Awesome. I went with those as well cause I have 245s in the front and didn't want to rub as well. I rub in the rear already so hopefully the f sway will slightly reduce the rubbing issue.

 

whoa what size tires are you running in the rears that its rubbing??

 

It's my offset. I have 275s in the rear and rubs on dips and tight turns. =(

 

Whats your offset?? Im running 275's with +38 offset with no issues. I did rub but that was due to a failed shock absorber which is being fixed this week. The other side doesn't rub.

I just had the rear sway bar installed too... it improved cornering a lot.. but it still rub on dips on the broken s-absorber.

Maybe it's just the difference between 1st gen and 2nd gen IS-Fs.. Hope there isn't a big issue with your suspension.

 

No..it's definitely not my suspension. I am on spacers and extended studs and my wheels are quite flush in the rear. that is why it rubs...

 

Glad to hear it feels much better now with the 15mm and proper bolt length.

Just my opinion though...between the two...the 25mm drop looks better than the 15mm.

Do you remember the bolt length (excluding the bolt head) of the AF kit?

Here you go Pete and and check out that cool ruler I used lol

 

lol @ "Fairy Girlz"...did you steal your little one's ruler?

 

So the reality is, this changes the geometry of the suspension. It changes roll center, instant center, roll couple, and possibly scrub radius since Lexus does not have the upper and lower arms moving in parallel arcs for camber or caster.

How this impacts the car from a performance perspective is unknown without modeling the stock setup, then modeling the modified setup. As I said initially, in all likelihood those who drive on the street would not be able to tell the difference between the two while driving if they couldn't see the drop before getting in the car. If you autocross or road race, you have the watch to tell you pretty quickly if it's better or worse than stock.

Flipside909 said the front of the car was raised from pre-production height to ensure the bumper cover would clear parking blocks a long time ago. I asked him how much but he could not say. So, it's possible the front suspension is less than optimum at the stock height and improves with a small drop - I'd bet on 10mm. But by changing the fundamental geometry, essentially lowering the lower control arm 10, 15, 20, 25, or 30 mm relative to the upper control arm impacts way more of the work the factory did to get the suspension to work.

Still, Lexus did change the rear suspension pretty significantly on all IS and GS models in 2011 - different subframes, different knuckles, different links - all to improve the ride quality and also reduce lap times pretty substantially. So it's really hard to say how changing the front suspension this way impacts the car's performance unless you do some timed runs before and after (which would be pretty easy actually), so what we really need is an autocrosser or road racer to test this out and report back what it does to lap times.

 

why does this pic look like the front wheels changed in caster? it looks like its not centered in the wheel well. maybe a camera angle.
I looked at making these but we need to make out own m14 hardware. We did the IS/GS m12 versions and they run about $150.

 

Hey Figs, Lobux this was my F with 25mm spacer looks like casters is off, when I drove the car it had vague light steering feel like it was over boosted not sure if this was caused by the bolts supplied being to short and not enough of bolt residing in hub assembly? I have since drop down to just 15mm spacer, steer feel has improved but at higher speed above 90 plus into triple digits and on twisty roads the car still exhibits some light steer feel no were near as bad as before but never the less its still present kind of felt like my old IS350

25mm spacer






15mm spacer

 

^^ yes the change in caster angle is going to make your wheel tuck under during cornering, so it will have less mechanical advantage and probably feel pretty weird as the tire rolls to its outside edge.
I wonder what it would look like through the whole cycle. This might be a fun time lapse experiment with a tripod and the lift.

 

I received my kit yesterday. Thanks PHML!! I will be installing today or tomorrow.....20mm kit.

 

has anyone done a full alignment after install? how much did the camber change if any?

 

I looked at this again this weekend Just be warned that due to the geometry of the knuckle and additional spacing will push the caster back and can have impacts on the steering response. It may also make more tire interference depending on how thick it is and what tireyou run.


RCA spacers were originally designed for flat knuckle vehicles, but the gen2 IS and Gen 3 GS have a slanted knuckle.

 

thanks for posting your findings Figs...I think I'm going to wait off on this mod now.