What should I do for rear radius rod in a Model A? I'm using a 47 banjo rear that I will convert to open drive and the stock rear spring. Are the Model A radius rods strong enough? I guess I should mount them as close together in the front as I can. I think I can use tie rod ends on the front, are they strong enough?
Thats what I thought, But the thing is, It will work with just the two stronger radius rods and the rear transvers spring even with the "open" rear? has anyone made any rear radius rods?
The Hot Rod Torque Arm Rear Suspension Picture Thread. Here is a thread with some good info, there are many others to search through. You can run without a torque arm depending on power and or driving style.
Using 35 up front wishbone is a strong cheap design. Put the ball in a mount and fab up some mounting plates for the axle end.
I mocked up my whole set up with weight on the ch***is, engine and trans in and then made some templates for brackets on the banjo rear out of 1/4" mdf and some spacers the same niceness as the rod ends I planned on using. Then I used some dowels to mockup the radius rods...mailed the whole mess to Ron at Ron Pope motorsports and he cut the brackets front and rear, made the radius rods, included all the rod ends and jam nuts, maile d the whole thing to me for 293.00, betas the so cal ones for price...custom made too. I am not crazy about the Speedway welded parts, there was a post on here awhile back about a failed front hairpin I think it was, with pictures, not very encouraging. Ron can be reached at tbuckets@ Comcast.net. Nice guy, great welds!
After getting checking out the thread Harv linked to (thanks again Harv) I just don't see how the torque arm does much. I would think if this torque arm is to stop or control the rotation of the axle housing under acceleration and braking the best place to mount it would be as high on the center section as possable. that is if the radius rods are mounted at the lower part of the axle. Most of the torque arms in the thread are mounted right at the pinion area.
Just so we all know what I'm building, '30 tudor with 292 Y block and automatic. I will end up with a mild cam and 4 bbl carb
Here's a simple setup that works just like original. If you use a 36 rear end, it already has very heavy pads in the proper place on the axle tubes.
Pete, what is that? it looks like a Model A front wishbone with an adapter in place of the ball and a tierod end installed. and what is it connected to?
Connected to axle pads in the rear. The front is connected to the belly band which is made of 1 1/2 inch .120 wall 4130 tubing. The end is a Kenworth tie rod end with home made socket. I use the same setup on both front and rear.(***uming open driveline) Depending on how soft you set your springs, you get a very soft smooth ride and no windup with minimum body rise on accelleration. It is the same basic thing the car came with originally.
so, if I follow you right, the part at the top is a crossmember made from 1 1/2" tube and the bottom part is a Model A front wishbone attached to the axle at the rear and your Kenworth tierod end adapter atthe front. Is that right? what about a torque rod? I was thinking of making some brackets that would bolt to the backing plate mounts and that would weld to some box tubing, something like 3X1 inch. I could taper the front foot or two down to an adapter that would attach a tierod end. your large truck tierod end is a good idea. I'm worried that the smaller ones would not handle the load.
You don't need a torque rod. The radius rod/wishbone is all you need. I forgot to mention I only use the model A ends at the tie rod end. The main tubes are 4130 tubing..You could use a hairpin design also. Lots of ways to make it look. The main thing is don't skimp on strength. The car drives through the radius rods and tie rod end..(Not the spring) That's why they are BIG. I have built 5 cars with this setup and I know it will handle at least 500 hp all day.
Thanks for the help, i have spent most of the night looking at some of the torque rod set ups, and I understand the thing about keeping the rear from twisting on hard acceleation and breaking. I just don't see how another rod running forward in the same plane (or close to it) keeps the rear housing from twisting. It just looks like if the thing is keep it from twisting you would need to mount the torque rod up top to get the leverage to keep the twist under control.
As you put the power to the rear, the pinion wants to rotate up and down on decel. Yes you are right, you don't need a torque arm, if the wishones and their mounting points are strong enough. The arm is mainly there to help take up some of the stress that the rear rods attachment points see under acelleration and decel.
One other idea, if i use the backing plate bolt holes, cut a plate to capture the top and bottom front holes. make the plate extend alittle above and below these bolt holes by about 3 or 4 inches and weld two tubes at these points, bring these tubes forward to a single pivot point.
^^^yes that could work if done with the right pieces. Maybe mount with three of the backing plate bolts.
Yes that will work. Just bore the holes out to take 5/8 high strength bolts. Just remember, you are driving the car forward through these bolts.
The Hot Rod Works makes the best open drive line conversion on the market. http://www.hotrodworks.com/ They also offer a strut rod kit that is simple and easy to duplicate if you would prefer to make it yourself. Your Model A rear bones are flimsy. Use 36 and later.
I did some research on this rear suspension thing and like allways the more you get into it the more questions you have. from what most of the responders said I would want to anchor the radius rods to a common point like a front wishbone ball. But I looked at Speedways radius rods and they are set up for tierod ends. One on each rod, the rods are not tied together. I went through about two years of Rod and Custom Magazines and found about three articals about setting up rear suspensions and they have the radius rods mounted solid on the rear axle and mounted seperatly with a tierod end or hemi ball ends. It looks like to me if I do not mount the two ends together and the rear hits a bump on one side and goes up it would twist the rods to some point. this twist may not be too much but if I make them too strong, so they cannot twist, will something break?
"It looks like to me if I do not mount the two ends together and the rear hits a bump on one side and goes up it would twist the rods to some point. this twist may not be too much but if I make them too strong, so they cannot twist, will something break?" YES, and if you don't make them strong enough to stand the torque you are going to apply, they will wind up like a clock spring. I fixed 2 sets that the guys tried to use stock radius rod material. Had to cut the rear end out of the car. These were 400 hp cars.
What about a low hp open drive set-up, would it best to split the radius rods to the frame rails or try to keep the stock angle under the driveshaft. Will stock A radius rods still be to weak even for a 4cyl.
Keep the anchor point as close to directly under the U joint as possible. Stock radius rods are not strong enough for anything but original application.
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