4-link Length Limit?

[mjensen]

I'm curious if any of you that do custom builds knows of any guide lines for minimum link lengths for a 4-link suspension. I assume (maybe wrongly) that because the shorter the links are, the tighter the arc they travel in and the greater the variations in the wheelbase, there must be a point where it becomes detrimental to handling and crawling ability. I'm mainly concerned with bottom links since the top links are going to be based off the bottoms and what caster you're looking for. Any ideas?

[HumboldtEF]

How short of a wheelbase do you have in mind?

I think the important points will be link separation and triangulation.

I posted up a few helpful 4 link videos here, I'm not sure they will directly answer your question but it will run you through the basic factors to consider.

Another 4 Link Thread

[mjensen]

Originally Posted by HumboldtEF

How short of a wheelbase do you have in mind?

I think the important points will be link separation and triangulation.

I posted up a few helpful 4 link videos here, I'm not sure they will directly answer your question but it will run you through the basic factors to consider.

Another 4 Link Thread

Well, my build is a 6x6 based originally on a Traxxas 6x6. I've shortened the wheelbase about 30mm already but I'd like to bring the middle axles and in turn the rear axle closer to the rear of the FJ45 body I'm using. The rear links can't really be shortened beyond the stock length without clearance issues with the tires. The the fronts are also as short as they can be and still clear the steering servo. The links between the skid and the middle axle could be shortened about 15mm and still have tire clearance on the cab but that would make them 80mm and that seems very short. I've looked through a number of build threads and of the few that mention custom link lengths I haven't seen any that short.
Thanks for the links.

[meatmonkey]

It's more of a link length to suspension travel ratio to maintain. Short links are ok with limited suspension travel. In the 1:1 rock crawler realm a good minimum ratio is twice the link length as the amount of suspension travel. As long as your running the stock length trx shocks you should be fine shortening the links that much.

[mjensen]

Originally Posted by meatmonkey

It's more of a link length to suspension travel ratio to maintain. Short links are ok with limited suspension travel. In the 1:1 rock crawler realm a good minimum ratio is twice the link length as the amount of suspension travel. As long as your running the stock length trx shocks you should be fine shortening the links that much.

I actually ordered 3 pair of Dravtech medium shocks which are about 10mm longer the the stock TRX6 shocks when they have the spacers installed. I was planning on running them with about 75% droop which worked well for me on the custom Capra chassis I built. Since I'm cutting the shock hoops out of carbon I have a lot of leeway to make things sit right. I have no idea what the travel will be because until the shocks arrive I won't know what the difference between the compressed vs extended length will be.



I added a couple of pictures to give this some context.


The body will sit higher once I get some sliders made and figure out some mounts.