What is Unsprung Weight and does my Crawler care?

[@stuartcopley2170]

Watching this channel for the first time… and wtf?!? In the best way possible! You are great at sharing technical and practical information. If that wasn’t enough, you gotta distract me most of the vid with signed world champ DH jerseys?!? I’ll be watching much more. Thanks for doing you! (My dog wasn’t interested in suspension set up until the very end of the video haha)

[@BoomslangSuss]

😂🤣😂 Your comment made my morning. Thanks for that! 🙏🐾

[@wingnutbert9685]

Great video! This is why I love this channel! You bust out the sock puppets for the Dyslexics like me. Confirms that it's ok for me to show up to a baseball game, wearing a hockey helmet, on a short bus and sit at the top of the cheat seats. Thanks! Happy Festivus for the Rest of Us!

[@BoomslangSuss]

Happy Festivus to you as well.

[@kylethatcher5828]

One of your best videos! I love that it presents a whole new way to look at an old and fairly entrenched set of rules and practices. Keep up the great work!

[@BoomslangSuss]

Thank you 🙏 🤘

[@allscalerc]

Another excellent video. Thank you.👍👍👍👍

[@BoomslangSuss]

🙏🙏

[@forrestcrabbe]

Merry Christmas 🤘🎄🤘

[@BoomslangSuss]

👊👊🤘🙏

[@jdmtyteeeyo]

Great info for people to know great breakdown

[@BoomslangSuss]

🙏👊🤘

[@erickenz8579]

Curious if you’d agree: Statement: in order to optimize grip, the ratio of spring/unsprung weight of a 1/10 drift RC car with a) “hard plastic, zero-deformation tires, b) low friction driving surfaces is the INVERSE of the relationship of 1/10 crawlers. Rationale: tires aren’t absorbing any impact.

[@BoomslangSuss]

That’s a great question. Crawling and drift cars could not be more different. Virtually every vehicle, including drift cars, need suspension for bump absorption and traction, even on smooth surfaces. So yes, a drift car wants as low of unsprung weight as possible. Wheels and swing arms should be as free to respond to the ground as possible. Especially since the tires are offering zero suspension.

[@pocketfuloducks1062]

Great stuff. A good way to change the mindset. Also, orange is your color, huh? Down to the electrical tape!

[@BoomslangSuss]

😂 Yep! I used to say “Orange is the color of closeout” because all my outdoor gear (packs, shoes, jackets) were purchased on discount closeout and was always orange - the last color anyone wanted. In RC Crawling it seems to be one of the premium colors! 💀😂

[@Lewis-kf2pj]

Just got a quick question if I may? Is it possible to buy internal spring shocks that are also oil-filled? I’ve had a brief look on Google and I even bought some of the Injora absorbers but they leaked like a sieve. By the way, much like the chap from Roach RC, you’re criminally undersubscribed because this channel goes into great depth of the actually interesting parts of RC crawling. Anyone who has had even a passing interest in engineering would love this channel. It’s pretty exceptional really. Oh, don’t get me wrong here, 2K+ subscribers is a massive achievement and I’m saying nothing against that, it’s just that I’m fairly sure this channel will one day have the following it deserves!

[@BoomslangSuss]

Very much appreciated! I only started about 6 months ago, but I sure hope the channel will grow. The positive response thus far makes me optimistic. Thanks for the encouragement! Are you talking about internal negative spring, full droop shocks? Only Desert Lizard (medium quality, oil filled, not a lot of spring or length choices) and Priceys in Australia (impossible to get, won't sell you alternative springs to do your own tuning) are the only two I know of. There are a few random, traditional positive spring shocks like Hot Racing, but I never liked them very much. That is why I built my own: kzbin.info/www/bejne/l3-oh4V4gK-of5o

[@Lewis-kf2pj]

That’s brilliant, thank you very much! I’m fairly handy so I’ll have a go at creating my own via your design. I’ve not watched the video as yet but going by the others I’ve watched so far, I’m fairly confident it’ll be spot on information, As for the channel, you’ve put a very impressive body of work out for such a short time and I’ve still got loads to catch up on (my life hasn’t been my own for years now 😀). Though as long as you’re enjoying the process of making and uploading the videos (to be picked over by the online vultures that pick at everything) then please keep up the great work. Try to ignore the miserable swines as best you can! :) :) It’s always good to see decent people doing good things for the RC hobby. Anyway, all the best for you and the channel in 2025!!

[@jerryvolpini7987]

Is there some reason you didn't use corner scales? I thought it would be easier/faster? Then, just lift the body and the difference is your sprung weight (opposite of having the rig upside down and lifting the axle but same result). Another great video! 👍 Merry Chritmad 🎅 and Happy New Year 🎉

[@BoomslangSuss]

That would be faster if I owned a corner weight scale. 🤣 Too cheap. And BT is a hassle. The single scale approach cost less than $20 and I already own the scale so it was kinda free. Merry Christmas to you as well.

[@AdVANtureWolves]

Seems like a vote in favor of full droop with internal springs keeping the minimal sprung weight as low as possible. Or am I missing something... In a low speed crawling situation is there any reason to not be full droop with 'negative' springs?

[@BoomslangSuss]

You are reaching the same conclusion that I have and that’s actually going to be my next video. However, there are a lot of people that still like 10% or 20% positive suspension though it’s hard for me to justify why. It raises your CG but does give you a little suspension action and may improve articulation freedom.

[@themountain59]

@@BoomslangSuss well...I would not generalize that full droop is the answer. For a dedicated extreme rock crawler it might be an option but certainly not for a Trailtruck or class1 rig 😑 Happy holidays🥂

[@BoomslangSuss]

Droop Tuning Made Easy kzbin.info/www/bejne/epyZl5dtndaGsJo

[@slappomatthew]

seems like you could just put the rig upside down on your scale and lift the axles to get weight without hanging it.

[@BoomslangSuss]

That would work!

[@jeffrash6900]

Why are you not including the tires and inserts into the unsprung weight measurement?

[@BoomslangSuss]

I added those weights in later. It’s easier to get an accurate measurement with the tires off and I had an extra set of unmounted wheels anyway.

[@Dozern90]

So when talking unsprung ratio and its importance. How does wheel weight come into play? (Let’s pretend we have brass lock rings) 50% of the wheel weight will always be above the centre of the axle. Does it even matter as long as the ratio is good?

[@BoomslangSuss]

Lower is always better. You are absolutely right - rotating wheel weight is always 50/50 above/below the axle, so weight "hangers" that put the weight below the axle is preferred. This is why Dlux builds hangers that mount to the knuckle and hang lower. Here is a video explaining why lower is better. kzbin.info/www/bejne/Y6jKk2h3bKacjM0 Here is a video about a weight hanger I designed. kzbin.info/www/bejne/Y6PTpGVtn9mknbM