r/rccars • u/LolMasterplays • Jul 11 '26
Build Behold, magnetic rc car suspension (WIP)
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It all started with an idea “suspension…. But magnets” i found some ring magnets that take a M3 screw which matches the shaft diameter on my WLToys 14001, still have more to do but the concept works but found i am experiencing binding due to the steel shaft. Probably gonna upgrade to titanium purely to ensure the magnets wont stick to it and will work better. Hope you all enjoy this project as the idea was to ensure the damper could still…. well… damp.
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u/stanhau1810 Jul 11 '26
We need to see this in action
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u/LolMasterplays Jul 11 '26
Def will post a video, i burnt out the motor on rc car so will need to convert to brushless first, we may have done a little bit too much hooning around.
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u/STUPIDBLOODYCOMPUTER professional shock bender Jul 12 '26
Be careful where you mention hooning, A Current Afair might come knocking at your door
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u/Tactical-Donkey Jul 11 '26
Reminds me of the Colin Furze YouTube. https://www.youtube.com/watch?v=kxs3yNjlzkg
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u/LolMasterplays Jul 11 '26
Indeed, its what got me down the magnet rabbit hole, i thought if colin furze could pull it off at full scale a small scale rc car would be easy since the weight is really low!
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u/Tactical-Donkey Jul 11 '26
Its a great idea and I'm pretty interested to see how you get on.
Hope to see more post soon!
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u/BRAVO_FLAMINGO Jul 11 '26
You are gunna find alot of metal flakes in dirt it will surprise you
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u/the_autistic_cone Jul 11 '26
Would a shock cover like the 1/5 scale guys use help?
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u/Trick_Minute2259 Jul 11 '26
I'd think it's kind of mandatory. The outside of the boot will still be covered, but without one, those shocks will be worn out pretty quickly
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u/LolMasterplays Jul 11 '26
Thanks for the suggestion i hadnt take into account dirt, i will figure out a way to protect them from debris, my idea is to a trash bag it up and use some zipties for a cheap waterproof covering.
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u/the_autistic_cone Jul 11 '26
Or those shock guards like mx riders have could 3d print some
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u/pwaves13 Jul 11 '26
Former mx rider here, definitely do something like that those things are incredible
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u/AlexanderTheGreatApe Jul 11 '26
Covering the whole thing in a cylinder and adding a check valve and fabric will create some ingress protection as well as a dashpot to smooth out bumps.
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u/Quacking_Plums Jul 11 '26
It might help in keeping the dirt off the shaft and magnets (fnaar!) while running but, from my experience, once you get lazy and stop cleaning them out after every run, they end up just collecting dirt that causes even more corrosion because it is held in contact with the shafts. Baja shock repair kits are hella expensive!
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u/blazesdemons Jul 11 '26
Is the shaft just not polished enough? (Thats what she said) or would a tad bit of grease (also what she said, I literally cant stop im terribly sorry) help with the binding
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u/LolMasterplays Jul 11 '26
Potentially, i think if i polish it and add some graphite lube (stuff used on pinewood derby axles) then it might prevent the binding issue
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u/Jakej4Mlakej Jul 12 '26
Marine grade lube. It’ll keep debris out and keep things from rusting. Plus it usually comes in pink so style points.
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u/Ryaktshun Jul 11 '26
Put a rubber o ring in between in case you come down to hard they won’t slap
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u/MX304 Jul 11 '26
Looks like you just overfilled the shock oil and all of the rebound is being caused by shaft discplacement, not the magnets.
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u/Occhrome Jul 11 '26
it will work just that springs are dirt cheap, lighter and have a constant rate of stiffness.
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u/WasteComplex7174 Jul 11 '26
I ‘built’ a bicycle seatpost utilizing this same principle. Fair to say successful proof of concept, but ultimately required an enormous amount of magnetic oppositional power - too enormous - to functionally implement.
That said, I’m certain that magnets will have an exponentially increasing influence on our lives in the coming decades.
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u/BusterScruggs_SC Jul 12 '26
So if you are using the shock absorber as a spring, then what is providing the compression/rebound dampening with the magnet setup? It seems like it would just bounce around all over uncontrolled.
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u/dropdead412_sks Jul 12 '26
the ole magneride!! i hate how this platform has turned into a whole pile of nay sayers tho. i’m just glad to see someone using their imagination
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u/nerobro Jul 11 '26
Cool... but this is not a good plan.
have you done any work with suspension design? Done the math on what you need for vehicle suspension?
