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Read a mention of this on several Saab and reviewing sites.. Does anybody have more info? What is this, how does this work, and what models have them? Thanks!

According to this page my 2003 Vector is supposed to have it:
'ReAxs' Passive rear-wheel-steer characteristic. The kinetics of the rear suspension are tuned for a unique rear-wheel-steer response designed to improve handling and stability.
http://www.saabnet.com/tsn/models/2003/pr1.html
 

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What i means is the rear wheels will turn with front wheels to assist stability in hard turns. I think some suv's or trucks had this a while back. When ur tires get kinda low on grip, u definately notice this, especially on grooved highways like ny state thru-way on i-95. Can be alarming at first if u hit a bump, but makes u feel reassured in turns going at high speeds.
 

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This is basically a "passive" 4-wheel steering system that changes rear wheel toe under cornering forces, which reduces understeer. A similar system was used on mid-90's Nissan sports cars (300ZX, 240SX) called "HICAS". You can't really see the wheels move and it only operates at speed. All it really does is improve handling a bit.
 

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Saabseeker said:
This is basically a "passive" 4-wheel steering system that changes rear wheel toe under cornering forces, which reduces understeer.
I think that's the bottom line. The main drawback of front wheel drive is the understeer associated with this setup. One of the things that impressed me so much with the 9-3 is just how neutral the car stays at its limit. It handles more like a RWD automobile while having the superior traction of front wheel drive.
 

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On the 300ZX TT didn't the refer to it as "Super-HICAS?" AKA better than just HICAS!

Anyway, in Michigan we have a lot of divided highways and a lot of places where you have to turn right to go left ("michigan left turn"). Sometimes I take the turn-arounds at a little higher than normal speed and that is when I truly feel the ReAxs. Kind of odd and almost discomforting at first. You are expecting some push/understeer and then it feels like the rears begin to come around like with oversteer, but in they end the rears just better follows the path of the fronts more closely than expected. It doesn't really lessen the understeer as we still have front heavy FWD cars, but it gets the front pointed in the right direction sooner so when the forces normalize, she's point and shoot.
 

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VectorDC03 said:
Read a mention of this on several Saab and reviewing sites.. Does anybody have more info? What is this, how does this work, and what models have them? Thanks!
So does anyone know what models have it? I have a 04 Arc conv, do I have it?
 

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ive yet to ever feel this in action and have my doubts about it working (i mean obviously it has too but no one outside my car watching, or inside feeling has ever noticed it)
 

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Im sure that the ReAxs only moves the wheel 1/100th of a degree in the opposite direction. I really cant see how this can be that noticable, but saying that i'm happy with the way my car whips round corners - so something is working right;) .
 

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The Reaxs system is one of the things on the SS that makes me think that the description "Sport Sedan" is a bit over the top. The SS doesn't really communicate very well what happens to your wheels when cornering. It has a very "light" feeling, and the Reaxs doesn't improve that - it makes it worse. I used to drive a Golf, and althoug that Golf was half the price of the SS, it's steering was much better. Same goes for the Audi's i've driven.

Cheers,
BaRa
 

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brammelo said:
The Reaxs system is one of the things on the SS that makes me think that the description "Sport Sedan" is a bit over the top. The SS doesn't really communicate very well what happens to your wheels when cornering. It has a very "light" feeling, and the Reaxs doesn't improve that - it makes it worse. I used to drive a Golf, and althoug that Golf was half the price of the SS, it's steering was much better. Same goes for the Audi's i've driven.

Cheers,
BaRa
My guess is that if you had the "Sports Suspension" on your "Sports Sedan," you would feel otherwise. I love the ReAxs; especially when executing shallow curves at high speeds. I always feel at one with the car, especially with what is happening with my wheels.
 

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As far as I know is that you can feel it when your in the back. Then it's a smoother ride trough corners than without ReAxs. I also think it's more than 1/100 degrees. ;)

By the way: The ReAxs also does a "Toe-In" when breaking hard. That means the wheels are going slightly inwards (the right one steers a bit left and the left one a bit right) to enhance the grip and the breaking power due to more friction. This is to help you keep the track when breaking hard from higher speeds. At least that's what the german info leaflet tells you. ;)
 

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finwake said:
My guess is that if you had the "Sports Suspension" on your "Sports Sedan," you would feel otherwise. I love the ReAxs; especially when executing shallow curves at high speeds. I always feel at one with the car, especially with what is happening with my wheels.
Aha... but I have the sport suspension (on a Vector). Although I have it installed on 17" rims, not on 18". Perhaps it feels different for a diesel engine (heavier in front)?

Cheers,
BaRa
 

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brammelo said:
Aha... but I have the sport suspension (on a Vector). Although I have it installed on 17" rims, not on 18". Perhaps it feels different for a diesel engine (heavier in front)?

Cheers,
BaRa
Then we have parity in experience, but difference in conclusion: I adore the handling of the SS, it is my favorite capability. Of course, I am not moving 'down' in sports capability from a mid-engine roadster or the like...
 

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if you don't feel it, you're not cornering hard enough. 1/100th of a degree may sound like nothing, but when you're expecting the car to turn like a normal fwd car, it all of a sudden REALLY starts turning. fun as hell.
 

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Just to set the record straight; according to the latest Saab press release the Re-Axs actaully moves 1/100th of a degree for each degree steer of the front wheels !

I knew it was more than 1/100th degree to have such an effect as it does;) .
 

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EP Doc said:
It handles more like a RWD automobile while having the superior traction of front wheel drive.
Not sure that FWD cars are widely regarded as having superior traction to rear wheel drive cars. If this were the case then there would be more FWD cars doing 0-60 (a pretty good test of grip in a straight line, power and weight) in under 6 seconds. As it is there are virtually none.

When you begin cornering, then ultimate grip gets worse, the grip used for generating steering forces must also react tractive forces - a major compromise.

I am happy with how the 9-3 handles, and have no real complaints about it being FWD, because it is a good FWD set up, but I must disagree that FWD has superior grip to a RWD chassis.
 

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My old 1986 Porsche 928S had this. It's called the Waissach (sp?) axle. I believe Porsche pioneered the passive rear wheel steering.
 
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