Quick suspension question

[Nik99]

Over the last weekend all the fluids were changed in my car as the first step in its maintenance program. (Thanks again for all your help Nick and Ben ) While I was under my car there were a couple of things that I noticed and some that were brought to my attention that need to be addressed. One rather critical area is a leaking rear shock.

This has become the priority in terms of my next maintenance task. I have located a set of Rogue rear shock mounts that I plan to install with the new setup. I’ve been able to also locate a lightly used suspension set, which includes Bilstein shocks all around and Racing Dynamics springs front and rear the seller told that this setup has about 8K miles on it.

My question is who has experience with racing dynamics springs for the e36 M3? Do you know how low the drop is? Also any information on durability of the springs would be nice (as in will they sag after 6months??). Worst case scenario I figure I can just through the springs on the classifieds section and run the stock springs until I come up with a better setup.

Any info would be much appreciated

[99MPower]

never really seen the RD springs in use, but their other stuff that RD makes is top quality, parts, and would not expect any problems with them..

not sure on ride height

[fiveightandten]

A quick look on their website yielded this:

This spring kit lowers the car down about 1.75" (40mm)

Spring Kit, BMW M3 96-99 w/3.2L S52: Racing Dynamics, Inc

Riding on stock-type shocks, make sure your towers are reinforced well and you have good condition RSMs back there. You may also want to confirm the range of travel of the Billies and make sure you're not going to be bottoming them out.

[Nik99]

Thanks for the information guys, i talked to the seller and he had this setup along with camber plates and wheel spacers on his car before recently switching to a full coilover setup. I'm getting the rogue engineer rsm's so that should be plenty of protection for the rear shock mounts.

This maybe a dumb "just go do a search" type question so just let me know if ir is, but how can i calculate the travel of the suspension to figure out if i'm going to be bottoming out the billies?

The truth is i'm buying the kit for the shocks most of all. The seller isn't willing to split up the springs and shocks, but if i have to i will just sell the spring.

[fiveightandten]

Originally Posted by Nik99

Thanks for the information guys, i talked to the seller and he had this setup along with camber plates and wheel spacers on his car before recently switching to a full coilover setup. I'm getting the rogue engineer rsm's so that should be plenty of protection for the rear shock mounts.

This maybe a dumb "just go do a search" type question so just let me know if ir is, but how can i calculate the travel of the suspension to figure out if i'm going to be bottoming out the billies?

The truth is i'm buying the kit for the shocks most of all. The seller isn't willing to split up the springs and shocks, but if i have to i will just sell the spring.

Most after market RSMs are stiffer than the OEM ones, and therefore technically transmit more force to the tower. A well designed shock mount shouldn't harm a tower that hasn't been previously weakened (sometimes they can have hairline cracks that are super hard to even see). But don't forget that most of these things are probably designed with reinforcement plates assumed to be used.

There are 2 problems with the OEM setup. 1) Longevity and 2) The stress impacting the tower from the top, where the diameter of the mounting nuts is the sum of the area that sees downward force when the shock rebounds.

What you get with after market RSMs over OEM is longevity, and in the case of the RE RSMs, you get the added convenience of ease of replacement and the rubber is replaceable. You are using a stiffer mount though, so be sure to use plates and check the towers very very well for cracks while you have things apart.

With regard to the Billies, if it were me, i'd spend a few minutes looking through threads at BFC, and if I didn't find it there, i'd contact Bilstein and ask them. They should be able to tell you what kind of a drop would be safe to run on their shocks. Some of the more knowledgeable vendors that carry them would likely know as well.

[BadGTho]

don't run the springs./

confirm the p/ns for the billies as all but the latest versions have some issues and the warranty is only valid to the original owner.

I have 1 band new billie in the box i would sell if you want to buy another new one.

[Nik99]

This is an actual picture of what i'm getting in terms of the RSMs. They do come with some heavy duty reinforcement plates, so in that sense i hope i'll be alright. The bushing it self maybe harder than oem, but i figure if my towers are in good shape (fingers crossed) i should be in good shape with these RSM. If anybody here has specific information about these RSMs, good or bad, please share

[Nik99]

Originally Posted by BadGTho

don't run the springs./

confirm the p/ns for the billies as all but the latest versions have some issues and the warranty is only valid to the original owner.

I have 1 band new billie in the box i would sell if you want to buy another new one.

Thanks for the information Ben, the warranty issue might really make me reconsider. I was planning to do this because it looked like a great deal for lightly used components, but a warranty issue really throws a curve ball into the mix.

I'll send you a pm about the billie you have.

[BadGTho]

cool... billie's warranty is good but without box/receipt you're screwed for sure.

the only reason i bring it up is because one of mine failed.