Originally Posted by
Dave Cutter
I always replace BOTH... then dispose of the more-worn rear tire. And set the front tire(s) aside. That way if I do have a catastrophe event that destroys a tire... I have a replacement readily available (I also keep tubes in my parts cabinet). And because I usually buy a particular tire.... I sometimes have a near new looking set I re-use on a project bike.
You're certainly free to do whatever you want and I won't complain. For me, it'd just be a waste of money to replace the front at the same time. Rather than keeping old tires kicking around looking for some action, I just stock up on new ones when they're on sale. No one needs to know this, but I also don't have a set replacement rule for cassettes, like every second or third chain, like many advertise here. If the new chain doesn't skip, the cassette stays on, for many chains.