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JMortensen

TC rod pivot relocation / Bad Dog subframe connectors / Slotted Crossmember

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Jon,

 

Your weld on bracket will make the connection plenty strong enough. However, I think you may still have trouble with your tire hitting the T/C rod when the wheel is fully turned.

 

Here is an image of my set-up and a drawing of the bracket.

 

DSC000651.JPG

 

ControlArmBracket.jpg

 

The dog leg in the bracket serves two purposes: First, it moves the T/C rod back away from the tire. Second, it aligns the force from the T/C rod with the rear most bolt on the control arm. This minimizes the bending moment seen by the dog leg of the bracket.

 

The bracket is secured using 7/16" grade 8 hardware. The clevis is from QA1 (3/4-16 with 3/8" slot and 1/2" hole). I reamed the holes in the control arm and ball joint to match the holes in the bracket and get a close tolerance fit with the fasteners.

 

The tube is 1 1/8" x 0.058 4130 with tube adapters from "ChassisShop" TIG welded in the ends.

 

Dan

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Well I think I'm going to take your previous advice and put another tab on the bracket and have it go over and bolt to the outer rear hole for the ball joint as well. Cary's got me convinced it's going to fold up like a piece of paper the first time I hit the brakes. :D

 

I figure if the tabs are roughly the same top and bottom and the top one is welded to the existing bracket that should work. I checked for clearance and didn't see any problems with the lower tab. I suppose I ought to check again before adding the upper tab.

 

I realize there may be some issues with tire clearance, but I'm moving to a more positive offset on the wheels and using a smaller diameter turnbuckle than I had before, so I think I'll squeak in there, if not I'll put some sort of steering limiter in there like Terry Oxandale has.

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Any updates? How's the final design look?

Nothing new to update here. I haven't been working on the car in about 4 months, and this was not what I was working on when I stopped. I'm getting back out there to start some new rear control arms soon. Got some parts coming and then I can tear into it. Should be fun.

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Your weld on bracket will make the connection plenty strong enough. However, I think you may still have trouble with your tire hitting the T/C rod when the wheel is fully turned.

I should have listened... When I went to install this with the strut in place I found that the bolts that hold the strut to the steer knuckle are hitting the bracket that I welded together. I'm going to have to redesign the bracket and lose the TC rod's direct angle to the ball joint. What's one more do-over?

 

I'm going to see if your bracket clears my sway bar bracket that is welded to the top of the control arm. Not sure if it will, it looks close from the pictures.

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Hey, i am trying to finish up my front tube chassis. Currently i am at the TC buckets. my setup is almost exactly like yours. i have 2.5inch frame horns and have done what 74 5.0 and mortenson have done with the buckets, 2x4 tube and have slotted them as much as possible without the rod end hitting the tube itself. My question i guess is it seems that even with the tc rod mount in its lowest position it still will be slightly higher than the inner lower control rod bolt. Auto X probably isnt in this cars future but will this have a big affect or should i take a peace of 3/8 plate and weld that to the top of the box which would lower the tc bucket some.

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Having the rear pivot of the T/C rod slightly above the inner pivot of the lower control arm is a good thing. It provides a small amount of increased anti-dive (assuming the outer ball joint is lower than the inner pivot), and a little bit of dynamic caster gain during braking. Just be sure that the inner pivot on the lower control arm is a spherical bearing, or you will get some binding.

 

The inner pivot of my lower control arm has been raised my 3/4", and the rear pivot point of the T/C rod has been raised by the same amount. I have been toying with the idea of raising the rear pivot point a little bit.

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