Everything I've read says don't install 8" wheels w/o some sort of conversion kit, whether that's a offset axle or what. It can cause the rails to bend or break. I am going to use a an extension made for 8" wheels. (I'm waiting for them as I type this... been waiting a while now.) If you aren't extending your track then use an offset axle. You don't need to use Alum billet wheels, Arctic has stock 8" wheels on their Mtn sleds, I think Doo also has stock 8" wheels available, they are much cheaper than buying billet wheels. I shopped ebay and found 3 - 8" wheels for less $75 for all three and they were brand new. I hope this helps.