Wel back to the subject of a receiver pack or booster, my receiver pack crapped out today, got all puffed up. It was a LiFe pack. I ended up putting back the booster back in. We run 13.5 non boosted. I rather run a booster than a receiver pack, its a lot easier for me not having to charge 2 packs before a run.

can this servo supported by 1S (3.4V)? since The spec. from the websit only say it run at 6V (6V fet) and did not mention the anything like the torque at 4.V.

You need to use either a RX pack or booster to provide more voltage to the radio gear or a 1s esc that has a built in booster to boost the voltage. This is for any servo.

1s systems need to run with a rec pack or booster to operate.
Some esc have an internal booster.

So the servo will have 6 + - volts anyway.

i am using LRP SXX V2 ,is it ok ?

Yes, that esc has an internal booster.

Thx so much.

what a good starting roll-out for SP V3 4.0T motor?

I just got a 12R5.1 with an LRP SXX and an LRP 13.5. My front tires are 44mm and the rears are 46mm. The spur is a 96t, what pinion should I run?

Those are large dia tires, can we assume you are running outdoors ?

Seeing as how that esc does NOT have boost, you are going to have to gear it up a bit.
Maybe start @ 85mm roll indoors and 95 on pavement, so you will need a smaller spur gear. I doubt a 55 to 65 pinion will fit with that 96t.

Try a 72t 64p spur, and a range of high 30's to high 40's pinions maybe.

Gearchart.com can help you with your roll calculations

70 is a good rollout to start with, so you're looking at about a 46T pinion. You may have to pick up a smaller spur and adjust down on the pinion to keep the ratio, I'm not certain 46/96 will fit.

Sorry, its a SXX V2 that does have boost and no, I am running on carpet. What diameter tire should I be running?

I wouldn't start any larger than 44 mm i the rear. 43 is a common starting size. With boost in the esc I usually run a 76/42 with 43-ish tires. But obviously there can be large variations in timing and gearing with different motors, traction levels, layouts, and esc's so you will need to do some guess and check with your particular set up.

Unless that's a "Stock Spec" SXX, it does not have much boost at all.

Not a stock spec, I run SXX V2 in all of my cars except for my B44.1 which is an SXX V2 TC-Spec. I went with the SXX V2 for my 1/12th because not only does it have boost, but it also has a dual BEC so you don't need any extra shit in the car. Thanks for all of the input, I figured it would come down to some trial and error, it always does.