Offset RTABs w/ OE BJs by Jalopi: Group-buy thread

[jalopi]

Hi All,

So it seems that some of you may be interested in having a set of offset trailing arm bushings which use OE-style ball joints. For people in the dark about what this means - what would be the benefits of using a part like this?

*Greatly increased articulation when compared to a solid poly/aluminum bushing. You get to retain the articulation offered by the OE-style soft rubber trailing arm bushing without the downsides that come with a soft rubber bushing

*Long lasting, sealed OE-style ball joint. If you have these bushings installed long enough to wear out the OE-style ball joint, the worn part can be replaced with an off-the-shelf component from your favorite part supply company

*The bushing design is offset, which can help get desired toe alignment with slammed zero camber cars or vehicles that have tweaked frames due to impacts


Here are a few artistic renderings of what the finished product should look like:





So here's a general breakdown of what I need to happen before this project can kick off:

1. I'll go take some real measurements and post the revised rendered model in this thread, Estimated completion time: a few days

2. I need at least five people to let me know that they'd be purchasing a set of these bushings once they're complete. Just reply to this thread to let me know. Estimated completion time: ??

3. After getting my five people on board, I will go and make a physical prototype. Estimated completion time: about 1 week after getting my five people

4. After the prototype is made and I post some sweet pics of it, the group buy will begin. I will once again need a minimum of five people to commit to purchasing before the parts are made. This will require a refundable $50 deposit. Estimated completion time: ??

5. After getting my five deposits, I will announce in this thread that my goal has been reached and that production will begin in 72 hours. After 72 hours has passed, I will be using the deposit money to order the metal/tooling necessary for this project. After this happens, the deposit will become non-refundable

6. Once the metal and tooling arrives, I'll begin the process of machining the RTABs. Estimated completion time: 1-5 days

7. After the parts have been completed, I'll begin shipping packages out on an individual basis once I've received the remaining $50 from the purchaser.




TL;DR: The group buy price is a $50 deposit followed by a $50 payment once the RTABs are ready to ship. After the group buy the price will be $120 shipped. Please note that OE-style ball joints are not included in either price. Shipping outside of the continental USA will be prorated accordingly

[tptrsn]

I'm in. TL;DR didn't include where to send my deposit.

[RandomHero27]

I may be in. I just dont know if i need offset. If i get them will i have enough adjustment? Im not slammed, just lowered and i want to run 0 camber. Dont wanna get these and be too far offset to bring it in.

[MikeE36]

I'm in, but I would want to see what kind of toe adjustment range we are talking about. Currently with my modified RTAB brackets via welding, etc. with Turner spherical bearings, I can only achieve about 0.20" toe-in on the RR right now at my current right height. I want to be able to at least double that and get close or up to 0.50" per side. I recently helped my buddy align his S14 with some grippy specs and his car at 0.35" toe-in is unbelievably quicker in drift that before (i can't catch him anymore)./

Mike

[jalopi]

@Thad - I don't want to start taking money before I actually have a finished prototype in hand - once that happens, I'll definitely be OK with accepting payment

@Hero - In regard to these offset bushings fixing specific alignment issues goes, I have no idea man. Answering this question accurately would require that I know exactly how low your car is and what your current range of adjustment is. Answering that question in a general sense would require that I spend 10+ hours taking measurements of all the moving parts of the rear suspension and modeling them up, just to make a part that others have seen success with on their cars. I'm only trying to tick off the boxes of [ ]spherical, [ ]sealed and [ ]offset that some people were requesting in the other thread.

FWIW though, my car was also lowered and not slammed. I had about 3-4" of ground clearance in the rear and had non-offset RTABs. I had no issue getting the toe I wanted in the rear (zero was what I went with)

I don't see making these in a non-offset version adding too much extra work to my plate. For those interested, I can do a non-offset version that will count towards the group buy number

@Mike - If you're willing, PM me (or post it publicly, doesn't matter to me) a pic of the modifications you made to the RTAB brackets. Try to include measurements if you can, pics of it installed on the car are ideal. I am optimistic about offset bushings getting you the extra .25" of toe that you want

[MikeE36]

Here is what I did, which allowed more adjustment, but not enough.







Mike

[jalopi]

Here is what I did, which allowed more adjustment, but not enough.

Holey smokes dude, how tight is the gap between your RTAB and the bracket? The rough math I just did says you need a shift of about 8-9mm at the RTAB in order to see an additional 1/4" of toe at the tires (25" tire diameter assumed). Do you have that kind of space to work with?

[MikeE36]

Holey smokes dude, how tight is the gap between your RTAB and the bracket? The rough math I just did says you need a shift of about 8-9mm at the RTAB in order to see an additional 1/4" of toe at the tires (25" tire diameter assumed). Do you have that kind of space to work with?

It's extremely tight in there on the inside. I would probably have to use feeler gauges.

I'll put it on the alignment rack again soon and try to measure it.

Mike

[jalopi]

Well, I don't think that what I've got in mind is gonna help you, unfortunately. I might have a suggestion though. Is the head of the bolt in this picture:



a limiting factor in how far you can move the RTAB bracket inside of its pocket? If so, you could remod the bracket and instead of having a through hole in the pictured location, thread it and run the bolt in from the other side. Other than that I have no idea what to suggest, you've got a pretty extreme setup bro

[RandomHero27]

Im in. Cant pay till the 15th though.

- - - Updated - - -

Cross post this in the regular e36 section. So many stance cars in there.

[tptrsn]

I'm having trouble posting today for some reason. But I'm here. All I ask is that you make this happen sooner rather than later please.

[RandomHero27]

I cant access the site on desktop

[jalopi]

Bad news everyone. The trailing arm bearing I measured off of my car is 2.2" long, but the bracket for the RTAB is only 2" wide. It just simply doesn't fit. I guess the Bimmerworld guys used a bearing off of a car that wasn't an E36. I don't really have the energy to hunt for the right bearing.

Sorry for the letdown

[tptrsn]

Damn..