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Thread: Super Struts vs Regular Struts

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Posts: 1-10 of 27
2015-02-03 21:03:00
Super Struts vs Regular Struts
TIL Ford uses what's called a SuperStrut, which they claim is the main reason the Focus ST doesn't have torque steer. The biggest change seems to be knuckle rotates independently of the strut. This design looks like a halfway point to the Multi-link design that G20's use.

Please note this thread is for discussing Super Struts vs Regular Struts only and their technical differences and advantages. I spun off another thread and moved all of the multi-link vs strut posts there: [url]www.sr20-forum.com/brakes-suspension/76918-multi-link-vs-super-strut.html[/url]

Car and Drive Source

Originally Posted by Car
Ford’s RevoKnuckle and GM’s HiPer Strut both split the strut into two major components. The core spring-and-damper assembly [red] provides the up-and-down flexibility needed for a controlled ride over bumps. A new knuckle [green] attaches to the main assembly through pivot bearings to provide the steering movement. The GM version has a handy camber adjustment not included in Ford’s design.

Splitting the steering and suspension functions does wonders for front-end geometry. The steering axis (an imaginary line around which the knuckle pivots) is more vertically oriented and located closer to the tire’s centerline. This shortens the effective spindle length and moves the center of the tire contact patch nearer to the intersection of the steering axis and the ground, yielding a significantly smaller scrub radius [see diagram]. Since a long spindle and a large scrub radius are key contributors to torque steer, any reduction of these dimensions benefits steering feel and directional stability.

Another benefit is significantly reduced camber change (the tilt of the tire away from a vertical orientation) as the car is steered off-center. Keeping the tire more perpendicular to the road during turning is a boon to handling.
Last edited by Vadim on 2015-02-09 at 17-12-38.
2015-02-06 17:05:59
Super strut reminds me of the 1970's land cruisers/FJ40 front suspension.
Last edited by Keo on 2015-02-06 at 17-07-03.
2015-02-06 21:40:00
Doesn't seem all that complex. Sure you have an extra small ball bearing now, but technically it's not since traditional struts have ball bearings up top in the spring perches.

@1:15 they kind of explain on why it helps reduce torque steer, still not too satisfied with it though.

Audio is talking about using the revo knuckle in their FWD sports car. Now you would think they would have enough money to just use a multi-link/doublewishbone....

Looks like Renault made a similar system too:
Last edited by Vadim on 2015-02-06 at 21-47-22.
2015-02-09 07:15:05
Cleaned up this thread to only have informational posts about the Revo Knuckle and removed all of the Multi-link and opinionated posts (my own included) to this thread: [url]www.sr20-forum.com/brakes-suspension/76918-multi-link-vs-super-strut.html[/url]
Last edited by Vadim on 2015-02-09 at 17-13-34.
2015-02-09 15:04:18
A Focus ST does not show a lot of torque steer because the ECU applies the brakes to the tire that is spinning more. That is a cheap method that Ford installed on there cars to bypass creating a mechanical LSD to help maintain the tires spinning at the same rate.

This suspension is simply reducing the harmful qualities of a strut be limiting the movement. (The same thing that stiff springs and lowering your car does, the stiffer springs limit motion and lowering the car puts you into more static camber, the stiffer springs limit the strut leaving the negative camber zone before it begins to go positive camber like all struts move) You can become more successful with struts if the user would understand how the strut works and use that to their advantage.
2015-02-09 15:09:24
That I can get behind with. Even our regular struts can be made not to have torque steer, but it does come at a cost of NVH. After installing stiffer motor mounts, stiffer LCA bushings, my B15 had no torque steer, but a person who buys a brand new car would not be happy with the level of NVH those fixes brought. This is why manufactures have to innovate and make better suspensions (multi-link, double wishbone, etc.) to increase traction.
2015-02-09 15:35:27
Torque vectoring, as it is referred to as by Ford Kyle
2015-02-09 15:46:26
Originally Posted by Boostlee
Torque vectoring, as it is referred to as by Ford Kyle

I cannot expect everyone to know what torque vectoring is, let alone to go on their on to learn about the system. That and I really dislike just "google it".

Thank you for the brevity!
2015-02-09 15:51:16

See you at the convention Kyle!
2015-02-09 15:57:52
Now I'm curious by how much they control the torque. Boost by gear is definitely a good way to reduce torque steer (because your reducing torque). I'll do some digging on what they power wise in first two gears vs 3+ gears. If it's 100% torque vectoring that reduces the torque steer then I agree it seems pointless to do more complex yet still strut based suspension.
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