One of my favorite bicycle wrenches are Park Tool pin/peg spanners. It’s because they are handy, strong, cheap and simple tools but also because of the different coloured grips that break the monotony of any tool wall display.
My own experience tells me they are not on a daily basis tools anymore, but still esential for any all-round workshop that services freewheels or old fashioned bottom brackets for example.
The green handled SPA-1 fits the adjusting cup on many old three pieces cranksets. The pin ends are round with a diameter of 2.9mm.
The most popular repair you can tackle is a cup and cone type bottom bracket service.
On the other hand, the SPA-2 red spanner has 2.3mm pin diameter. Due to its smaller size fits better a wider range of hole widths. It releases retaining rings on Shimano and Campagnolo crank bolts and the adjusting cone on most freewheel clusters.
A very interesting repair suitable with this tool is the removal of certain type of non-serviceable freewheels that don´t have an extraction tool option. A freewheel destructive removal method will require this spanner to get rid of the lockring.
The third and last peg spanner I own is the discontinued yellow SPA-4. It has a flat section designed to uncrew the adjusting cone of one-piece cranks. This is virtually the only repair you can do with this tool, the service of entry level cranksets on BMX’s and department store bikes.
At this point you might wonder what happens with the Park Tool reference SPA-3. Does it exist? Well, it does. But I haven´t seen one so far. It took me a lot of time to find a presentable picture of this tool and some information.
Meanwhile SPA-6 uses replaceable pins of approximately 2.2mm in diameter. The distance between the pins is adjustable, allowing use on virtually all hanger cups using pin holes. I have to say I do prefer fixed pegs as they are faster and more comfortable to use.