rear axle carrier mount - which version

[autokunst]

Hoping to get some practical input on this topic. As with many of the part for my restoration, I bought them years ago. Which is to say, I've been accumulating parts that I am now re-discovering as I dig into each area of the car.

My wife asked me this morning: "Are you capable of building a car that doesn't have a harsh ride?" In response, I paused, and then realized I had nothing to say.

For the rear axle carrier mount, I bought new replacements - the motorsport version of course with the solid rubber insert. The standard version has a couple of holes drilled through it and half of the mount is slotted. I imagine this provides some compliance, although I'd imagine more/most on the rebound as the original impact would allow this entire rubber part to be compressed.
I'm wondering if anyone has changed these to the solid "motorsport" versions, and if you have any objective feedback (no pun intended) on the ride. I also realize this is a difficult subject to isolate, because if you are changing this mount, you may likely have also changed other items including springs, shocks, wheels and tires... But if there is any place where great input will be garnered, it is here. Thank you in advance.

STANDARD MOUNT:

MOTORSPORT VERSION:

 

[bavbob]

I am interested in this as well. I used BMW mounts but also added these from IE.

I have solid 2 piece Powerflex subframe bushings in my M6 and 635. Primary reason was they did not need to be pressed in and the labor to get the old ones out, well I never wanted to do that again. The ride did not change at all but the rear of the car is better behaved.

 

[Ohmess]

Stephen - the number one thing you can do to address your wife's question is smaller diameter wheels. Most folks think they can make their cars change direction faster with a smaller sidewall, which works in more modern BMWs. Our cars flex so much that there is a distinct limit on how much improvement we can get with smaller sidewalls (and stiffer springs and harder shocks, etc.). And, with every attempt to stiffen up the tires/suspension, we are transmitting more noise, harshness and vibration into the chassis, thereby increasing the stresses on 50 year old sheet metal.

I run 15s on my car. I think our cars look much better with fatter sidewalls filling up the wheel wells because they were designed with that look in mind.

The subframe mount will not have a big effect on ride quality, but they will transmit a little more vibration.

 

[autokunst]

I have 15s currently, and don't plan on going taller at this time. Probably different wheels, but not larger. I agree with the sidewall appearance, as well as compliance. Could always go back to 14s if it came to it.

 

[Ohmess]

I have 15s, Carl Nelson springs, Bilsteins and upgraded sway bars. The ride on my car is more Grand Touring than Sport, and I don't think it is harsh.

And, tires can make a difference. I like the ride of Michelins.

Another trick is tire pressures. I ran at 32 psi all around, but am now at 33.

 

[autokunst]

I have 15s, Carl Nelson springs, Bilsteins and upgraded sway bars.

You just described my setup.

 

[Ohmess]

You just described my setup.

I suspected you had good taste.