“Runners are not squares.”
The Turntec Invincible was one of the only running shoes I know of that used polyurethane cushioning instead of EVA. As the ad states, polyurethane is more durable, but it doesn’t mention the fact that it is generally firmer as well.
Jerry Turner, the owner of Turntec, had some pretty good ideas for shoes, but Turntec is no more. Leave a comment!
I believe the Nike Vortex, and a couple other similar shoes from that era (1986) had polyurethane mid soles. I ran my first and only marathon in a pair. They were durable but very unforgiving when it came to cushioning. Not particularly light, either.
Am enjoying your posts about the old running shoe ads. I remembered a lot of these ads as soon as I saw them. There were sure a lot of false starts with the designs, but the progress was there and fairly rapid. The availability of good fitting shoes that didn’t jar the average person to death was one of the main drivers of the running boom.
That’s cool to hear! I’m glad you’re enjoying the old ads as well!