if I'm not mistaken, the 801 and 851 derailleurs are slightly different designs,, the 801 basically being a copy of the Nuovo Record, with pivot located almost centrally between the two pulleys. the 851 has a pivot located more in line with the upper pulley, similar to the later Campy Super Record mechanism.. Neither of these has a sprung upper pivot and probably operate just like the models that inspired them. I'm not really sure why they didn't incorporate Simplex's innovation.. perhaps it was patented and defended well ? maybe some national loyalty came into play... ?
if you'd like better performance maybe you'd be interested in the (i guess) off-topic Mavic 840 ? it has a slant parallelogram design and a sprung upper pivot, and is index compatible too.. it also came in a long cage version. there's one on ebay right now, item no. 270207378104.
i've never used any of these, so i can't say how well any work
andrei padlowski glen ridge, NJ
On Jan 28, 2008 9:29 AM, Adam Hammond <anhammond@gmail.com> wrote:
> Dear List,
>
> I have developed a bad habit of starting threads that inadvertently
> begin off-topic, and then head even farther afield. I must say, I'm
> foggy on the exact date of manufacture of these derailleurs. So my
> apologies in advance if I've done it again.
>
> I purchased one of these derailleurs on eBay a few months ago. In the
> interim, I've joined the CR list, read every back issue of BQ, and
> generally become a more informed person. But -- happily -- the more
> one learns about bicycles, the more one wants to know, and so I have
> developed some questions about my derailleur.
>
> First: does it, like the Simplex SLJ, have a spring in the upper
> pivot? I bought this thinking it would go on my yet-to-be-built Velo
> Orange randonneur, so it's not yet in use. But I have bolted it onto
> one of my other bikes, and it doesn't seem have an upper-pivot spring.
> It behaves like my NR derailleur. But it would seem odd for it not to
> incorporate this innovation since these seem to have been manufactured
> at least into the late 1980s, and since, being French, Mavic certainly
> would have been very familiar with the SLJ. (At the very least, Greg
> LeMond would have told them about it, I suspect!) Although, if this
> was made strictly for closely-spaced racing freewheels, perhaps the
> extra chain up-take wouldn't have been important.
>
> Second (and related): the washers that my 801 came with seem different
> from those that come with most others. I've been watching several
> subsequent eBay auctions, and most washers (when included at all) have
> two tabs to support the sides of the derailleur body around the pivot.
> Mine have no such tabs. Does it seem not to have "spring action" in
> the upper pivot because I have the wrong washer?
>
> My derailleur and its washers are photographed here,
>
> http://www.flickr.com/
>
> And the seemingly proper washer is photographed on the listing for
> eBay item 190190848318
>
> I'm also curious in general about this derailleur. It seems to have a
> good reputation, but there isn't very much written about it. How
> similar is it to the SLJ? Or is it derived from the SR derailleur? Or
> does it have an entirely independent existence?!
>
> Thanks,
>
> Adam Hammond
> Toronto, Ontario, Canada