Mid-Life Cycling

Mid-Life Cycling

10 July 2013

An Old Conversion

In an earlier post, I wrote about the Schwinn Super Sport, a bicycle Schwinn produced from 1962 until 1973. 

At the time, Schwinn marketed it as a “lightweight” model.  It was indeed lighter than the Varsity or Continental, which were essentially ten-speed tanks.  The Super Sport featured a frame made of Chrome-Molybdenum tubing and most of its components, including the rims, were aluminum alloy.  One of the notable exceptions was the one-piece “Ashtabula” crank of the kind commonly found on cruisers, heavyweights and kids’ bikes.  (Some of those kinds of bikes, on which weight is no object, still come equipped with such cranks.)

However, it was possible to take a couple of pounds off the bike by changing the crankset.  At least one company offered a bottom bracket assembly that allowed the use of cotterless alloy cranks on frames made for Ashtabula cranks.  They seem to have been most widely used on motocross bikes; around the time that sport was developing, Gary Fisher, Joe Breeze, Tom Ritchey and other early mountain bikers were using crank adapters on old Schwinn balloon-tire bikes they adapted for use with derailleur gears.  (Most of those bikes came with single-gear coaster brake hubs as original equipment.)  I haven’t seen, or even thought about such a crank conversion in ages—until today.

This bike was parked, with a few other bikes that were being used for deliveries, outside a bodega/takeout luncheonette not far from where I live.  I spotted it on my way home from a lunchtime ride:

Unfortunately, as the bikes were locked to each other, I couldn’t get a better photograph.  But I think you can see how the bike was converted.

I’m guessing that this conversion was done some time ago, as the crank is a Sugino Maxy from the mid-1970’s that shows its age.  At the time, they were one of the least expensive cotterless cranksets made.  Many mid-level Japanese bikes—including the Nishiki International I once owned—came with the Maxy as standard equipment.

It wasn’t bad:  It was definitely an improvement over the cottered steel cranksets found on most European bikes in the same price range, or Ashtabula cranks.  On the Maxy (and other cranksets like the Takagi Tourney), the large chainring was “swaged” (pressed) onto the inside of the right crank arm, and the smaller chainring was bolted to it.

That meant, of course, that the outer chainring couldn’t be changed.  But cyclists rarely wanted to make such a change:  Outer chainrings usually had 50 or 52 teeth, and the smallest cog on most freewheels had 14 teeth.  (Thirteen-tooth cogs were still exotic items used by professional racers.)  And, it was believed, few people would ride enough miles to wear out the large chainring. 

Anyway, the Super Sport was probably the one full-sized, derailleur-equipped bike on which such a crank conversion made sense.  (The next model up in Schwinn’s lineup, the Super Sport, came with a Nervar or TA cotterless crankset.) 

Because the Maxy is of more or less the same era as the bike (and the conversion kit), it didn’t look out of place.  All of the other components, save one, were original.  The rear derailleur—an all-black Shimano Deore—is definitely an improvement over the Schwinn-branded Huret Allvit that came with the bike.  I couldn’t photograph the bike from an angle in which I could show the derailleur, but I think you’ll understand (and perhaps agree) when I say that it screams “replacement part” in a way the crankset doesn’t.

1 comment: