I have a question that I couldn't find specific information on, only things I found were like 8 years old and electronics have changed a lot since then so I'm asking now.

I have a...
- Tekin RSX (rated at 7.4v?)
- KO PROPO KR413FH RX
- Savox SC1258TG servo (6.v)
- Trinity RevTech Formula X 5000mah shorty (7.4v)

Is my Tekin pushing 7.4v and the servo only takes 6v of it? Or is my Tekin only pushing 6v from default? Or am I overpowering my servo?

Can someone help me out and explain how this works, please?

I beleive that ESC is switchable 6v or 7.4V. To be safe, you should run the BEC to match the servo requirement (6v). It will more than likely work at the 7.4v, but you run the risk of overvoltage on the servo motor.

Also, the ESC will provide the voltage you have it set for to all other electronics and will source the current required (up to 5amps for the RSX).

In the specs:
BEC: 6.0v / 7.4v @ 5.5amps

So the BEC has 2 settings. Open the manual and read how to set it.

so that means then the motor won't be getting 7.4v either, correct? also what about the rx does that have anything to do with the equation?

No the bec won't affect what your motor is getting. your receiver is rated 4.8v-7.4v so it will be fine and won't affect final voltage to your servo.

ok, thank you, so i set the BEC settings on the RSC to 6v and im good?

im also thinking of dithing the 1258tg and getting maybe a FUtaba BLS471SV?

any thoughts? going in my xray xb4

Yep, the esc should be already set to 6v as default, but check it anyway to be sure. I run savox and never had a problem yet, the 1258tg should be just fine in the xb4. Futaba is a great quality but you do pay for it, so the choice is yours.

hmm, choices. thank you!

Savox servos are power hungry and if you're running a Spectrum radio system, it could cause brown-outs. Very common between the two. (Savox/Spectrum)

You have to have the Hotwire to change the BEC settings. It can not be done with the buttons. If you have not done this, then it will be at its default setting of 6V.

There is a reason manuals come with them...