Anyone tried different tire sizes?

[rxrunner]

I have a 2007 Kymco 125. Stock tires on it. 130/70-12 on rear. 120/70-12 on front.  It is new to me, and still stock, including the tires. If I am going to upgrade the tires anyway (maybe to Michelin City Grips), I am considering upsizing the tire diameter by putting on slightly larger tires. I am also looking to gain a net result of a higher seat.

Has anyone run any tires any other size than stock? If so, what was the result?
 
Example: It seems that I could run taller tires -- 80s or even 90s -- on front and rear and get a smoother ride, and slightly higher seat/perspective while driving. For my example, I will be describing the rear tire size  to keep it simple.
I calculated:
130/70-12 to be the stock size. Plenty of room between rim and fender.
130/80-12 - .51 inches diameter bigger than stock. Should not rub at all. For a total of 1.2 inches higher seat.
130/90-12 - 1.02 inches diameter bigger than stock. For a total of 2.04 inches higher seat.
 
Anyway, not sure if you ever looked into this further or not.
Obviously, I would need to modify the fenders with with spacers to use the larger tires.

[cnydreamr]

Your math is slightly off. Even if the size stamped on the tire is accurate, the diameter is the total height of the tire. You will only gain height/ ground clearance with half of that, that's the radius. So for a .50 inch diameter increase, you gain .25inch of ground clearance. I also want to change tires, more of an off road tread. Best i've found are 140/70/12 kenda 761 dual sports. I'll bet there are other tires for street use.

[rxrunner]

thank you for helping me with that math, cnydreamr. that makes sense. In fact, that also "corrects" my math I was thinking about in regard to putting bigger tires on my RAV4.

So, I guess that makes me lean more toward staying with stock for now. I think I would like the look of offroad tires on it at the 140 width. I also like the look of Supermoto tires. Some day soon, I would like to do a trail ride and/or logging road ride with some folks. I have not connected with any other riders yet. I live in Seattle WA if anyone can recommend a club.

If anyone has the time, it woudl be good to either find on the Internet, or create a table that shows what size tire sizes generally fit on the Kymco Agility '07 to '11 models, and what the clearance is, what the ground clearance gain is, etc.