What do you think about having different stiffness ratings among mounts? I was thinking about doing 75a on the sides and 95a in the rear. I wanted to do this to cut down on vibration through the car, but have a stiff mount wear it counts. I was also planning on using the stock front mount with inserts.

 

thats actually something interesting never thought about that curious to see what others say

 

Sounds like you'd probably put extra stress on the harder mounts since the softer ones will be giving into more movement.

 

nice thought, but your not going to get rid of any vibration by doing that

 

Why do you say that? I was thinking this too, I figure most of the vibration comes from the rear mount anyway

 

stiffer rear mount = more car shaking.

 

Using a 75a over 95a is not going to be that noticeably different.

I run 60A mounts and it still vibrates like a bitch. Your not going to get that much more comfort driving a set up like that.

 

We use 70A polyurethane. Our material is 100% polyurethane not a mixed material which some Co's use which can cause issues. 60 is pretty soft, next is 70 which we feel does about everyone up to 500hp+. 80-90 will have a lot of vibration recommended for race applications. Having different grades of poly on each mount probably isn't the best idea. It should cause a different ryhthm and vibration putting more stress on the less grade mounts.