[BrianG]

What about overall efficiency? Yeah, the motor may be at max eff at 30krpm, but the ESC and batts might be working hard depending on gearing. Remember that efficiency is a curve; the max may be at 30k, but there is still very acceptable eff numbers at a decent range above and below that.

I could see setting it up for 30krpm in a plane where you know the speed you want to run at and it's fairly constant. But in cars, there is a lot of stop and go (except maybe top speed runs), so you have to look at it a little differently.

If designing a setup for high speed runs, the extreme gearing needed would necessitate higher rpms - maybe well into the 50k range. That will give off the line snap AND high top speed. Yeah, it's hard on all components, but that's what top speed is about, and you generally go into it knowing that. If you gear too high with low motor rpm, the chances for ESC-damaging cogging are much greater at startup since the motor has to push the vehicle further for each rev.

If designing a setup for racing, gearing is more moderate. You don't hit top speed very often, so setting it up for 35-40k is fine. That still gives good acceleration off the line and decent top speed. And since you'll only hit max rpm rarely, like on straights, the motor is actually in the 30k rpm ballpark most of the time. If you set up for 30k rpm, that means you will typically be in the 20-25k range.

Same idea with bashing. Just a matter of analyzing the usage and tailoring the setup for best performance. So, there is no "one setup" that will work for all cases.