Crankset loose/wiggling ?
 

I recently took off my old crankset on my road bike conversion.

I used the crank extractor to remove it (This is my first time ever messing around with cranks)

Then I slipped in the new track cranks.

I used a rubber mallet to smack it in as far as it went, then tightened it down as much as I could.

It rides fine, but whenever I track stand of balance myself I see the right side of the crank wiggle back and forth...

Should I be worried? >_>

Help.

I have no idea what possessed you to use a mallet to install a crank. That's a good way to have the end of the spindle shave the arm and make a crank wobble.

But if it spins true you've dodged that bullet and it's probably OK. It's normal for chainrings to appear to flex when the cranks are heavily loaded. The key is the difference between flex and wobble, so it's up to you to determine which it is.

Make sure and check the nut that holds the crank arm on. I had an older fixed gear bike that had the same sort of issues; one part of the problem was that the bike needed a new bottom bracket (unsealed bb cartridges can cause slippage), but the main problem was that the nut threads for the crank connection was stripped. The nut would continually try and work itself off, and if you weren't careful, the entire crank would fall off under stress. You may have stripped out the threads by mashing on the crank with the mallet, so you might want to pull the cranks again for an inspection..

I didn't hit it while the nuts(Do you mean bolts?) were on.
But I will indeed pull them off right now and check.

This is my first time installing a crank.
I saw that there was a big gap between the frame and crank so I thought maybe I should hit it in more?
Sorry. I try my best to save money .__.

That sounds like the spindle of your current bottom bracket is too long. However, if the chain runs straight with your setup you should be OK. Hitting it more won't help.

IMO, you should make sure the crank bolts are tightened properly before you ride the bike much more. They require about 30 foot-pounds of torque- which is quite a lot if you don't have a torque wrench. If you don't have a torque wrench, go to a shop that has one and make sure the bolts are tightened to spec. More cranks are ruined by inadequate torque than by any other cause.

If he had used a hard headed hammer, he might have done some damage. But a rubber hammer isn't going to do anything. I have often used a soft headed hammer to seat cranksets. I's not an issue.

On the other hand, if the crankset itself is wobbling, pandita didn't dodge anything. Wobbling cranksets quickly become damaged cranksets...especially if they are square taper.

I suspect, pandita, that you have the wrong taper on the bottom bracket spindle. That's why it's wiggling. The tapers must match. As I said above, you can very quickly damage a crank that isn't installed properly. Quit riding it and find out what the taper for the crank is and what bottom bracket it needs. Sorry to say but it may be too late already.

+1 Bottom bracket taper may not match crankset. If so, all the beating on it with a mallet of your choice won't make it fit. Time to head to a bike shop.