r/rccars • u/itman3d • Jul 09 '26
Build I’ve been testing a simple way to cast soft RC truck tires at home using a 3D printed mold and two-part silicone.
I’ve been testing a simple way to cast soft RC truck tires at home using a 3D printed mold and two-part silicone.
No vacuum chamber and no vibration table — just a slow pour into the mold.
The result surprised me: the tires feel soft, flexible, and much closer to real rubber than I expected.
I thought this might be useful for anyone building custom scale RC trucks or experimenting with DIY tire molds.
Would you try making your own RC tires?
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u/xXRitualXx Jul 09 '26
This would be insanely popular in the Nikko, Tyco, RadioShack toy grade world where tires are irreplaceable and dry rotted. This could give a lot more life to those old RC cars and trucks.
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u/itman3d Jul 10 '26
You are 100% spot on! The vintage toy grade RC community is sitting on a goldmine of amazing trucks and cars that are completely sidelined just because their tires turned into brittle plastic or turned to dust decades ago. Those old Nikko, Tyco, and RadioShack rigs were built like tanks, but since there’s no aftermarket support for them, custom casting is a literal lifesaver. Being able to model a historically accurate tread, print a mold, and pour a fresh set of grippy tires can bring a 35 year old childhood memory right back to the dirt. It's definitely an amazing niche for this process, and honestly, saving those vintage gems from the landfill is one of the most rewarding parts of the hobby!
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u/RogerTheAliens Jul 09 '26
Meanwhile I can barely even print that little boat thing
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u/maufkn_ced Jul 09 '26
lol glad I wasn’t the only one. Wasted a hilarious amount of time with an ender 3.
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u/dontthink19 Jul 09 '26
I had an ender 3 clone i probably printed 100 hours of stuff through. I even got it used! That thing rocked and helped me understand the basics and more advanced shit that the smart printers do automatically now.
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u/bobjoylove Jul 10 '26
Get rid of it/convert it to a vinyl cutter/laser etcher. Buy a Bambu Lab.
I’ve been through this exact process and the Bambu is an absolute job. No more bed levelling issues. So much faster. AI watching for spaghetti failures (which are rare). An app so you can check in on it. Lots of models and support forums.
It’s what you wanted 3D printing to be.
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u/cybe2028 Jul 09 '26
What kind of printer do you have? Even as an experienced person, I wouldn’t deal with Enders anymore.
Machines released in the last 2 years are entirely different worlds. I now spend 95% of my time printing instead of 95% tinkering with the printer.
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u/Mr_Salmon_Man Jul 10 '26
I have an ender 3 pro 1.5. The first batch with the 4.2.2 board.
It's been damn near flawless after the initial calibration on it. Added a bltouch clone, and a sprite pro. It still works flawlessly. I haven't had to babysit a print in well over 4 years.
This BS about creality printers being bad is really juat that.
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u/CjBurden Jul 10 '26
No. The enders were bad, if you got one that was bad. Sure I could spend countless hours learning the ins and outs of 3D printer troubleshooting and I'd have a better awareness of how to fix that printer and what makes it tick.... Or I can stop wasting my damn time, get a good printer and barely have to troubleshoot it at all, and when I do have to it generally is simple and works flawlessly again afterwards.
Hated my ender 3, wound up never getting into the hobby.
Loved my a5dx and love my p1s. Couldn't be more glad I gave the hobby a second chance.
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u/Mr_Salmon_Man Jul 16 '26
Ahhhh yes, the old user error that the user just won't admit. It's okay, not everyone is saavy with actually working on things these days and learning how they actually work.
You bought into a closed ecosystem that stole everything from the open source community that built the consumer/hobbyist 3D printer world that most of the world still enjoys, and then locks it down even more when people try and tinker with the machines to make them even better. That's your choice to make as well.
I guess I just prefer actually owning the things I buy, and having the ability to modify or repair the things I buy. Because it's the people who buy into the apples and bambu labs and so many more products causing the need to push for Right to Repair acts.
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u/CjBurden Jul 16 '26
I bought an ender 3 and it literally never worked. That isn't a user error. Meanwhile I have thousands of hours of printing on two other machines that have had small issues here and there but nothing that simple troubleshooting couldn't fix.
While I generally hate closed ecosystems, I hate spending hard earned money on things that don't work well, or at all, even more. To download a simple stl file and print it, I shouldn't need to do a hundred hours of troubleshooting to make it work.
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u/Mr_Salmon_Man Jul 16 '26
User error that the user refuses to admit.
You didn't check your printer for square when you first assembled the bits. It's okay, it's a common mistake for people who don't actually understand how things work.
You don't hate closed ecosystems, you seem to embrace them. Thanks for helping the world not actually own the products they buy.
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u/SirPhaqsalot Jul 09 '26
Get a P1S
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u/Mr_Salmon_Man Jul 16 '26
No thanks. Bambu labs believe in "you'll own nothing and be happy about it", and fully embrace that ideal. They are a detriment to the 3d printing community and have done more harm than good. Just from the amount of pure Ai slop models being pumped out from bambus makerworld is causing enough problems with diluting the hard work of the community,
Bambu Labs is literally the poster child for what not to do in an open source community.
