Originally Posted by
chagzuki
On 3 speed SA hubs or all types? The shuttle pin part has thrown me.
The pin extends farther through the axle on a 5 speed than it does on a 3 speed. The pin is ramped to either push the locking balls out to lock a sun gear to the axle, or drop into the recesses to allow the sun gears to rotate freely. Which sun gear is locked to the axle determines your drive ratio in all but 3rd gear.
This function does not exist in a 3 speed. It's the primary difference between the two.