UPDATED: Replacing Rear Shocks: Reducing the rear end bounce.

[azerik]

(((((Not to de-rail this or add confusion)))))
I was able to take out that stiffness via the Viking shocks. However they, because not gas charged, were hollow on small stuff in the road. Hollow meaning when you ran over a manhole cover you'd get a hollow sound from the tire. Because with gas charged shocks they'd slightly pressed with pressure keeping the tire planted. It's almost time for me to fart around with the Vikings again and see where I can get with them, because it's thankfully only sub 100 degrees daily again. *I'm curious to see how much of the hollow sound is gone from switching to the Eibach rear bar, which translates less road noise to the frame.

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[markboris]

(((((Not to de-rail this or add confusion)))))
I was able to take out that stiffness via the Viking shocks. However they, because not gas charged, were hollow on small stuff in the road. Hollow meaning when you ran over a manhole cover you'd get a hollow sound from the tire. Because with gas charged shocks they'd slightly pressed with pressure keeping the tire planted. It's almost time for me to fart around with the Vikings again and see where I can get with them, because it's thankfully only sub 100 degrees daily again. *I'm curious to see how much of the hollow sound is gone from switching to the Eibach rear bar, which translates less road noise to the frame.

I just sold the Viking pair I had for testing. You can really dial in the Vikings for a better ride but so far that has not happened yet as there is so much to adjust and test and it takes so much time. That is why I went the Koni route. Also, the Vikings having a poly bushing at the bottom which introduce more noise/vibration into the car. I'm sure we can change it to a rubber bushing but again more work than needs to be done or at least what I am willing to do. If I wasn't able to get a decent ride out of the Koni's, I would still be looking into the Vikings for sure.

 

[azerik]

All of that ^ I was going to try to cast a bushing (I had to do it on a G20 back in the day) after trying the supplied ones.

 

[kennethjk]

The jury of 1 has given her verdict, thumbs down on the new shocks. Doesn’t feel any different.

tried to explain to no avail.

drove the car again tonight, def a bit firmer and seems a little more internal noise but not as bumpy.

question- after a while will the shocks be a bit, softer, after putting some real miles on it?

still glad I did it.

 

[azerik]

Yeah they loosen up a touch but it’s not going to turn into a Cadillac . I think I have about 4000 miles on mine. I have some other adjustments to try in the rear that are in the plans for October. When I switched to the GT tires a lot of my road noise was gone. Those AS3’s are firm tires. Have you tried about 35 psi in the rear!

 

[kennethjk]

Yeah they loosen up a touch but it’s not going to turn into a Cadillac . I think I have about 4000 miles on mine. I have some other adjustments to try in the rear that are in the plans for October. When I switched to the GT tires a lot of my road noise was gone. Those AS3’s are firm tires. Have you tried about 35 psi in the rear!

Not looking for a Cadillac ride. Set to 35 this morning and a bit better

 

[kennethjk]

I just realized I have my 1 year old grandchild‘s stroller in the back that might be making some of the noises I am feeling, ?

 

[Anton]

I just realized I have my 1 year old grandchild‘s stroller in the back that might be making some of the noises I am feeling, ?

I had my rear hatch plastic panels making noises with the firmer ride which I thought was coming from the suspension.

 

[azerik]

And I just removed my solar shade in the pano roof. My left rear noise is gone, yay.

 

[Mach-Lee]

I wanted to share that I finally installed the Koni shocks from Mark on my Premium AWD ER, and they have mostly solved the rear bounce issues for me. I've been driving around with them for several weeks to give a good test.

To summarize the experience, the rear end ride now feels unremarkable, which is a very good thing compared to before. If a stranger rode in the back my car, they would no longer say "Wow this thing is bouncy". The damping level is now normal, or as normal as it can be considering how stiff the springs are. After going over some good pavement dips that cause gross rear end movement, the bounce has now been reduced from 3 cycles down to about 1 cycle, which is acceptable!

Repeating my body slam test with accelerometer data back from post #17, I now see an improvement after overlaying the data:

The blue line is the before data, the orange line is the after data. The second events line up well with a similar excitation. You can see the amplitude of the resulting rebound and compression oscillations has been reduced significantly, by about 40-50%. The magnitude of the second cycle has been reduced to the point it's now barely noticeable. There remains some "wiggle" for subsequent cycles, but I think that's mostly the elasticity in the tires and bushings. The shocks are done moving after 1.5 cycles at the very most. Suspension frequency didn't really change much, still high around 2.5 Hz.

Because of the high spring rate, the suspension still feels "fast" and stiff, but not much can be done there without redesigning the springs and increasing rear suspension travel to absorb more. Going over speed bumps, the rear now feels extremely similar to the front in terms of damping and stiffness, which is a good balanced feeling. At night, the headlights are still bouncing around on the signs quite a bit, but this is due to the stiff springs following every bump on the road. The Mach-E just has a very sporty fast/stiff suspension. But you can visually see on the signs there is only 1 bounce per bump instead of 3 bounces per bump like before, so still a big improvement.

The only slight negative of this mod is that traction after bumps is slightly reduced. If you go over a bump while accelerating or regening hard, the suspension will compress, and the tire will become airborne for a slight moment behind the bump as the shock limits the speed of the wheel coming back down. During this situation, you may experience a traction control event where the ABS system cuts power or regen for a second after hitting the bump. This is a very minor gripe that doesn't happen very often, I'd still rather have the greater rebound damping and sacrifice a tiny bit of traction going over bumps.

FYI the rebound travel is slightly reduced by 3/4" compared to the stock shocks. There is a slight risk of topping out the shocks if you go fully airborne Ferris Bueller style, so keep the wheels on the ground and you'll be fine. Also you'll want to avoid keeping the rear wheels jacked up for long periods since the shock will be holding back the last little bit of suspension travel.

