No I'm right...... don't pay attention to Eric he's new
Yes, you could use both... 05112 is 44 teeth - 02112 is 42 teeth.
44t for more top end ( I think)
42t for more acceleration
Right Eric??
we have 02112 if you need it here:
http://www.topspeedtoys.com/RGC10102-pg1-parts.html