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Who has a brushless motor? Is it an upgrade or worth it?

TRX4

Newbie
Joined
May 6, 2019
Messages
32
Location
Milwaukee
I currently have a Defender TRX4 with a few upgrades, and i currently have the Holmes and Hobby 8T motor in it. This motor is definitely an upgrade from the stock 21t traxxas motor! It has better low end control and also has about 20-25% more top speed with the same exact gearing. I can go from a 11T (stock) to a 9T pinion and while racing my brothers TRX4 i still had slightly more top speed.

I am looking to upgrade again if it makes sense. Can i get just as much or more control with a burshess motor on the same gearing?

My goal is to be able to run a 2 and 3s battery, but also a 4s for those moments when i want to just hoon around (hopefully not break anything). So getting a motor and ESC to handle 4s would be a requirement.

Also, would i need to upgrade anything else besides the motor and ESC, can i use the stock transmitter/controller?
 
For a dedicated comp crawling rig no. But for most other situations it's worth it. Skip 2s completely, even if brushed. I run 4s hv and gear way down, unbelievable drag brake and great low speed control.

Sent from my SM-G970U using Tapatalk
 
I ended up going with the Brushless Axe 3300kv combo, i think itll work good for what im using it for!
 
I ended up going with the Brushless Axe 3300kv combo, i think itll work good for what im using it for!

I’m going to assume that you read the specs on this combo. Only mentioning since you said 4s capability is a requirement and this combo is rated for 3s max.
 
I've been happy with the 2 in 1 Fusion 2300kv system in my trx.
3s lipo only

I have a 1800kv Fusion in my Gmade GS02 Komodo Double Cab, a 1800kv Fusion in my Capra, and a 2300kv Fusion in my “EctoKeeper”. Absolutely incredible systems!
 
I ended up going with the Brushless Axe 3300kv combo, i think itll work good for what im using it for!
That will probably be my choice as well, if/when i go for brushless. Both the motor and the ESC seems darn nice!
The hefty price tag says I won't go that route any time soon though. Other details will have more impact at a lower price.

whats a brushless motor ?
Essentially speaking it's a brushed motor turned outside in. Static windings and rotating magnets.
The advantage is reduced friction and somewhat increased efficiency, allowing for more power to the wheels.
The disadvantage is that it needs an alternating current feed from the ESC, making that part more expensive.
As a rule of thumb brushless motors are far from smooth starters, so buying just any motor won't do it for crawlers. Hobbywing AXE is one of few specifically designed for crawler use.
 
Essentially speaking it's a brushed motor turned outside in. Static windings and rotating magnets.
The advantage is reduced friction and somewhat increased efficiency, allowing for more power to the wheels.
The disadvantage is that it needs an alternating current feed from the ESC, making that part more expensive.
As a rule of thumb brushless motors are far from smooth starters, so buying just any motor won't do it for crawlers. Hobbywing AXE is one of few specifically designed for crawler use.
i dont own a brush why start now brushless it is
 
Is the 2300KV much faster than the 1800KV?

Hi,

maybe I am wrong but: The Kv rating provides an estimate of how many rotations a motor will undergo for every volt applied to it. This rating can be helpful for comparing motors that are of the same size physically, but have different performance characteristics due to their inner workings.
Theoretically, the difference in speed at the same voltage will be as much as the difference between KV motors, but this is just a theory :-]

regards,
BB
 
Is the 2300KV much faster than the 1800KV?

Let's math. KV means the number of RPM's per Volt, unloaded.

I'm gonna cheat and ignore the "unloaded" part... This means the answer is going to be wrong, but at least it's a sorta-kinda workable comparison.

Let's use my TRX-4 Sport config as a semi-baseline: I've got a with a 12T pinion, and I've thrown in the 45 T main spur gear. A manual for the TRX-4 Scale & Trail puts the gear ratio for that at 59.25:1.

I run 4.75" Tires. So the TRX-4 will move 14.9" with each turn (ideally).

So: running flat-out, a 2300 KV motor on a 3S pack has 11.1v; so it will run: 2300 KV x 11.1 V = 25530 RPM at the motor, so 25530 RPM / 59.25 = 430.88 RPM at the wheels. 14.9"/Rev * 430.88 RPM = 6429.93 inches per minute. (6429.93 in/min) / 12 = 535.8 feet per minute. 535.8 feet / min * 0.0113636 will give us: 6.08 Miles / Hour.

For 1800 KV, I'll skip the units (forgive me, for I will sin):
A 1800 KV motor on a 3S Pack: 1800 x 11.1 = 19980; 19980 / 59.25 = 337.21.; 14.9 * 337.21 = 5024 inches/min. 5024*0.0113636 = 4.75 Miles / Hour.

Actual speeds are going to be slower.

If I were to guess (taking in transmission losses, etc), I'd say that for my TRX-4 sport's tires & gears, flat-out, a 1800 KV motor would be roughly the speed of a slow-to-leisurely walk, and a 2300 KV motor would be a moderate to brisk walk.

Now excuse me while I barf. Doing math on a forum just sucks... I just can't express the math properly.
 
I have a Hobbywing Fusion Crawler 1800kv Motor/ESC combo in my TRX-4 and I just love it. Its perfect for me.

I run it on 3s, 1.9" tires and stock gearing.
 
I haven’t used a brushed motor for crawling in ten years. Crazy smooth. I use a Holmes hobby 1200kv two pole with a Castle Mamba x set up as per his video. Very incredible.
 
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