In terms of aggressive performance driving, you'd probably want a little bit more damping (go with the Vikings if you have time to tinker with the settings), but for most everyday driving the Koni's provide the right level of damping so I think most people will be happy with them. They are sort of a "one and done" solution. I'm happy with them and consider the rear bounce "fixed". This is how the car should have rode from day 1 of ownership.

Not sure if Koni is still working on developing a purpose built Mach-E shock, but that would be great if happens so that all the specs are perfect.

The next thing I would do to further improve the ride if I could—is reduce the spring rate. More turns of a thinner spring would be ideal. This would also reduce the natural frequency of the suspension, which is badly needed. 2.5 Hz for a family SUV is insanity.

Thanks again to Mark for developing this mod and allowing me to test shocks!

 

[21st Century Pony]

IMHO the (pricey) KW v3 shock + spring assemblies eliminate the bounce. My car is also an AWD extended battery Premium. Too bad about the cost but this is the most complete solution.

 

[markboris]

I wanted to share that I finally installed the Koni shocks from Mark on my Premium AWD ER, and they have mostly solved the rear bounce issues for me. I've been driving around with them for several weeks to give a good test.

To summarize the experience, the rear end ride now feels unremarkable, which is a very good thing compared to before. If a stranger rode in the back my car, they would no longer say "Wow this thing is bouncy". The damping level is now normal, or as normal as it can be considering how stiff the springs are. After going over some good pavement dips that cause gross rear end movement, the bounce has now been reduced from 3 cycles down to about 1 cycle, which is acceptable!

Repeating my body slam test with accelerometer data back from post #17, I now see an improvement after overlaying the data:

The blue line is the before data, the orange line is the after data. The second events line up well with a similar excitation. You can see the amplitude of the resulting rebound and compression oscillations has been reduced significantly, by about 40-50%. The magnitude of the second cycle has been reduced to the point it's now barely noticeable. There remains some "wiggle" for subsequent cycles, but I think that's mostly the elasticity in the tires and bushings. The shocks are done moving after 1.5 cycles at the very most. Suspension frequency didn't really change much, still high around 2.5 Hz.

Because of the high spring rate, the suspension still feels "fast" and stiff, but not much can be done there without redesigning the springs and increasing rear suspension travel to absorb more. Going over speed bumps, the rear now feels extremely similar to the front in terms of damping and stiffness, which is a good balanced feeling. At night, the headlights are still bouncing around on the signs quite a bit, but this is due to the stiff springs following every bump on the road. The Mach-E just has a very sporty fast/stiff suspension. But you can visually see on the signs there is only 1 bounce per bump instead of 3 bounces per bump like before, so still a big improvement.

The only slight negative of this mod is that traction after bumps is slightly reduced. If you go over a bump while accelerating or regening hard, the suspension will compress, and the tire will become airborne for a slight moment behind the bump as the shock limits the speed of the wheel coming back down. During this situation, you may experience a traction control event where the ABS system cuts power or regen for a second after hitting the bump. This is a very minor gripe that doesn't happen very often, I'd still rather have the greater rebound damping and sacrifice a tiny bit of traction going over bumps.

FYI the rebound travel is slightly reduced by 3/4" compared to the stock shocks. There is a slight risk of topping out the shocks if you go fully airborne Ferris Bueller style, so keep the wheels on the ground and you'll be fine. Also you'll want to avoid keeping the rear wheels jacked up for long periods since the shock will be holding back the last little bit of suspension travel.

In terms of aggressive performance driving, you'd probably want a little bit more damping (go with the Vikings if you have time to tinker with the settings), but for most everyday driving the Koni's provide the right level of damping so I think most people will be happy with them. They are sort of a "one and done" solution. I'm happy with them and consider the rear bounce "fixed". This is how the car should have rode from day 1 of ownership.

Not sure if Koni is still working on developing a purpose built Mach-E shock, but that would be great if happens so that all the specs are perfect.

The next thing I would do to further improve the ride if I could—is reduce the spring rate. More turns of a thinner spring would be ideal. This would also reduce the natural frequency of the suspension, which is badly needed. 2.5 Hz for a family SUV is insanity.

Thanks again to Mark for developing this mod and allowing me to test shocks!

Thanks Lee for your detailed opinion on the Koni shocks. Glad they are working out for you. As I have stated many times, it all depends on the roads being driven on and some experience better results than others. Last I heard from Koni is they were working on a solution for the Mach-E and were still looking for testers in the Cincinnati area. I'm sure they will eventually come out with shocks which would be great because it would be nice to have a matching set for the front.

 

[markboris]

IMHO the (pricey) KW v3 shock + spring assemblies eliminate the bounce. My car is also an AWD extended battery Premium. Too bad about the cost but this is the most complete solution.

If I didn't have the GTPE with the active suspension, I would have gone the KW route. The GTPE has less bounce than any other Mach-E suspension, the Koni shocks take it a step further and eliminate a little more and the KW's from what I have read eliminate almost all of it.

 

[21st Century Pony]

If I didn't have the GTPE with the active suspension, I would have gone the KW route. The GTPE has less bounce than any other MME suspension, the Koni shocks take it a step further and eliminate a little more and the KW's from what I have read eliminate almost all of it.

....but I am still jealous of your Magneride suspension haha

 

[azerik]

I’m actually working to see if I can have a friend of mine build some 1 inch longer shock mounts that would solve the Koni’s being shorter problem.
Also was going to work on seeing what tension I could reduce from the 15 points of rubber. (Safety and $ being the hold up, and how to make it repeatable for others)

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