[HelioMagalhaes]

Hi Jason, thank you for sharing your experience and good results. It's hard to find some detailed information about this as you did. That's why I wanna discuss a little bit more: 
- How did you make the mould?

Here's what I am about to do it.....

MY GOALS
- Replace the Carrera's melting tyres (pure fast UV decomposition) to have my cars running (it's hard to find in Brazil Carrera tyres, and buying NSR/Slotit tyres it's expensive because you have to buy the rim together because the tyres don't fit on Carrera original rims).
- I don't need a super ultra grip, because I like sliding on the curves (so does my kids), and I don't and ultra high velocity...the faster they go, the hardest they crash and destroy.
- I might try make urethane tyres for testing after I make my silicon rubber tyres.

MY FIRST TEST
Use silicon rubber shore A 10 for the mould, and silicon rubber shore A 55 for the tyres.

THE MOULD
I was inspired by this video https://www.youtube.com/watch?v=fHz4-ErV..._rel_pause
But the tyre this guy uses (3D print) has a really wide flat face so it's easy to glue it at the bottom (to avoid the tyre floating as you said).
My first try will be to cut off the bottom of the plastic cup, and use a not so strong tape to cover it, and them place the tyre inside. well, let's see if it can hold down the tyre.

SYRINGE
After mixing the catalyst for the tyre silicon ruuber, I will use a syringe to inject in my mould, but before injecting it, I will position the tip of the syringe upwards, use my finger to shut the syringe hole, and pull the syringe to create a vacuum inside. All the air will go up as if it were a vacuum chamber. Then I am going to slowly release my finger on the hole.


I will update my results soon.