Sakae Ovaltech, Shimano BioPace : An unfair (and most enjoyable) advantage

I bought both in the '80s. Ovaltech 52 42 32, and Biopace probably 48 38 28. The latter is rather used up, and no longer used. The former being almost as new, I put it on a new touring bike I built recently. So I'm not talking from hearsay, unlike most of what I've read in forums.

Both my chainwheels are not oval, but sort of rounded losange. And, contrary to the first ovoids, they are both "lower" in the "pushing" phases, and "higher" in the "transit" phases. This enables you to pull a higher gear than you would have thought, and makes you go faster through the passive, transit phase. That makes for a slightly different feel, and for more efficiency.

You don't notice much difference when pedalling on your own. But now that I pedal much more with friends, I can compare with them and their classic round chainwheels, and with myself among them, on an ovoid or a round chainwheel.

The Sakae being on my touring bike, I can tell you that, always among the same cycling friends:

- over 2 5 day trips to mountainous areas in Spain and in Greece, and despite this touring bike being 15 kgs naked, plus 4 kgs tools for the group, and more clothes than anyone else, I was comfortably in front, even though I'm the oldest by up to 30 years (57)

- during a similar trip, but unladen, when I had taken my 9 kg carbon racer with classic 105 among similar racers, I was never in front

- I have now taken my 15 kg tourer + 4 kg tools on 50-80 Km Sunday tours among my friends on their 8-9 kg racers, and I am comfortably in front...

- when I go in front on the tourer, I find it difficult to keep a good pace for those I'm sheltering behind, I don't feel effort like them, and invariably go too fast.

- despite the 6kg weight penalty between their racers and my tourer, it is uphill I feel most favoured.

Now, does anyone know where these beauties could be remanufactured or obtained ? I'd like to buy me a new one for a 29 MTB, and a few spares.