these are F horns right?

Yes - to the tooth count.

As for the LV. Here is the thing about HV and servos. majority of the time, there really is not a need for that much speed and power from the servo.

We have seen a lot of drivers who are having erratic handling, or very twitchy cars - and they are running HV servos or the voltage turned up. Where slowing down the steering would give them control and make driving easier. The more you can turn with the least amount of slip angle (wheels turned), the more efficient your corner speed will be.

Also, as an example so drivers use LiFe batteries for RX packs in nitro cars, those are a lower voltage, so you don't need the HV servos. Still get quality torque and speed.

I got my xpert servo. Comes with the shortest servo lead ever, but it looks nice. I guess you can always use an extension.

I recently purchased Xpert RC PI-3431. So far it is overall a great servo but two things I have noticed. There were two instances the servo did not bind. Turned on radio, turned on car, had throttle response but no steering. Turning off and on again solved the issue. I hope it is nothing more than that. And second, with no load after a run. I would slightly touch my steering controller and the servo would rapidly jitter moving about a millimeter both ways, but when I'm on track its smooth as butter. My friend commented that it is a trait digital servos have. Any others experienced these results?

I have a pm-3401 low profile servo that does the exact same thing, in regards to not operating when the receiver/radio are turned on. When they are switched off then back on it will work. I was curious if it was an actual issue or just some normal thing. It is an excellent servo, works great and once it operates I never have any issues! Just sometimes the initial turn on, no operate until you turn off and back on! Curious as to the cause of this as well, hoping it never goes any further and becomes an issue to get it to operate!

Apologies for not seeing the posts -- don't know how I missed them.

Check and make sure that all the pins are making a solid connection in receiver. It would be on for a unit to not turn on some times unless there was a loose connection. Internally the power wires are not only soldered on the board, they are then epoxy covered to make sure that there is not chance they come off -- or modified in any way.

If you took off the plug to shrink wrap the wire or something also check that the pin is all the way down and locked into the plug. Again to help make sure that connects. Finally, keep an eye on your radio. I have a 4pks and sometimes it goes into C1 mode and my receivers are C2, so I have to turn it off and back on.

I'm pretty sure it's not a pin/connection issue, in that the servo only does it on initial power up. I would think that if it was a pin/connection issue the servo would at least occasionally stop working while the car is actually running, especially being that it would be getting jarred around. Also just to be clear, I only need to turn off the receiver and then back on, not the radio. Sorry about my previous post, I gave the impression of both but only meant the receiver. I would have to say it has only done this maybe 10 times since I have had it, out of say 70 runs, just a guestimate! I was also trying to remember if there was ever a time that shutting it off then back on did not work and whether I had to repeat it more than once to get it to work. Unfortunately I can't remember for sure, but it seems just the one shut off/on has always seemed to work. Like I said though, once it operates, absolutely no issues at all, works flawlessly after initial power up!

Also On a side note, It also seems that the servo is getting power! on one occasion when it did this, first few times it initially did this, I felt and put my ear up to the servo when it wouldn't operate, I felt/heard a slight hum. I don't remember if I checked to see if the servo had any resistance to move by hand or not! The next time it does it I will check to see if it resists to move.

^^ Agreed. I've come to a point now to check my steering before laying it down the track. Other than the initial issues this servo is flawless.

First, you guys are certainly open to send them back to be tested. It's strange that it only happens so rarely. If it was a power or processing problem, thought would be it would also happen when unit was being used under load. If it happens again try to notice if the light for your receiver is on and/or speed control is working. To verify you receiver is armed and getting the signal from he transmitter.

The receiver is deffinately working, because I still have throttle when it does this, just no response from the servo! I ran the car 10 times yesterday, not one single occurance. I'll keep a closer eye on it, when it does it again, I will check for the hum and whether or not the servo resists being moved. I will also keep an eye on whether or not I have to turn the receiver on more than once on different occasions. I am not overly concerned at this point, like izzyracer said earlier, I have also had it initially do this to me as i was heading up to the drivers stand, and of course no steering, so I had to head back down to see what the issue was. Now I just turn the car on and the radio and check to see if it steers right before the race and just turn off the radio and leave the car on. I have another spare servo, same low profile just without the aluminum case, but I am not using this one at this time, thought about swapping them to see if this one does the same thing.

Also one other thing I forgot to notice is whether or not the servo did its Beep, Beep chime sequence when it does this! I don't remember if it did it's audible tone or not, but I will also get in the habit of listening for it when the issue occurs.

Its an audible tone when it starts up. Pretty strange that its the one thing that didn't start up, just that one time. Weird, haven't had that happen in 7-8 months of using the 3 I have.

I love this servo in my TC. Short wire and all. Unfortunately its always out of stock to buy more.

I just noticed the other day that there was an extra noise coming from my car when I turned it on. Thought it was the esc making a new noise. So its the servo you say. Hmmmmm

yeah, the servo chimes and dings at startup

hi,

i consider buying si-4431 servo. it has good enough speed and torque. it is cheap and brushless. But, i wanna know warranty duration. Because, i am not living in USA. Also, Any feedback about servos performance would be appretiated.

i checked xpert usa website and find that those servos have 1 year limited warranty. it was not mentioned in this thread. Now, it is.