4link geometry

Jeremyfc1

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Joined
Jan 10, 2016
Location
Chapel hill nc
ok In a perfect world i.e. No oil pan no steering issues (full hydro). No hanging accessory drives. What style of link suspension would you build. My chassis I am using for my electric buggy was built before I got it. The previous owner mocked up some new upper links as the old ones hit the oil pan. I'm looking to reuse the original link location but if I'm ordering links and playing with it already maybe I'll change it up. As it currently stands I'm not sure the front driveshaft will clear the upper link. And I have to get everything mounted before I have a shaft made and it would suck if the driveshaft interferes with the upper link

Pic is before I went to dual cases and did away with the trans. But shows the temp upper link location
 

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Tcase front output has moved up 10". It is 2" behind the boxed upper link mount you can see in the pic as this is my first time playing with links should I move the upper links somewhere else. Or try the original location
 
Start by reading this thread.

Link Suspension Basics

Then download a copy of the 4 link calculator. There are a few floating around.

Post your finding and which calculator you used. Also post exactly what info you enter, so that we can enter in your exact link locations and try to help.

50-80% antisquat(AS). Try to keep it consistent through travel. Try to avoid increase in AS through droop.

Getting this close will result in upper being around 70% of upper length.

Disclaimer: this will result in the pinion rotating down through droop.

You must compromise pinion change with AS change through travel.

Total travel will be set by driveline style and length and u joint misalignment capacity.

Try to get your roll center height as high as possible or as close to cog height.

If you are already planning to run an antisway bar, get the roll center low, so that there is less side to side movement of the axle through travel, and tune the bar for body roll.

Front 4 link is a compromise between keeping caster consistent through travel, and AS increase in droop.

This usually results in near equal length link, and little pinion rotation. This will also typically cause AS increase in droop.

In the front, this is antidive(ad) while braking, and anti-lift ( or pro squat, however you want to describe it) while under throttle.

To sum it up, it's all a compromise of what you want, and getting all locations into decently acceptable range.

Keep in mind,

100% AS in the rear, is based on 100% rear torque bias(2wd) and 100% traction.

100% Anti-dive in the front is based on 100% brake bias to the front with 100% traction.

You must take torque, traction, and brake bias into account for the anti- anything forces to be accurate.

However you can use them as a comparison point as they are.

Post your #s and we will all go from there.
 
Full hydro steering as in no mechanical link between steering wheel and wheels. A lot of link fronts are built around steering arms and tie rods. I have no oil pan no accessory drives hanging no steering arm to contend with. This can place my links for better suspension design without having to compromise for space
 
This may sound a little off the wall, what about a 3 link with track bar, 2 lowers, 1 upper on non-driveshaft side, track bar running parallel with draglink. I've used this on a couple custom setups with a ram (not full hydro). It seems to be the best mix of both worlds. I have pictures if you'd like them.
 
49willys said:
This may sound a little off the wall, what about a 3 link with track bar, 2 lowers, 1 upper on non-driveshaft side, track bar running parallel with draglink. I've used this on a couple custom setups with a ram (not full hydro). It seems to be the best mix of both worlds. I have pictures if you'd like them.
Click to expand...

This works great for traditional steering. Since he is running full hydro, I would suggest a 4 link, unless there are clearance issues.
 
Jeremyfc1 said:
Buggy is already 4link front just trying to figure out links. Is there an advantage to running longer upper links than the lowers
Click to expand...

It can keep pinion from rotating down through droop. But this will cause a lot of castor change through travel, and will bind the front driveline if using a drive shaft with single u joints at each end.

Put your points into a calculator and start looking at the #s.

Move the mounts in the calc, to get a better design.

Compromise that with what will work with your chassis.
 
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