These are actually notched trailing arms as recommended in my GM manual on how to prep a corvette for road racing.
You do not need special welding skills, a stick welder works fine and NO jigging is required.
You do have to have the trailing arms off the car.
These knotched trailing arms will clear any tire that clears the frame. The frame becomes you limiting factor.


First locate where you want the knotch and how big. You know the radius of the tire so this is the center of the knotch measured from the center of the axle or carrier center.
The dept of the knotch is actually the thickness of the trailing arm at this point.
I am calling the front the part closest to the tire and the back the side towards the center of the car.
Anyway the back wall of the existing trailing arm never gets touched. It becomes your new front.
I don't have dimensions because I did this 10 years ago and never kept notes but with a tape measure all dimensions can quickly be figured out.

Decide the dept of knotch by measuring the thinkness of the trailing arm where the widest section of the tire would rub on the trailing arm. This is the depth of the knotch minus the thickness of the rear wall which is about .100

You can add the back wall in the form of a rolled radius or a box. Sorry I can't draw it but look at the picture that I will post.
Add whatever shapt you want to the back side and weld it in place.
Make a top and bottom cover matching the shape of the knotch and weld it top and bottom.
Remember clean metal always welds better the rusted or painted.
Now cut out the front wall matching the conture of the top and bottom plates. I used a band saw. Remember you are not cutting through the old original back wall just to it and along it leaving it intac.
Now fill in the front wall with a shapt matching the back that you decided on.
Grind all the welds and repaint.
The new trailing arm has a knotch deep enough for any tire and is actually now 3 walls thick in the knotched area.
I have run mine with slicks and a nitrous big block for years without a problem and now behind my blown bigblock.
I am posting this then going looking for pictures. I will add the pictures in a few minutes.



[Modified by norvalwilhelm, 12:33 PM 5/1/2003]

 

That looks great Norval. I wouldn't mind trying that with my own sometime :)

 

YEP, thats the trick. Then a little notching of the frame and viola! 11 inchers in the rear without flares!

Norval, you are a dangerous man and I love you for it!

Chris

 

This is really interesting..Keep èm coming.. :cheers: :cheers:

 

That looks too easy. :eek:
When I eventually have to take mine off I'll have that done.
Thanks Norval.

 

I think Norval is the Martha Stewart of the C3 world....

Mike :cheers:

 

Guys it is really simple. I could wipe up a set of these in an evening no problem. After grinding and sandblasting my son powder coats them and they look great and garanteed you never have to worry about tire clearance again.
At least between the trailing arm and the tire.

 

Damn you Norval !!!!!
My project is falling behind schedule, and you have to post an awesome mod like this.
I have my (never installed) rebuilt trailing arms sitting in the box.
Damn you Norval !!!!!
Now, I'm gonna have to seriously think about doing this. It will be a long
while before I want to remove them from the car - after installing.
Damn you Norval !!!!!
Now, we will all have to buy bigger wheels and tires. $$$
Maybe I'll wait to do this and a new upper link - like yours - next winter.

Thanks Norval !!!!!

 

CHRIS!!!!!!""""YEP, thats the trick. Then a little notching of the frame and viola! 11 inchers in the rear without flares!
Norval, you are a dangerous man and I love you for it!"""""""

What do you mean a little notching and 11 Inchers without flares ???????

Don't start nothin' we can't finish!!!!!

How much would it take? MiniTub?

PS Update me on your project when possible. JIM




[Modified by PROSOUTH, 6:06 PM 5/1/2003]

 

Norval, that's slicker than snot on a brass doorknob...just gotta LOVE IT!!!!


now it looks like about 3/4 to one full inch in additonal clearance above just moving the e-brake tab like I did....

which means...I can get a set of stock ZR1 rims and bolt them on!!!....
looks as if I wouldn't need another adaptor either.....

you know, now that I look at it again, it's better than that!!! it's slicker than a two headed peter in a mule facking contest!!!!!


GENE

 

I like it. :smash: :thumbs: Gotta keep it in mind. Was thinkin about getting the ones made to accept 10" rims. Will have to remember this post

 

Very Cool :D

 

DAMN YOUR GOOD!, Nice job :smash:
:cheers:

 

Would love to be able to do that but don't have the tools or skills :D

 

Norval, that is awesome what you did there. I have my T-arms going to Van Steel as we speak. I am getting the offset arms and was wondering if they have as much clearance as yours. My goal is to run 10 inch Tourque Thrust D's without them sticking out of the fender.

 

I have a question for you guys who want to run wide wheels.... where is the end of your spring in relation to your tire? Mine is about 1/2 an inch away when the car is just sitting on the ground. Under heaving side loading (cornering) the spring rubs on the tire. It wasn't a problem until I went to the composite spring and 10" bolts to get the ride height that I wanted. I'm not sure of the backspacing on my wheels, but the tires are only 255/60-15. I can get a pic later if needed.

(I'm done hijacking Norval's thread now. Thanks for reading)

 

I am running a VBP plastic spring and bolts, and ride is set about 1.5 inches fron bolt end to nut.......and I do not show any evidence of any scraping at all....as I recall it's a 360? spring....

GENE

 

A lot of us are running 17 inch wheels and the spring end is closer to the rim then the tire which gives more room. A problem I noticed with the plastic springs is that they have too much arc to them. Look at an installed steel spring with the car on the ground - is is pretty much flat with the spring ends clearly above the bottom of the rim. A lot of the composite springs will have a lot of arch in them even under load. You shouldn't have to run long bolts to get a stock ride height, or even a little lower. I sent my original composite spring back because of this and they sent me a new one, which was a little better, but not much. It is one of the downsides to the composite springs. Having that spring rubbing against your tire is incredibly dangerous, because it means that when the spring finally tears thru the sidewall, it will be during hard cornering where there is no room for a massive blowout. Not only that, but since the spring ends and bolt ends are closer to the ground then the bottom of the rim, when the tire does blow, the spring end is going to dig into the groound and it will tear everything apart back there. That is why I sent mine back. Safety first. You might also ask about slightly shorter springs when you call them about your current spring. I really wish the vendors would get it together in this area, but until they are facing a massive lawsuit because someone died because of this, they will let it ride.

Chris

 

Scooter70 A metal rear spring is easy to shorten but I don't know about a composite spring. This is one of the reasons I am still running a steel spring because I don't know how to shorten a composite.
A steel spring cuts easy enough and with a sharp drill bit, slow speed and lots of oil you can drill a new hole. Only cut one end, drill a new 3/4 inch hole then a new 3/8th hole in the center of the new spring.

 

Which publication are you referring to?