Droop Vs. others

[Inspector86]

IMO, counter sprung shocks are not an optimal setup, it is an artificially induced droop which does not work as well as a natural droop setup. If you want droop simply install a softer rate main spring which will allow the weight of the vehicle to create the desired droop. From there you can fine tune the shocks with different weight oil and/or different shock pistons.

[shiggy]

Originally Posted by Inspector86

IMO, counter sprung shocks are not an optimal setup, it is an artificially induced droop which does not work as well as a natural droop setup. If you want droop simply install a softer rate main spring which will allow the weight of the vehicle to create the desired droop. From there you can fine tune the shocks with different weight oil and/or different shock pistons.

I won’t be using negative springs. I am familiar with balancing positive and negative springs in mountain bike suspension, mostly used to reduce stiction and increase low frequency bump response. Not really an option on a mini crawler (SCX24).
I have soft springs coming for the long travel low CG modified truck.
Already running about 75% sag on my tweaked stock truck.
Shock tuning is pretty limited.

[diby_2000]

Another thread dig from the dead.

Full disclosure - I'm an RC crawling noob, looking to get into the comp game soon. I have been trying to figure out what all the fuss is with this 'droop' or 'full droop' suspension. This is how I understand things at this stage. So please correct me if I'm wrong.

Firstly, RC droop suspension is nothing like a 1:1 droop setup, I'll go into why soon.

I agree that a sprung suspension setup can run the same belly height and even CoG (Center of Gravity) as a droop setup but the whole idea of the droop setup is to MAINTAIN a low CoG when crawling steep inclines and or side slopes where a sprung setup will typically unload. When the suspension unloads, the sprung mass then moves up, raising the CoG. The droop setup is acheived by the reverse sprung shocks holding the body down in a low position where the regular sprung setup will extend the shocks due to there being less weight on the springs.

Why this can not be compared to 1:1 crawlers, is simply the weight distribution of RCs vs real rigs. Typically, an RC crawler will have lots of unsprung weight (weight in wheels and axles etc) vs sprung weight (body, motor gearbox electronics etc) and a 1:1 will have a much greater proportion of its wieght sitting in the sprung section. I think this is where the RC droop setup confuses people.

The springs below the pistons in the droop setup are soft. They only have to be strong enough to control the sprung weight (to stop the suspension from unloading) when on an incline. Because there is so much more weight in the unsprung portion, when a wheel is not on the ground, the unsprung weight esily overcomes the internal spring rate and they extend the shocks to max travel or they find a surface.

The other thing I picked up on in this thread, that I would like to comment on is the concept that because a spring is 'pushing down' or 'sucking up' does not mean there is more or less 'traction', only that the forces on the contact areas are different. I will try to explain. There is always the same downward pressure (the weight of the vehicle) distributed over the contact patches of the tires touching the ground. If at any time there was less force than what the vehicle weighed, it would float away into the never never! So a sprung setup driving over a 1" rock, has the same tractive forces as a droop setup over the same rock. For example the sprung setup has more force on the tire under the rock, compressing its spring, but that extra force is taken from the opposite side tire, the one that has now extended the shock due to there being less load on the 'pusher' spring. The droop setup on the other hand losses some force on the tire still on the ground, because it is fighting the internal spring but this force is still transfered to the tire on the rock, giving it more tractive force.