i got 17" tenzo r av7's on my car right now.
i just bought new tires and one of the rims cracked.
i was thinking of just buying one super cheap rim of the same size just to use up the new tires. after that i was planning on switching to a new set of 16" rims.

so
my questions:

1. if i do that, is there anything i should look out for? like is the tire going to wear differently since the weight may not be the same as the tenzo's?
(i don't even know if that matters)

2. can i even buy one rim at a store?

 

I'm sure you could pick up one Motegi 7 wheel at Pepboys (I think it maybe a similar looking wheel) and just use that for the moment until you wear those down and get your 16's.

 

Unless the offset is radically different, you should be fine.

You might want to try and match the width as well, since the total diameter of the tire could be slightly effected.

But really, have you seen how different the size on a spare tire is? Granted, you aren't supposed to use the temp spare on the front or go freeway speeds on them, but the speed has more to do with the tire construction, whereas than the size is why the drive axle shouldn't use it.

I'd say, buy a cheap wheel and don't really worry about it.

 

What color are they? I have a set of AV-7's in my garage...silver