Help design custom rear trailing arms

[q-tip]

this site has just about every type of rear suspension ever thought of. lots of ideas here http://www.susprog.com/susptype.htm

[goichi1]

yea, that's a real PITA, I did mine with a cut-off wheel, If I remember right, I cut off the ears and then you can get the cut off wheel in there to get the base plate part....an air chisel might have been involved too, it was a while back when I did mine.....but they will come off!!

[RonM]

yea, that's a real PITA, I did mine with a cut-off wheel, If I remember right, I cut off the ears and then you can get the cut off wheel in there to get the base plate part....an air chisel might have been involved too, it was a while back when I did mine.....but they will come off!!

Thanks G,
I'm putting together a new arsenal of weapons before going back into battle with that X-member, and an air chisel is on the list. I'll be back at it later this week.

[Byron510]

Are we talking about removing the mounting ears off the X-member here?

If so, confirm and I'll share my experiences - I've done many of these with my camber/toe plates that I sell. One would say you become proficient at it after a while.

Byron

[two_68_510s]

Yeah, I think he is doing that to the '68 crossmember I sold him a couple of weeks ago.
I am not sure if he is adding adjustable stuff or is just looking for a clean slate.

[Three B's Racing]

I just installed some of your brackets Bryon510 I picked up from Dave Patten. I used a 3" cut off wheel cutting the welds on the top and bottm portion of the brackets. Then cutting across the inside of the brackets ears removing them. Then cutting just inside the welds removing a large section of the center, then cutting the welds and smoothing everything over. You could cut the welds at an angle after removing the ears. I'd advice against an air chisel because that area is pretty thin and you may warp it but then again it can be knocked flat again. I'm doiong a complete rear suspension rebuild with all new bearings, 2"studs and disk brakes. So far I have one swing arm left to do

Lou

[RonM]

Are we talking about removing the mounting ears off the X-member here?

If so, confirm and I'll share my experiences - I've done many of these with my camber/toe plates that I sell. One would say you become proficient at it after a while.

Byron

Yes I am removing the ears though I'm not altogether sure of the direction I'm going with the connecting points. Wether C&T adjustable at the X member, or on the arm itself, the stock mounts aren't in the cards. Byron, if you have ANY advice on doing this more proficiently I'm all ears, and would be very grateful.

Quick question:

Why is the diff opening in the X member offset to one side? It seems to me everything would need to be centered, but I'm sure there's a reason.

[duke]

Quick question:

Why is the diff opening in the X member offset to one side? It seems to me everything would need to be centered, but I'm sure there's a reason.

If you look at a diff they are not symmetrical about the drive shaft input. This is because the pinion gear sits on one side of the ring gear, so the housing must be offset to one side to accommodate this, which in turn means the opening in the crossmember must be offset as well.

[RonM]

Got it. This is why the diff housing sits cattywampus (highly technical engineering term) Thanks Duke

[rnorrish]

that's catawampus.

[two_68_510s]

catawamptious; catawampous; cattywampus; cattywampous; caliwampus; caliwampous; cankywampus(my favorite); kittywampus; gittywampus,

and used by a native: "Waal, I noticed ez the aidge o' one o' them boards war sot sorter catawampus,"

[RonM]

OK now I know way more about colloquialisms for uneven. Thank you Joel.

I'd like to preface a few questions with this presupposition. The pivot angle on a rear trailing arm is designed to give active toe shift when cornering via body roll. This design is dependent on a specific ride hight where the trailing arm, pivot points, hub axles, and half shaft stub axles are all more or less parallel in relation to the ground. Obviously the best way to maintain this geometry when lowering the car would be to raze the rear X-member relative to the chases, but this is Not easy, or adjustable.

Here's the question:

Not sure if there's enough room above to do this without cutting into the floor of the trunk, but would it be a reasonable alliterative to make the T/A adjustable at both pivot points to raze the arm equal to the amount you are lowering the car? Although the hub axle would higher relative to the rest of the suspension , wouldn't this help maintain the intended STA design? Has anyone done this and given feedback on what they found?

[RonM]

Bunp'n this cuz I posted these questions late last night and it didn't circulate. Any thought?

[duke]

I think this has already been posted here, but if you look through this build: http://www.the510realm.com/viewtopic.php?t=13582 you will find that he has done exactly what you are describing. Also the DAMB penultimate crossmember raises the pivot points on the crossmember for better suspension geometry. So I guess the answer is yes, it has been done with positive results, but as you do point out, it is not the optimal solution mainly because you still have to deal with half shaft angularity.

[RonM]

Wow Duke What a find! Thank you man. I hope this guy finished his car, because it really looks like its going to be a stunner. His trailing arm design looks very simple, and very similar to the direction I'm going. This has a great deal of potential. Very exited to see this.