gator11

Hi Im kinda new to bikes and im wondering if there is some kind of general standard for a crankset size like where the tube through which the bearings go. The point of the question is could I take this bike: https://www.diamondback.com/items.asp...d=8&itemid=226 and put a crankset for a 20in bmx bike on it to beef it up and lower the tooth count. This may seem strange i know, and there are probably better ideas but i would just like to know if it could be done.

Wordbiker

The bike you linked to has what is called an "American" bottom bracket (the one-piece "ashtabula" cranks give it away).

Bottom bracket is a slightly confusing term though as it refers to the "tube through which the bearings go" that is part of the frame as well as the spindle, cups and bearings as a set minus the crankarms.

The good news is that many 20" BMX bikes use this same standard, and 3-piece cranksets are abundant. You should be able to find many choices for both quality and price.

EDIT: You may want to check the crank that's already on the Octane (if it is still the stock crank). Most one-piece cranks do allow for the chainrings to be removed once the crank is pulled from the bike. You may only need to swap the chainring.