Hello,
I customize a new size M frame at the moment with 4,8 Vittoria Cannoli on 100mm rims, and I had also concernes if the tyres would fit.
Front is not an issue, because the King Pin can accomodate 5" also in the Mukluk, but I was not sure about the rear.
The bike is not jet finished but the tyres fit - I tried it in the frame.
There is enough clearance to every side - approx. 1cm each.
The diameter ist not an issue. so, everything looks very comfortable.
I measured the tyre width - it is approx. 115mm (4,5"), which is almost the same like my 4,8 Jumbos on 80mm DT Swiss rims.
I don´t expect that the tyres would become much wider when using them, because the Jumbos didn´t also.
The clearance in the frame I measured is approx 130mm (5,1") (chain stay / seat stay)