RocketBike™ offers conversion kits including CYC Motor's X1 Pro and X1 Stealth mid-drive systems.

The X1 Pro kit comes with three chainring options:

  • 11/53T
  • 11/63T
  • 11/72T

While the X1 Stealth offers two options:

  • 11/53T
  • 11/63T

Choosing the right tray option depends on individual needs and preferences. RocketBike™ provides advice and assistance to help you make the best choice, as well as after-sales service.

If you are unsure which option to choose, we recommend selecting a chainring option similar to your bike's current configuration. For example, if your bike is equipped with a 32 or 34 tooth chainring, the 11/53 tooth option with a 32 tooth inner chainring will be most suitable. For those with a 40t or larger chainring, the 11/72t option with a 40t inner chainring will be a better fit.


Now let's look at the technical differences between the different platforms.

Table comparing the three different chainring options:

Option Inner tray Diameter Compatibility
11/53T = 32T with 53T engine plate 32T 104BCD 140mm X1 Pro & X1 Stealth
11/63T = 38T with 63T engine plate 38T 104BCD 165mm X1 Pro & X1 Stealth
11/72T = 40T with 72T engine plate 40T 104BCD 190mm X1 Pro

The most common misconception is that the chainring has a significant impact on top speed. In reality, the chainring mainly affects cadence and clearance.

Chain options affect your cadence

Switching to a larger chainring, for example 53 to 72 teeth, with the same motor rotation speed, will reduce the rotation rate at the crank. Simultaneously, the transmission ratio to the rear wheel will increase into overdrive, canceling each other out. However, this is based on staying in the same ratio of your cassette.


When it comes to torque, a larger chainring will provide more torque when powered by the motor. However, the difference in torque is not significant, and therefore should not be a primary consideration.


Top crank speed will vary depending on the chainring options you choose, but your overall top speed will remain the same. The reduction ratios between motor and crank for the 11/53T, 11/63T and 11/72T options are 1:28.9, 1:34.4 and 1:39.3, respectively.


Here is a table that represents the RPM (revolutions per minute) values ​​for each chainring option at different battery voltages.

Tray option 36V batteries 48V batteries 52V batteries 60V batteries 72V batteries
11/53T 190 RPM 250 RPM 270 RPM 310 RPM 370 RPM
11/63T 160 RPM 210 RPM 230 RPM 260 RPM 310 RPM
11/72T 137 RPM 183 RPM 198 RPM 229 RPM 275 RPM


If you are unsure which option to choose after reading this article, do not hesitate to contact ou to check out their FAQ page.

RocketBike™ is here to help you with advice and assistance when choosing CYC Motor chainring options for your e-bike conversion, ensuring you get the most out of your investment.

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