I broke out the Ninjaflex for the first time ever, having owned a 3d printer now for almost 3 years. I printed this 100% infill and 20 mms. It took about 15 hours to print.
Is the infill with Ninjaflex supposed to be at 100% or can it be less? The tire I printed doesn’t look like it would wear out anytime soon.
I think most people find that lower infill gives better grip. Ninjaflex isn’t really formulated for tire grip… kind of the opposite in fact, since it has to feed through extruders without binding up.
Sure seems like it would have awesome tire grip to me. I’m trying one at 50% infill. 10 hours to go.
What kind of 3d printer do you use. And what kind of extruder.
@Ricardo_Arredondo This tire was printed on my Printrbot Simple Metal.
@bcrazycramer I have a prusa i3 clone the anet A8. That I modified to an AM8 where 20-40 aluminium was used to switch with the acrylic cheap frame. I am stuck on the whole setting up my Bowden and printing new x axis carriage and a few other parts here and there. So far it’s been a task to complete.
I bet it has been a task. I printed all the pieces for my larger 3D printer Eustathios Spider V2 using my Printrbot. I swear I’ve been printing nonstop for almost 3 years. 
@bcrazycramer yup it’s a steep learning curve but as long as I have 2 3d printers to use life is good
I made Daniel Noree’s formula one car. I only did 2 perimeters and 10% infill (this was tpu not ninjaflex) and it feels like a good consistency. I’ll see if I can find a pic
I use TPU on Airwolf AXIOM: it suggests 12% infill (I guess), but I print as 25% or 33%. Smaller infill gives very smooth tires (like with real air inside) but often the top surface is not closed. Larger infill results for me in messy surface (I see the infill edges at the outside perimeter). 100% (or a solid fill) does not make sense to me: we want to have flex by the shape, not the material only. At the end, I trim and smooth with a solder iron (melt and smear the surface). In terms of grip: no clue, but I would assume 25-33% infill is fine.
BTW: if too small infill, e.g. 12% and infill is rectangular mesh - it might result in a tire not really weight balanced (not center mass aligned), a larger infill might make the weight balance (smooth rotation) better. I had some broken rear axles just because of it (not trimmed rotation balance).
@Torsten_Jaekel when I printed mine at 10%, I also cranked up the speed on the infill to kind of make all the infill stringy and not so solid, also helped with squishyness, but I did 2 perimeters.
I ended up printing them at 25%. Guess we will see how they work out when I get the rest of the car printed.
my tire: 20% infill, but the outer vertical surface needed a trim (with solder iron). If you trim with solder iron: a) melting point is quite low and if exceeded, it shrinks a lot (disappears), b) the thermal resistance of material is quite high (takes a while until it melts, but then it fades away - be careful with temperature and pressure from solder iron).
I am printing right now with 33% infill again, which looks like very dense infill already. Anyway, TPU is tricky, esp. for hollow shapes with low infill, experimenting would be my answer.
