Swapped torque tube for open driveshaft need a solution for radius arms

[brian herres]

I used a rear axel conversion kit and want to go with an open driveshaft but I have no idea what the best solution is for the radius arms.
47 Mercury coupe. Same setup as 46-48 Fords. Thanks for any recommendations. Brian

[RalphM]

If your keeping the transverse spring, speedway sells a kit that anchors the rear axle in the center. You will also need to anchor the radius arms, spread apart enough to clear the driveshaft.
Anpanhard bar is also a nice addition.

[JSeery]

Lots of ways to go about this, are you looking for a bolt on?

http://www.hotrodworks.com/product-c...is-components/

[RalphM]

Looks like you turned that into a four bar setup.

[JSeery]

Originally Posted by RalphM

Looks like you turned that into a four bar setup.

A regular 4-bar can be an issue if you don't retain a central pivot point. These photos are from a HAMB thread on various methods to achieve an open drive and transvers spring setup.

[rich b]

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While there are many ways to approach the situation, here is my take on the easiest.

If you want to retain the transverse spring, get a Pete & Jakes ladder bar set-up.

If you want to switch to parallel leaves; CE and others make kits for this.

If you are an experienced fabricator, there are many more options; but then, you probably wouldn't be asking about it.

[flatford8]

“A regular 4-bar can be an issue if you don't retain a central pivot point.“
By this statement do you mean if you hit bump with a rear wheel on just one side, it could bind and make both sides bounce?....... Mark

[JSeery]

Without a central pivot point the radius rods will bind. The same issue exist when you split the front wishbones and move them to the side of the frame. Because the original front axles are an I-beam the axle can twist which allows the split wishbone setup to work. When a tube front axle is used there is a problem as the tubular shape resist twisting and over time something has to give! The rear axle is even more resistive to twist. If a four-bar setup is used there needs to be provisions for movement at both ends of each link. I like the more traditional look of the original radius rods myself, so I think it is worth the effort to modify it to work.

[RalphM]

JSeery,
I only saw the first picture when it posted, and didn't look close enough at the front section of your setup. So did you graft in a front wishbone to retain the ball as a pivot? I can see where this would work well as it would entirely take the place of the torque tube as an anchor.

[JSeery]

Not my design, but yes. I can post more of the setup if your interested. You can use either a single or double upper radius rod(s). (These photos go with the ones posted in #3 above)

[19Fordy]

Brian,Before you go any further do lots of research on "torque arms" and how they function. The OEM radius rods are not strong enough to sustain the torque once the OEM torque tube is gone. Radius rods were not designed to endure torque. They will crack and break. Go to HAMB and do a search for "Torque Arms". Here's an example of what you will find.
https://www.jalopyjournal.com/forum/...#post-11609358
Also Google "torque arms". There are many opinions on what the safest way to go is in order to compensate for the lack of a torque tube and also whether or not you stay with the "buggy spring" set up or go with parallel leaf springs. I would also call Hot Rod Works and get professional advice.

[flatford8]

Thanks..... Mark

[brian herres]

Yes i want to keep all the orig. Front and rear susp. Thanks for the info. Will need to compare prices.

[brian herres]

Not going to be as easy as i thought ��

[JSeery]

Sorry 19Fordy, but I found very little useful information in the link provided! However, there have been good threads on this issue on the HAMB in the past. I prefer the ball similar to a front setup and the photos I posted above is similar to one I am currently building for a 33 with a quickchange.

Here are some that might provide some food for thought:

https://www.jalopyjournal.com/forum/...#post-11939809

https://www.jalopyjournal.com/forum/...#post-12142357

https://www.jalopyjournal.com/forum/...#post-11898050

"The OEM radius rods are not strong enough to sustain the torque once the OEM torque tube is gone. Radius rods were not designed to endure torque. They will crack and break."

I disagree with this comment and by the way, apparently so does Hot Rod Works, as there approach uses the OEM radius rods. Think things are getting confused here about the lack of an additional upper torque arm. Some type of additional upper torque arm has to be added.

1935-1940 Ford Radius Rod Mount Kit
$110.00

1935-1940 Ford Torque Arm kit
$145.00

[19Fordy]

Brian, read this. Yes I agree that the radius rods can still be used if you also use a torque arm set up like HRW.
https://www.jalopyjournal.com/forum/...s-argue.22539/

[JSeery]

Originally Posted by 19Fordy

Yes I agree that the radius rods can still be used if you also use a torque arm set up like HRW.
https://www.jalopyjournal.com/forum/...s-argue.22539/

Think that is the point, no one has said otherwise. Anyway, several approaches to solving the open driveshift issue. You know what really sucks? All the linked photos in these older post that are no longer available!

[cas3]

i thought the common practice is to use 36 bones with the spring mount on them, no?

[JSeery]

That is a common approach, but with the open driveshaft you have several issues to deal with. You need to fabricate a mount for the forward end of the radius rods (originally connected to the torque tube) and you need to add a torque arm of some sort to control the rotational torque of the axle.

[RalphM]

The later 37-41 radius arms are very strong as compared to the earlier Ford arms.
I would not hesitate to use them (correctly) unless I was putting a 500 HP motor in,
but if were talking flatheads, yes.

Reminds me of High School, we had a kid with an early 50's Chevy truck, he hot rodded it and changed out the rear Torque tube(chevy's version). Every time he was showing off and got on it, it would twist the rear end out from under it!
I don't recall if he ever got it to work right with that setup.