MTB チェーンセット (クランクセット)

This depends on the groupset and the chainset. The big groupset manufacturers recommend using all their components in a groupset, however some smaller manufacturers such as Hope, Rotor and DMR make chainsets which integrate with various different groupsets.

Converting to 1X is a bit more complicated than just changing the chainset or chainring. For riding off-road, clutch derailleurs stop the chain from bouncing around & keep the chain taught. If you are converting a road bike, you will need to consider what to do with the front gear shift / brake lever. On a mountain bike with non integrated shift levers, it's easy to remove the left / front derailleur shifter. There are lots of youtube videos of 1X conversions, its a good idea to look into these before starting a 1X project.

We always recommend following manufacturers instructions for fitting any component. The Youtube channels of Park Tools and GCN Tech have very indepth and comprehensive advice for completing all sorts of jobs on bikes, these are also worth watching particularly if you are inexperienced or unsure.

To stop your shoes touching the chainset as you pedal, adjust your shoe plates to move the shoe away from the chainset crank arm. Any changes in shoe plate position are best done in smaller incremental 'tweaks' rather than huge adjustments.

Keeping your bike's transmission clean and lubricated will reduce the amount of wear on chainrings. Replacing the chain when required, and cassette when it gets worn, also prevents excessive chainring wear.

If you are replacing a like-for-like chainring, choosing the chainring should be relatively straight-forward. If you are aiming to match chainrings for a specific crank, chainrings have a couple of things to consider. Firsly the number of 'arms' on the right hand crank arm usually 5 or 4. The bolt circle diameter (BCD) is the measurement of a circle diameter which passes through the centre of all 4 or 5 bolt holes. If you are unsure google your bike's crank BCD.

The number of teeth on the chainring also needs a little thinking about, particularly if you are running 1X transmission.

No. Chainging from 2X to 1X, using an existing 2X or 3X chainring will result in continually oily fingers! 1X chainrings alternate between narrow and wide teeth. These alternating teeth fit into the narrow and wide (alternating) openings in the chain - providing much more contact, securing the chain onto the chainring, even on the largest or smallest sprocket.

When converting to a 1X set up, you will also need shorter (1X or singlespeed) chainring bolts. 

Yes, a smaller chainring will help. It might be more cost effective to replace your bike's cassette instead. Check your rear derailleur's maximum sprocket size. For example, changing from a 25 sprocket to a 28 biggest sprocket with a 39 chainring would give a similar gear to 34 X 25.