There is a school of thought that says a Watts linkage is not geometrically perfect, but I don't understand what their problem is. I can't see how or why you'd need a car centralised with any more precision than a Watts linkage can provide.
Good points, ****. Another reason the track locator or wishbone is preferred on a big tire car is it usually allows a much lower roll center than a Panhard (too hard to mount to the frame). Couple that with an anti-roll bar, and now you are controlling launch roll rather than binding the suspension.
Watts Link and jacobs ladder, I kinda have wondered why no one has used a jacobs lader on a hot rod. Might look kinda cool
A Jacobs ladder has different roll resistance in left and right corners. Ok for sircle track racing, but might get kinda spooky in the twisties on the street.
Well that's a really good reason not to use what is probably the best solution for street driven vehicles. TSM Manufacturing do some very nicely engineered Watts linkages - http://www.tsmmfg.com/Watts_Linkage.htm
Didn't say my car wouldn't run through the rough. Just said my back and kidneys didn't like it much. The track I ran at ten years ago would run a sprint special every month. It also had a weeping crack in the front straight wall, such that there was always a soft stripe across the track going in to turn one. On nights when it was just the regular show, there was never a problem, just a brown stripe. When the sprints would run with us, that stripe would pump and get wider and wider and roll up an edge. Then, their big tires and big motors would cook all the moisture out of the track, so that by the time our feature rolled around, we had the equivalent of a concrete BMX ramp to jump over heading into turn one. You hit a 6" tall ridge with no give at 120 mph and see how your kidneys feel, to say nothing of how the hell you turn a race car after jumping over something like that and still keep it under you. Like I said, never much cared for sharing a track with the sprints. Fun to watch though. Now, maybe it was track prep to blame and not the sprints, but it only ever happened when they ran, so I'm guessing if it's not their fault outright, they at least contributed to it. And it's not like I was alone in this ***essment. I know I certainly wasn't the only guy there who was less than enthusiastic to see the wings arrive. The roll center for a Jacobs ladder can be set on the centerline of the car at whatever height you care to choose. If you set the bars like they do on a sprint car, you're certainly going to have issues with roll center location and roll stiffness 'cause of the drastic offset in the roll center location. That can be overcome by proper location of the links and tuning of the angles. The problem is that it doesn't deal with changes in driveline angle very well. Now, in a sprint or hotrod with an enclosed driveline (torque tube), that's not a problem. But on a four link where the bars are different lengths, or a three link with torque buffer, there is too much pinion angle change for a Jacobs ladder to tolerate. They're made to translate straight up and down. They can't handle a rotational component. I guess you could mount it to a floating collar on the housing and get around that, but that's a lot of trouble and it wouldn't be as strong a straight bolt-on or weld-on mount.
Maybe for a car-about-town, but from a performance standpoint a triangulated four link leaves some things on the table. All suspension systems are a trade-off, you just have to decide which aspects you must have and which ones you're willing to sacrifice.
Don't think so, have run em on the right rear and left rear, have run panhard rods on the left side and right side, even ran one on the front axle before.
cool hand,I wouldnt tell any of the big three that.some of their cars work as good as a lot of after market stuff.
Look at race cars. How many race cars use a triangulated four bar with rubber bushings for a rear suspension? Not too many, and I'd wager none that are not required to do so by the rules. High performance suspension systems get complicated because they seek to optimize all aspects of wheel control. OEM suspensions seek a decent ride quality from a system that fits in the space allotted and is the cheapest to build that it can be. Simple is cheap, but simple is very rarely the optimum solution. If a triangulated four bar works in your situation, good for you. But that don't make it the absolute best solution ever.
that is true that is why I run a track bar on my drag car and triangulated on my hot rod.I plan to drive the hot rod a lot of miles and want it to ride nice.My 4 bar shouldnt be a problem when I cob on it and drive good.It is hard to find one awnser for all uses.I would guess that most hot rods get driven more than raced .
What exactly is it that makes you think a car with a panhard bar will not ride very well? That makes no sense. The harshness of the suspension is pretty much a function of the shocks and springs you have on the car. The car doesn't know how many bars are connecting it to the rear end housing. So long as they don't bind up or otherwise fall victim to geometric chacanery, the suspension will do its thing according to how it's sprung and damped (shocks and springs). Now, body roll and other handling characteristics depend on the arrangement of the links and their relationship to one another, but just going down the road conforming to bumps and dips and such, them bars don't make a hell of a lot of difference.
Good sound advice...thanks so much. Your link makes my case. Like I said...MY case. That's not what I'd have under anything of mine. Looks "wrong" to me. Out of place. No matter how well engineered or how well it works.
I have driven some cars with a panhard that get jiggy when you hit a big bump that is what I have against a panhard.
I wonder why the triangulated 4-link isn't used by drag racers? Seems like it would work as well as a parallel 4-link w/transverse contol bar in the drag racing arena. One small advantage would be getting rid of a litte weight in the form of a track locater or panhard bar.
Watts Linkage. comes stock on PT cruisers even. Everytime I see a watts linkage i wonder how could anyone use anythng else. It is s simple so perfect . Don
The triangulated setup "eats up" a lot of axle torque reaction on launch. Remember that on hard launch the housing is actually pulling on the upper links. Drag cars use this to lift on the ch***is and help plant the tires. The most efficient "pull" comes with straight upper links. It should be pointed out that no matter what side locating device is used, a drag type 4 link (not a parallel 4 bar) will go into bind with a limited amount of body roll. It's not the best geometry for handling, but most cars running that setup can get away with it. You don't see many drag type 4 links used on cars that need to handle well. V8 Bake, the car you rode it that got "jiggy", had another problem... Some of the best handling cars on the planet use panhard bars to locate a solid axle. Really.
Indeed, the triangulated bars waste axle thrust in directions that don't help plant the tires. Exactly.
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