I have an old pair of asics nimbus 12s that are fine and have never given me any trouble. But they've got 700 miles on them and are getting a bit stale.
So I bought a new pair of the same shoes that I cannot wear more than 4 miles without them rubbing my heels raw. Same shoe. Same size. Happens with any socks - thin or thick.
Any ideas on how to break the heels in so I can fully switch over?
no ideas ?
Assuming looser shoes = blisters, perhaps the old pair had shrunk a bit after all the sweat soaking/drying cycles it went through. Perhaps the two pairs are from different factories, and there's just some variation in the sizes.
Here's an idea! Look at the heel of your old shoe. Look at the heel of your new shoe. Observe how they are different. Ask yourself what you can do to make one more like the other.
You told us nothing specific about the heels of the shoes that could be helpful and have simply invited us to imagine every possible scenario. Makes it hard for us to work up the energy to give a serious reply to all the possible abilities.
Here's my attempt to actually be helpful. Odds are you've worn down the cushion in the heel counter of your old shoes and are accustomed to it. You need to minimize the friction by a) reducing the cushion in the heel counter, b) getting distance between your heel and the heel counter, or c) wearing socks that chafe less.
There are many ways to accomplish some of those things, but the details of your specific case are relevant to which way to go.
Put a good, thick plastic bag into the shoe. Pour boiling hot water in. Deform the plastic thats shapes the heel.
Try it with the old pair first, though.
Wear nylon socks, if you wear socks, as they have the least friction.
Lining the inside of the heels with gorilla tape helps to eliminate the friction. It also covers up wear, ridges and holes.
well that was unnecessary.
the gorilla tape idea is a good suggestion.