1x (Single Chain Ring) Bicycle Drivetrains: View this before conversion or buying

My daughter wanted to convert her 9-speed bicycle which has a triple in the front to a 1x (also called a 1 by or one chainring) for ease of use to get up big hills and coast down the other side. The triple was just a hassle and she never used all 27 speed combinations. If you want to know more about such a conversion, see the video in the upper right. In the process we learned a lot about 1x that also applies to some new 1x road bikes. Here are the pros and cons of a change to a single chainring and items you need to test out if you're contemplating a 1x. The front is a narrow wide 1x chainring 38T and notice how the wide tooth fits the wide part of the chain link and the small tooth fits the narrow part of the link. This prevents the chain from falling off the chainring when the chain is angled toward the large cogs.

Pros:
1. Lighten bike by removing front derailleur
2. Easy to shift when you only have to think about the rear cassette

Cons:
1. Less gear choices
2. Extreme angles similar to cross chaining resulting in noise from the narrow wide chainring when in larger cogs. We can see that the chain at an extreme angle click onto the wide teeth of the narrow wide chainring as the culprit in creation of the noise.
a. Let's look at the chain line. We can see when we check with a chain line gauge, the front chainring lines up between cogs #3/4 out of the 9 rear cogs. This results in an extreme angle for the chain when in the larger cogs.
b. If you're in the larger cogs, pedaling backward will cause the chain to jump down to a smaller cog. I, myself, to not pedal a bicycle backward. Bicycle derailleurs are not built for that. But some, for some reason, cyclist do this.
c. This may indicate more wear of components as well as on the derailleur but I have no concrete data on that yet.

To change that, we tried another crank in which the chainring sits inboard of the crank spider as opposed to outboard on the crank. The chain line now is between cogs #4/5 with less noise in the larger cogs and the chain does not come off when pedaling backward. Later, we replaced the rear cassette with an 11/40 T to allow a greater range in shifting choices. If you want to spend the money, you could convert your shifter, derailleur, chain and cassette to a 11 speed (correct spacers may be needed to fit the 11 speed cassette on the hub) to increase the shifting choices.

The importance of a 1x setup for a road bike is debatable. But for the casual cyclist, it could make the ride easier and hill climbing a breeze. Then again, so can an E bike. There's also less maintenance and repair with a one 1x upgrade.