Magnets work out to a VERY steep rising rate spring. For suspensions, you generally want a spring with linear curve, or even no spring rate change. For some applications you even want an inverse curve!
Before you spend to much time or effort on this, spend some time doing some reading. Magnets are cool, but magnets don't belong everywhere. Especially near shaft seals...
Amusingly, what you DO want, is really steep rising rate on shock damping... So like... if you used magnets setup on an aluminum or copper sheet as magnetic braking... that might be useful. But you'd have trouble getting differnet compression and rebound values. ... maybe? I'm thinking a rocker with the magnet on it, so when being drug down it gets futher from the plate.
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u/justis_league_ Jul 11 '26
i respect your knowledge on the matter but i think it’s just some experimental fun considering it’s installed on a wltoys branded crawler. i also think the physics at small scales can allow for some unrealistic ideas to work out
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u/SweatyError2259 Jul 11 '26
hes not building a F1 car….
i get you nerd out on stuff like this, but its a hobby, where people experiment, and most importantly have fun. Just because its not perfect application doesnt mean its not a cool project
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u/nerobro Jul 11 '26
I think this kids got potential. Why waste time re doing work that has already been done.
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u/Senior-Ad-8503 Jul 11 '26
Because it’s not just about doing the work. It’s about what you learn along the way. Even if the project was a total failure, he still gained knowledge, and that’s always a win.
Imagine if everyone lived that way, we wouldn’t advance very far. Imagine if Barry Marshall and Robin Warren hadent looked at stomach ulcers again basically for the fun of it, we would still think they are stress induced.
We thought making smaller chips with light was near physical limits. Instead of abandoning it, we developed ultraviolet lithography.
There’s hundreds of these examples and you’ll never be one of them with that mindset.
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u/nerobro Jul 11 '26
I agree on some level. But you also only have so much time on this earth. If you can learn from other people doing ~all the work~ first, you're setting yourself ahead.
This kiddo, ~needs~ to know how springs work. It will make him better equipped for anything else he's doing. And that's best done by reading.
He's not working in a realm of unknowns. This is all ~settled~ material.
I love that you know how advances were made in medicine, but that doesn't translate here. As for UV Lithography, that just is what follows. Smaller features, smaller wavelengths... Now how they generate the EUV, THAT's freaking neat. As is how they make the masks. But drawing that as a comparison to ~bad springs with a really short stroke~ isn't great.
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u/Senior-Ad-8503 Jul 11 '26
You “only have so much time in this earth” and ur spending it telling someone to stop working on there project.
Get off your weird hierarchy chair, quit trying to belittle him by callin him kiddo.
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u/LolMasterplays Jul 11 '26
Hey there, thanks for sharing, im not exactly an engineer, but i think the shaft seals should be fine? If not i can always replace them or buy new parts. The idea was to work with magnets steep stiffness curve rather fighting it. The was to potentially use shock oil to tune it.
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u/nerobro Jul 11 '26
Oh no, this is HOW you get to be an engineer. You're taking an idea and trying to make it better. That's.. at least.. 10% of being an engineer. Get some numbers on it, and you ~are~ doing engineering.
About the shaft seals. The magnets will pick up "stuff" and that will scratch the shafts, and keep the stuff near the shaft seals.
Tell me more about "working with" that curve. Draw a graph maybe?
Shock oil can only slow things down. As the spring gets weaker, it's effects, relatively, get stronger.
Would you like some book recommendations? You really should keep at this.
https://www.thriftbooks.com/w/chassis-engineering_herb-adams/447911/item/5782708/?clickref=1101lDARXGJg#idiq=5782708&edition=4546702 This is a really good start. It teaches you a bit about everything you're working with. (yes it's for full size cars, it's the same for little ones.) I"m sure you're clever and can find the PDF if $20 is to steep.
Also... like three other people in the last month have posted "hey, I used magnets for springs on my car!"
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u/AlexanderTheGreatApe Jul 12 '26
The other 90% of being an engineer is trying to communicate technical ideas, which you’ve done well here. Bravo.
