While you might believe that a material used for automobile tire construction would have to be durable, polyurethane deteriorates faster than latex (natural) rubber. PU (great abbreviation) quickly spontaneously deteriorates without exposure to UV, moisture or heat. Latex rubber does not. Since converting to using polyurethane, most tire manufacturers have changed their warranties to 5 years, and recommend replacing tires older than that, and “obsolete” tire models every 4-5 years to assure that tires are sold before they can show signs of obvious deterioration.

When a new tire/sole is used on a daily basis, the wear isn’t as noticeable, but if the product is used infrequently, the PU actually breaks down faster. In tires this manifests as cracking along the bottoms of the grooves and spies. In shoes it manifests as rapid tread wear and outsole separation.

To get maximum tread life from a shoe with a PU sole, buy a new model shoe from a major manufacturer and wear it until it starts to show uneven treadwear. When it does, recoat the worn areas with a thin layer of Freesole. A thin coating of newly cured PU will be more durable than the older uncoated area.

Hyperspeed 4 – 2000km and still using, but the red foam is sort of gone till the mid-eva. It is a very soft and mushy shoe, every small road items penetrate through the sole.
I am not really a shuffler, but when the surface is wet, I tend to have slippage forward. So for me the best time for posture practice is on wet roads, or at winter time on snowy and icy roads. I think the “running in place with high knees” exercise can help a lot to understand what should happen during real running. They call it sometimes 100 knee-ups or sg. I am doing a lot for warming up, to imprint it to my mind. Land softly under my body on for/midfoot, when heel touches the ground relax the calves, then use the hip-flexors to lo drive up the knee, quads, glutes and hammies are relaxed.

I agree, video can be extremely helpful in figuring all of this out.

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Pete Larson’s Web Links:
My book: Tread Lightly – http://ow.ly/bdUO0
Blog: https://runblogger.com
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Wow – interesting perspective on the calf issue. I’ve had a few issues with my feet that were supposedly because of tight calves with my transition into more minimal shoes (Posterior tibial tendinitis in my right foot and a bit of tendinitis on the top of my left foot which I know can be caused by too-tight shoes and/or tight calves, so I’m trying to fix both). I also tend to wear out the bottom of my shoes, though it’s in the forefoot and not the heel (good), but it’s pretty concentrated in a few spots, which shows me that my stride is not right.

What type of shin splints do you have? Pain on the front of the shin, or on the inner side above the ankle?

—-
Pete Larson’s Web Links:
My book: Tread Lightly – http://ow.ly/bdUO0
Blog: https://runblogger.com
Twitter: http://twitter.com/oblinkin
Facebook: https://www.facebook.com/Runbl…

I adjusted my form and switched to minimal shoes about 4 years ago and I now see little or no wear on the heel, except maybe a bit on the ones I do walking in. I do see a fair amount of wear in an oval at the center of my forefoot, and a little bit under the big toe. I tend towards the forefoot end of midfoot striking, and think I have a little bit of a twist on lift-off (possibly pronation related – more wear on my right side which pronates more), which may increase wear. I wore through a pair of Vibram KSO’s after ~1000+ miles (small hole right under base of 2nd metatarsal), and recently tossed a pair of Merrell Trail Gloves after 1200 miles. The Trail Gloves were still quite runnable as a road shoe (the trail nubs under forefoot were worn flat), but the stink had reached a critical level.

http://www.dailymile.com/peopl… A picture of my wear pattern on my (fairly) new A4s :( Left foot is where my current foot is bothering me (what I’m guessing is tendinitis on the top of my foot) and the knee that was formerly hurting. This is a new tendinitis (the right foot was posterior tibial from TMTS in 0 drop shoes… this injury appeared last week after a 10-miler)

However it seems as if I am still heel striking a little on one foot. I like your analogy of the way a helicopter lands, meaning that the foot should be landing pretty much flat on the ground.