DesertRider8

Currently, my mountain bike is a 3x8 system. I really would like to convert it so that it is a 1x. I'm not the best at mechanic stuff and I dont know if it would be better to try 1x8. Or go to 1x9 or 1x10. And my biggest issue is, I dont know exactly what to buy. I've watched various videos and read some articles but I'm still unsure of which parts I would need to purchase, exactly.

If it's too expensive obviously I just wont do it, but I would like to try

Can anyone help??

Bill Kapaun

Just don't shift the front and you can pretend you have a 1x8.

DesertRider8

I'm tired of having the unused shifter on the handlebars and the extra chain rings collecting dust on my bike. I dont want to pretend.

Bill Kapaun

You'd probably be better served by changing the cassette to something like 13-23 or 13-26 and using 2 rings.
You have much closer spaced gears and basically 2 "ranges".

Iride01 

Then just remove the offending shift lever and front derailleur. Then at least you'll still have the option of getting your fingers grimy and going to the smaller chain wheel if you ever need it.

There's a chance the chain won't want to stay on the big chain wheel. If that happens, then you'll know you have to think about the chain line of the 1x when you do buy a new crank.

But as for wanting to just buy a 1x crank or any crank, then you mainly just need to know what bottom bracket shell is on your frame, pick a crank you like and see if there is a bb to fit both crank and shell. Depending on what bb is in your bb shell currently, you might can just get a crank.

Drew Eckhardt 

13-14-15-16-17-18-19-21 was the ideal 8 speed cassette.

Regardless, 53 x 21, 23, or 26 is inadequate for places with hills.

Bill Kapaun

Then the OP can add the smallest ring and have 3 ranges.

AeroGut

There are two parts to your question - first, is it desirable to go to 9 or 10 cogs in the back and second, how to set it up. It's best to deal with the cogs first.

It sounds like you already ride using only one of your chainrings. Do you feel like the 8 cogs you have now work well? If not, do you want more range, tighter spacing or both? To get more range, you can use a wider range 8-cog cassette, understanding that the resulting gear ratios will be more widely spaced than what you have now. If you go that route, all you need to do is buy a new cassette, as long as the largest cog does not exceed the range of your rear derailleur. If you want close spacing and wider range, that would be a reason to go to 9 or 10. 9 and 10 speed cassettes will fit on your current hub, but will require a new chain and shifter as well. And again, make sure that the largest cog is not too large for your rear derailleur. As long as the cogs aren't too large, your existing "8-speed" rear derailleur should work with a new 9 or 10-speed shifter. The derailleur is not specific to the number of cogs.

For the front, as others have mentioned, the inexpensive approach is to take off two of your chain rings and leave the chain on the one you use. You can remove the derailleur and shift lever as well. If you have problems with the chain coming off, leave the derailleur on as a chain guide, but remove the cable and shifter. Use the limit screws to lock the derailleur in position. If they aren't long enough, replace them with longer screws. Having a triple crank with only one chainring, however, might offend your aesthetic sensibilities, in which case you'll need to buy a single-chainring crank. If your bottom bracket is still good, you can look for a crank that is compatible with it. Otherwise, just get a bottom bracket and crank that match.

To sum up:
1x8: optional to buy new cassette with wider range, optional to buy new crank with or without new bottom bracket.
1x9 or 1x10: must buy new cassette, new chain, new shifter. optional to buy new crank with or without new bottom bracket.

Drew Eckhardt 

Exactly.

I rode 50-40-30 x 13-14-15-16-17-18-19-21 in the 8 speed era because that got me a 13-19 straight block for plains rides, and a low like 42x29 or 39x27 for mountains.

That let me show up for my lunch hour ride with ideal gearing regardless of what direction the group felt like riding that day.