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

[markboris]

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)

Erik, since the Koni is only about 1/2" shorter, what problems do you think this would cause in normal everyday driving? It was the closest shock I could get to fit the Mach-E with the mounts and lengths. They have been installed in over 20 MME's and so far have not had anyone complain about over extension or whatever you might call it. One thing that I like about them is I actually got MORE travel out of them than the OEM shocks have which is nice. The body of the shock is shorter so there is a bit more travel.

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[azerik]

I don't think there's a problem. I'm more curious if there's a vacuum so to say with the piston being nearer to full extension. Usually we'd want 2 more inches of travel on each side of full extension and full collapse. It's possible (wild mind wandering thought) that there's not enough oil to allow the shock to respond as fast as it's designed to. That initial firmness. I can't speak to how Koni designed it but usually theres enough oil to allow the piston to move a little without having to pull or push oil from the other side of the piston disks. 2 inches sounds like a lot but the shock piston is probably only about the diameter of a quarter. Think about the size of a shot glass of fluid. The more fluid available allows more compression or rebound of that fluid (think marshmallow) before the valving (which is the main stopping force on long) comes into play. I'm on the hunt for a way to lessen that stiff initial hit for all the little stuff still lol. Also if I get the angle of the upper rear shock correct the Viking/QA1's become a option again. Still doesn't make any sense why there's about a 5 degree angle on the lower shock mount. (Light bulb: I could trim that tiny amount off the Viking mount to help keep it from making noise when I start digging into those again soon)

I need to get some time to dig into the rear suspension and see if it's entire extension is limited only by the shock.

I also REALLY wish KW would just sell the rear set up.

 

[txaggies07]

I finally got around to installing my Koni's over the weekend. Thank you to everybody who helped in this whole process with an obvious special thanks to @markboris and @azerik.

 

[RMoore]

Any word on whether Koni will be coming out with a version for the MME that doesn't require any additional reworking--versions that you can bring to any shop that replaces shocks and just swap them in?

 

[markboris]

Any word on whether Koni will be coming out with a version for the Mach-Ethat doesn't require any additional reworking--versions that you can bring to any shop that replaces shocks and just swap them in?

Not yet unfortunately.

 

[FlowDesign]

Regarding the banging from the rear in my 2021 SR RWD (Job 2):
https://www.macheforum.com/site/threads/thumping-noise-feel-from-rear-axle.33535/

I have had lowering springs mounted 1,5 years ago which are 25 mm lower, but I think they are also a bit less stiff/hard than standard, for more comfort and less bounce. So I'm thinking it could well be that the rear end just drops more when accelerating heavily, which could affect the banging I experience as described in the other topic.

Now I saw in this topic about the Koni's. So now I'm wondering, would it make sense to mount a harder dampened shock absorber (i.e. more pre-load) on the rear to make sure the car doesn't bounce as much when accelerating hard? Or would that not help to compensate for the softer springs?

 

[kennethjk]

Just an FYI, I had the Koni’s installed late last summer. My wife said the car was worse After the installation.

I have the car in Florida for the winter and they seem great, wife doesn’t complain.

short answer is, NY roads suck!

 

[21st Century Pony]

Just an FYI, I had the Koni’s installed late last summer. My wife said the car was worse After the installation.

I have the car in Florida for the winter and they seem great, wife doesn’t complain.

short answer is, NY roads suck!

I swear by the pricey but oh-so-worth-it KW v3s. Don't even remember what the Mach E bounce had felt like.

Besides, the OEM Ford shocks are known to wear out pretty fast... at 63.5 thousand miles now the OEM shock set would have pretty much been toast by now. The KWs are still going strong.

 

[markboris]

Regarding the banging from the rear in my 2021 SR RWD (Job 2):
https://www.macheforum.com/site/threads/thumping-noise-feel-from-rear-axle.33535/

I have had lowering springs mounted 1,5 years ago which are 25 mm lower, but I think they are also a bit less stiff/hard than standard, for more comfort and less bounce. So I'm thinking it could well be that the rear end just drops more when accelerating heavily, which could affect the banging I experience as described in the other topic.

Now I saw in this topic about the Koni's. So now I'm wondering, would it make sense to mount a harder dampened shock absorber (i.e. more pre-load) on the rear to make sure the car doesn't bounce as much when accelerating hard? Or would that not help to compensate for the softer springs?

