i know this question has probably been answered a million times, but i'm too high to preform a search right now. sorry.

the schwinn i'm planning on putting my friend on when he comes to visit in a few days is in worse condition than i thought. it's a '78 (i think) schwinn continental. the one-piece cranks are in horrible shape, so i want to put in a single speed crank before he needs to ride (then i can make this bike my winter beater). what bottom bracket should i look for? i need something cheap that is readily available used on ebay.

what kind of crankset should i look for? i know people say bulletproof is the best cheap, so i'll probably do that if i can.

thanks for your patience. i hate one-piece cranks and i will not put my dear acquaintance on a set for a week.

needs a new bottom bracket too
https://sheldonbrown.com/harris/opc.html

so i need 24tpi?

what kind of bb should i look for? any specifics with cranks or will one size fit all (i've never had to buy cranks / bb stuff before)?

i'm perplexed.

i just put a 68x110mm shimano un-53 into my 84 schwinn world, this will be used with an IRO crankset.

any certain bb shell(?) i should look for?

Um, the bottom bracket shell is built into the bike. It's the big metal thing that's got four metal tubes coming out of it. Hope you find it.

You should take the bike to a bike shop. They can help you with all of this. I don't think you should be installing cranks and a bottom bracket just yet in your bicycle mechanics career.

i hope i do too.
i'll be screwed if i don't.

afaik - schwinns use the standard us 68mm bottom bracket shell. 70mm is italian and 73mm is english.

Schwinns with one-piece "Ashtabula" cranks didn't use bottom brackets, but used hanger cups, ball bearings, and cones directly on the crank threads (the BB shell doesn't have threads). To convert a one-piece crank to a three piece crank and a bottom bracket, you need an adapter like the MRP BBC 1 conversion kit.

derrrr, i missed the one-piece cranks part

would this do the job?

It should, but measure the inside diameter of the BB shell on the bike to make sure the 2" bearing cups will fit OK.

awesome. will i need a new spindle too?

It looks to me like the eBay seller is including a spindle. The question is whether the spindle is the right length and configuration for the crankset you plan on using.

will a square spindle (or whatever i need to run bulletproof cranks) fit that adaptor?
i'll ask the seller for some specifications of the adaptor.

that adaptor kit includes the spindle.. it is that special spindle which does the magical conversion. normally(on a three piece BB) the cone is built into the spindle, and the cups thread into the frame with the bearings between. On this adaptor the cups are pressed into the bike, then the cone threads onto the spindle with the bearing between. The first link to sheldon brown's site states that sometimes that conversion is unsatisfactory as the spindle in the kit(which you cannot just swap out)is generally longer than the one most cranksets are designed for, therefore giving you a weird chainline. That same link shows another conversion option where you press/bolt in two big threaded pieces. With this you can use any standard bottom bracket.(the one on sheldon's site is a bit cheaper than the one scooper linked to)

argh. sheldon's link to the adaptors doesn't work...

just get a decent frame.

out of the question right now.
thank you though.

This answered my questions too.

Thanks to everyone who contributed.

danscomp.com sells a bb adapter from the american style to the threaded english style

amr-euro adapter and get the iro crankset and bb it is the least expensive I think or go to nycbikes.com they have un52 for 10 bucks and get fmf crank arms for square taper 18bucks and a rocket ring and rockn roll

What's actually wrong with the cranks? This mess is going to cost you $50 minimum just to get a turd of a frame running with the same chainline it already has. Also, you will need new pedals, the ones from the one piece rig won't fit a 3 piece crank, so there goes more money. Bracketing the fact that you could almost surely get a new beater for that price, I'm not sure what could be so wrong with a set of one piecers that you would need to do all of this.

I've rode/commuted a couple thousand miles on an old Schwinn with a one piece crank (one of my many bikes). I just pulled off the chainring combo and threw a 44t chainring on the front. Just scotchbrite the bearing races and clean/lube the bearings and you will be in buisiness.

Save the $$ to buy some drinks with your friend, I am sure he would appreciate that more than a bling crank on a tank of a bike.

just my $.02


my one peice crank hoopty:

the Ashtabula crank is one of the most bullet proof pieces of bicycle tech ever invented. I can't imagine what you could have done to it to make it fail. On a bike as heavily built as your Schwinn the weight isn't going to matter.

Go out and buy a new set of bearings and some lithium grease and rebuild it yourself. ANYONE can do it. All you need is a 15 mm wrench to take the pedal off, a large crescent wrench to remove the nut and a hammer and screwdriver to loosen the lock ring. Go on YouTube and watch a how to video and have at it. trying to replace it with something else would be expensive and foolish.

Better to spend your time adjusting the brakes and derailers so the bike works like it's supposed to. And don't forget to oil the chain.

He probably already solved the problem........since asked the question ELEVEN years ago.