Granted my knowledge of skiing then was limited to what I had learned from the movie Aspen Extreme. I had REI mount my 500's on a pair of Kneissl Magic Cruise (170), I bought from Play it Again Sports for 30 bucks. This was back when I thought mounting bindings was a black art, left only to ski shop sorcerers. Next I purchased a set of skinny skins with tips and tails from an old cross country racer; one inch wide. Finishing off my "kit" were my trekking poles and La Sportiva K3 Mountaineering Boots. I then headed out to the mountains in my 2wd truck to cut my teeth on this skiing business, pulling over next to any group of parked cars, and hitting any snow mobile track I could find. Boy was I clueless.
I learned alot from those early days of skiing. Though EVERYTHING in my original set up has been replaced, those Silvretta 500's were the only thing that I had gotten right. The 500 is a basic rail or platform type AT binding. The boot clips into a platform which is hinged at the toe for touring. The rear of the platform in locked down with a latching heel piece for downhill alpine skiing. My 500's have seen over 200 days of use and performed flawlessly. Back country, resorts, cross country, these bindings did them all. I have even taken them into the park to stomp on a box or two. I used these binding while participating in Diamond Peaks Vertical Challenge (Chinese downhill) where I place fifth, skiing over 50,000 vertical feet in 6 hours.
Several features make the 500's unique. The pivot is set further back to optimize the pivot location, requiring less lifting of the boot with every stride. The Carbon fiber rails create a relatively lightweight binding. But the feature that makes the the 500 a much sought after binding even today is the fact that it will accept a mountaineering boot. In fact it will take any boot that can accept automatic crampons (clip on); AT boots, Alpine Boots, leather mountaineering boots, and even telemark boots. I soon learned that though possible it is no good to ski down hill in leather mountaineering boots. The 500 also features a rear DIN release, three level heel elevators that you can actuate with your ski pole. One can expand on to the feature list by adding ski brakes and ski crampons. The ski crampons are well designed and are able to be attached with the ski is still attached to the boot. This is especially important if you find yourself in a step icy spot and need to install your crampons immediately. Published material show the crampons to be constructed from Titanal, which is not titanium. It is in fact a age hardened aluminum with no amount of titanium in it at all.
There are however some faults with this do-it-all binding system. The primary issue I had was that it was not step in. One has to toe in, then reach down and flip the heel lever into place. This heel lever was designed to be able to adjust to all types and heights of heel notched, and not for convenience. Not a big deal, but coupled with the fact that I did not have ski brakes and required leashes, made these ski difficult to work in as a snow maker. The constant in and out of your skis at every snow making gun was tiresome. Lateral binding flex was another thing the 500's suffered from. Since the binding is only attached to the ski at the toe and by the heel, the long rails between the attachment points were able to flex. This is common of all platform type AT bindings, the 500's might have been slightly more susceptible due to the lightweight rail material. However this was only an issue when viewed on a bench top, they reportedly skied like a normal pair of bindings by much better skiers than I, who borrowed them. Don't blame the gear when it is the skier's lack of skill is really at fault. Unlike a modern alpine downhill binding, the 500's do not have a front release. I have never found this to be an issue in any of the falls I have taken on them; even slow twisting forward falls. However this could be a concern for those with injury prone knees.
To address some of these mentioned shortfalls, Silvretta made two variations to the 500; the 505 and 555. The 505 had a step in heel lever. This however made the binding less versatile as it could not longer accept ANY boot heel. Most boot heels however were still accommodated by this binding. The 555 was the most downhill oriented of the three variation. Built with the 505 step in heel lever and a plastic shrouded toe piece. The toe's wire bail was still there, but the plastic shroud keep the bail from flipping and made for an idiot proof step in AT binding. Because the 500's true calling is a mountaineering boot compatible binding, the 505 and the 555 were short lived and are not longer in production, and the 500 still live on.
Because of the fact that you can ski bindings in mountaineering boots, it make them very desired even today. Climbers looking for approach skis can now do so in their climbing boot, without having to lug around a second pair of boots. Though the 500 is still in production today some slight changes have been made to the latching heel pieces. This is denoted as the 500 LSV. The LSV used the same latching heel piece found on the Silvretta's Pure line of AT binding. Though this is a claimed beefier heel piece, I found the older heel piece easier to manipulate with a ski pole.
Though adjustable, platform type AT bindings are offered in several sizes to match boot sizes. Typical adjustment on span a range of couple of boot sizes. Silvrettas are offered in three sizes: SML. However I have seen kids size as well. This makes looking for used bindings more difficult. However there is a ray of hope. The Carbon rails of all Silvretta bindings can be easily cut shorter to accommodate a smaller boot size. Drive out the roll pins, cut rails down, drill new roll pin holes and voila, bindings that are shorter. Sorry no way to make the rails grow. Though this write up is for the Silvretta Pure, the 500's are very similar. http://www.wildsnow.com/969/how-to-shorten-the-silvretta-pure/
A tip for users. When touring with these bindings always use the heel elevators. If the terrain is level, use the lower of the two elevator settings. The two carbon rails are held together in the rear of the binding by a steel "U" shaped connector. The seat of the heel piece is aluminum. After a million steps, the steel "U" wears into the aluminum heel piece. This increases the amount of play when the binding is in ski mode. If your binding already has this area worn, and little bit of tape can be placed at the contact zone to take up the sloop. I used a 3m type clear film with much success. There is not adverse effect if you wear down the seat of your evelvators, they will still function fine.
If you are DIY ski mounter, Sir Lou Dawson at Wildsnow.com has provided a mounting template. The 500's did come with a paper template.
As a parting shot I included this photo of a joint collection of Silvretta bindings between my friend and I. From right to left. 404, 500, 555, 3rd gen Pure Performance, 4th gen (current) Pure Performance.
As a North American Skier this might be the first time you have heard of Silvretta bindings, or heard of them mentioned in a positive light. Light, well engineered, reasonably price, durable, what is there not to like.
A second article has been written in case you want to know the nitty grittys of the binding, such as adjustment and the every so mysterious Lateral DIN release reset.
UPDATE-If you are looking to buy some 500's here is are some deals .