TOPIC:

Hi, finally rebuilt my rere tamiya  hotshot. On the first run both the esc and motor got hot to the point where I couldn’t keep my finger on it for more than a second. I’m running a sports tuned motor with a teu-105bk esc, 15t pinion, the stock spur gear (56 teeth), stock tires and 3600mh batteries. Should I worry about the heat or is the setup fine. 

ps both motor and esc cooled down pretty fast (5mins) and they are cold again.

IDK what your tolerance for heat is, but if the ESC didn't "thermal" (temporarily shut itself down due to heat to protect itself) you're probably ok - but three seconds is usually considered the appropriate test (around 70 degrees C).

Driving style, location & surface will also have a big effect on heat - on & off the throttle on a small grassed back yard will put much more strain on the electrics than say a wider open space on a looser surface.  

You could consider lower gearing (more acceleration, less top speed), I'd also check that nothing is binding (pinion gear spacing, driveshafts/bearing etc). You could buy a cheap IR thermometer if you are concerned.

TBH I used to use excessively handwound motors with tall gearing & extra cells in inappropriate cars on stock MSCs BITD, I considered mild bluing of parts as completely normal, & anything less than a fire was fine   

Yeah thanks! Esc didn’t shut off so I hope I’m fine

How is the gearmesh?

Vehicle should be easy to move back and forwards with your hand.
Any binding or tightness will hurt the drivetrain and your esc.

Gears move pretty smooth. I have ball bearings as well. I can push it and it will keep rolling.