Holmes Puller Pro R 540-L - 4100kv - Gear Down Question

[DrVest]

Hello,

Watching John's video on Brushed vs. Brushless, he makes a comment along the lines, if you want more torque gear down and/or get a (physically) motor; don't worry about kv. With that in mind, I purchased the 4100kv Pro R along with the BLE Pro esc.

I have the option of running the truck on a 4S lipo. The truck is specifically for crawling / climbing. i.e. no speed runs / trailing, etc.

All of that said, is it a bad idea to run the 4S if I gear down properly? If not, what would the ideal spur and pinion gearing be? For what it's worth, I have a 9T pinion on the way.

If I'm approaching the whole gear down, volt up, bigger motor logic incorrectly, please let me know haha.

[svt923]

You got the theory but the TRX4 doesn't have much more room to be geared down. Even in low gear with a 9T pinion on 4s, it will be pretty fast for a scale truck.

I run the same gearing on a 2200kv motor on 3s and I think it is the sweet spot for the truck.

[Evo93]

4100kv sounds very fast for crawling. I haven't upgraded my trx4 to brushless, nor do I plan to. But I've heard 1800-2700kv is what would best suit this truck. Or any crawler/trail rig.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[Inspector86]

The installation of a 9t pinion with the stock 45t spur is as low as you can gear a TRX4 without major modifications. Given that the gearing physically can't go any lower, a 4s and 4100kv motor is going to be very fast and a poor choice for crawling / climbing IMO. I actually called CC and ask what they recommended for the TRX4 and as a result of that conversation I went with a Mamba X and 2280kv motor. I could not be happier with the performance. With the 9t pinion it is not a speed racer but it has gobs of torque to crawl with and I can adjust speed and power depending on conditions by running either 2s or 3s batteries. One other caution is that as you increase battery voltage, you also increase heat in the electronics which can become a totally separate issue.

[DrVest]

Thanks for the replies, so 4S is a bad idea, haha.

Perhaps worth mentioning, the truck is currently weighing 9.06 lbs with a 2S 7600mah. If I put the beef patties back on, takes it to 9.62.

Is this too much motor even with 2S or 3S?

With a 9t pinion, is there a better option out there for the spur in terms of tooth count vs. the 45t stock?

I had the Stubby 2700 in the TRX4 but moved it over to a Marlin I just got. I loved it. I figured with the Pro R being 33mm vs the 26mm length of the standard, why not?! Bigger motor, more powa!

[Inspector86]

Like I said you can't gear the TRX4 any lower than 9t pinion and 45t spur without major modifications.