Hi I am looking for a bicycle (mainly mountain bike)and with limited budget i have now, i found these types : Oscar Backfire 300 - front absorbers - shimano revolshift 21 speed - disk break - alloy double wall rim - size 16.5" http://neocycle.wordpress.com/harga-ori-mtb/mountain-bikeadult/ Oscar FS Steel - front / back absorbers (full suspension) - shimano revoshift TZ 21 speed - disk brake - alloy double wall rim http://neocycle.wordpress.com/harga-ori-mtb/mountain-bikeadult/ Oscar Mountain Bike Alloy SE Edition Spec : 1) SE Alloy Edition Frame 16". 2) 7 Speed Shimano Revoshift gear 3) Disk brake Front Back 4) Easy Front Tyre Remove. 5) Shimano Tourney derailleur. 6) Easy Seat post remove. http://oscarcycle.blogdrive.com/archive/1.html All 3 of them are having more or less similar budget. Just wondering : - what's the difference between (shimano revolshift 21 speed) and (shimano revoshift TZ 21 speed) and (7 Speed Shimano Revoshift gear) ? - i saw this bike, there are 2 types : steel and alloy... Should alloy better as steel has been used in old days of bicycle and now they are replaced by lighter alloy / durable too ? - Will this sufficient for me to get it ? i mean i wanted to get one just for leisure cycling on the road.... maybe axx km of cycling around part of the city ? Many thanks