I have a project bike in the works, and looking to hit about 70 gear inches on it. I got a flip-flop rear wheel for free, which has 16t cogs on both sides. The stock crankset is an old steel road double with a 38t inner chainring. It looks like a 42t chainring would get me into the territory I want, but I don't see much in the way of 42t single cranks on the market, and I'm guessing I'd need to replace the BB (or at least the spindle - I don't think it's a cartridge on this bike) if I did the crank. Chainline looks good with the inner chainring, but it's too small to be of much use unless I can find a 14t freewheel (does that exist?)

I'm looking to put as little money into this bike as reasonable, while still getting the desired functionality out of it.

Can you just replace the chainring? If you figure out the BCD, it shouldn't be too tough to find a replacement.

Not sure. I'm about to go out to a shop that sells used parts, I'll see what I can find out there.

Looks like a cheap steel riveted crank, chain-ring changes might not be possible.

44/17 Do a skid

I got a replacement crankset and a 42t chainring used at a local shop this afternoon. Now I just have to figure out how the hell to get these old chainring bolts out so I can put the new chainring on. They're not holding the chainring very tightly, there's a lot of play...but I can't get the nut to turn on the bolt at all. I hit them with some PB Blaster, but no luck yet.

Look at the back side of the chainring bolts. They usually have some kind of indentation into which a tool fits so you can hold the one side fast while unscrewing the other. In the event you don't have the tool for that, a knife, screwdriver, or any number of other tools can usually do the job.

I tried a few screwdrivers and a chisel (since it was the only screwdriver-like tool I have with a wide enough blade), and a penny held in place with a wrench, and lots of PB Blaster. No luck yet!

I managed to get the chainring bolts out this morning, by using a power drill and a vise.

Good news mate, nothing like stalling at the first step to spoil a project.

Yeah...now I just need to get the old BB out! Really fun when you don't have the right tool. There's a shop where I can use their tools that I go to sometimes, but I don't have an easy way to get the bike there, and probably won't be able to until Friday anyway.