I'm making my first single speed. The crankset for the bike is the old-style single piece (not the newer tapered square bottom bracket). As such, I'm finding it difficult to find a new chainring that will work for it. I found one on Amazon, but it is listed as a BMX chainring. It's a single chainring, and it has the right amount of teeth, so I'm wondering if this will work for a single speed, or is there some big difference for BMX chainrings that will make it undesirable?

Just make sure the bolt pattern matches your cranks

can you post pictures

I have a BMX chain ring on my one piece crank (that's what she said). If the hole on the ring looks in the right place I think it's likely to work.

Wait a sec...

I just looked here;

https://sheldonbrown.com/opc.html

where Sheldon claims: "Virtually all one-piece-crank chainwheels are interchangeable. They have a 15/16" hole in the middle, and another, smaller hole for the drive pin of the right crank to engage. You can buy single chainwheels of various sizes, usually for 1/8"
chain, or double or triple chainwheels for 3/32" chain. The doubles and triples are usually riveted together units, with standard ratios. Doubles commonly come in 39/52. Triples are most often 28/38/48, but other combinations are available."

This is the page you want;

https://sheldonbrown.com/harris/opc.html

@hairnet: I read your post and was about to run to the garage to snap a few pictures, but here vidvis posted some links after you that has some great photos (especially the first link). That is exactly the setup I have on my project bike.

I appreciate the responses, and they have given me a lot of information that has been helpful. But I think I neglected to highlight part of my concerns. Most of the chainrings that I have been finding the fit this setup have been labeled as "BMX". I'm not sure if there is any difference between "single speed" and "BMX" when it comes to chainrings. I know that I want a cassette that is specifically labeled as "single speed" because it means better teeth built to make sure the chain doesn't slip. But in the case of the chainring, does one built for a BMX bike function just as well as one built for a single speed bike?

They typically put BMX in catalog copy because the BMX market is the primary market for replacement chainrings for one-piece cranks.

Most BMX bikes are single speed bikes, so yes they function the same just different interface.

BMX = American
BMX adapted old American standards for parts, so if you encounter a part that looks like it will fit and it's labelled "BMX," it will work for your bike. OPC chainrings come in 1/2" (for single speed chain) or 3/32" (5-6 speed chain) sizes. 3/32" will work with either chain size.

If you can't find an OPC chainring you like, you can buy a spider that will let you use regular chainrings (IIRC, Porkchop BMX has them on clearance cheap) or you can get an OPC to 3-piece adapter from Truvative and run square taper cranks.

As an alternative you can ditch the one-piece crank and use this adapter to install just about any BB/crankset you'd like:

https://www.amazon.com/Truvativ-Ameri.../dp/B003KS00EU

Jinx!

Oh yeah. hehehe