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Xpert 4000 Series "High Speed" Aluminum Center Case Servo

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This is the Xpert 4000 Series "High Speed" Aluminum Center Case Servo. Xpert servos feature brushless motors, combined with metal gears, 4096 resolution and a unique SIC (Single Integrated Circuit) to deliver incredible performance and durability. The lightweight design includes a molded upper and lower case, with an aluminum middle case that provides optimized thermal dissipation. Additionally, over current protection, over temperature protection and a built in fail safe delivers reliability that make this servo a great choice for a variety of applications.

For more Xpert Servo specifications and recommended applications, click here.


  • Brushless motor design provides extremely high speed, top efficiency, and low power consumption.
  • 4096 resolution and SIC (Single Integrated Circuit) for the highest performance and durability.
  • Light weight design
  • Aluminum middle case for optimized thermal dissipation.
  • Strong Metal Gear
  • Glitch-free
  • Sophisticated error correction
  • High-Speed, High-precision 12-bit AD converter and CPU calculation
  • Fail safe
  • Over current protection
  • Over temperature protection
  • Start tone
  • Speed:
    • @4.8V: .100 sec/60
    • @6.0V: .080 sec/60
    • @6.6V: .070 sec/60
  • Torque:
    • @4.8V: 14.00 kg-cm (194.93 oz-in)
    • @6.0V: 17.50 kg-cm (242.90 oz-in)
    • @6.6V: 19.25 kg-cm (267.19 oz-in)
  • Input voltage: 4.8 - 6.6V
  • Dimensions: 40x37.80x20 mm
  • Weight: 62.50 g

This product was added to our catalog on February 18, 2014

Verified Owner
Monday, Mar 9 2015 (about 4 years ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
My son runs this servo in his b5m and it has taken the abuse of him rising up through novice racing and into expert buggy. Never a single moment of hesitation from this servo, the specs are borderline insane, and it delivers. I love the start up tone, and the fact that this servo does not snap to attention when it boots up is really nice. It does a slow and firm come to center, which is not only kind of cool, but much less violent in a cramped pit space, making you less likely to knock something over or pinch a finger when working on your car. It has the speed needed for buggy, and the muscle torque required for short course. Way quieter than my Savox, but not as quiet as my XP. Great servo for any 1/10 scale application.
Wednesday, Dec 27 2017 (about a year ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
I put this servo in my B6D and it has worked out great. After a year of racing (mostly crashing) it is still going strong.
Verified Owner
Saturday, Oct 22 2016 (about 2 years ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
It worked great while it lasted, which was about 2 hours. I used it as steering servo on my nitro truggy, it went dead all of a sudden while on the bench, not even running. I had high expectations from this brand, but got very disappointed. I will stick to Savox, they might be loud but at least they're reliable.
UPDATE: after contacting Xpert, they are sending me a new servo free of charge. Their customer service is absolutely amazing, I hope my bad experience was due to an isolated bad batch and the next one will not fail.
Verified Owner
Tuesday, Jan 12 2016 (about 3 years ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
Have ran these in - MBX6R, Serpent SCT, Serpent 811 TE, Losi 8ight 3.0 and still they keep going..

They are awesome servo's that are super fast and provide more than enough torque, I run mine from a 6.6v life pack.

At any point I need servo's I go for Xpert.
Sunday, Mar 8 2015 (about 4 years ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
I purchased this servo 2 1/2 weeks ago and installed it in my TLR SCTE 2.0. It is an extremely fast servo, so fast it took me a little while to adjust to being able to turn so quickly. I have logged about 4 hours of track time with the Xpert SI-4431 servo and it has performed flawlessly. I would recommend this servo for anyone looking for a quick, reliable servo at a good price.
Verified Owner
Tuesday, Feb 3 2015 (about 4 years ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
it is very nice quiet and fast brushless servo that you can buy for this price. the torque of the servo is sufficent for 8th scale buggies and 4wd sc trucks. i am using this servo without any trouble.
Verified Owner
Wednesday, Dec 17 2014 (about 4 years ago)
Xpert 4000 Series "High Speed" Aluminum Center Case Servo
I run 2 of these. 1 in my sworkz s350 and other in my b5m. They are fast and smooth. No gear issues either. Definitely recommend.