Droop Vs. others

[run2jeepn]

I mention this in another thread and would like some feedback or opinions on this topic. I'm not bashing, pointing fingers or saying one is worse then the other. This is just my opinion and what Facts I have been told and seen. Just want to see what you guys think. Now correct me if I'm total wrong..

The way alot of Droop set ups on RC Crawlers have the spring always pulling up on the Shock Piston to keep it Closed. So when Flexing the weight of the tire pulls on the shock. But the shock is always trying to pull the tire back up and keep closed. This would take away from Traction as the shock is trying to stay closed. Many 1:1 Crawlers run a Droop set up, but they are completely differernt then what most are running on RC Crawlers. They run Coil-Overs or AirShocks that were made for the weight of rig they are on. They also run Bump Stops to stop the Up Travel and limiting strap to stop down travel.

A good Link and Shock set up would do better. The only thing I can think of that Full Droop set ups help is to keep the COG lower and help on Side Hills. Also keep in mind that with a Droop set up that when driving you rig can change it's wheelbase in certian spots. So a limiting strap off the center of you axle to only allow a small amount of axle drop. This will fix the wheelbase changing issue, but still allow full Flex. I have watched a lot of these Droop Set ups and seen just about everyone have that issue when climbing over a rock the wheelbase changes b/c both axles are drooping to much at the same time.

Not saying that Everyones Droop set up is the same, but some I have seen would hurt more then help.

I think you would be better off Using some good Shocks and Making some Bump Stops either inside your Shocks or off your chassis to you axle to keep the axle from moving up. This way you can lower you rig as the tires won't be traveling up into the body. Now your shocks will always be pushing down for Traction and not trying to pull closed.


Here is a Picture that should explain what I just wrote. When most guys on here talk about Droop set up. The set up is not really like a True Droop Set up. Now correct me if I'm wrong. Buy doesn't the shock with the Droop set up always wants to stay closed. Now the normal shock always pushs down which would give better traction. Now like rigs like the Huslter with the Droop Set up. The Huslter and any other Tube Chassis will have a Higher COG then say the Stick Chassis, SW2, Pimp Cane or any other Light weight Aluminum Chassis. But since the shocks are set up with that droop set up. ( Now I said the Huslter just b/c it was the first production Tube Chassis to advertise the Droop set up and is the most well known chassis sold with the Droop set up) The Shocks help keeps the chassis pulled down and the axles pulled up. With a Tube chassis this set up might be better. But with any other chassis I think a Good Shock with a Spring rate for that rig with some sort of Bump Stop and something to limit down travel. Will be the best set up.

 

[renoirbud]

Hey there

About the shock pulling the tire off the ground in a drop set-up. Yes it does but it does so by using the other tire as a leverage point. Therefore over all traction is the same.

for example; if you drive over a 1" rock with the left front, a conventional set up compresses the side going up the rock and adds down force to the tire that is going up the rock but takes that down force off the tire that is still on the flat surface.

The drop set up does exactly the same but exstends the side that is going to stay on the flat surface. The net effect is the same. The front right tire has less down force.

Rene

 

[run2jeepn]

I answered in Yellow...

Hey there

About the shock pulling the tire off the ground in a drop set-up. Yes it does but it does so by using the other tire as a leverage point. Therefore over all traction is the same.

So does the conventional way. It uses the leverage as well. Matter of fact the tire that is being pushed by driving up on the rock is still being pushed down my the Shock.

for example; if you drive over a 1" rock with the left front, a conventional set up compresses the side going up the rock and adds down force to the tire that is going up the rock but takes that down force off the tire that is still on the flat surface.

The Tire thats still on the Flat Surface is getting it's force from the weight of the rig and the Shock.

The drop set up does exactly the same but exstends the side that is going to stay on the flat surface. The net effect is the same. The front right tire has less down force.

It's not the same thing. In no way. With the Droop set up like that there is no dampening. Basically all it is doing is keeping the Chassis pulled tight to the axles. But then in Return the axles are always being pulled to the chassis. So it's taking away from the Traction. The net effect can't be the same. You don't even get the full weight of the tire and axle for traction as the shock is stealing some of it. So the only benefit your getting is better COG and and side hilling, but your losing traction.

