hmm.. i've never heard of a "shimano sgm". nowhere in the shimano website is there an "sgm".
i'm guessing this is a mall bike with knock-off components. even the kenda tires are dubious.
at P8500, you're better off saving up a bit and getting a decent second-hand built-bike. check out the forum on trade central on whole bikes:
http://www.pinoymtbiker.org/forum/forumdisplay.php?f=57
good luck.
