How to Choose the Right Spring Rate of Your RC Crawler

Spring suspension is important to absorb shocks when driving over uneven terrain and to allow enough flex when going over large obstacles. However, springs lead to unwanted body tilting at slops and shaking due to forward/backward acceleration, centrifugal acceleration or torque twist.
This video shows, how to determine the optimum spring rate (also called spring stiffness, spring constant or spring coefficient). A simple equation is being derived that can be used to find the best spring rate and spring deflection during rest. The mathematical model behind these derivations are based on the assumption, that movements are rather slow, which is valid for careful crawling over obstacles.
Here you find a link to a video that shows how to maximize crawler flex (i.e. articulation, suspension travel): • How to Increase the Fl...
More about tilting at slopes is here:
• How to Optimize Tiltin...
Footage about torque twist was kindly provided by "Nycosp" and "lordofbasement":
• Vaterra Ascender No To...
• Traxxas TRX-4 & Axial ...
Music:
Luminescence_Colossus_instrumental_04_58, license from Soundstripe

[@gangsterHOTLINE]

My roommates saw me watching a video with RC trucks driving and everything is normal. My roommates see escalated defining of variables and equilibrium of forces condition as I measure my TRX4's flex just to tell them that the included springs from the factory are the proper rate...

[@JPGrc]

Thanks for sharing your know how 👍

[@antoniofajardophotography]

This is some next level nerd stuff! I love it!

[@keough-rc6552]

This was crazy to watch but was very helpful to know the stock shocks that come on the trx 4 are the right balance. Thanks for the video!

[@rcscientific6004]

Thanks for watching! And for your positive comment, with which I fully agree.

[@el86lo36fky]

Your shock absorber calibration calculation is good from a mathematical point of view if and only if the shock absorbers had no friction. Which is not the case, especially on the lightest crawlers (under 3 kg) for which the friction of the joints is important compared to the force of the spring.
On mine (2.5 kg), I fitted traxxas GTS 0.22 springs (Ref 8042 - yellow) to have 50% SAG. With your calculation I would have used 0.30 (too stiff)

[@rcscientific6004]

You are right. My calculations ignore friction, especially static friction (stiction). However, if you get a suspension system with little stiction, and consider slow movements only (to ignore dynamic viscous effects), they should be a good estimation for a good spring rate.

[@paulschryer9571]

# 120 !! 👍😁 - I am "brushing-up" on the whole shock set-up process, thank you !!
😉

[@texavon6168]

How dose shock position, placement or angle affect deflection / flex, body roll and stability characteristics, is their an optimal shock position and or angle to maximise crawling performance?

[@SlavaRC]

Great interesting video, thanks my friend!)🤩💥💯👍👏

[@rcscientific6004]

Many thanks!!

[@user-yf5xp3pv7o]

For Most of Rc lover what they actually do is trial and error