I have a 2010 Giant Boulder Jr. I was putting new pedals on it, and the left arm stripped when trying to take off the left pedal (pedal is stuck in the hole, just spins and won't come out), so, I need a new arm. This is the first repair its ever needed. I don't know what type of tool/crank puller I need to take off the arm. Please help.

I found specs for the 2012 model, I can't find specs for the 2010. They're probably similar to mine, or the same. I can't post a URL; Google 'Giant bike Boulder Jr' and Giant's site should be the first result. Scroll, and you'll see the specs.

Crankset Alloy 3-Piece, 38T
Bottom Bracket Semi-Cartridge

I popped off the plastic dust cover and took off the bolt with a 15mm socket. There's no washers or anything. Just a silver square thingy threaded through the spindle. That's the only thing keeping the arm on. Here's a pic.

http s :// imgur . com /nM2JPKV

If you need more specifics/info, let me know. Thanks in advance for any help.

It's a square taper assembly. A "universal" type crank puller will work well, especially with a socket.

Since it's a left crank, all you need to do to replace it is match the length and square broach orientation.

Okay, thank you. I know nothing about this and wanted to make sure before I started buying tools.