DDM/Killer/TR/Hitec HS-900SGS 1200 oz. Losi Steering Servo

Now available at ddm is the long awaited Hitec HS-900SGS Servo and installation kit! Available to ship TODAY July 30, 2013. This thread will serve as a central hub to help answer any tech help about this conversion/install as well as any general questions and feedback that can be addressed. Below is the story on how we were able to get the most complete and refined steering solution for the Losi 5IVE.

Purchase link to Servo Kit: ddm HT900K Complete Kit
Purchase link to Servo Only: Hitec HS-900SGS

Late in 2012 Hitec contacted us at DDM about a servo that they had designed years ago for the industrial robotics division of their business. They saw the need for something stronger than the current offering of servos for the Losi 5IVE and asked us for our thoughts on the project. After sending us the spec sheet we determined it was definitely something that we wanted to set out to do.

There were a couple of challenges that presented themselves. The footprint of the servo was the same as the 5765, but quite a bit taller. Another thing to overcome was the huge operating voltage that the servo called for (with the minimum being 12V). The answer was to enlist two people with a history for making the best products in their respective specialties. We were able to get a pre-production prototype sample back in November and the first stop was a trip to Turtle Dave. In less than two weeks we had this!



Being overly anxious he hooked his battery from an impact driver directly to the servo and it had power! We were able to surmise at this point there was going to need to be the now extreme angle of the steering link to be address (due to the increased height of the servo). An all new billet aluminum arm was designed and made in the USA by DDM to address this issue, as well as a slightly increased length to help speed up the steering speed.

After testing at the Turtle lab it went to Kent @ killer rc for the electronics treatment. We needed to have a 4S LiPo battery spec’d out along with a voltage regulator to handle powering the receiver and T/B servo. Kent was able to design a genius compact unit we have all come to expect from him. With a direct line to power the servo from the battery, a selectable voltage range going to your receiver can be changed from 6V to 8V depending on the users preference and T/B servo.



The 3600 4S1P battery fits perfectly in the stock battery box along with the Killer Regulator.


All of the wires are neatly stickered so there is no confusion on how to install and wire together. This unit is nicely complimented with the use of the new killer rc Super Power Switch

FAQ/Installation questions

What modifications are required to install this? Do I need a new radio tray?Minimal modification is required. You will need to cut away with a Dremel the plastic radio tray where the steering servo resides to install the new turtle racing servo mounts. All stock hardware will be used. Your radio tray remains otherwise complete, included receiver box, T/B servo mount, and battery box. See pic for reference:


Do I have to use a LiPo battery?

  • Yes. You must use a 3S or 4S LiPo battery. Use all necessary caution when handling LiPo batteries! DDM strongly suggests use of a 4S LiPo battery. A LiPo charger capable of balance charging is highly recommended

My steering servo has a bare red and black wire, what do I need to do?

  • The servo does not come with a connector on the power leads. You will need to solder a red JST connector to these wires. The necessary connectors are included with the Killer RC Servo-Max regulator

Doe the standard warranty still apply to this servo like all of Hitecs other servos?

  • Yes. All warranty issues must be dealt with Hitec directly through normal procedures. Their contact info can be found here.

Can I purchase these parts all separately?

  • The Servo, Mounts, Regulator, and Battery are available separately for purchase. The servo arm is only included with the kit. When purchased as the ht900K kit it is the best value

Are these the “updated” servos?

  • Hitec had planned on making a change to the drivetrain by adding a pin bearing. Tolerances and performance of the pin bearing turned out to be something Hitec could not do. A running change will be made to the composition of the gears. Should anyone experience a problem with their servo Hitec will service/warranty them within the United States. Customers outside of the United States should contact DDM on warranty claim.

Videos courtesy of Killer (Prototype testing)
Hitec 1222oz Servo in Losi 5IVE w/ 4S LiPo (Prototype Testing) – YouTube

Hitec HS-900SGS 1,222 oz servo test Losi 5IVE – YouTube


To get more information follow our forum thread HERE

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