.

 

[2013DIBGT]

We got the new front bar up on our site this morning.

http://www.bmrsuspension.com/index.cfm?page=products&productid=1340&superpro=0

Hoping to have the rear bar up soon.

Considering all the talk about posting swaybar rates in this thread I'm curious as to why in the end there are no actual rates listed in the link above for this bar (or any bar on the site for that matter) for the various adjustment holes?

Sure, a little math could help figure out the rates while using the softest and hardest setting as a guide but who wants to do math

Maybe I'm just a retard but going on the percentages listed for the 11-14 model year cars one could come to the conclusion that the stiffness settings would be as follows for each of the various holes but as seen below Hole 5 would appear to be 29% +- stiffer then what is listed (162%) assuming a increase of 32.4% per hole (ie..162 divided by 5)

Hole 1 = 62% Stiffer
Hole 2 = 94.4% Stiffer
Hole 3 = 126.8% Stiffer
Hole 4 = 159.2% Stiffer
Hole 5 = 191.6% Stiffer

Listing percentages are great and all but I feel they tend to leave too much to the imagination as seen here.

 

[BMR Tech]

^ Call the number in my sig, and ask for Pete in the marketing dept. He can probably answer that for you. I requested rates to be in the description, but I guess he wants to stick with the typical % increase stuff.

As for this front bar, all someone had to do is ask me. I'll gladly share the rates. For you, well....there's a post above with the info.