Building my first scratch-ch***is, going with homemade truck arms (thanks to "Clark" on the HAMB, I'm using 2x3 I-beam). Thinking I'd like to do a Watts Link, looks cool, a little different, and apparently does a better job than a panhard for axle location. BUT, the kits are expensive and some of them polished... But then, I found this on Speedway's website... and I know some Alliance Vendors deal Speedway's stuff, so I figure to give it a shot. Anyone with experience or advice???? http://www.speedwaymotors.com/p/3398,325_Watts-Link.html
I've built them for race cars. The problem with that type of watts is that the roll center is at the pivot center and that is quite high. It would be better if the pivot was centered at the axle center line.
I am working on one at work that is basically like a crossmember just behind the rear end that dips down in the middle and has a vertically adjustable pivot point and if you picture a propeller type flatbar that pivots in the middle about 7" long set verticle with a hole at each end, a link bar with hyme joints at each end attatch from each hole to either end of the axle where you would weld a hyme mount. no pics yet sorry, some kits pivot from the diff. and attach to the frame or c-notch
Its funny how so many people get the same ideas at the same time. Here's another thread on these http://www.jalopyjournal.com/forum/showthread.php?t=245694
LOL I "requested" that tech from him! His build thread is kick***! His was the first Watts link I saw, his tech is cool and the watts thing has got me REAL interested
Using a Watts Link you can put the roll center anywhere you want by varying the length of the links/levers (left link + right lever = right link + left lever --- think of the pivot diamond as two levers with a common pivot point) to vary the placement of the pivot point (just as you can by changing the mounting points of a panhard rod). I've also seen examples with the pivot diamond mounted horizontally under the rear differential pumpkin. Generally lower is better and placing it on the axle stops it from moving up and down as the sprung m*** moves around. Three arm rear suspension with a single U shaped lower arm pivoting off a single point under the differential works similar and it too is simpler (multiple vertical forward control arm mounting points with this setup makes it very easy to adjust the antisquat for planting the tires without upsetting the ch***is, too). Important point to remember, any lateral locator requires ultra strong mountings for the pivot points, well bracketed and gusetted, and in double shear if at all possible. Adding a little more food for thought, a few years ago car builder Keith Randall (think sprint cars, but he also built the Orange Crate when Bob Tindle made it made into a show car) showed me that properly placing a long panhard rod (as long as clearances and ch***is rail placement permits) to locate a straight axle resulted in minimal side movement (sprint car ch***is) of 1/32" or less, and it's movement changed the roll center insignificantly enough to negate any theoretical advantage the far more complicated and difficult to build and package Watts Link might offer. I won't go into the left to right and right to left panhard rod mounting arguments here, it's been covered quite well on the HAMB before. If you don't have any idea of what your needs are for your ch***is, it sounds like it's time to break out the Carroll Smith books and do a little studying before you start building.
thehotrodguy, If you want one of the Speedway Watts Linkage kits just PM me, I bought one from them about a year ago and never used it because I couldn't figure a way to mount it on my quick change.............I'd let you have it for $30 plus whatever the shipping is................... The watt linkage is still used by LandRover and other European car/truck manufactures. I put a Steeda Pan Hard/control arm relocation kit on my Mustang Cobra and keep bending the panhard bar(plus pushing holes in my trunk floor)............Steeda kept telling me I adjusted it wrong..................NOT I went to a watts linkage designed by some of the Ford SVT team and all I can say is that the Cobra would do very, very close to 1G on the skid pad(I had done a couple of other suspension mods also)..............raced it twice at the SiverState Cl***ic and the watts linkage far outperformed the panhard bar setup designed by that famous company.............. IMHO
Man, I LOVE the HAMB! Here's my plan. Like I said, this is my first scratch build, but I have rebuilt a few cars before... mostly muscle cars, and '68 and '70 'vettes. So, I started with something I know how to work with.... wood. (My 30 Chevy is FULL of it!) Its cheap, my previous life as a contractor left me with lots of tools, and I had plenty in the shop when I got time to start on this crazy idea. I built a pattern with wooden 2x4 to help work out perimeter dimensions, angles, etc. I want a car that sits and rides low. This is a problem, because I live down a 1/2 mile dirt road and have about a gazillion speedbumps and things to navigate in the "cruising areas"... so I pulled the trigger on one of the Air Lift kits from kustombuilder to spring my ride with. I am ditching the parallel front springs from the 30 chevy frame and using a 4" drop tube axle that I have in stock. I was going to buy one of Hammerndollie's air-ride crossmembers for solid axle frontends, but am now attempting to make one myself first. I will be fabbin' my own truck arms with I-beam to locate the rear (thanks to the HAMB's "Clark" for the design idea). Watts links look cool, seem to function well and the only real drawback I have found in my planning to use them is the cost and the complexity. That, and I have never seen one in person. All the more reason to do it. Lots of things I haven't done are achievable, and the bigger the challenge, the bigger the payoff. I would rather build one car all-the-way-my-way than to redo any part of it. I have lots to learn, and fortunately I have the time, the space and the money to learn the hard way. Basically, I plan to learn a little from my own mistakes, and am hoping for some constructive advice (and criticism) in the process. I am taking lots of pictures and plan to post a build thread once there is something to really see. Maybe I should mention that I decided to use a sbc because I really dig the zoomies I already had for it... so the fresh 427 bbc will still be waiting for the next build. BTW, before the question comes out, the stock frame is all in tact with the orig suspension, and I figured by the time I patch all the holes, box the rails and re-do the suspension at both ends the new rails are the way to go.
Being installed parallel to the axle centerline, a lateral locating device like the Watts Link (asymmetrically built or not) has no effect on the roll steer characteristics because it does not have the ability to skew the axle centerline from perpendicular to the vehicle centerline. It is the placement of the longitudinal locating links that would determine any rear axle roll steer characteristics.
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