Holmes Hobbies TrailMaster Sport 550 Brushed Motor (21T)

Holmes Hobbies TrailMaster Sport 550 Brushed Motor (21T)
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The Holmes Hobbies TrailMaster Sport 550 Brushed Motor is a budget motor built for messy, dirty, off road action. Whether on the rocks or in the dirt, the TrailMaster Sport is perfectly at home. Great choice for young drivers or running in the muck without ruining an expensive motor.


  • Zero timing, universal installation and rotation direction
  • 1/8th inch shaft diameter
  • 36mm OD x 57mm length (not including shaft)
  • m3 mount holes, 25mm spacing, "540" standard
  • ball bearing on output side
  • bronze bushing on end bell side
  • High strength Y45 Ferrite magnets

This product was added to our catalog on November 17, 2017

Verified Owner
Tuesday, Oct 15 2019 (about a year ago)
Holmes Hobbies TrailMaster Sport 550 Brushed Motor (21T)
I'm quite surprised nobody has yet made a review of this motor in this site. Well, for starters it's the best bang for the buck motor for budget-conscious hobbyists/and or beginners like me who wants to upgrade their stock motor. I have read and watched a lot of reviews praising this $20 motor, and so i put it in my Redcat Gen8 and TRX-4 rigs. Paired with the HobbyWing Quicrun 1080 ESC, that combo is unbeatable in cost-performance ratio in my opinion. Holmes Hobbies really did a great job, this motor runs smoothly and has a lot of torque,runs cool even on 3S, quiet, and durable.
Verified Owner
Sunday, Jul 5 2020 (10 months ago)
Holmes Hobbies TrailMaster Sport 550 Brushed Motor (21T)
This motor is way better than the stock motor that came on my TRX-4. I also paired this with the Hobbywing 1080 ESC, and wow, what an improvement! The motor ran much cooler, quieter, and a whole lot smoother. I took my TRX-4 out on the trails yesterday on an 87F hot summer day.

I mostly ran it under the shade (under lots of trees), but there were a couple of times where I ran it under direct sunlight. It ran nice and cool (perhaps a bit warmer than before it hit the trail, bit the heat was not noticeable) under the shade. Under direct sunlight, it still runs cool (still a ton cooler than the stock) but has more noticeable heat (perhaps the coloring of it being black?).

In terms of noise, it is probably one of the quietest motors that I have ever run. All I could hear while the car was driving were the gears (the motor probably makes some sound, but you would probably have to listen specifically for the motor to hear it). You can hear it during full throttle, but it definitely sounds very controlled. The stock motor sounds like it will blow up! LOL

For the smoothness, there is no doubt that this is an impressive motor. Running this motor in high gear had nearly as much torque as the stock motor in low gear. No kidding!

For all these benefits, you would think that this motor would not have as much wheel speed, right? That's what I thought too, and man how I was wrong. I have two TRX-4s, and the one with this motor was running an 8.4V NiMH with the stock tires, while the one with the stock motor was running a 2S Lipo with slightly larger tires. Mind you, they both also have the same gearing. I seriously expected the TRX-4 with the stock motor to be the fastest. However, when we did a drag race, the TRX-4 running this motor was at least running the same speed, if not faster, and it is only on a NiMH!

All I can say is that I am very impressed with this motor. The price is amazing, while at the same time performs great! I will definitely order some more of these in the future when they come back in stock!
Verified Owner
Saturday, Apr 24 2021 (2 weeks ago)
Holmes Hobbies TrailMaster Sport 550 Brushed Motor (21T)
I used this motor for the TRX-4 Sport unassembled kit that I geared down with a 45t spur and 15t pinon using a 3S setup. I also have the RTR version of the Sport that is modified with the same 3S and gearing but with the stock Titan 21t motor. Comparing the two the HH is noticeably better having a lot more bottom end torque that feels a lot more smoother managing throttle over changing obstacle loads. Using a full 2200mAh pack over with moderate throttle demands the motor is barely luke warm where the Titan can be a lot warmer. One last difference is the front pinion shaft has ball bearing installed where as the Titan has bushes. Both motor comes with internal fans for cooling.

If you do not want to gear down but want to upgrade to 3S for the TRX-4 Sport - I would recommend the TrailMaster 550 27t whcich is slower and will help manage wheel speeds and throttle resolution down low with the higher voltage. Remember the stock spur gear will allow you to gear down the pinion up to 15t (17t stock) without requiring the optional larger spur gear (including a new clutch friction pad) so that will save you some tuning money if you stick with the 27t motor.

Very happy with the purchase and the performance.
Verified Owner
Friday, Mar 6 2020 (about a year ago)
Holmes Hobbies TrailMaster Sport 550 Brushed Motor (21T)
This is my third Holmes Hobbies motor and as always it is just outstanding. Best brushed motors I know of.