ba-b4

I just got my F sways but haven't really looked at them to see what size they are. Maybe I should go check again. Will get them installed next week maybe and report back on how they feel.

darkdream

if they are too stiff they will induce oversteer; however, just making them stiffer will not...especially since the F sport parts are from lexus, they aren't going to sell parts that induce oversteer,

carchitect

iTrader: (1)

IS250/350 RWD swaybars specs:

ft Dia mm 27.2 X t5.0
rate N/mm 132.9
rr Dia mm 15
rate N/mm 32.2

IS AWD swaybar spec:

ft Dia mm 26.5 X t4.5
rate N/mm 111.0

rr Dia mm 14
rate N/mm 24.5

IS-F swaybar spec:

ft Dia mm 28.6 X t4.0
rate N/mm 141.3

rr Dia mm 16
rate ?

F-sport spec

ft Dia mm 28.6 X t4.0
rate N/mm 141.3

rr Dia mm 19
rate N/mm 81

Its apparent the F-sport front is exactly the same as the OEM IS-F swaybar. The rear is different though and can be purchase seperately if one were to purchase it for the AWD model. The AWD model's front is significantly different from the RWD cars and the F-sport front will not work for it. The F-sport swaybar does come with poly urethane bushings which is definitely an improvement over the rubber OEM ones.

-Joe

Sgt_K

So let me get this straight...

The stock 250 is 27.2mm in the front and 15mm rear, the "F" is only a 28mm front with a 19mm rear.... What’s the point to buying the "F" ones if their only one millimeter bigger? I looked into the F sway bars and I didn’t find any information whether or not they are solid or tubular like the stock bars. The Hotchkis ones are larger in diameter but they are also tubular, which is ok because it doesn’t add a lot of extra weight to the car. And solid sway bars are only used in racing applications. As far as I can tell the only advantage to the F bars could have over the Hotchkis is if they are solid, but for the price they are selling them for I am willing to bet that they are just a slightly larger sway bar set from stock with polyurethane bushings. So realistically speaking, the only thing your spending $495 on is a set of polyurethane bushings…. LAME!

Kurtz

iTrader: (1)

You wouldn't be buying the F-sport bars for the slightly larger front bar, you'd be buying it for the significantly larger rear bar, which should mean considerably less understeer than stock...



So the bars are

Front:
27.2 stock, the F-sport are 28.6, and the Hotchkis are 32

Rear:
15 stock, F-sport are 19, Hotchkis are 19

Interesting both Hotchkis and F-sport went same size rear, but the Hotchkis bar is significantly bigger in the front...

All else being equal larger front bar=more understeer.

Now, of course, the Fsport and Hotchkis bars could be vastly different stiffness due to materials or geometery... some else would have to speak to those... but if they're similar then the diameters would suggest the F-sport setup would have -less- understeer than the Hotchkis one, which is surprising.

ba-b4

If the IS-F's front bar is also 28.6 then that's good enough for me. Plus if you get the F sport sways installed by the dealer you still get your warranty in place. The price difference between the Hotchkis and F sport isn't enough of a difference to choose Hotchkis. At least not for me.

GSteg

iTrader: (15)

It could be 1mm bigger on the outside, but what if the inner diameter is actually smaller? 1mm could make a big difference.

AndyL

Hi all,

I am a complete novice to swaybars. With swaybar such as F-sport one , will it reduce the durability of the chassis? Besides, will it reduce the ability of dissipate the shock coming from potholes or cracks on the road when compared to stock?

Thanks

Gernby

iTrader: (1)

^^^ Anything that you do to stiffen the suspension will add stress to the rest of the car which will lead to more flexing and rattles.

AndyL

Hi Gernby,

Thanks for your response. So would just adding a F-sport brace also has the same drawback? From my understanding, it reduces the flex of the chassis.

lobuxracer

iTrader: (2)

Despite all the hoopla about it, I don't really think the F-sport brace will do much of anything, but even if it does what it is advertised to do, it would only stiffen the chassis, not the suspension. It may still present issues at some point in it's service life for someone who drives extremely aggressively, but not at any mileage a street driver would see.

al503

For a hardcore track junkie, it might have some benefit. Otherwise, I think of it as more dead weight.

suicidesam

this thread is funny...

nabbun

^^^ why do you say that?

carchitect

iTrader: (1)

IMO, the F-sport brace does a lot of benefit for the vehicle. Every unibody vehicle has frame sections that hold the chassis together and help reduce the flexing to some point. The rear frame section rises up from the floor to head rearwards right after the rear of the floor pan. The frame then makes its way all the way to the rear of the vehicle. The F-sport brace helps triangulate this area and strengthen the rear frame so the suspension can do the work. If you still think these braces don't help, look under the rear of an Acura NSX and then make your decision if its important or not.





Anytime the chassis of the vehicle is stiffened the suspension does the job better which results in a predictable and consistent driver's feedback and control. It can help reduce the chances of snap oversteer followed after understeer.

The F-sport sway are designed for the F-sport suspension. While they will work out great for the stock suspension they are designed for the f-sport suspension. Some of the guys may need stiffer stuff and if thats the case they should look into the Hotchkis sways. The Hotchkis sways have a larger front and maybe desirable to those of you who are running a set of coilovers designed for roadrace.

For the Supra I'm planning on running 900 lbs/in front springs and 700 lbs/in rear springs along with shocks which have valves tailored for it. Its the Japan Ohlins road race setup. Needless to say the OEM swaybars ot even the aftermarket swaybars won't do much for a car running this stiff. So I had a set of custom swaybars made from MVP motorsports that were 36mm front and 26mm rear.

I also feel my sport pack IS350 has a tendency to understeer. Funny thing is that since I've lowered the front, (to make it look even) the vehicle drives like it was except the understeer tendency has been significantly reduced. I really thought 1/2" drop won't be that much of a difference.