Questions about New F-Sport Front/Rear Sway bar for AWD
03-04-09, 04:29 PM
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Questions about New F-Sport Front/Rear Sway bar for AWD
Have you guys seen these? they have them on sale at sewell and i have a couple of questions regarding the specs. maybe i'm not understanding sway bars in general.
1. Front Bar Specifications - Stiffness Increase (versus OE IS250) - 50% Increase
Do we even want this? the AWD already understeers as it is... and stiffer front means more understeer right? do we really need more understeer for the front?
2. Rear Bar Specifications
Size - 17.5 mm diameter solid bar
Spring Rate - 59.6 N/mm
Stiffness Increase (versus OE IS250) - 145% Increase
This makes no sense to me. The specs I took off of f-sport.com gave specs for the old AWD rear bar (same as RWD rear):
Size - 19 mm diameter solid bar
Spring Rate - 81 N/mm
Stiffness Increase (vs. IS250AWD) - 42.8%
How does a smaller diameter bar, with a lower spring rate, create a whole 100% more stiffness for the rear? am i understanding spring rate wrong?
1. Front Bar Specifications - Stiffness Increase (versus OE IS250) - 50% Increase
Do we even want this? the AWD already understeers as it is... and stiffer front means more understeer right? do we really need more understeer for the front?
2. Rear Bar Specifications
Size - 17.5 mm diameter solid bar
Spring Rate - 59.6 N/mm
Stiffness Increase (versus OE IS250) - 145% Increase
This makes no sense to me. The specs I took off of f-sport.com gave specs for the old AWD rear bar (same as RWD rear):
Size - 19 mm diameter solid bar
Spring Rate - 81 N/mm
Stiffness Increase (vs. IS250AWD) - 42.8%
How does a smaller diameter bar, with a lower spring rate, create a whole 100% more stiffness for the rear? am i understanding spring rate wrong?
Last edited by Foodplz; 03-04-09 at 09:46 PM.
03-05-09, 10:09 AM
#2
You know I thought the same thing when I read the specs. I wondered if they paired a softer rear bar since they were upping the front bar spring rate? I have the original F-Sport rear bar now and it works wonders for the handling, but now I thinking possibly I could not use the front bar from this new AWD set with my rear bar. Possibly they are engineered as a set. The other explanation is that Sewell posted the wrong info for the bar specs. And yes that 145% vs the 42.8% for the larger bar with a higher spring rate has got to be wrong.
03-31-09, 04:53 PM
#3
I did find out tha for those of us IS250 AWD folks who bought the rear bar already, according to Sewell there is now a matching front bar - part PTR02-53085. Quoted price of $286.
04-04-09, 08:42 AM
#6
I don't know about stiffness increases, I always took the figures listed by Lexus for stiffness increases for the F-Sport sway bars with a grain of salt. They just looked wrong to me.
As you have noted the AWD IS now has a new set of bars, unique to it. It no longer shares the rear bar with the set for RWD IS models.
IMHO, this new set makes for a better package for the AWD car. The front and rear bars are now matched to each other.
I have attached a word document with the specs of all IS sway bars, as I know them.
BTW, Mr. nubbun, you are incorrect.
Lou
As you have noted the AWD IS now has a new set of bars, unique to it. It no longer shares the rear bar with the set for RWD IS models.
IMHO, this new set makes for a better package for the AWD car. The front and rear bars are now matched to each other.
I have attached a word document with the specs of all IS sway bars, as I know them.
BTW, Mr. nubbun, you are incorrect.
Lou
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