Yes, I use the Killer Headwind all the time and at 1/2 open when doing some short intervals. So your 42" belt broke? What about your 72" one? After reading your post yesterday, I took my fan belt off of the rollers and inspected it. Unlike my main belt, it has no cracks in it so it should last for several more years.
I measured the main belt at 75" and the fan belt at 44", probably due to stretch. I cut my replacement belt at 74" and it seems to work fine. If it stretches over time, I'll just cut it shorter. If I were going to make a new fan belt, I'd probably start at 43-43.5".
The squeaking you experienced might go away as the belt wears, perhaps the way shoes squeak when they're new. I'm always listening to my MP3 player so I don't hear much when I'm riding.
I've learned a bit about welding urethane belts in recent days. I think the most important thing is to apply enough heat to the belt. The material will melt as soon as it touches the iron but I keep applying heat for several seconds. You'll see the stuff start to boil. The next most important thing is to quickly put the ends together and hold it for at least 30 seconds (longer, if possible) and then let it sit for a minimum of 30 mins. I don't try to align the ends in the moments after putting them together. I think that weakens the joint. If it's not aligned good enough the first time the ends touch, I pull it apart, reheat it, and try again. After it's cool, I trim away the flashing with nail clippers or scissors and then use a Dremel to grind it smoother. I also clean the soldering iron tip before doing a weld.
Welding these belts can be difficult. Apparently, Ekco has some difficulty with it.
