Could I install this on my Mafia Bike so I could then have three peice cranks if I get a new sprocket?
Please give the store a call on -01424 460943 and we should be able to figure out if this will fit or not - we just need more information on your current set up. Hope that helps.
do the sealed bearings fit over the spindle threads on a gt air
I believe that bike has a loose ball bearing BB which means that this will not fit over that spindle. If you wanted to upgrade to a sealed bearing BB you would need to update your cranks too. Have a look at these for a affordable and sturdy upgradehttp://www.sourcebmx.com/en/Jet-BMX-Consort-Cranks/m-32491.aspx.
If you just want to replace the bearings then you can do that with these: http://www.sourcebmx.com/en/4-jeri-US-Looseball-BB/m-30402.aspx
Hope that helps.