re-using the rear disc brake caliper?

[JerboaJohn]

I was curious if I can buy a disc setup front/rear and just re-use the rear caliper and rotor on another bike for the front? I'm looking at an Avid BB5 or BB7 160mm set. it's a lower end set < $60. I can only mount the fronts, on the 2 bikes I have. probly won't do rear disc for a while bc previous sprocket spacing hassles soured me on that for now.
I just thought it would be nifty if I can get 1 set and it's good for both my bikes

 

[Spare_Parts]

The calipers are the same. Should have the same brackets too.

 

[LewieBike]

As long as the disc isn't deeply cored or visibly worn thinner, it should be fine. I'd take some 800 grit wet-dry paper and take some the glaze off the wear track on both sides.

 

[FurryOnTheInside]

At worst you'll have to get a 20mm larger diameter rotor or a smaller PM/IS adapter to position the caliper at the same radius from the axle. The BB7 needs a PM/IS adapter to attach each Post Mount caliper to the International Standard mount on the frame/fork, so the rear one supplied with a 160/160mm f+r brake kit is bound to be larger, a "plus 20" PM/IS, I think. I don't have a set myself.


(+20mm is what they call it when it's actually only ten because of the way rotors are referred to by the diameter "160mm rotor"
Ordinarily, or at least on mountain bikes, the rear IS mount on the frame is 10mm closer to the axle centre than the front IS mount on the fork.)

The calipers are identical. If your rear PM/IS adapter labelled as R/160 then it will be great for a 180mm front rotor. I used a R/203 PM/IS plus a couple of aluminium washers on the front for this exact reason, to fit a 225mm rotor.

Just to prove it and definitely not showing off..

 

[JerboaJohn]

and the saying goes, bigger is better, right? Thank you Furry for some extra info and the pics!

 

[FurryOnTheInside]

and the saying goes, bigger is better, right? Thank you Furry for some extra info and the pics!

and the saying goes, bigger is better, right? Thank you Furry for some extra info and the pics!

Well braking power is always limited by the traction of the tyre.
It looks cool! 
and I'm sure it does cool faster.

I would rather buy a 180mm rotor and use the R/160 adapter (if that's what you receive in the kit). I wouldn't buy a F/160 adapter and use the 160mm rotor. Just personal preference but either is absolutely fine!