Hi I have never posted in this forum before. I have a mid 70's Schwinn Continental. I want to replace the one piece cranks with modern cranks. I read that in order to do this I would need some type of adaptor. Is it possible to just replace the bottom bracket entirely and throw on some new cranks or do these old bikes require some special BB?

Thanks
Matt

Look here https://sheldonbrown.com/harris/opc.html#opc

One of the best on the market and also at a good price is the FMF
https://fmfbmx.com/Merchant2/merchant...tegory_Code=BB
You'll need the adapter shown at the left.Then a BB axel and cups.also shown,or you can get another brand.

I just completed this conversion using the FMF adapter. Everything went together well but I was challenged to figure out the correct BB length. I tried a couple of traditional BB that I had and neither worked. I ordered a 121.5mm Shimano cartridge BB from Harris but it was too long, but it then allowed me to measure and determine the right size, a 110mm. But is this the right size for your Continental? Probably not. Reverborama used a 107mm cartridge. It all depends on the crankset that you are using. If you have a friendly LBS nearby, I'd take the bike with the adapter installed and the crankset you plan to use and let them fit the BB.

thanks for posting this question , I'm thinking about trying this on my 75 continental. The yellow one not the chestnut 21 speed.

There's one tricky bit to fitting the BB conversion: The two sides are retained by 3 screws so when you press them in, you need to have the holes for the screws line up. The screws themselves are NOT strong enough to draw the two sides in -- you'd strip the threads. I made a ghetto press out of some big washers and a bolt. I drilled 3 holes in one washer so I could press the two sides in while the screws were installed and tighten them as I went along. I'm happy to lend the washer to anyone who wants to do this conversion.