JC was kind enough to send me an Ultra Leicht kit as thanks for the forum (oh the perks ;) ) Now that I’ve had a couple months to play with it I thought I’d try to present an unbiased opinion here…
Overall pros:
This hub makes the diabolo feel smoother on the string than any other diabolo axle/hub combination I have tried
The best finger grinding diabolo I’ve ever tried (and none of that hot metal problem you can get with wide axled finesses)
All the other advantages that come with wider hubs or axles: mainly less string rubbing on the cups which opens up many possibilities
I have had no problems tightening the axle or getting everything centered despite the use of plastic washers. This is in contrast to my Henrys ultra light regular width kits that I still haven’t got to stay tight or be centered.
This kit reduces weight around the axle (as any of the lightening kits do) thereby improving rotational inertial properties and therefore stability.
Con:
You loose some stability just as you do with any wide axled diabolo
Some people may just not like the feeling of a wider diabolo
JC has also sent me some pictures of 2 new hubs he has designed: one that is standard width but with the same curved design and another one for the Jazz. Also, white hub fanatics take note – the Ultra Leicht kit is now available in white. See JC’s avatar for an example. I am very keen to try out the normal width rounded design. Here's a little preview pic before JC gets his website updated:
(http://diabolo.ca/images/forum/Circus-Diabolo-rot-mit-Stan.jpg)
Anyways, I think JC is on to something good here. It's also nice to see someone who cares about diaboloing himself pushing the (otherwise often stagnant) diabolo equipment development process and do so with quality well thought out products.
Sean