I was talking about having 10 coins during a race at all times even when you take damage, and I can adjust my total coin count with JGeckoU.That's what I though, it seems you got gold tires by collecting 15000 coins, I did 14990 in order to complete 15000 at the end, but it saved my progress, never got the notice, and still can't get the tires.
It works with glider though, not sure why it does with one but not the other.