How to avoid cross-chain
You need to avoid being in the most difficult gear on one shifter and the easiest gear on the other shifter. This is called “cross-chain” because the chain runs at an angle, rather than more or less in a straight line. The cross chain puts a lot of pressure on the chain and often causes the chain to derail before rubbing. This makes a lot of annoying noises that can rough your gears.

How to find the best gear combination
There is no perfect gear combination formula-it is really a matter of personal preference. Don’t be afraid to play around and find the most comfortable and efficient pedal speed, or “rhythm” for you.
As we mentioned earlier, derailment before shifting (left hand) will cause more noticeable gear changes, and derailment after shifting (right hand) will cause smaller shifts. Through practice, you will find that moving forward is very helpful for large changes in elevation and backward movement, which is helpful for fine-tuning your gear until you pedal at a speed that suits you.
Generally speaking, most riders find that a rhythm of about 90 pedal rotations per minute is the most effective and comfortable. A slower tempo can feel like a struggle, while a faster tempo may feel like you stepped on a ton, but didn’t really go anywhere. If you are interested in measuring your rhythm, many loop computers or applications can use sensors to read this. Using sensors to measure your tempo may be a good way to learn at a good time to change gears.

Pro tip: gently step on the pedal when moving!
You need to keep the pedal to be able to move, but the movement works best (and is the smoothest) when you pedal lightly. If you put a lot of pressure on the pedal when you change gears, the gear changes tend to be heavy and sudden. This is especially important in the mountains-so if you see a hill going up, put on an easier gear before you start climbing! If you need to steer to a more relaxed gear when climbing, try to reduce the pressure on the pedal when climbing.
We also recommend that you change gears when you stop slowly, so that when you have to start pedaling again, you won’t be fighting with really hard gears.