Last Updated on September 17, 2023 by Jaxon Mike

For radio controlled (RC) enthusiasts building or modifying their model trucks, buggies, drones, boats, and planes, choosing the right brushless motor is critical to performance. Two popular sensored brushless motors for RC applications are the AR630 and AR631. But what are the differences between these two motors and which is better for your RC vehicle? This guide examines how AR630 and AR631 motors compare.

COMPERISION TABLE

Specs	AR630 Motor	AR631 Motor
Max Power	500W	700W
Max RPM	60,000 RPM	60,000+ RPM
Kv Range	1400-4600 Kv	850-4000 Kv
Torque	Good torque	More torque especially at low RPMs
Efficiency	Very good efficiency	Superior efficiency across RPM range
Gearing Needs	More reductions needed	Fewer reductions needed
Weight	148 grams	170 grams
Size	36mm diameter x 53mm long	39mm diameter x 56mm long
Shaft Size	5mm	5mm
Cooling	Requires moderate cooling	Handles more heat but still needs cooling
Cost	Lower cost	More expensive
Applications	Small drones, light RC builds	Larger drones, performance RC builds

What is the AR630 Motor?

The AR630 is a durable, high efficiency 6-pole sensored brushless motor produced by Castle Creations. Key features and specs:

• 6 pole sensored design
• Kv ratings from 1400-4600 Kv available
• Max power around 500 watts
• Max RPM 60,000 with 5-6S LiPo
• Diameter of 36mm, length 53mm
• Shaft diameter 5mm
• Weighs 148 grams
• Internal BEC for ESC
• Optional external plugs

This lightweight, compact motor provides excellent torque and high RPM potential from small 1S drone builds up to high-voltage speed runs. The integrated BEC eliminates need for a separate ESC. Sensored performance provides excellent low speed control and efficiency.

What is the AR631 Motor?

The AR631 motor from Castle Creations builds on the AR630 with some key upgrades for added power and torque. Key features include:

• 6 pole sensored design
• Lower Kv options from 850-4000 Kv
• Increased max power to 700 watts
• Max RPM 60,000+ on 6S LiPo
• Larger diameter of 39mm, length 56mm
• Same 5mm shaft diameter
• Heavier at 170 grams
• No internal BEC
• Must use separate ESC
• External plug option only

While dimensionally similar to the AR630, the AR631 has 20%+ more power capability, lower Kv offerings, and heavier construction to handle bigger loads. It trades the integrated BEC for higher power capacity. Made to excel in large RC models.

Torque and Efficiency Comparison

A key difference between these motors is torque production and efficiency.

The AR630 offers good torque, but the larger AR631 generates even more torque, especially in the low to mid RPM ranges important for RC driving performance. Its lower Kv options also improve torque.

This translates to stronger acceleration and climbing ability. The AR631 is optimized for higher load applications.

Similarly, the AR631 achieves markedly better efficiency across its RPM band. The superior copper windings, magnets, and lamination design maximize usable power and runtimes.

Speed and Gearing Differences

While both motors can hit 60,000+ RPMs on high voltage, their gearing needs differ:

The AR630 requires more gear reductions to reach targeted RC speeds. This allows a wider range of top speeds, but adds drivetrain losses.

The AR631 needs fewer reductions thanks to lower Kv options tailored to RC use. Less gearing means less parasitic loss and heating of components.

So the AR631 will reach desired surface speeds with better efficiency and less strain on the driveline.

Power Handling and Heat Resistance

The larger AR631 motor is built to handle 700+ watts continuously and over 1000 watt bursts.

In contrast, the smaller AR630 maxes out around 500 watts continuous before overheating.

This gives the AR631 a sizable power handling advantage. It can turn much larger propellers or churn through resistance while staying cool.

The AR631 uses a larger housing, beefier magnets, quality lamination, and improved windings to sustain high power loads and resist heat damage far longer than the AR630 can.

Weight and Size Comparison

Despite larger diameter and thickness, the AR631 weighs only around 20 grams more than the AR630. So power-to-weight ratio is improved.

This minimal size and weight increase is negligible in most RC builds, but the power capacity jump is substantial.

In terms of mounting, both have the same 5mm shaft diameter and use standard hardware. Either can fit in typical RC layouts with room for cooling.

Cost Factor

Unsurprisingly, the more powerful AR631 costs about 15-25% more than the AR630 on average.

But when factored into the full build cost, this price premium is justified for the AR631’s much higher power density and superior low-end performance.

For high-end racing drones, planes, or performance RC builds, the extra cost is worth the torque and efficiency gains.

FAQs

Q: Can I use 3S or 4S LiPo with these motors?

A: Yes, both the AR630 and AR631 can run safely on 3-4S batteries. This hits a good power sweet spot for many RC applications.

Q: Do these motors require active cooling?

A: Adding a cooling fan is recommended if running high power for extended periods. This will prevent overheating damage.

Q: What ESC works best with these motors?

A: Castle Creations’ Talon/Talon Pro or Phoenix line ESCs are ideal matches. Just ensure your ESC can handle the max power rating.

Q: How are sensored motors different?

A: Sensored motors use Hall Effect sensors to precisely lock rotor position for better low-speed control and efficiency.

Q: Can I rewind these to change Kv ratings?

A: Yes, specialty shops offer rewinding services to alter kv if needed. Check first about impact on power capacity.

Conclusion

While both offer compelling sensored brushless performance, the Castle Creations AR631 ultimately outperforms the AR630 in torque production, efficiency across the RPM range, power handling, and heat resistance.

This makes the AR631 the superior choice for larger RC models that can utilize its additional power, especially higher-end racing drones, planes, boats, and performance-driven trucks or buggies. It provides more speed and acceleration for aggressive driving maneuvers.

The AR630 still works very well in low to moderate power applications like small drones and lightweight vehicles. It’s a cost-effective option for budget builds.

So consider your models power needs, budget, and performance goals when choosing between the AR630 and AR631 brushless motors.