You mentioned in your other thread about the thumping noise that it did not change or get worse after you installed the lowering springs. I'm not sure if you change your rear shocks to stiffer ones (the Koni's) that the noise will be any less. I can tell you the ride in the back will be more firm though.

 

[FlowDesign]

You mentioned in your other thread about the thumping noise that it did not change or get worse after you installed the lowering springs. I'm not sure if you change your rear shocks to stiffer ones (the Koni's) that the noise will be any less. I can tell you the ride in the back will be more firm though.

True, but springs do tend to get a bit softer after a while, which made the thumping more apparent over time. This could have happened with the original springs as well.

It seems really hard to get a good balance in the Mach-E between comfort, stiffness and the bouncing back.

But in general, would a stiffer shock with more pre-load result in the rear dropping less when accelerating? Or can that only be achieved with stiffer springs?

 

[markboris]

True, but springs do tend to get a bit softer after a while, which made the thumping more apparent over time. This could have happened with the original springs as well.

It seems really hard to get a good balance in the Mach-E between comfort, stiffness and the bouncing back.

But in general, would a stiffer shock with more pre-load result in the rear dropping less when accelerating? Or can that only be achieved with stiffer springs?

Agree with the Mach-E being extremely hard to balance between comfort, stiffness and the bouncing back. Your slightly softer springs which are probably similar to the Eibach springs I installed are giving a slightly more comfortable ride. Going with stiffer shocks in the rear do lessen the rear end bounce as has been seen with quite a few members that have installed them.

About the shock having more pre-load, I'm not so sure. While the Koni's compression is firm, I forget how much different they are from the stock shocks. It's the rebound on the Koni's that are adjustable and what we set to the most firm setting to reduce the rear end bounce. I'm thinking you would want a more firm compression to lessen the the rear from dropping so much under hard acceleration. Steve (HuntingPudel) is really good with suspensions and let's see if we can get him to chime in about this.

 

[azerik]

The Koni’s are firmer than the stock rear shocks on compression. That will help a bit on impacts but not so much on the backend weight transfer as that’s technically a low speed impact on a shock. The Koni’s are much firmer on high speed impacts like a pot hole at 35mph. This is the reason Kenneth’s wife says it’s rougher for the Prem. But the shock won’t slow the load up of the rear. That would have to be done with the spring rate. But all other ride quality would suffer as well.
from what we’re seeing you’d probably want a rate between 800 to 950 in the rear on a linear spring.
I’ve ‘lost’ the grand majority of the Koni firmness (read: that overly firm initial hit on imperfections in the road) on my ER with the progressive Eibach rear springs. Mark has the rates listed in his thread.

 

[HuntingPudel]

True, but springs do tend to get a bit softer after a while, which made the thumping more apparent over time. This could have happened with the original springs as well.

It seems really hard to get a good balance in the Mach-E between comfort, stiffness and the bouncing back.

But in general, would a stiffer shock with more pre-load result in the rear dropping less when accelerating? Or can that only be achieved with stiffer springs?

Technically, springs do not lose rate over time. They do sag, which reduces spring load carrying capacity and ride height. Once they have taken a set, springs generally do not lose any more ride height unless acted on in an abnormal manner (over-loaded, bent, cut, etc.) ??

A shock with stiffer compression damping will slow the rate of suspension compression, which in turn would slow the rate of squat. They will not reduce the magnitude of the squat unless the duration of the event causing the squat is less than the amount of time required to reach the ultimate amount of compression that the event would cause. The only things that would affect the magnitude of squat on acceleration would be the spring rate at a given height and changing the suspension geometry to increase the amount of anti-squat (which forces the wheels away from the body as a resultant opposite force to the rotation of the rear wheels). Increasing the rear anti-squat can have the negative effect on braking by unloading the rear tires as braking force is applied, causing premature rear lock up or axle tramp. Likewise, increasing front suspension anti-squat would increase nose lift on acceleration and nose dive on braking events. ??

 

[azerik]

The gist of the posts above: ‘suspension work is hard’
?

 

[HuntingPudel]

The gist of the posts above: ‘suspension work is hard’
?

And it’s harder without thumbs! ??

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