You would assume that there is no wrong way to use your gears, however there can be an issue specifically with double chainring’s. When you are in the small ring at the front you should not use the two smallest cogs or hardest gears on the cassette. Likewise, when in the bigger chainring you should not use the 2 biggest cogs or easiest gears.
This is called cross-chaining and can cause many issues. For one you can get chain rub on the front derailleur or even on the frame, and we all hate any noise coming from the bike or unnecessary damage. It can also cause shifting issues along with premature wear of the chain and will reduce efficiency of the drivetrain overall. Most importantly it may cause damage to the rear derailleur as it is put under extreme pressure that it is not designed for, especially if you have a shorter chain or a larger cassette and chainring fitted.
Best way to manage this and choose your gears correctly is to get to know your bike and understand what gear you’re in, keep an eye out and shift to a more efficient gear at the front derailleur and then likewise at the rear to choose an equivalent gear for similar cadence but have a better chain-line. This is why Shimano’s di2 has syncro shift and will choose a more optimal gear for you to be in and not allow any cross-chaining. It’s worth noting 1x set-ups (a single chain ring) you can’t cross chain, but the theory still stands, and the most efficient gear is when the chain is in the middle of the cassette, where it has the least friction.
Finally, some advice when changing gears. Pushing watts and shifting you may notice a big clunk or difficulty for the chain to find the teeth of the intended gear, causing damage to the cassette’s teeth. This is essentially shifting gear under load. It is best to ease off on the pedals, so less torque is applied but still rotating the cranks, shifting simultaneously and letting the derailleur and chain do the work. This happens in an instance, and you should notice how smooth your drivetrain is. To reduce chain drop and causing any paint damage, it is advised to choose the correct gear before hitting any climbs. This may mean shifting down to the small ring at the front, while choosing the best gear on the cassette to keep up your speed.
By Jordan Colledge, Head Mechanic Vélo Presto
