i dont wanna swap wheels because i know it will cost toooooo much...
heres the issue!
I feel like im not getting the grip i shold, so i went and investigated....
what i WANT is the widest tire size possible on my rear wheel, and i just found that the reAr tire is narrower than factory....

swing arm has way tons of room for more width....

the swing calls for a 150-70-r17...bridgestone to be exact.

the tire currently on it is some crappy Kenda 140-70-r17.

so if it says 150x70.....what is thewideest ican go in size?
possibly a 170? 
tires size by a ratio of tread width x percentage of with of width equals sidewall height....blah blah...
i wish it was like my j3ep.... 36x10.50r15.  All inches not a mystyrious code....sadly, ive worked as a tire monkey, but hell if i know how the sizes work...

 so my basic question is can I go to a taller or wider tire on a 17-inch rim and what size should I be looking for I would like to go wider than the 150 70 then it calls for maybe something 170? 
 the real problem was noticed a couple of days ago when I finally got comfortable enough with the bike to push it into the corners and it seem to want to walk out from under me and I know the spike should be able to handle better than its doing so please any input would be greatly appreciated I'm going to try to order tires soon as possible.... and not crappy Chinese knock-offs!

by the way with the current 140 70 I am chewing off the side wall and I would like to get lower in the corners plus I also like the look of a wider Tire on the rear so maybe a 170 55?
 also I've been told that Shinko tires are extremely good for the money but I wouldn't have a problem going to a higher end Tire as long as I can fit a good wide one of high quality and good tread wear because if I replace this tire and it's expensive it better last