Many climbers using the white 5.10 Anasazis (Blanco's, V2's) have problems with the tightness of the heel strap putting pressure on their achilles tendon. I normally climbed in Anasazi Verde's, and saved my whites for hard slate routes (well ok not that hard but hard for me).
On long trad pitches I always found the Verde's too soft and tiring on my feet and wanted the support of my whites but knew I couldn't stand the heel pain for long enough. Its not that they are too small, in fact the fit apart from the heel is perfect and one of the few shoe that's fits the rest of my foot well, it just seems to me that the heel strap is unnecessarily aggressive.
I know other climbers who have cut through the strap to release the tension a bit, so I thought I'd see if there was a way to do this well. It turns out the heel strap is made of two layers of the rand rubber. So it was a fairly simple job to cut through one layer of the strap and remove it leaving the single layer below to do its job.
(with heel strap layer removed)
The difference was like night and day, the single layer stretched so much more that it took all the pain off my achilles whilst still pulling my foot snuggly into the toe-box. The added support over my Verde's has been revolutionary to me (maybe I just have weak feet?), and every day climbing since has been a pleasure. They've gone from barely getting me up a single short slate pitch to feeling fine on a long multi-pitch trad routes. In short they are transformed.
It a fairly easy job to do yourself if you that way inclined. Just cut very carefully into the strap at either end a small amount at time until you see you are through one layer only. Make a cut around the back and then heat it up with a hot air gun which reactivates the glue until you can peel the layer off. (Obviously be careful not to cut right through your shoes, and please don't blame me if you do.)
If your not into doing that kind of thing yourself then I'll happily do it for £15. I know I'm never going to get rich doing this, but I hope to those of you with this problem I can make as big an impact on your climbing experience as I have on my own.
Of course if your shoe are under warranty then 5.10 probably wouldn't approve, but personally next time I need new shoes I'll be getting whites and taking the heel strap off right out of the box.
Any queries, including advice on doing your own, do get in touch.