Top to bottom are:
7222 wide GT axle - what B4 wheels generally call for
7459 inline T4 axle - a tad wider than stock, needs to be drilled out to 1/8" to use on anything but a T4
6220 standard RC10/T/GT/B2/T2 axle
7221 standard B3/T3 axle - too short for an RC10 steering block without modification, posted mainly for reference
