Long Travel BS Thread

no. no, no, no, no no no no, no.

you need to factor in anti-squat, roll center/center of gravity, the angle of the lower link/links in relation to the lowers, length of your links too. there's a lot more math to it than just buying parts and slapping them together.

 

Well yeah I'm just doing a cliff notes here but... you're right I haven't done enough research on some things

I thought your coilover spring rates and lengths play a big part in some of those issues...

 

I was under the impression that a 4 link isn't ideal because the gas tank gets in the way... Unless you're talking about super short uppers like in the rear of a JK?

impossible to 4 link with the stock gas tank in place

Gotcha.

Gotcha. Uniballs always seem better...

Ok so this is what I don't get. What do you mean come up with a perfect geometry on paper? I don't really understand what you could do different.

the position and length of every link and mounting point makes a huge difference

The trailing arms/lower links just fall where they fall. I was thinking I would tack them in place with the leafs in place if they don't get in the way. They just hold the axle the proper difference from t-case so the driveline is happy, correct?

no, they don't just fall where they fall. if you are using prefab links you really need to plan and cycle the rear end without your leafs to assess driveshaft plunge. the position on the front mounting point of the link matters and the oisition of the tabs at the axle matter a lot too and impact tge location of your 3rd on the axle as well


Then with the upper link I just need to place it where it twists the axle to the same angle to the driveshaft as the angle coming off the t-case, correct?

no, the length and the mounting points of the 3rd need to be within a very specific range for it to work properly

Then I mount the pan hard so the axle stays centered.

no, with a 3 link the axle is only centered at ride height and again the placement of the mounting points and length of the pan hard matter a lot



Cycle, make sure the driveshaft isn't going to fuck the t-case, Make sure all the joints are happy, and then bam figure out what size coils I need.

Wobble stoppers?
google it, if you use uniballs up front you need them

I would highly suggest you do some research online first because the placement of every mount, every set of tabs and every link is critical. There is a ton of 3 link design info online and even some great calculators to help you with it. If you do it wrong you can get very adverse suspension reactions, it can squat horribly under accelleration, lift on accellerstion, your axle can move excessively laterally, your driveshaft can self destruct, your pinion angle can be horrible etc etc etc

 

Ok I'm going to google for a bit before I embarrass myself more...

 

This is 100% correct. I'd start doing some research on rear linked suspension. Otherwise you'll end up with a truck that performs far worse than a leaf spring truck. It all starts on a piece of graph paper. Once that's under control then you can move onto the real world. That's where it gets fun.

If I were you I'd start by reading chassis engineering by herb Adams. It's not directed towards long travel, but all the principles are the same. Then you can supliment that reading with the small amounts of written knowledge on the inter webs regarding long travel link geometry. But definetly start with the chassis engineering book. Most articles reference it.

You will also want to incorporate a rear sway bar into your design. It will be tight, but don't make the mistake of designing a rear setup that won't allow use of a rear sway bar. You can thank me after you test drive your truck without it.

 

The spring rate mostly dictates ride height. That's about it in simple form. I usually have atleast as much tie in planning geometry as I do in the actual building. A poorly designed link can actually decrease your traction under acceleration and/or braking.once you have a grasp on it, laying it out on paper becomes very simple. Making the adjustments to fit your packaging issues while keeping the suspension characteristics how you want them is the fun part.link suspension on factory frames is ful of comprimises, I hate comprimises

 

Thank you! This is the type of info I need. Ok I'm going to be busy with reading for a while haha.

Hmm... I've seen people run antirocks in custom setups...

 

I hate compromises too lol. I just want something that will articulate a lot, but support the ass of the truck with a damn RTT and armor, and allow me to sorta keep up with the front. Bouncing off bumpstops is getting old.

I understand though, the last thing I want is worse wheel hop soo to the drawing board I go.

 

Why not toss a spring under kit on there with some heavy duty LT leafs and tune it for your weight?

 

Told Ya Chevys weren't gonna be great haha

 

Yes, you can run a sway bar. What @glorifiedwelder is saying is that it is very difficult to physically fit one into the equation. You are adding so much stuff to the frame between the pan hard mount, bed cage mounting points, bump cans etc etc that pyhsicslly fitting a sway bar and it having room to move is very difficult. On my truck an anti rock style sway bar will not work, I have to use an axle / links mounted set up.

 

Well because I already spent a lot of hours into swapping the chevy leafs... I kinda don't want to mess with leaf springs anymore. I know they're better than my current setup but they're still not as great as links or as easily tunable.

Yeeeerp. I mean they're not bad. Better than Dakars or something haha. But yeah not once I added more weight and got LT up front.

Makes sense. So you basically just got your geometry figured out to the point where the links control your body roll?

 

Geometry for links on our truck isn't gonna control body roll. The only thing you can do besides a swaybar is change shock valving. But it's better to valve the shocks for the terrain you intend on using the truck on rather than valving them to combat body roll.

 

Nah, just seriously pre plan the sway bar build into the equation...hell looking back on my build we would have had to start with the sway bar first and then tie in the bed cage and bumps differently to leave room for the sway bar arms outboard of the frame. The other option is this style of sway bar set up :

 

Isn't your truck mainly a crawler? Just stick with leafs. Once you get the correct leafs it won't be a problem.

 

Just throwing this out there anybody have a set of 18" Long 3" 600 Lbs coils?

 

Understood.

Well damn man, that idea doesn't look bad at all! A true sway bar is still better though?

Well I mean yeah... but I want to do more of this... and more gracefully lol



Plus all the serious crawlers are linked. I mean links just trump leaf springs at everything... besides towing and payload I guess lol

 

Don't forget ground clearance. If your plans are to stay with the plus 2 front end, a giant link killer rear setup will out run it all day. And perform a million times better than a flat set of 63 springs. If you're set on going with links you may want to look into running your links more like a pro 2 suspension or a rock crawler, won't give up near as much ground clearance that route and you don't need 24+ inches of rear travel with 12.5 or so inches up front.

 

rockslayer offroad makes a badass 2nd gen kit id look into that

 

I think @dakotasyota is trying to keep the factory gas tank so that kit may not work, but for someone who isn't too familiar with setting up links, plumbing a fuel cell is probably easier than designing your first suspension. But something like that in the form of a parallel 3-link with c/o's on the axle would be very simple to do and prett easy to get to handle weight