Word of caution for all who want to carve the asphalt during summer. I am not a ski instructor so take this advice with a grain of salt and apply your better judgment to it.
Rollerblades and Carvers have one advantage over skis, they grip and do not skid.
So all the skidding movements you use in your turns are immediately uncovered (GOOD).
I believe that, this good thing is also a BAD thing if you are not careful. I have been using roller skates to simulate ski turns since 94, they have helped me a lot, but also I got some bad habits because of them.
On skates you can extend your legs more aggressively and much earlier in the turn (as early as 2 o?clock using clock analogy). This propels you and is fun. You can get the momentum going and skate with parallel turns on a flat (I was even able do that and accelerate uphill!).
This is a habit forming movement, it stores in you muscle memory and may affect your skiing. If you extend your legs aggressively early in the turn you skates will grip but your skis will skid.
I believe the issue is more with standard rollerblades rather than Harb Carvers (I have not tried Carvers yet ? I am waiting for the shipment
). Harb Carvers have two edges and will take longer time to roll on the edge. However, the overall principle of more grip applies, so the same problem should be accounted for.
Also, there are many books on skating. I have found many of them to be fun to read and excellent source of good ideas on how to skate. However, I found none, which provided good advice on how to train for skiing. Many of them offered advise such as: rotate your upper body (as opposed to counter rotate) when making parallel turns!, many teach movements, which are great on skates but when applied to skis, they produce too much pressure and result in skid. So stick with harbskisystems.com lessons on how to use skates if you want to train for winter.
I have never used Skiers Edge, I only have looked at their promotional tape. I am afraid to incorporate this tool into my summer training. The exercise (as I understand it) is about doing a sort of reversed pendulum. To get the momentum going you end up pushing your feet to the sides. This maybe great exercise for muscles used when skiing, however, I think, it could create bad habits. Pushing left, pushing right, etc, is contrary to the idea that the skier should NOT be turning his/her skis. I believe this could form a bad habit and introduce more skid into skiing. If you an expert and ski 100+ days a year, this maybe no issue. If you are like me and struggle to do perfect you turns skiing 20 days per season, it is a different story. I decided to stay away from this product.