kansascity 

I know for someone this be a very easy game, but I am interested in learning more about frame identification in general.

Clues:

• Serial Number running parallel to frame is probably '6M019350' although it has been painted to make this much more difficult to decipher
• Bottom bracket also marked with 'CB' in the Center
• Under top tube at lug marking 'G2'
• 'Swooped' at tire on front steel fork
• Vertical Rear dropout
• Downtube stops

Non clues include the entire 105 9 speed setup, the FSA headset, Promax seatpost, Nitto stem.

Senrab62 

Vintage trek is my guess. Early 90s-ish?

francophile 

When I saw that cluster, first thing I thought was Trek also, but I feel like some expected cues aren't there.

Have you run a black crayon along the BB shell to help highlight the "50" or whatever mid-shell, or the number off to the side?

juvela

-----

steerer appears to exhibit internal splines/"rifling"

how many are there?


-----

T-Mar

I don't see any splines/rifling. It looks like there are four blocks that cast into the crown to act as a seat for the steerer tube insertion during fork manufacture..

unworthy1

I wonder can we draw @JohnDThompson
into this as the Trek expert? I agree the socketed stay caps/seat lug looks Trek-ish but that fork does not (to me, anyhow). And OFTEN you'd see the Trek logo cast-in to whatever the investment-cast piece in question (also not here)

JohnDThompson 

It doesn't look Trek-ish to me. The Trek socketed seat lugs had shorter sockets, and the tang was on the side, not the back. The fork doesn't look like anything Trek used while I was there, at least (1980-86).

francophile 

May want to spend some time in this thread for other samples. There are a couple other fastback stays threads I've seen.

https://www.bikeforums.net/classic-v...eat-stays.html

kansascity 

The Mid-shell reads 'GM019350', although that first character could be a 6. I am going to pull the fork tomorrow and look for more markings.

kansascity 

Took the fork out this morning, but it did not provide any more markings.

What would the shape of this fork be called?

T-Mar

OK, revised GM0 prefix for the serial number makes it consistent with Giant mid-1990 manufacture and the frame features match their Allegre model.

kansascity 

Thanks! Now if we just had more catalogs for 1990's Giant Bicycles.

T-Mar

I do have price lists for 1990 and 1991 and a catalogue for 1992. In 1990 the Allegre was 2nd in a line of six road models. It cost $499-$550 US MSRP and was spec'd with SunTour GPX. For 1991 the component group was switched to Shimano RX100. 1992 was also spec'd with RX100 and the frame appears identical to 1990 except for a more elaborate paint finish.

francophile 

Unicrown.

T-Mar

While it looks similar, Unicrown forks use blades that are attached directly to the steering tube, eliminating the traditional crown. They are typically lighter, more rigid and less expensive than a fork with a traditional crown. Generally, they are TIG welded and the weld beads are plainly visible. The subject fork uses an investment cast crown. While I'm not positive, I believe this one is proprietary to Giant.

Personally, I just generically refer to it an an aero(dynamic) crown, as it is sheltered almost entirely behind the brake caliper with little area directly exposed to the airflow. Giant's literature calls it a "flat side, investment cast crown".

francophile 

I never mind being wrong, as long as I learn something new

had to scroll back up to look really closely at that one. I now see the weirdness on the inside and lack of apparent weld, plus the round-out on the inside. Glad to hear it's apparently a one-off, I've definitely never seen anything quite like it from the inside view.