Sprocket/chain

[Campe23]

Ok, last couple questions. If I get an aluminum rear sprocket. How long should that last me, and when that gets worn out, will I have to replace the chain and front sprocket again?  It looks
LIke I will go with the 15/43. I will still gain acceleration with those gears from stock huh? 

[Rjunky]

you replace all at once... so if you replace the chain you SHOULD replace the sprockets with it..

[f3racer]

15/43 will gain acceleration.  you should, not required, but should replace them all at once.  the problem is, if you replace one worn out part and not all three, then the other worn out parts will cause the new part to wear out prematurely. it wont really hurt or damage anything, just is good practice to change them all at once.

[Jason748]

Honestly,  If it's a streetbike and you plan on changing it only once (until the next time everything is worn out) - I'd recommened steel sprockets, not aluminum.  Steel sprockets wear MUCH slower than aluminum.  There are a couple companies (Drive Systems & Sprocket Specialists) making lightweight steel rear sprockets that are almost or as light as aluminum...  a lot of places even have a "Kit" that has the lightweight steel rear (RK Steel Quick Accerlation kit).
Also go with a 520 chain.

If you decide to go with Aluminum, make sure it's HARD anodized... not just anodized...