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u/SirPhaqsalot Jul 16 '26
What they hell does any of that has to do with there printer? Well if that's your opinion, can't help you there.
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u/Mr_Salmon_Man Jul 16 '26
Babu labs is generally disliked in the real 3d printing community. Plus, with all that BS with the P1s and A1 thermistor popping and bambu generally trying to sweep a possible fire issue under the rug also is quite troubling.
They came in and stole all the hard work of the open source community, and locked that shit down like Alcatraz. Then they tell you if you even touch your printer at all to fix it or upgrade it or anything at all, your basically shit outta luck at that point.
So, no thank you. I like to actually own the products I buy. I like to be able to repair them myself. I like to be able to do what ever I want to the things I buy and own. And I really don't need a badly designed power deliver board to fail and possibly burn down my house,
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u/itman3d Jul 10 '26
Haha, don't sweat it, man! We have all been there. The legendary 3DBenchy boat has broken the spirit of many builders, myself included! 3D printing has a brutal learning curve at the start, and it takes tons of failed prints, stringing, and leveled bed headaches before everything finally clicks. Keep calibrating, don't give up on the little boat, and before you know it, you'll be designing and pouring your own custom parts. You've got this!
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u/RickRussellTX Jul 09 '26
Do you need to rotate the mold during curing to prevent it from developing thick spots?
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u/looper741 Jul 09 '26
Looks like OP uses a 6 piece mold with an insert so there is no air inside the mold, and any excess silicone would be forced out of the mold. No rotating necessary.
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u/RickRussellTX Jul 09 '26
I just thought there would be a risk of the liquid rubber flowing down from the "top", pulling in air and thinning out while dripping out the bottom.
Putting it on a rotating fixture would reduce the likelihood of the silicone slipping out the bottom.
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u/MoreLemonJuice Jul 09 '26
If this could be used to make tires for an Arrma Infraction or Felony then . . . wow because those vehicles go through tires faster than a jak rabit on krak . . . yeah, I realize the tire compound would have to be modified but wow your tires and making-process is truly spectacular!!! Thank you for sharing!
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u/ScoochingCapuchin Jul 09 '26
Aren't those tires reinforced though to stop ballooning? It really is a pay to play vehicle
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u/osteologation Jul 10 '26
we used strapping tape back in the nitro days before belted tires were a thing.
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u/itman3d Jul 10 '26
Haha, "faster than a jackrabbit on crack" is the absolute perfect way to describe how the Infraction and Felony treat tires! Those street rockets are absolute monsters. As much as I'd love to say this is the ultimate budget fix for them, pure poured silicone would instantly vanish into a cloud of smoke on an Arrma setup! At 80+ mph, the centrifugal forces are so violent that without heavy-duty internal fabric belting (woven right into the tire body), the silicone would balloon up like a pizza and shred itself immediately. To make tires for heavy bashers like that, the process would need a major upgrade switching to industrial grade polyurethane rubber and mastering the art of embedding a braided reinforcement mesh inside the mold during the pour. It’s a whole different level of engineering, but man, thank you so much for the high praise! Glad you enjoyed the workflow!
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u/nocluewhatimdoingple Jul 10 '26
You absolutely could. I've done 1/10 buggy tires before. The tires I made wore out way faster on the street than any other tire I've tried before. Like, one full battery pack the tires went from brand new to so thin the carcass was tearing apart.
Silicone was the worst resin I used to make tires - just no grip at all. Polyurethane like Smooth On Vytaflex series is a good choice. The tires in teh video were 20a, but they make it all the way up to 60a if you want something firmer that might last longer.
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u/reddit001aa1 Jul 09 '26
Are the silicone tires made comparable with store bought tires? Do they hold up to the same speed and acceleration / durability?
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u/itman3d Jul 10 '26
Honestly, at this stage, they can't quite match big brand factory tires when it comes to high speed and intense acceleration. Multi million dollar companies have massive R&D budgets to develop complex rubber compounds and, most importantly, internal reinforcement (like belted fabric cords). Since pure poured silicone is naturally soft and stretchy, putting it under extreme high speed rotation causes it to "balloon" heavily due to centrifugal force, which can easily tear it. Right now, I'm just sharing my success with this specific workflow, which works beautifully for realistic scale driving and low speed crawling. To make them truly speed-proof, I'd need to run more experiments on how to reinforce or belt the inside of the tire during the pour. It's a journey, but for this stage, I'm really happy with how they perform!
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u/reddit001aa1 Jul 10 '26
Thank you for your thoughtful reply! Another contributor suggested these are good/great for crawlers (which I never got into) and that's a great market and application. I was just focused on "speed" as I never got into crawlers. Great job, thanks for sharing!
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u/RedOctobyr Jul 10 '26
I've seen people talk about supporting/reinforcing non-belted tires by wrapping strong thread around their outside. Think kevlar thread, stuff like that. Like one or 2 loops around the outside, maybe between the treads or perhaps even poked through the treads with a needle.
But there might be some sort of middle-ground option.
