I installed a 2 up in the back sprocket, left the front stock and my stock chain.. but I can't seem to be able to pull the wheel far enough to be able to install the axel. Is this even supposed to fit ? is there a easier way ? Do I need to go one down in the front in order for it to reach? Or do I need a different chain ? Or am I not pulling hard enough on the tire ?
Thanks.

 

Because the new rear sprocket is a larger diameter, it is going to utilize more chain, thus decreasing the available chain length. You'll probably need a new (longer) chain. If you need to pull that hard on the wheel to get the axle in, the slack is going to be WAY too tight anyways. Remember, you'll need at least an inch of slack in the middle.

EDIT: ...and I'm assuming you screwed the adjusters all the way in, lol.

 

either a smaller front sprocket or longer chain are your options, or always go back to a stock sprocket

personally i always replace both sprockets and the chain at the same time to extend the chains life, but it's your bike