A traditional Chinese roadster is designed with a few things in mind:
1. Ease of construction, because the factory will have to make millions upon millions.
2. Durability, because they will be used forever and for everything.
3. Ease of repair. Better be able to fix it with a hammer.
Most of the traditional roadsters have a cottered crank, which is certainly easy to repair, if not exactly the most durable item. If you are a heavy or strong rider, the cotters can deform and you will get "the squeek". Sure you can pound in new ones with a shot from a hammer, but wouldn't you rather not deal with it at all?
Most of the modern roadsters, have a cotterless tapered crank. Easy to make? Sure. And less problematic than cottered cranks too.
But isn't there something else? Some other avenue to address the shortcomings of a cottered crank? Sure!! A one piece Ashtabula crank! Very strong. Easy to make and the whole crank, just not the arms, can be replaced with no special tools. Seems like a natural, but you never see this in China..
Until a few weeks ago that is: This is the first and only Ashtabula roadster I have ever seen. Take a look. 
It was old and unmarked. Still it leaves me wondering why Ashtabula never made it in Beijing. A missed opportunity perhaps.
LOL... a one-piece forged, slide through crank. How novel... and quaint! Actually, quite common here in the States back in the day. Pretty much all Columbias, Schwinns, Rollfasts, etc. of American Manufacture were thusly equipped.
Looking at the picture, it's almost startling to see such a thing on a Traditional Roadster.
And I like the name.... "Ashtabula"... has a realy charm to it. I wonder what... if anything... it means? ;-)
Cheers!
Larry "Boneman" Bone
Posted by: Larry | January 24, 2009 at 09:27 PM
Ahh, too bad such a thing cannot be retrofitted easily, but the ashtabula uses a much larger bottum bracket shell to deal with the whole crankarm needing to be passed through it.
John
Posted by: John Timbes | January 25, 2009 at 09:35 AM
Yes... I recall rather large bottom brackets on a couple of the bicycles of my youth. That being said... the ball bearings were quite large... and were in "cages" so when you disassembled the B.B. they came out as an assembly.
Made for easy re-assembly... but cleaning them was tedious.
BTW... forged cranks made excellent boat anchors. ;-)
Cheers!
Larry "Boneman" Bone
Posted by: Larry | January 28, 2009 at 09:13 PM
Larry-
"Ashtabula" is the name commonly used for one piece cranks as supposedly they were once made n Ashtabula Ohio.
Boat Anchors ya say...:->
BYW: Just got aback from India. Got hundreds of pics of fabulous roadsters...but not Abley!
Posted by: Jeff Stracco | February 08, 2009 at 02:00 PM
The Flying Pigeons I sell do away with the old Raleigh standard thread count for the bottom bracket - so am off-the-shelf 68mm cartridge bottom bracket can be swapped with the cottered bottom bracket.
Good news for those of us looking to use an easier gear ratio on our Pigeons!
The bikes I got from the factory have 46 teeth on the front chainring! Stepping down to 32 teet makes these bikes a lot easier to ride in a place like L.A.
Posted by: Flying Pigeon LA | February 12, 2009 at 05:50 AM