Date this Motobecane?
 

But have her home by 11:00. :)

Here's a pic of that Mirage I picked up last week. I'm hoping one of the resident Francophiles can tell me what year it is. Not shown in the photo are; Nervar cottered crank, Atax stem, Suntour V-GT derailleurs, steel rims with checkered sides. All cable fittings and RD hanger are brazed on.

http://home.comcast.net/~mswantak/ws...7/site1371.jpg

May I throw in a guess...? 1977.

Wow, looks a lot older than my '81 Mirage -- I'd have to guess mid- to late-70s.

I've got a '76 Grand Touring, and it's definitely older than that, based on the steel crank, chrome-crowned fork, and seat tube decal. What year did Motobecane switch to alloy cotterless cranks?

But isn't that the later style headbadge? I think they started using that one around '75 or '76.
I believe the steel crank was used on the lower range models back then, and not really an indicator of build date. It is the "Mirage" model; right? Grand Touring was a bit higher up the scale.

Early 70s **********??

I agree with TheOtherGuy. It looks like '77.

Yeah; later headbadge. My '76 GT has the red, white and blue 'M' on the seat tube though, where the Mirage has the older winged cameos. The Atax stem seems older than the SR on my GT, but that may only reflect my relative ignorance on Moto matters.

Is there anywhere to pull a date from Atax or Nervar components? The Weinmann calipers came up with '1234', and I just don't think they date from the 13th Century (they only had Altenburgers back then, right? ;) ).

Here's a couple clues from the frame; the serial number on the outside of the left rear dropout is: 2496200.

On the inside of both dropouts is stamped a number: 73916. What's it mean?

I Googled up an old thread from here on dating Motos, where Walter says there's a two-digit number stamped at the top of the seat post lug that indicates date of manufacture. The Mirage's says '75'. Oddly enough, my Grand Touring's reads '73'.

(Walks away, hitting himself over the head with a Stronglight crank arm...)

My guess would be 1974-1977. The 1973 models used Huret Allvit. Your description is a good match for 1974 & 1975. I have nothing on the 1976 or 1977 Mirage. The 1978 model used 2040 tubing and cotterless cranks. The SunTour V-GT should have a two letter date code which you can decypher using the info on Vintage-Trek. That should narrow things down.

Aren't the numbers stamped on the lugs the angle?

On head lugs, yeah. Knowing that angle can provide useful information about the steering geometry. I'm not so sure how important it would be to know the angle of the seat tube though.

Well, my Puch Mistral was made in the 80's and the Bocama seat lug is stamped 74.

http://www.classicrendezvous.com/France/bocama_3.htm

I think that the different sizes require different lugs to keep the wheels in the right places; the lugs were stamped with the angles to keep them from getting on the wrong bikes in manufacture...

It looks just like mine. I got mine from Goodwill a few months ago. It came to me with Suntour cranks (non-cottered) and Suntour stem-mounted shifters with Suntour GT (I think) rear derailleur.

I have a 1020 tubing sticker in the same location as yours.

I have another sticker on the seat tube from Palo Alto Cycles and above that is a city of Palo Alto bicycle registration that expires 12/31/1976. The detective in me says my bike was purchased new in 1976.