scott1256c

I can't seem to find any consensus on how much stiffer the f-sport sways are relative to stock.
Best guess is 150% stiffer for rear and 6% stiffer front??? But people seem to notice a difference when they put in the front sway, and I wouldn't think you would if it were only 6% stiffer. That of course makes me wonder how accurate the rear stiffness value is.

Is there any conclusion to the stiffness issue for the f-sport sways?

The hotchkis #22438 claims 83% stiffer front and for the rear, 2 adjustments, 70% or 140% stiffer.
I've added coilovers with a 13k spring rate in the front (8k rear) and am wondering if I'll even want to stiffen up the front with a sway or not, after I stiffen the rear.

Thoughts? Anyone really tried hotchkis? I can get them (delivered) for about the same price.Well, hotchkis would cost me about $60 extra (lexus san diego dropped their ebay price by $20 in the last few days).

jgr7

iTrader: (1)

Its really hard to put a number on how much stiffer it is but I just did front and rear on my IS350C and noticed much less computer intervention on the mountain road I travel home on when traffic is heavy on the highway. I just put new rims and wider tires on also so it is really hard to tell what is giving me more traction in the turns. I will also be installing my new BC BR coilovers this weekend with 12K front and 10K rear with Megan upper control arms adj camber and Megan rear camber arms.

Gville350

iTrader: (10)

^New tires helps ALOT with the traction obviously; the sways help with reducing body roll. Until someone actually cuts a stock and aftermarket bars open, we can only judge increased OD (outer diameter). We do not have a clue if any of the aftermarket items have an increased tube thickness, which is an important factor in figuring in sway bars.

scott1256c

you shouldn't have to cut it open though. It would depend on the type of steel anyway.

If you remove them, then fix one end (like clamping on a workbench, and hang a heavy weight off the other end, you should be able to get some idea of the deflection. If you tried that with the OEM vs. f-sport, you should be able to get SOME idea of the change in stiffness.

I trust Hotchkis isn't completely full of **** when they provide their numbers. I would have said the same of Lexus but it has been pointed out a few times that the 250 and 350 must either come stock with different sways, or the stated stiffness increase you'd get for each car by switching to f-sport sways must be wrong.

Gville350

iTrader: (10)

^I doubt any of us have a trusted method of measuring deflection though, the same with a tool to measure metal thicknesses without cutting one open.

Jeff Lange

iTrader: (1)

For the RWD sedan there are 3 types of front sway bar and 4 types of rear sway bar depending on year and package. IS250 and IS350 are the same.

Types of sway bars on the GSE20/21 IS250/IS350 RWD Sedan:

Front:
2006-2008
2009-2013 without sport suspension
2009-2013 with sport suspension (Sport or X-Package)

Rear:
2006-2008
2009-2013 without sport suspension
2009-2010 with sport suspension (Sport / X-Package / F-Sport)
2011-2013 with sport suspension (Sport / X-Package / F-Sport)

You'd need to get the spring rates for those and the new bars in order to compare stiffness between what you have any what you'd be getting. I don't think I've ever seen any percentages that state what they were actually comparing it to.

Jeff

240M3SRT

iTrader: (3)

I was told that the FSport swaybars were designed by Hotchkis, not that this helps your decision but interesting info none the less. I did the front and rear FSports together on my IS350 and couldnt be happier, makes the car handle incredibly well compared to how it used to. I dont even have Sport Suspension, probably my age showing but its plenty stiff over bumps now as it is:P

Jeff Lange

iTrader: (1)

The F-Sports are made by Hotchkis, though I think the ones they sell are quite a bit larger than the F-Sport ones.

Jeff

scott1256c

Well, it's interesting to know Hotchkis makes the f-sport. Don't know if that will affect my decision. Since my front springs are a bit stiffer than most peoples coils, I'm worried that adding in a stiffer sway will just make it too stiff. I'm starting to thing I should just get a rear sway, then add a front afterwards, if I feel the need.

reyoasian

iTrader: (2)

does larger mean stiffer, more rigid and better handling?

Jeff Lange

iTrader: (1)

Larger doesn't necessarily mean anything, without measuring the spring rate it would be hard to know the exact differences, but they're probably stiffer, and as such will provide less body roll than the F-Sport, but without actual spring rates it's hard to know how much stiffer they are.

Jeff

reyoasian

iTrader: (2)

I see, thanks! Too bad they don't fit AWD so I can't even buy a set to compare lol

buister

iTrader: (1)

The stock front sway is already fairly stiff on the IS350 that's why the car is way understeer. If you go down the cloverleaf at high speed you can feel that the nose just wants to go straight. I only have the rear f-sport sway and the car is much more natural. You can change both if you want, but the less mod you put on, the less problems you have in the future such as squeaks, breakage, etc. Speaking from my IS300 experience which I modded to the wazoos.

Boomin

I did the f sport well worth the money, might have not needed the fronts but o well

scott1256c

I got in touch with Hotchkis. They have discontinued making sway bars for the isx50, at least under their own name. I did ask if they were manufacturing the f-sport sways. They didn't comment on that. But they did tell me that (for is350 at least) the
front is 85% stiffer than stock
rear is 70%/140% stiffer than stock (2 way adjustable).
If that interests anyone, there are a few places that still have stock.