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Author Topic:   Short two link, advantages & disadvantages?
xhubby
Member
posted October 21, 2003 08:08 PM
What are the advantages, if any, to running short bars as opposed to say 17" bars on a two link? For the past two years, we've run 17" bars, & need to get faster. We run in a limited mod class, & the only rear suspension we are allowed to run is a two link, or leaf spring setup. I don't know of anybody else in our class running short bars, but it seems alot of people do run them. Would this be something we might want to consider? Thanks.


tilley88
Member
posted October 21, 2003 08:30 PM
I don't think anyone knows. I'm tryin to get a little help on this subject myself.


snowman
Member
posted October 21, 2003 11:10 PM
The shorter bars provide more roll steer, and more weight transfer for the same amount of body roll....more rear bite on acceleration......

It makes the three link behave more like a four bar but less radical.

In your case, you would be using spacers to bring the bracket out.....But if the car is designed from the beginning to run the short bars, then the cage can be moved rearward to pick up some more rear percent.

Give it a try......just don't put much angle in the bars first time out.

Good Luck,
Snowman


tilley88
Member
posted October 22, 2003 12:04 AM
How much angle are we talkin, left and right links?


Wauge28
Member
posted October 22, 2003 12:48 AM
The short bars do give more rear steer. The biggest change is the leverage and how quick the car gets on the bars. With most suspensions, the idea is to drive the car forward buy using the wrap of the rearend and spring/coil over placement to press down on the tire as it rotates clockwise. With a leaf or long 2 link, the rearend pushes against the bar or leaf and pushes laterally on the chassis.
With the short bar or 4 bar the rearend is trying to driver under the chassis...pushing up and laterly. The rearend driving under the car and the weight of the car pressing down on the tire creates more bite. If you picture a long bar compaired to the short bar, you can see how much easier the rearend can "tuck" under the car. If it is longer, it puts much less downward pressure on the rearend because it is almost impossible for the car to raise high enough to let the rearend travel to the point it is pressing down...it more just lets the rear end push the car forward not forward and up. You will notice the car rises up more like a 4 bar on the gas with the shorty. Again, it is because the rearend is pushing up on the car and in turn pressing the rearend into the ground...

Wow...that was a really confusing explination. Does that make any sence. I am just a dumb racer...sorry.

tilley88
Member
posted October 22, 2003 01:52 AM
Clear as mud!lol! You did good. I kinda get the picture. I'm a dumm racer, too! Now if I can just get It to work......


xhubby
Member
posted October 22, 2003 06:07 AM
Tilley88, I knew someone would come to our rescue sooner or later. That's why I come to this forum when I'm confused. Thanks guys for the explanation of the short bars.


dirtbuster
Member
posted October 22, 2003 04:02 PM
We finished out the season on short bars and car was best its ever been. Ran about 12 degrees angle on both left and right bars, with LR spring in front and RR spring behind axle. We tried staggering the bars some but we seemed to have the best luck with the bars the same angle. I know several other guys who said the same thing or maybe just a bit more angle in LR.
Advantages are more forward bite and more roll steer. Disadvantages are it can be hard to drive on a rough track, when you are up on bars there is no spring to it just solid suspension. Car can get thrown around a bunch which can be hard on parts and hard to control.

[This message has been edited by dirtbuster (edited October 22, 2003).]

[This message has been edited by dirtbuster (edited October 22, 2003).]

dluna
Member
posted October 22, 2003 06:42 PM
What type of panhard and pullbar combination are you guys running with the short bars to allow for all of this movement on a 3-link?

I suppose you could slow the roll a little with a longer panhard bar. (maybe j-bar instead of the short panhard bar)

Thanks

EMOD1
Member
posted October 22, 2003 07:45 PM
I'm lookin at 17" on my shortbar, DW8.


dirtbuster
Member
posted October 23, 2003 09:42 AM
We ran with a short panhard bar something like 12" i think. About 7"up on the frame and about 1 1/2" below pinion.
Ran it with both a afco spring pullbar and a Quickcar bar. I dont know the length somewhere around 24" i think.
When we first started we tried running about 14degrees in the LR bar and 0 in the RR bar and car was very tight as a previous post states. Would yank the LF a foot off the ground but would try and turn the car to the wall at the same time. In the end we wound up taking some angle out of the LR to calm it down a little and eventually had the RR bar even with the left. Seemed to work the best for us. Played with LR bite some too and finally settled around 0 to maybe 10 or 15# RR bite. We also ran our front springs softer on the RF than the left, like many 4 bar cars do.


tilley88
Member
posted October 23, 2003 12:19 PM
So I should run my short bar below the pinion, on the left side?


dirtbuster
Member
posted October 23, 2003 12:45 PM
I would either use the short bar or a mediium straight bar from the left side of the pinion to the frame. WE never tried the jbar but i can see where it would have adavantages also.
If I were you I would try the short bar about level with the pinion and about 8" up on the frame and go from there. I think that is about where DW reccomends starting maybe even a little higher on the pinion side. We were having trouble getting the car to roll over and get side bite unless we lowered it as far as we could. Other DW guys were running it higher with the same results. Just depends on you and your car.


Majic Maker
Member
posted October 23, 2003 10:06 PM
I've had better luck with the long trailing arms. The ones that dirtworks have on their cars are just too short.



MJC
Member
posted October 23, 2003 10:37 PM
What is the logic with having different length links on a car (have seen on some cars). It seems to me that if you were to run a 2" shorter link on the LR, it would drive the LR under like a 4-bar and possibly roll-steer the car, yet the longer RR link would keep the chassis from getting as upset as an even length short bar car might?
Make any sense?

------------------
Go Fast, Turn Left?


Wauge28
Member
posted October 24, 2003 12:11 AM
Yep. The longer RR calms the car down. With the longer arms there is much less roll steer and in the bumps not nearly as wild. A short LR and long RR is comparable to a 4 bar LR and Z link RR.


jonniet
Member
posted October 24, 2003 12:49 PM
This forum is awsome ,somehow after lots of research my car ended up being a short left long right.......after lots and lots of contemplation on what rear suspension to run ,the short, long 3 link seamed to be the best of both worlds so to speak .....I cant wait for spring to get here !,I hope the learning curve isnt to steep for my tiny little brain


tilley88
Member
posted October 24, 2003 04:47 PM
One brain fart comin up.......