We’ve never heard of the Arcobaleno, but we can dig this.
They were made with Columbus Neuron, apparently.
RARE EDDY MERCKX ARCOBALENO ROAD BIKE CAMPAGNOLO – $900 (Fremont)
This is a solid bike that is in nice usable condition.
Has been cleaned and tuned including a new chain.
This is a fine steel frame bike with Campagnolo Centaur
indexed shifting with a double in front and nine speeds in rear.
It appears that the component group is Centaur.
The frame size is 57CM with a 32.5″ stand over height and a 57cm top tube.
This would best fit a rider 5’10” to 6’1″.