3-link w/watts link or 4-link w/watts link?

[brrymnvette]

Trying to decide on my rear suspension for my build. What is better? 3-link with a watts link or 4-link with a watts link? I can't really see a benefit of one over the other.

[COPO-RAT]

Is a watts link even necessary when using a triangulated 4 Link? Serious question, not being a smart a$$. I could see using one with a parallel 4 Link, but I thought those were typically for drag cars.
Excuse my ignorance, I'm not being smart here.

[JRouche]

Is a watts link even necessary when using a triangulated 4 Link? Serious question, not being a smart a$$. I could see using one with a parallel 4 Link, but I thought those were typically for drag cars.
Excuse my ignorance, I'm not being smart here.

Honest question. He didnt say triangulated 4-link but did say he was looking for lateral control so Im assuming he was thinking parallel bar 4-link. Im just assuming.

And as far as the parallel 4-link goes yer right, they have been mostly geared towards the drag cars or pro-street trucks and cars. I dont know why. Maybe because you loose the rear seat on a street car and folks dont want to go that far. So they work well with a street truck cause there isnt any seat to loose.

But, in my opinion, a parallel bar 4-link can be used for the twistys too, not just straight line roads. But some modifications should be done.

I have a parallel bar 4-link and watts link. Havent got to drive her yet but Im thinking she will be fun on the turns. Who knows.

Here is what it looks like and hear is the mods done. Ive done some more since the write up. Replaced all the rod ends for some QA1 heim joints. A lil more "looseness", no binding with the poly ends. JR

The thread....
https://www.pro-touring.com/forum/showthread.php?t=55420

https://static1.pt-content.com/images/pt/2009/05/c-3.jpg

[JRouche]

Trying to decide on my rear suspension for my build. What is better? 3-link with a watts link or 4-link with a watts link? I can't really see a benefit of one over the other.

Better??? Not sure one is better than the other. Every suspension design has its positives and negatives. Some trade offs.

I like the 3 link for packaging. Gonna use up less space where it might be nice to put an exhaust. Then the watts link might eat all that up.

You only talked about two designs. There are so many out there. Dont know what car you have but if its a main stream model there may be a whole lotta options for you. There are some really solid "kits" out there if you have a common car.

Now if your car is say a AMC gremlin, or some other off brand, like my car then you just look to do what you can. Oh, I love them lil gremlins. LOL Yeah, kinda ugly, but they look like a wheely hound. I like the not so popular cars.

Anyway... Umm, Id go with a 3-link. Simple.. JR

[brrymnvette]

It's an extremely common car. But it has no mounting points anymore due to being mini-tubbed. 88 Mustang Notch. I'm putting a 9" in it and will be building the rear suspension from scratch basically. I could do a triangulated 4-link, but was thinking of a parallel when I posted. The pic posted, is exactly what I was thinking it would look like.

[BillyShope]

JRouche, I don't know if you're in a position to do so, but I'd like to see you market that suspension. If I weren't so old, I would beat you to the punch. There's a number of racers who insist on driving their race cars on the street and the 4bar eliminates the link binding problem. I'd make one suggestion: Use a fully pivotable link...near the front of the links...to tie upper and lower links together and prevent the user from trying to convert it to a 4link.

(You'll note that I refer to a "4bar" and to a "4link." This is to make a distinction between the arrangement where the upper and lower link are constrained in a parallel configuration in side view (4bar) and the arrangement where they are not so constrained (4link). I first noticed this distinction at the Art Morrison site and assumed that this was universally understood among racers. Mark Ortiz has recently questioned me on this and I have to admit that I'm not really certain. But, if it isn't, it should be, as it saves a lot of explaining time.)

I've tried to get Morrison to offer a heavy duty adjustable version of his 4bar, but with no success.

To explain to others why JRouche has all that adjustment at the front of the links: Parallel lines meet at infinity, so the adjustment holes allow him to place the instant center on a number of constant percent antisquat lines. So, the 4bar can do anything that the 4link can do. And, by adjusting for more antisquat on the right than on the left, it can even match the performance of an asymmetric 3link.

Yes, roll oversteer can be introduced, but, remember, roll steer changes only the relationship with steering wheel angle, NOT the tire loads.

Excellent work, JRouche!
http://www.racetec.cc/shope

[JEFFTATE]

What about a torque arm ???
The packaging is good ..
The geometry is close to a 3-link ...

[JRouche]

JRouche, I don't know if you're in a position to do so, but I'd like to see you market that suspension. If I weren't so old, I would beat you to the punch.

Haaa.. Yer killing me.. Im also too old, heck!! Im retired. Im just playing with my Lego car :) Thanks though.

But yeah, its just a Lego car. I didnt build or design anything. Its a lil piece from here and a lil piece from there. Art morrison 4-link, air ride tech spring/shock, a watts link that I pieced together and a speedway engineering roll bar. Lego land here I come.




(You'll note that I refer to a "4bar" and to a "4link." This is to make a distinction between the arrangement where the upper and lower link are constrained in a parallel configuration in side view (4bar) and the arrangement where they are not so constrained (4link). I first noticed this distinction at the Art Morrison site and assumed that this was universally understood among racers. Mark Ortiz has recently questioned me on this and I have to admit that I'm not really certain. But, if it isn't, it should be, as it saves a lot of explaining time.)

Yeah, good point. I didnt see the 4-bar come in till, oh, I dont know, maybe the 2000s for art morrison. When I bought my 4-link from them in the mid 90s they werent offering the 4-bar, I would have jumped on it. I imagine they saw a market for guys that didnt want to remove the entire rear seating. And the antisquat issue wasnt a concern for the street crowd as was having a back seat. Thanks for the support :) JR