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Discussion Starter · #1 · (Edited)
Our Ascents have a McPherson suspension with just a single control arm. The inboard (chassis) end of a control arm is attached by a single pivot. It can thus control the position of the outboard end in only a single degree of freedom (up and down), maintaining the radial distance from the inboard mount. Although not deliberately free to move, the single bushing does not control the arm from moving back and forth;

In the rear, there is a diagonal rod that connects to knuckle that constraints forward and backward motion. Not knowing how the forward backward motion of the front strut/wheel is being constrained remains a mystery to me. How is it done?
 

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Our Ascents have a McPherson suspension with just a single control arm. The inboard (chassis) end of a control arm is attached by a single pivot. It can thus control the position of the outboard end in only a single degree of freedom (up and down), maintaining the radial distance from the inboard mount. Although not deliberately free to move, the single bushing does not control the arm from moving back and forth;
The lower control arm is an "A" style control arm with two connection points, not one. One is directly back from the arm (noted at part #13), and the other branches rearward and mounts beyond the wheel well area (noted at parts 11, 12, 14, 10, 8).
11655

So, forward/backward forces (at the wheel) are controlled in one way... two ways if we discuss movement possibilities at the knuckle and strut connection (which we will, because I am bored tonight, lol).

The first, which allows the second to work is the two connection points to the frame, noted at #13 and #11. Point #11 is moved back to allow more lateral rigidity, thus preventing the end of the a-arm from traveling forward or backwards.

That leaves the McPherson style strut connection. Because the A-Arm can't move laterally (not beyond the limits of the bushings, anyway), the two vertical bolts, in combination with the mounting mount at #15 (ball joint that mates the control arm to the knucke (part #1) and the strut being mounted to the car, help make it one solid piece (laterally speaking) from control arm to strut mount on the body (the three bolts sticking into the engine bay on the strut tower). So, because the connection of knuckle to strut is similar to how one cisterns joists, that connection is irrelevant. And snice the A-Arm has two connection points on the frame, it means #15 (ball joint) has limited forward/backwards movement, and is instead a pivot (left/right) to allow upwards/downwards travel of the knuckle, and thus wheel .

In the rear, there is a diagonal rod that connects to knuckle that constraints forward and backward motion. Not knowing how the forward backward motion of the front strut/wheel is being constrained remains a mystery to me. How is it done?
The rear has a bit more than that... NOT counting the sway bar end link (connected from the lower control arm at the second hole to the left of bolt #19) to sway bar. SO...

  • #4 is the upper control arm.
  • #9 is the lateral control arm (toe in adjustments are done here, and you can see one of the parts responsible for the toe adjustment at #12).
  • #21 is the trailing arm.
  • #16 is the lower control arm.

Not shown:
  • sway bar end link (2nd hole to the left of bolt #19)
  • shock (1st hole to the left of bolt #19)

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Discussion Starter · #3 ·
The lower control arm is an "A" style control arm with two connection points, not one. One is directly back from the arm (noted at part #13), and the other branches rearward and mounts beyond the wheel well area (noted at parts 11, 12, 14, 10, 8).
So, forward/backward forces (at the wheel) are controlled in one way... two ways if we discuss movement possibilities at the knuckle and strut connection (which we will, because I am bored tonight, lol).
Thank you! I finally get a closure on this. I see your point about the strut top nuts (3 of them accessible from the hood area) and the strut itself being another means of constraining the forward/backward motion. I do not disagree with you but its efficacy must be limited. The strut is long and the 'leverage' it generates at those bolts (14 mm?) will rip them right apart don't you think?
 

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Have you seen the things I've done with my Ascent? 😂🤣😜

Those bolts will outlast the rest of the car, lol.

Seriously though, the forward/backwards force at that point is carried on the heavy, and literally solid "knuckle". That's the last point it would move or bend. I took a pic of mine for you. It is a thick piece of solid steel.
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Well, those adventures, plus the ones through the mountains in coal country, and off roading in three of this country's four deserts, and in the Rockies, and many National Forests. My beast has been all over the country to off road. 😉

In two weeks, I do my installation. Looking great so far. Lack of a garage slows me down a LOT with our recent weather.

It'll be getting a 1,500 mile off road test in Utah and Arizona in the second half of May, which will include a 5,000 mile on road drive (to and from Utah). I'll let everyone know what I think as I put it through the paces.
 

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Something to add. When the bushings do start to wear they allow some movement which could lead to a damaged internally strut bushing. But as with anything automotive a lifespan should be expected out of these parts hence why they are all replaceable. Given the nature of our awd system and torque management they should have a very long life compared to a 2wd setup producing similar amount of power.

Our Honda odyssey went through front struts every 30k miles, it was not what I expected from the best in class minivan and the service advisor could only shrug his shoulders when I asked if that was the lifespan I could expect.
 
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