Author Topic: Watts Link vs. Panhard (for my Ratrod coilover/4-link rear setup) (Read 1812 times)

70_Fastback · « **on:** March, 04, 2010, 07:22:35 AM »

I'm thinking of fabricating a Watts Link for my 4-link/coil over rear in lieu of a panhard bar for the ratrod rear end setup.

(Something similiar too this)

What are some Pros & Cons of doing this Vs. a panhard bar for my particular application? Which is not really a "performance" based vehicle. I think this would eliminate the slight sweeping 'arc' from a single sided panhard bar installation. But is that the only real difference?

Discuss.

Thanks.

tarafied1 · « **Reply #1 on:** March, 04, 2010, 03:54:50 PM »

I have no expertise to offer but I do think it would look cool!

stangg · « **Reply #2 on:** March, 04, 2010, 05:19:12 PM »

I'm building a watts link for my '65 El Camino. I think it looks cooler than a panhard bar, plus I like that of all the systems it minmizes side movement the most.

On mine the swivel arm / propeller is mounted to the frame as opposed to the rear end. I'm not absolutely certain which version is better, but I think the frame mount swivel is better because the roll center stays consistent with the body/chassis and not the axle. Fays and Steeda both use the frame mount pivot method.

My main reason for the frame mount pivot is that I didn't want to build extensions off of the frame for fear of adding too much torsional stress to the frame, and I also wanted to keep the links short to keep the packaging pretty tight to allow plenty of room for the exhaust.

The frame mount is done in the second picture, for the axle mounts I'm probably going to make permanant mounts so I'll need to wait until I can build the 12 bolt rear end. For mockup on the 10 bolt I just welded some tubes / nuts to the axle tube.

For the swivel arm, I'm hoping my son can CNC mill out an aluminum piece before he finishes high school this year... If not, I may just cut my own pieces and fab it out of three pieces up like shown in your picture. My first attempt failed since the holes weren't exactly equi-distant. These holes need to be precising cut. Someone with a waterjet or laser jet could cut them too. For the center pivot I might use an small wheel hub with bearings and a center spacer. The other thought I had was to use the roller skate bearings used on roller perches. The $10 links are from speedway motors, and I already had the hiems.

If you build your own, there is a company in street rodder magazine that sells the urethane bushings and adjustable end links. I'm not sure but I think they sell the DOM tubing too.

Anyway, my vote is for the watts.

70_Fastback · « **Reply #3 on:** March, 05, 2010, 05:49:33 AM »

The dudes on the RatRod forum are recommending just a triangulted 4-link setup and ditch the Watts & Panhard. I like the looks of the Watts though. I think a person could get really creative in the fabrication of the brackets and locations.

daveSanborn · « **Reply #4 on:** March, 06, 2010, 05:50:44 PM »

I'm using a panhard bar. When adjusted properly, the side to side movement is negligible... maybe 0.5".

While I like the Watts link design, I think it'll cause issues with the coilover mounting locations. For instance.... look at your (really cool BTW) animated graphic of the Watts link in operation.... where/how would you mount the coilover springs so as not to interfere with the operation if the links?

The Watts link would be more fun, but the simple Panhard bar will get the job done just fine.

70_Fastback · « **Reply #5 on:** March, 08, 2010, 06:10:23 AM »

Hi Dave. That is a good point, but would think as far as location of the coilovers; they would have to be located on the front side of the axle tubes. And maybe (though I don't care for the look much) fabricate an elipticle bracket (like in the picture above) to move the Links further behind the axle.

I've have material to try both ways, so I think I'll just play with it and see which one I like better.

stangg · « **Reply #6 on:** March, 08, 2010, 08:40:54 AM »

If you go with a 3 or 4 link then I think you'll want to mount your coil overs on the rear of the axle tubes... this will essentially preload the axle and lessen the chance of wheel hop under hard accelleration. Also, mount them as far outboard as possible for more precise handling / tuning. On the watts link, I don't think longer links are nesseacary like on a panhard bar.

70_Fastback · « **Reply #7 on:** March, 08, 2010, 08:43:21 AM »

Makes sense. So basically reverse my previous statement.

And is there a "better" angle for the coilove shocks - in/out? Or just straight up and down?

gt289 · « **Reply #8 on:** March, 08, 2010, 08:43:57 AM »

The Watts is the best means of axle lateral control. It is also the most difficult to do, in terms
of engineering. Even a carefully thought out panhard bar usually introduces some unwanted
geometry when the rear axle goes through its movements.