So any spacers over 1 3/8 and you can't use the MMM? What spacers did you buy?I once owned a B3350 ROPS model. The 3350 is very similar to the 2650 aside from the engine.
I used tire chains on the 3350 without wheel spacers before I added wheel spacers for other reasons. Yes, there is adequate clearance but just enouth and you will need to install the chains tightly as should be done in any case.
I also had a 72" MMM that I could mount with or without wheel spacers.
FWIW, the Kubota wheel spacers that I had are 1 3/8" wide. There is a reason for this, and all bets regarding MMMs are off if one goes wider with wheel spacers and/or optional, oversized tires, which cannot be used with chains, cab or ROPS.
Seems like it would also depend on the chains you get....thicker.