Question about the 1721 and bullet size

[Forbes]

Can the 1721 be ran on a mmx8s? I know the 1721 comes with bullets that are 8mm and the mmx8s uses the 6.5 females, but are there “stubby” adapters that you can use to make this compatible and not lose performance.

https://www.ebay.com/itm/2838897724...5xJEih9a%2BbhoDCE%3D|ampid:PL_CLK|clp:2332490

For instance would this work and not have draw backs with bullets being necked down?

 

[Rcproponent]

I’d say no, not a good idea.. see below, these are castles warnings. They are very high powered motors that draw huge loads.



Product Use Statements:

• This is an extremely powerful motor designed for advanced and experienced users only. Below are suggestions for increasing your likelihood of success but it is not guaranteed.
• This is a VERY high RPM motor. Start with very conservative gearing (small pinion/large spur).
• Check your data logs, temperatures and setup closely after each run to ensure you are not stressing components.
• This motor is intended for single passes only; allow time between runs for the ESC, batteries and motor to cool down to ambient temperatures.
• This motor can pull very high amperages. Make sure your batteries, connectors and soldering are capable of handling the loads. Inadequate power can cause poor performance and damage the batteries and/or ESC.
• Do NOT free rev the motor with no load, particularly when running 6s or higher. The RPM output of the motor is much higher with no load as the kv and battery voltages do not drop.
• Set ESC timing to Lowest (0). This motor will pull considerably more amperage as you increase timing. This does not necessarily equate to more speed as it puts more strain on the batteries and causes the voltage to sag. Less is more sometimes.
• Do not exceed 33.6v when using this motor.
• Be sure your pinion and motor bullets are secure before and after each run.

Specifications:
Input Voltage Range: Min: 4s LiPo/Max: 8s LiPo (33.6V)
Kv: 2400
Max. RPM: 90,000
Diameter: 1.87” (47.6mm) at fins, 46mm at can.
Length: 101.2mm
Weight (w/wires): 816.4g (28.8oz)
Shaft Length: 22mm
Shaft Diameter: 8mm
Mounting Hole Specifications: M3 and M4 @ 25.4mm (1")
Cooling Fan: N/A
Connectors: 8mm male bullets on 8 gauge wire
Items Needed for Operation: Compatible Electronic Speed Control (ESC)
Recommended ESC(s): Mamba XLX2
Running Modes: SmartSense™ (with Castle Sensor capable ESC), Sensored and an ultra-efficient Sensorless mode.

 

[Diem Turner]

Agree with @Rcproponent . You probably could with really conservative gearing, but then you have to ask the question if it makes sense to get a 1721 for such a scenario. At the top end the MMX8S can provide around 400-420A and the 1721 can easily pull 600+. Taking into consideration that the 1721 can draw more amps than an XLX2 can provide without too much trouble tells me that the combination with an MMX8S just doesn't really make sense, before we even get to the size of the bullet connectors. If you're looking at Castle motors for the MMX8S the 1717 and 1520 are probably your best options. Yes, you can get them paired with 2028 motors, but both models are lower KV motors that don't have a super high current draw (unless you go full retard on over gearing), the choice will be down to what kind of vehicle it's going in.

 

[AIan]

I believe having 6.5 bullets soldiered directly to the motor leads is much better then any additional adapter. (But not ideal). But find a pro at soldiering as you don’t want to let the motor get hot using the wrong equipment.