When i was putting my motor together i put a rear rotor (from another 12a that i had laying around)where the front rotor is supposed to go. So i have two rear rotors in my motor. Got about 40 miles on it and some idling time with no problems.

I was looking at the mazdatrix website and noticed they have different part no. for front and rear rotors. So my question is, are there are any differences? Should i be worried?

The 12a's were of the same year from the looks of it. Oh and i'm also using an e-shaft from it too.

 

Rotors are balanced to the front counterwieght so there may be a slight difference but you'll probably be ok.
I wouldn't recommend any sustained high rpm use though.

 

as long as they are the same letter
they should be fine
if not they will give higher bearing loads and the e-shaft bearing will wear out alot faster

 

Yeah i did check the letters and the letter that i put was the same i had on my old front rotor.

 

What about the tub shape on the rotar faces? I think one would end up being backwards. Not sure how that would affect performance. I might have to do the same thing if i wanna rebuild this 12a.

 

Now is this the same for 13b's?

 

This man is a god at search ^^^

 

no, except for the Rx8 engines

 

Rotor-face tub shape is non-symmetrical in some years of the 12A.