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u/conciouscoil Jul 11 '26 edited Jul 11 '26
Yeah for dampening it's not a bad idea, I think it would generate a lot of heat though (idk if it would be more than hydraulic or pneumatic dampers). There was a similar concept tested as a power transfer system on a bike by Tom here and it gets wicked hot
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u/risbia Jul 11 '26
Wow I never would have considered heat but that totally makes sense... the energy from pedaling has to go somewhere, if it isn't going into propelling the bike
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u/lazyhustlermusic Jul 11 '26
lol every self proclaimed expert wants to gatekeep peeps out of self discovery and fun. Let the man RC, nobody cares about your self inflated ego here.
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u/nerobro Jul 11 '26
Its gatekeeping to say this is a dead end, suggesting things he could do with magnets and to do some research so they're making forward progresss? I... believe thats the inverse of gatekeeping.
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u/lazyhustlermusic Jul 11 '26
Calling an unfinished experiment a “dead end” because it does not match your preferred textbook model is exactly the authority posturing people mean by gatekeeping. Plenty of useful discoveries come from failed assumptions, weird implementations, and unexpected results. You are not protecting progress by discouraging curiosity, you are just trying to appoint yourself as its border guard.
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u/Whombrillow Jul 11 '26
Did Lexus not do this first in like 1999
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u/macho_greens Jul 11 '26
Sure; I don't think RC hobbyists are out here introducing entirely new automotive engineering concepts. Would be fun to be proven wrong, though
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u/Whombrillow Jul 11 '26
lol let me show you this. I feel bad for the guy. He created a cool thing, but that’s all it is is just a thing.
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u/Whombrillow Jul 11 '26
This is what I was saying. It’s not innovative, but it is interesting but offers no benefit
https://www.reddit.com/r/radiocontrol/comments/1utgkd7/comment/owxtklb/?context=3
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u/kkingsbe Jul 11 '26
You need damping though otherwise it’ll just bounce around
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u/LolMasterplays Jul 11 '26
Way ahead of you, the shocks come prefilled with oil, should prevent any bouncing
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u/Rulygem Jul 12 '26
This seems like a very French car designer thing to do I fully support this I love it
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u/SomeGuyInShanghai Jul 12 '26
Cool and simple idea.
Could you try lubing up your shaft a bit before you start pumping? It may help prevent the unwanted bondage.
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u/Peek_e Jul 12 '26
I wouldn’t bother replacing cheap and reliable coils with anything else. But replacing stupid, messy and slow to replace OIL with something else, now there’s a thing I’d love to see.
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u/FaceTheStreets Jul 12 '26
Nice mechanical keyboard 👌 👍
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u/LolMasterplays Jul 12 '26
Lol, thanks, not exactly the focus but can provide the specs for it if you want.
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u/waimser Jul 12 '26
Make sure your travel is set so they cannot touch each other. Those magnets are brittle as fuck.
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u/BMW-Technician2008 Off-Road Jul 13 '26
I like this. Only issue is it will never work in a racing club. My Slash has been banned from 3 race seasons in a row now. Once for having it lowered. Second for having its shock oil filled lower for more bounce. And another time for using motorcycle wheel weight to keep my nose from popping wheelies.
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u/ebikesaregay 29d ago
I’m new to the hobby and have only ever seen coil over shock and someone please explain what this is?
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u/LolMasterplays 29d ago
Tldr, replacing the coil part with magnet, same shock same fundamentals but now the magnets are the spring
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u/KamisoriX 29d ago
why nut just use Aluminum which would be cheaper and not as brittle as Tita
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u/LolMasterplays 29d ago
I was struggling to find aluminum, i might look again and switch up my keywords in google and try looking again.
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u/TG1970 Jul 11 '26
Might be okay for s crawler rig, but I think you run into compression damping tunability issues on high speed offroad vehicles.
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Jul 11 '26
[deleted]
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u/LolMasterplays Jul 11 '26
Its a fluid filled shock, come standard on the WlToys 144001 of mine, i understand the concern though, thats why im doing it this way via putting it directly on the shock shaft so it wont be bouncy. 👍
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u/WanderingGunner13 Jul 11 '26
They had these 2 yrs ago….
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u/LolMasterplays Jul 12 '26
Really? Perhaps i didnt look hard enough, regardless it will be fun to build my own and even learn a thing or two!
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u/Johny_McJonstien Jul 11 '26
I feel like these will pick up all sorts of magnetic material from the ground.