RTAB information/help

[ClimRox]

I'm preparing to do a suspension refresh closely following BMWCurves guide posted last year, and think I need to add the RTABs to the list. Could someone school me on the options, and point me in the direction of any good DIYs?

For my refresh, I have ordered mostly OE parts, and will order Rogue RSMs and Koni yellows. I think I would like to keep the RTABs stock or fairly close to stock, partly because I really don't understand the terminology and use of limiters, etc.

My car is a DD and not tracked. Thanks in advance!

[BMWCurves]

So I'm not even remotely close to an expert on suspension stuff, but when I was weighing what parts I wanted, I wanted an OEM+ feel, but to still be comfortable since I DD my car. That meant E46 M3 or equivalent bushings/parts where applicable. I ended up with Z4M RTABs in the back over the M3 ones because of the larger split case design. Whether or not this is actually beneficial is to be seen but Vorshlag provides their own explanation here:

http://www.vorshlag.com/product_info.php?cPath=1_4_26&products_id=515

Same thing with limiters, I didn't really know too much about them other than they're supposed to hold the RTAB in place better and prevent any flex. I picked up a set because other people had used them before with no negative comments. I did not choose poly RTABs because people had mentioned binding in the RTAB since it articulates in multiple axes, and the lack of give can cause binding in a particular motion. People choose poly bushings for their increased performance (less give) but they do increase noise and vibration in the car in most applications.

An alternative is the Bimmerworld sealed spherical RTABs, but they're quite a bit more expensive. The upside is they articulate properly and are probably the best bushing you can get back there. You can talk to Peter (username: slater) about them, since he has them in his car.

Hope that helps.

[ELCID86]

Sounds like you are on the right track with the OEM and Rogue bits. I'd go OEM on RTABs (at least that's what I did ). You need a tool to get them out. (I have one for rent that will also work on the large diff bushing).

You just have to jack up the car and remove wheel. I undid the bottom shock bolt. Then you shove a few boards in there to keep it down and accessible.

I think Vas and others have put in limiters. I chose not to.


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"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - anonymous

[ClimRox]

Thanks for the replies. BMWC - That was a helpful link. Shawn - Thanks for the heads-up on the tool for rent.

[Vas]

I went with the Z4m rtab to match the front Z4m fcab. Also added limiters mostly because people stated they extend the life of the bushing.

If you want the best, then Bimmerworld sealed spherical RTAB is the way to go. But iirc the price is $200 for a set.

Also rent a tool to replace them.

[ClimRox]

Thanks Vas. When you replaced yours, did you have to worry about preloading when reattaching the trailing arm, or just mark where the carrier attached to the frame before removal?

[ELCID86]

Thanks Vas. When you replaced yours, did you have to worry about preloading when reattaching the trailing arm, or just mark where the carrier attached to the frame before removal?

Mark it but I couldn't get one anywhere near the marks when reinstalling. Plan on an alignment ASAP.

[Vas]

Thanks Vas. When you replaced yours, did you have to worry about preloading when reattaching the trailing arm, or just mark where the carrier attached to the frame before removal?

I marked the carrier and then eyeballed the install. Then took it for an alignment.

As far as pre-load, you can tell how it is supposed to be installed and when it is just wrong.