chain&sprockets

Open ended questiom..lol. It all depends on what you want to do. Most guys go with 14/40 gearing for a little more speed. Front gears are cheap, for most uses I would say go with a steel rear instead of a trick Renthal alloy sprocket, just because they last longer, but they still look sweet. Stick with a real name brand, not a no-name chinese. Go with an o-ring chain. I've seen complete Primary Drive sets for about $50-$75.
 
people like 14/40 or 14/39,(blasters come stock with 13/40) if you drop your rear sprocket and raise your front then you gain more top end. if you lower your front you get more bottom end. i was using a 14/40 with 21 inch tires and i didnt like it. but i went with a 18 inch rear and then put my 14 on and i like it now.
 
I think different than most guys on here when it comes to gearing. I ride mostly in the woods on a stock pipe blaster. I run a 20 tires and a 12-42 gear. No I can't run 55 on the high way but in the woods my stock pipe blaster pulls like you wouldn't believe. I never use 6th gear in the woods any how so why should I care about more mph.
I guess a better way to put it the lower gear ratio gives you more acceleration and the high ratio gives more top MPH.
I work in the automotive realm and one of the most popular upgrades to any performance vehicle is to gear them down. I have never heard of a stock vehicle being geared higher for any performance reason except land speed records maybe.
 
I think different than most guys on here when it comes to gearing. I ride mostly in the woods on a stock pipe blaster. I run a 20 tires and a 12-42 gear. No I can't run 55 on the high way but in the woods my stock pipe blaster pulls like you wouldn't believe. I never use 6th gear in the woods any how so why should I care about more mph.
I guess a better way to put it the lower gear ratio gives you more acceleration and the high ratio gives more top MPH.
I work in the automotive realm and one of the most popular upgrades to any performance vehicle is to gear them down. I have never heard of a stock vehicle being geared higher for any performance reason except land speed records maybe.

I ran 13/42 for a while and with 18in tires, that was plenty low. Not good for racing, but good for climbing and tearing up trails. Without bothering to look it up, I would hazard a guess that that was in a similar realm as your 12/42 with 20in tires.