[Moderators: posting this here rather than the "for sale" thread because I'm not actually selling anything yet--just announcing that I hope to be selling something soon. Apologies if it this is a shocking violation of protocol--move it to where it should go if so.]

After years or frustration and maybe a half-dozen false starts, I’ve finally worked out an arrangement with a local CNC machine shop to go ahead with a limited run of 42-tooth 122/74 BCD triplizers. As most of those reading this will already know, this will mount as the inner ring on a Stronglight 93 crankset, or any other crank that uses the old Stronglight 122 BCD standard. It will have five additional holes on the smaller bolt circle, so you can use any 74-BCD granny ring—anything from 24 to 32 teeth--allowing the crank to function as a triple. You will need a longer spindle (or cartridge bottom bracket) and a derailleur with enough capacity to handle the total number of teeth.

Some other specs:

--Rings will be machined from high-strength 7075 aluminum.
--Bolt holes will be counterbored to accept standard chainring bolts on the outer bolt circle, and shorter single-ring chainring bolts (the kind used on singlespeed cranks) and 3 mm spacers on the 74-mm circle.
--Except for the triplizer “tabs” that mount the granny ring, the rings will be a close visual match for the standard Model 93 pattern.
--The 3 mm aluminum stock on the triplizers will be slightly thinner than the original Stronglight rings, which are 3.5 mm. That will make no difference in terms of mounting, and should be undetectable once the crankset is mounted (or even before it's mounted, for that matter). Although they’ll be slightly thinner and lighter, the triplizers should be more durable than the originals, thanks to the tougher alloy.
--The initial run is going to be for 42-tooth rings. They’re suited for an old-school 52-42-30 triple--convenient, since lightly-used 52-tooth rings are easy to come by. Alternatively, they can be half stepped with a 46 tooth big ring—a nice touring setup if you can get by with a high gear in the high 80’s. (My Gran Sport is set up that way and I like it, although I'm admittedly old and weak.) If this first batch finds an audience I hope to also have some 38s and 40s made a little later

Here’s the timeline: the shop is going to make me a prototype ring at the end of next week. I’ll ride it hard over the weekend and make sure that it works as expected. Assuming it does I will place an order for more of them on the following Monday—I’m hoping for an initial run of at least a couple of dozen. Price will depend on how many I order and has yet to be finalized , but my best guess is that I’ll have to charge $80-90 apiece for them. I expect to be able to mail them out to the initial purchasers the first or second week in June.

There have been so many failed attempts to get these things made that my original intention was to not bring it up again until I had the finished, tested ring in my hand and could post photos at the same time. Seeing is believing, right? But as the shop guy pointed out to me yesterday, if I have an initial run made while the CNC machine is still set up from running the prototype (assuming the prototype performs as expected), that saves some time, effort, and money.

So who wants one (or more) of these excellent things? I’m not asking for any money at this stage--just a show of hands. Don’t raise your hand if you think you might be slightly interested; at this point I want to find out how many people really are interested (again, subject to seeing photos of the finished and tested product).
If no one else is interested, I'll mount the $400 prototype on my own bike and enjoy having the only triplized Model 93 on the planet. I always knew that was one possible outcome, so I can't complain if that happens. But I can't afford to sink a couple of grand into the production run unless I'm pretty sure they'll find buyers.
If you’re interested, send me an email at jonwvara [at] yahoo.com. I’ll keep a list and get in touch when the rings are actually done, at which time I’ll be able to post some photos and a report on my test rides, and be able to provide a firm price.
JV

Sounds like a great project. Photos?

I'll post photos as soon as I have the prototype in hand, a week from now.