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4 link or 3 link
- Thread starter goompa
- Start date
Up front, if you want to mount the servo to the chassis instead of directly to the axle ... then yes, a 3 link is the right thing to do. It will allow the axle to move in the proper arc with the drag link and panhard bar. If you mount the servo to the chassis and run a 4 link you will have bumpsteer. Not the end ofthe world in an RC but it could mess with your EPAs and you may not get full steering or you may have too much depending on what the suspension is doing.
If you plan on keeping the servo mounted directly to the top of the axle then you can run a 4 link up front.
Out back, a 4 link is a great option. It allows the axle to flex without swinging side to side like the stock upper Y setup. It makes it a bit more predictable and certainly is more scale looking.
"thumbsup".
If you plan on keeping the servo mounted directly to the top of the axle then you can run a 4 link up front.
Out back, a 4 link is a great option. It allows the axle to flex without swinging side to side like the stock upper Y setup. It makes it a bit more predictable and certainly is more scale looking.
"thumbsup".
Mud Puppy
Rock Crawler
Note that a 3-link with a panhard is not the same as a stock 3-link. Same term, very different creatures.
thanks guys. im gonna try out the 4 link in the rear and 3 up front and see how that does. ive seen a lot of people set up like that so i guess ill try it out. oh, another questoin is that if i do the 4 link up front should i use the truss mount or us the holes on the aftermarket plate that the servo mounts on? does it matter or make a difference?
I think you should go 4 link both ends. 3 links can work, but without extra links (like a panhard bar) can result in more tq twist than a 4 link. I've had much better results converting to 4 link though my rig did not have a panhard. A 3 link + panhard may work better.
meatmonkey
I wanna be Dave
The only reason to run a panhard is if you have the steering servo mounted to the chassis, which may look more scale but typically doesn't perform as well as having it mounted to the axle. The chassis mounted setup has a higher center of gravity, and you get side-to-side axle motion as the suspension travels up and down. You also have the possibility of having the steering servo jack the chassis up or down if the panhard to drag link relationship isn't perfect. Another side effect of imperfect geometry is bumpsteer, where the tires physically steer side to side as the suspension cycles. Both of these downsides can be minimized by using as long a draglink and panhard as possible, and having them parrallel to the tie rod at ride height, which isn't alwasy feasible on certain setups.
The only downside to the axle mounted servo is that there is mild interference with the stock setup between the taller servo mounting brackets and the inside of the plastic chassis supports when the suspension goes from full uptravel on both sides, and then one side tries to droop out. This interference is easily remedied with a few minutes and a dremel on both the servo mounts and the chassis brace.
I run the Axial plastic 4-link truss front and rear on my SCX with the stock axle mounted servo and it has very balanced flex and minimal torque twist. For the cost of a couple Axial trusses and some links it is well worth the performance benefit. I'm actually surprised that it doesn't come out of the box that way...
My biggest complaint with the stock three link, and the plastic balled rod ends that come with the kit, is how much slop quickly developed in the whole system. After only a few packs the amount of play in the single upper ball end at the axle side was atrocious, easily ten degrees of castor change going from forwards to revers. By converting to the 4-link and to metal balls I have only a degree, two at most, even after many hours of abusive runtime.
The only downside to the axle mounted servo is that there is mild interference with the stock setup between the taller servo mounting brackets and the inside of the plastic chassis supports when the suspension goes from full uptravel on both sides, and then one side tries to droop out. This interference is easily remedied with a few minutes and a dremel on both the servo mounts and the chassis brace.
I run the Axial plastic 4-link truss front and rear on my SCX with the stock axle mounted servo and it has very balanced flex and minimal torque twist. For the cost of a couple Axial trusses and some links it is well worth the performance benefit. I'm actually surprised that it doesn't come out of the box that way...
My biggest complaint with the stock three link, and the plastic balled rod ends that come with the kit, is how much slop quickly developed in the whole system. After only a few packs the amount of play in the single upper ball end at the axle side was atrocious, easily ten degrees of castor change going from forwards to revers. By converting to the 4-link and to metal balls I have only a degree, two at most, even after many hours of abusive runtime.
