Chainring Options Explained
11/53T 219H sprocket with 32T inner chainring & carbon chainguard
11/63T 219H sprocket with 38T inner chainring & carbon chainguard
12/72T 219H sprocket with 42T inner chainring & carbon chainguard
CYC Motor offers 3 different chainring options in the X1 PRO kit. These options are the 11/53T, the 11/63T, and the 12/72T. Now the big question comes in... which one is right for you?
When choosing your chainring option, keep your desired ground clearance in mind as the different options obviously differ in actual size. We also recommend that you choose a chainring option that is close to your current bike’s set-up at the front chainring. So, if you currently have an 11/32T chainring before converting it to an e-bike, we recommend going for the 11/53T option with a 32T inner chainring. The same goes for an 11/42T chainring - the 12/72T option with 42T inner chainring will suit nicely.
This is of course our recommendation, but you are free to choose whatever option you see fit for your desired goals as you will see the technical differences explained below.
THE CHAINRING OPTIONS AFFECT THE CADENCE
The misconception is that the chainring has a large impact on your top speed, when in fact, the chainring only has a real impact on the cadence and the ground clearance you want to achieve.
See, when you change to a larger chainring, let’s say from a 53T to a 72T, the cadence RPM will decrease, but at the same time, your gear ratio to the rear wheel will increase in overdrive, canceling each other out. Keep in mind that you will need to stay in the same gear on the rear cassette. The real difference in the X1 PRO chainring sizes is what gear ratio you want from human input power to the rear cassette. I.e. how hard are you willing to pedal in PAS mode.
A smaller chainring will have more torque, but you will have to maintain a higher cadence in the same gear to achieve the same speed. The same goes the other way around. If you have a larger chainring you will have less torque, but less cadence is required to drive at a higher speed.
It is important to note that it is not always about the cadence rating but also the actual size of the chainring. For bikes that use BB92, the 72T chainring will clash with the chainstay of the bike. In which case, the rider will need to choose a smaller chainring. The second-largest option (11/63T with 38T inner chainring) will work just fine.
TOP SPEEDS AT THE CRANK
The top speed at the crank will vary with the chainring options you choose but as we mentioned, your overall top speed will stay the same. Below are the various outputs possible at the crank.
When you choose the 11/53T chainring option (with 32T bike chainring), the reduction ratio from the motor to the crank is 1:28.9. Therefore, the top speed at the crank with this option is:
190 RPM with 36V batteries
277 RPM with 52V batteries
311 RPM with 60V batteries
381 RPM with 72V batteries
If you choose 11/63T chainring options (with 38T bike chainring), the reduction ratio from the motor to the crank is 1:34.4. Therefore, the top speed at the crank with this option is:
160 RPM with 36V batteries
233 RPM with 52V batteries
262 RPM with 60V batteries
320 RPM with 72V batteries
If you choose 12/72T chainring options (with 42T bike chainring), the reduction ratio from the motor to the crank is 1:36. Therefore, the top speed at the crank with this option is:
153 RPM with 36V batteries
222 RPM with 52V batteries
250 RPM with 60V batteries
306 RPM with 72V batteries