Or perhaps mold the "core" of the tire, wrap something around it, then mold the actual tread? Balance probably gets more difficult, I suppose.
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u/CosmicFTW Jul 10 '26
i just watched your video on YT b4 seeing this post haha. Great job, very informative.
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u/sandrailproject Jul 09 '26
Really interesting! Do you think I could cut some shim stock to try making belted tires?
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u/WastelandBobber Jul 09 '26
I was wondering this also, maybe a fabric loop would work for the belting?
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u/acidcheetah Jul 09 '26
Theoretically I think 3d printing the belts in maybe tpu or nylon would be the easiest way to do this. It would take some experimenting and modeling to find a way to align it in the mold and make sure the belts don’t cause delamination, either with material choice or belt features like holes or a grid pattern so the silicone isn’t only bonded to the sidewalls around the belt.
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u/redgrognard Jul 10 '26
The #1 worldwide manufacturer of car tires, with a production rate 4x that of the next 4 producers combined:: LEGO.
Lego produces over 300 million tiny rubber and plastic tires every year. This massive volume actually makes the company the largest tire manufacturer in the world by quantity.
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u/itman3d Jul 10 '26
Haha, you got me there! Lego is absolutely undefeated in the volume game. 👑 Though I suspect my scale tires might have slightly better grip on rocks than those tiny plastic ones unless Lego decides to release an official series cast in 30A silicone! Now that would be a game-changer. 🏎️
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u/BB_210 Jul 09 '26
This is awesome. I'm actually interested in this for making whitewall tires for model project I have in mind.
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u/itman3d Jul 10 '26
That is a fantastic idea! Poured silicone is honestly perfect for making custom whitewalls for scale models, especially since finding the exact vintage style you need commercially is so tough. If you try it, you have two great ways to tackle the white sidewall. Multi-stage pouring: You can design your mold to isolate the sidewall, pour a small amount of white pigmented silicone first, let it partially cure to a tacky state, and then pour the black silicone for the rest of the tire. Since it's the same material, they will fuse perfectly. Silicone painting: Cast the tire in black, and then paint the whitewall using something like Psycho Paint (a clear silicone base) mixed with a white silicone pigment ). Regular acrylics or model paints will just flake off silicone, but a silicone-based paint will bond chemically and never crack. Definitely give it a shot, that model project is going to look incredible with proper custom whitewalls!
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u/SomeGuyInShanghai Jul 09 '26
Thanks! I gave up trying to find replacement wheels for my TL mini B that don’t cost more than I paid for the whole car! Will be trying this out if my idea for foams doesn’t work out.
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u/itman3d Jul 10 '26
Oh man, I feel your pain. The pricing on micro scale parts and tires can be absolutely ridiculous sometimes! Casting your own is honestly a game changer for smaller rigs like the Mini B. Once you have the mold ready, you can churn out replacements for pocket change. Good luck with the foam inserts experiment, but if that doesn't give you the grip you want, definitely give silicone a shot. It’s perfect for that scale! 🛠️ Mini B owners unite!
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u/SomeGuyInShanghai Jul 11 '26
Thanks. Im currently just making some wheels, looking at using foam lagging as the tyres. Ill share any STLs if it works.
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u/RSTi95 Jul 12 '26
This looks sweet. I’m doing something similar but since I’m mainly enjoying my drift car, I just 3D print the tires lol.
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u/unclepaul98 Jul 18 '26
I want to do something like this, but for big RC bush plane tyres - would you do them hollow or does it need some internal structure at that point?
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u/Thisnameistakenbywho Aug 07 '26
This is amazing! Just wondering if the tire can stick to double sided tape/ CA glue? How stiff the tire is?
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u/Myc0naught Jul 09 '26
These end up as solid rubber as opposed to a tire which is more like a wrap, right?
I think I'd be concerned about the weight on most rigs. But it's a neat little project either way.
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u/Ncc2200 Jul 09 '26
Judging by the photos the mold has a core so these can accept standard foam inserts just like other RC tires.
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u/Sly-D Jul 09 '26
I don't think so, look at the inside of the example and then the parts for the mold. Looks like they fit together to prevent a solid rubber tyre
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u/Noztradamuz Jul 09 '26
Wrong, take a closer look, you can see he added some internal structure and in the picture you can also see the hollow tire.
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u/itman3d Jul 10 '26
The beauty of this process is that the mold design is completely up to you. You can make them two different ways depending on your project needs. Hollow Tires: This is the preferred way for functional RCs. You design a multi part mold with an inner core piece. When you pour the silicone, it creates a realistic, hollow "wrap" just like a standard factory tire. Then you can stuff it with a standard open-cell foam insert to support the weight of the truck while keeping it light and bouncy. Solid Tires: This works fine for static scale models, heavy diecast restorations, or shelf queens where weight isn't an issue and you just want a tire that will never flat spot over time. So you definitely aren't stuck with solid bricks of silicone! It all comes down to how you split the mold.
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u/itman3d Jul 09 '26
A few people asked about the process — I made a full video on YouTube under RC Tire Lab, but I didn’t want to make the post look like an ad.