Hey there. I'm brand new at this hobby, just started not even a week ago. So I'm new here too.
I got to thinking about performance, how the wheels work, their tolerances, etc. What might work better?
Well ... What about teflon axles?
I asked about this on 3DBotmaker's Facebook page. Someone said that if I could find 1/16" teflon rod, it might could work.
Well .... I found 1/16" teflon rod. About 30 bucks for 4 ft of it. Pretty decent price I'd say.
They also have graphite filled teflon rod !! :O ..... That doesn't show a price. It's "request a quote." ... But can you imagine? Freakin teflon impregnated with freakin graphite!! Whoa! Talk about FTE! :O
They also have a huge variety of other types of plastics, but I don't know anything really about the properties of those plastics regarding friction. I don't know a lot about teflon either, but I know it's extremely low friction.
Anyhow, here's the teflon rod. They also have thinner (as well as larger. MUCH larger). (they also have glass fiber impregnated teflon, but not in small enuf diameters)
And the graphite impregnated stuff. I'm VERY interested in this one, and intend to contact them about cost. "Request quote" generally means pretty expensive tho I reckon.
I've had a couple other ideas as well, such as actual tiny bearing-based wheels. Sourcing bearing that small might be a pain tho; but I'm sure they exist. (I'll have to look in my bag of torn apart camera pieces and parts. Lots of cool tiny stuff in those)
Or perhaps gluing a short metal tube inside the wheels' holes, with that tube extending out a bit on the car side such that when the axle and wheel assembly is in place on the car, the wheels are locked in position. As in they can't slide in and out as much, like they do out of the box. There's a LOT of play in there, which totally affects how straight the car runs.
Just a couple ideas there. I'm quite interested in trying the teflon rods out. Particularly the graphite impregnated teflon if it's not too expensive. Who know? Maybe the company would find it amusing that a hobbyist would want to use teflon as die cast car axles and be like "LOL yeah sure. here. Just have a couple feet." heh ... ;)