Rene

I'd like to just add I'm not dissing anyones Set up just trying to figure the Droop set ups I have seen and the way they Real work and why....I know there have been many threads on it but nothing talking about this.

 

[DARKHORSE]

I think the droop set up would essentially almost hurt you, Except when your trying to carry a wheel over, But for cresting a ridge or narrow rock I would think that when you try to crest the hill it would let the chassis bottom out and not allow to keep the axels fully on the ground to gain the most possible traction and keep you high centered..

I understand the the weight of the axels and wheels would allow the unsprung weight to drop out, But the return spring would want to keep pulling the axels back up to the chassis not allowing for max traction..

Now, I also think that both setups are totally different, Because the conventional spring shock setup would want to lift the said axle when climbing a rock not letting the opposite tire that is on the other side grab traction, But then again the opposite spring is pushing as far down as possible trying to put the tire on the next closest surface to help with traction.. Where as the droop set up would be wanting to pull the wheel that is extending down over the rock back up ever so slightly..

But with it wanting to keep it as low to the ground as possible for a better COG for side hilling and steep climbs, it seems like it hurts you more where you need it. Just enough of the droop shock tention is just that much more not firmly planted to the ground when you have a object to climb when you get that one front wheel on to something..

The overall weight of the vehicle is gonna determine weather or not it is gonna stay firmly planted and rely soly on the rear to get it up and over..Where as the conventional is allways pushing the weight of all four corners of the vehicle to the ground..

HAHA, Try to read this one... Now I dont know what I wanted to say

 

[renoirbud]

I agree that the drop set up has a significant disadvantage in some cases. I ran my truck with a drop set up at the last comp for the first time. (I did not win because of my rear steer falling appart)

About the dampening, there absolutely is dampening on the wheel trying to drop.

I think that the drop has its possible advantages, but you never get anything for free, lower CG means less break over clearance.

I am no expert, I just get luck some times. (Also no dissing intended, just trying to get smarter)

 

[marmech]

What about a centre limiting strap with a springless droop suspension setup? Do you think that would unload on sidehills too easily?

 

[Rockpiledriver]

Depending on the course I am running, I do run limit straps. I also sometimes run bump stops. As far as breakover, I have not yet had a problem clearing a breakover obstacle that a conventional set-up can. I can almost always out-climb a sprung rig, especially if I limit the front.

As was mentioned above, droop or sprung both have advantages and disadvantages in certain areas.

 

[Double J]

completely understand your point R2J.
I'd rather have down force on my wheels than up force.

 

[Rockpiledriver]

completely understand your point R2J.
I'd rather have down force on my wheels than up force.

How does the pimp cane fit into this discussion?

 

[run2jeepn]

How does the pimp cane fit into this discussion?

Who said anything about a Pimp Cane? A Pimp Cane works off Torsion. Not Shocks or Links. I was asking about how a Droop set up works and why.

 

[renoirbud]

I have another tiny advantage of running a drop suspension. This is scale specific, on the chassis I am building for Augusta I have a drop rear end, that way I will not have to have the body sit up high to allow for the wheel travel.

 

[Double J]

How does the pimp cane fit into this discussion?

Just cause he sells the pimp doesn't mean he can't build other things.
:?:

 

[Highmark]

Droop is kind of cool if you think about it.

Droop is the only way you can build a suspension to roll towards an ideal roll center, of course you'll never get there on a functional rock crawler, but it does get better instead of worse (like a sprung rig) if the links are setup correctly. The Hustler is not a good example as it's links are setup almost exactly opposite of what I'm talking about, but I've seen a few NN's converted to droop that where dead on.

As for ground pressure, I have no idea, but I'm pretty well convinced that it doesn't make a damned bit of difference in the real world. In rock crawling the conditions are constantly changing, and you're not always in a "flat" environment, so gravity is not always working for you.

Who knows if that made any since to anyone, but I've driven and owned a droop-rig or two and really liked them. With that being said I've also owned a lot of everything, and so long as it's setup correctly just about any style of suspension will work.

 

[Rockpiledriver]

Who said anything about a Pimp Cane? A Pimp Cane works off Torsion. Not Shocks or Links. I was asking about how a Droop set up works and why.

I did, I guess I should have said torsion chassis rather then pimp cane, sorry about that. ;-) Since we are talking about traction and forces being exerted with relation to traction, I brought up the pimp cane because I think it would be closer to the characteristics of the droop rig then a sprung rig. Since the nature of the torsion chassis is such that opposing corners of the rig will either have increased or decreased forces due to the torsion design, much the same as the droop design. I am not pitting one type of rig against the other, just adding insight into the discussion.

 

[Rockpiledriver]

Just cause he sells the pimp doesn't mean he can't build other things.
:?:

What does that have to do with the discussion of chassis dynamics which is what this is. :roll:

 

[run2jeepn]

I did, I guess I should have said torsion chassis rather then pimp cane, sorry about that. ;-) Since we are talking about traction and forces being exerted with relation to traction, I brought up the pimp cane because I think it would be closer to the characteristics of the droop rig then a sprung rig. Since the nature of the torsion chassis is such that opposing corners of the rig will either have increased or decreased forces due to the torsion design, much the same as the droop design. I am not pitting one type of rig against the other, just adding insight into the discussion.

Thats fine you can say Pimp Cane all you want. There is also the BMVII and other Torsion chassis out as well. With a Torsion chassis like the Pimp Cane. The tire thats getting lifted up the chassis is trying to untwist and push it back down. Not wanting to pull itself back up. So it's getting almost twice the down force on that one tire. Now the other tire is just getting the weight of the Tire for traction. It's not the perfect set up. but there isn't a Perfect set up to date. There is a lot of Force in the backbone of a Torsion chassis. The thing is the longer the backbone and the more flex it gets and the more force it applys. Now I know I had alot of weight to my 2.2 Wheels. Giving me even more weight, More Leverage, and more traction to the ground. If you tried that on a Droop set up. You would have to change Springs to counter act that extra weight. If you didn't the springs would just pull out to easy. Then if you do change springs to a stronger one. Then that just counter acts the weight of the Tires.

 

[Double J]

What does that have to do with the discussion of chassis dynamics which is what this is. :roll:

You brought it up?
:arrow:

How does the pimp cane fit into this discussion?

They are two different animals.
the torsion (PIMP cane) uses the entire rig for it's limited articulation

A droop will in a cense be seperated to each axle because of link and shock set ups.

The torsion doesn't even need to be in the discussion.

 

[Rockpiledriver]

I never said anything about Run2 making a different chassis design.

They are ALL different animals.

One thing you can do with a droop chassis, is easily limit articulation as well as unloading, this can be achieved with something as simple as a zip tie, or as complex as a winch. Not as easy on a sprung rig and down right impossible on a torsion. Either way, Highmark made a very good point, none of this force on the tires really matters in rock crawling since the terrain is so varied. The weight of the vehicle itself, and where that weigh is placed has FAR more effect on traction then suspension does.

 

[Etype R]

Who knows if that made any since to anyone, but I've driven and owned a droop-rig or two and really liked them. With that being said I've also owned a lot of everything, and so long as it's setup correctly just about any style of suspension will work.

So how is the Juggajero doing these days? That was a partial droop in the back ;-)


I have had 2 droop TLT's now, and I love it. On my gopher most of the weight is on the axles, the chassis is pretty light. And the springs I run are very light, just enough to keep the rig predictable on the rocks. I have yet to have a unloading issue with my setup.

 

[KRAWLR4life]

R2J, I know you know alot, but dude, your opinion has become almost like a "lesson" to some of us and some of us cannot be "Schooled" on certian things... its a age difference thing I guess. In my opinion, your "stick" should not even be included in this discussion of droop and spring and like Rockpile said, it really depends on where your at, and how your chassis is setup. Droop works great on round, steep desert type rock, lava/beach rock to where spring works great on jagged, river bedrock, so to say what will be an advantage or disadvantage when it comes to suspension really depends if you have "Been there or done that". Thats the beauty of living in SO CAL, we have just about every style of rock you would want to test with..."thumbsup"
~John