Suspension Geometry and its effects.

[EddieB]

What is the general ideal starting point, parallel links? closer at axle? closer at chassis? What effect do the different setups have? I would think closer at the chassis would make it want to flex more, where further apart at the chassis would make for a stiffer less flexible setup.

 

[slowngreen]

Lots of things that depend. But parallel is a good start. So much of your link placement will effect antisquat. I personally like to start parallel. Its gonna depend on the chassis though on how to answer imo. Like my chassis, I have the higher rear link mount so their always going to be higher than the front, which doesn't make much different but it puts the rear uppers closer to the lower than the fronts would be if going off of parallel.

The best I have mine setup is like this. Although each link is bent, you can still get the idea of how they are angled to each other.

Although on alot of chassis you would beable to run your uppers alot longer and closer to the same attachment point as the lower, mine you can't but that doesn't hurt at all imo.

Id say for the most part you would usually have better results with the rears up higher than the fronts (uppers). My picture is dated though because I do have my front uppers mounted on the outside of the chassis which doesn't effect the articulation at all for me, just gave me more room for my electronics.

This is a good thread on anti squat. But imo it really depends on your personal setup.

http://www.pirate4x4.com/forum/showthread.php?t=212765&highlight=Anti-squat+hurts+brain

 

[EddieB]

Very interesting, not what I was getting at, but very usefull...lol I guess a better explanation is lets say the top link is an inch above the lower on the axle side, what changes would be made by having the chassis side mounts more than an inch apart? less than an inch? Parallel seems best, but for tuning ideas what changes when the link spacing at the chassis is changed?

 

[hamz9561]

I've always heard that a suspension set up like this for the upper links \/ and this like this /\ for the lower links still gives you plenty of flex and keeps the axle located and the drive shaft from binding.

 

[EddieB]

Still not quite what I'm looking for, I know about the reverse triangulation. What I'm looking for is the difference with the placement of the links when they meet the chassis on the sides.

 

[slowngreen]

Its just gonna depend on your setup, you will have to try out different variations. The link placement effects anti squat, which can be the gain or fail of your suspension and link geometry.

Changing the "spacing" at the chassis will effect exactly what I said, anti squat. Changing the links can make lots happen, the front end wont pull down on steep climbs, the back end can lift up under power wich wont help on steeper climbs either. Id start parellel and just keep tuning from there.

 

[Manners]

It depends on what you want the vehicle to do. Is it going to be a pure crawler or race in the baja 5000 or something in between like a street legal weekend warrior type ride that goes for the jack of all trades type approach.

If you want to crawl then you probably want a good deal of dive in the front end. Dive is the same as squat in the rear, its just called dive up front. But for crawling you want a high antidive value in the front so when you get you front tires on a ledge and hit the throttle the fronts will be pushed down into the earth and gin traction to pull you up and over while having a low antisquat value in the back so the rears don't push down and make it harder to pull the front up and over. This is great for slow crawling but would be awful on the roads or at high speed.

But either way you need far more info than anyone us goingnto type and you'll need a calculator with trigonometry functionality or an app. 90% of crawlers i see would collapse under their own weight if they were scaled up to 1:1 or the wheels and axles would tear out at 5mph. But its a hobby so fun is fun and at these scales you don't have to worry about it if you don't want too. And its not hard to move links around on an rc but 1:1 its going to need to be done right the first time. Its very funny to see the 1:1s that were built like most people build rc crawlers, then after all the money and time it can be outdone by a bone stock jeep lol.

 

[Manners]

It depends on what you want the vehicle to do. Is it going to be a pure crawler or race in the baja 5000 or something in between like a street legal weekend warrior type ride that goes for the jack of all trades type approach.

If you want to crawl then you probably want a good deal of dive in the front end. Dive is the same as squat in the rear, its just called dive up front. But for crawling you want a low antidive value in the front so when you get you front tires on a ledge and hit the throttle the fronts will be pushed down into the earth and gin traction to pull you up and over while having a high antisquat value in the back so the rears don't push down and make it harder to pull the front up and over. This is great for slow crawling but would be awful on the roads or at high speed.

But either way you need far more info than anyone us goingnto type and you'll need a calculator with trigonometry functionality or an app. 90% of crawlers i see would collapse under their own weight if they were scaled up to 1:1 or the wheels and axles would tear out at 5mph. But its a hobby so fun is fun and at these scales you don't have to worry about it if you don't want too. And its not hard to move links around on an rc but 1:1 its going to need to be done right the first time. Its very funny to see the 1:1s that were built like most people build rc crawlers, then after all the money and time it can be outdone by a bone stock jeep lol.