Current project status
It just takes a lot of time and patience to remove some parts like the fork, the handlebar and the bottom bracket. The saddle post is the worst. I gave up as I lack the tools. The bike shops said to come back in Winter. Which I now will.
My plans for the Thomisus
I want to turn this bike into my new daily. I think the frame geometry will suit me better than my current GT: longer with a slacker front.
There are some caveats
The width of the rear tire is limited, much more than the GT is.
The width of the chainstays is 125mm. Either I will widen the chainstays to 135mm to fit modern 10 or 11 speed cassettes. Or I will have to give up on my plan to use a 1x groupset.
The rear brake will be the one my Bianchi came with: the position of the rear brake is quite unique and therefore it is difficult to find brakes that fit.
About Bianchi Ragno ATBs / MTBs
The Ragno (spider) models were produced in the late 80s and early 90s by Bianchi and Puch. Both had been part of Piaggio at that time until they were sold to Cycleeurope in 1997.
I measured the seat tube length. Bianchi themselves produced a chart, describing this measure as their way to define the sizes. Mine is 58cm and therefore XL, the largest frame size they were offering :-)
There is little information on the Bianchi spiders.
The Ragno Hierarchie
Best to basic:
The Ragno you find most often is the base model "Meta" followed by the slightly better equipped "Thomisus". Apparently the both share the same steel and tubing. Araneus and Migale have the best tubing and are slightly lighter. I am not clear about Theridion and Pholcus. Do they form a third "middleclass" group or were they equipment variants of the top end (Theridion) or base models (Pholcus)?