Printed some 3D-printed "no-foams" for my Axial Capra!

[Gedrick]

I drove through a lot of water the other day with my Capra and forgot to drain them. The foams were fine (albeit a bit damp) but I realized what a pain in the ass it is to clean these things out! Plus, after driving through some river water, the whole car stinks.

I stumbled upon these "no foams" as some guy on Youtube was reviewing them, and found a few cool designs that would fit my Capra tires. Specifically these "Free Foams" (linked below). Having just bought 1kg of 95A TPU I gave them a shot - easy prints and took about 24 hours total for all four to print out.

Just to be plenty clear - these are inserts that go in the tires, replacing the foams. These do not replace the tires entirely!

Here is the link on Thingiverse: https://www.thingiverse.com/thing:5380473

They are super squishy (I printed the soft ones) were easy to install, and allow the tires to squish and grip nicely on climbs while returning them to their shape afterwards. They also hold their shape with minimal compression while at rest.

I haven't been able to take it on a proper rocky hike yet but around the rocks in the yard they've been gripping very well.

I'm not totally concerned with performance (I just want the convenience of not having to clean the foams and being able to vent the tires) as much as them performing as well as or better than the stock foams, and I think these may be the ticket!

It's a cool concept and I'll update as I have some more time out in the field. Here's some shots of the print to give you an idea of what I'm talking about.

Cheers!

Note: the reason there are only three pictured is because I tested the first one out, and it's already installed

 

[#ARRMArcfanboy4life]

I read the title as supra.

 

[Dan B.]

Why don’t you drill the outer circumference of your tires and just put the rig on blocks and spin the water out when you’re done? Not that those wheels aren’t a good idea…

 

[jkflow]

Why don’t you drill the outer circumference of your tires and just put the rig on blocks and spin the water out when you’re done? Not that those wheels aren’t a good idea…

Capra is a crawler, and typically you do not get enough speed into the tires for water to be flung out.
Simply solution is to run without foams though, usually that is what people do to get more grip.

 

[Dan B.]

Capra is a crawler, and typically you do not get enough speed into the tires for water to be flung out.
Simply solution is to run without foams though, usually that is what people do to get more grip.

Makes sense. Now I see the potential advantages of those printed foams, or no foams as you said. I know nothing of crawlers.

 

[kspitters]

You could try printing with little knobs too to maybe get more grip? Can you post some in action shots?

 

[jkflow]

Grip would be my concern as well, no experience with those printed versions.

 

[Radiocontrolsoul]

These are internal foams.

 

[Killacam]

Grip would be my concern as well, no experience with those printed versions.

these replace the foam inside the tires. for a crawler, you want foams that are stiff near the middle for better side hilling and softer around the outside so they conform around rocks to give you more grip. i typically run a 2 stage foam but anti foams are nice as well and some designs get pretty elaborate. With this 3 brothers design, you can see how the material is thicker near the middle and thinner on the outside to get that 2 stage feel.

 

[jkflow]

Ok, didn't get that this is replacing foams.

 

[islandlife]

I really got to print some for my crawlers!

 

[Gedrick]

Capra is a crawler, and typically you do not get enough speed into the tires for water to be flung out.
Simply solution is to run without foams though, usually that is what people do to get more grip.

Yup, the water would never fully get out of there.

I was able to go for a quick rocky ride yesterday and they performed great and it was nice getting into the water about ~tire deep without worrying about disassembling tires and cleaning foams out! I did notice one of the inserts shifted a little off the rim but I think that's due to me having installed it a little cockeyed. They have a nice amount of deformation to them but they spring back nicely, which is exactly what I was going for.

I also took them out just now and can confidently say they perform at least as well as the stock foams, probably not better but definitely on par, and with less/no maintenance. My next step is to actually ventilate the outside of the tires so they don't get bloated, because that seems to be what happened as water seeps in (since dense foam isn't inside there to soak it up).

These are internal foams.

Indeed! I think "no foams" is the name of another product that is the same thing, I see someone posted "Anti-Foams". Same idea.

You could try printing with little knobs too to maybe get more grip? Can you post some in action shots?

They live inside the tire and are super snug around the hub (and TPU is very grippy) so they don't have any trouble gripping inside the tire to prevent them from moving out of place during normal deformation.
To give you an idea of how squishy these things still get... and a slo-mo video coming shortly. They do a really nice job!
Still uploading but here is the link: