Need help IDing this '83 MTN bike

[Arthur Roy Brown]

the Sakae SR parts

With the Schwinn Frameset, only the shop of origin or original owner would know what the spec was on any of those builds. It could be SR, Shimano, Suntour, Ukai, Araya, or anything the shop could source or have in stock at the time of the original build (including NOS parts from previous years of manufacture).

 

[LIFE OF SCHWINN]

If it's a Schwinn? I'm tending to think so, but the loop is throwing me off...

 

[J-wagon]

My interest is to confirm what happened and the history of these frames,

Seems that frames were produced according to serial number code, like 1981 and made available for catalog purchase later, like 1983 or do. Maybe backburner delay due to number of unforeseen issues, factory, contracting, branding, etc

 

[GTs58]

Seems that frames were produced according to serial number code, like 1981 and made available for catalog purchase later, like 1983 or do. Maybe backburner delay due to number of unforeseen issues, factory, contracting, branding, etc

Schwinn frames were not built on the serial stamping dates. Good example of this is the MR serial stamped head tubes that Schwinn stamped out in December 1980 when the workers were on strike. No bikes were produced for 13 weeks, but parts were being made during that time. The December 1980 serial stamped head tubes were used throughout the 1981 production and some in 1982. They were also found on just frames that were sold in 1981 and on some early Sidewinders, more specifically, the ones that were painted White.

The serial number BS367823 on @Les frame indicates the bike was made for Schwinn due to the S being in the serial. Early Japan made frames for Schwinn had the letter S in the serial numbers and the placement of the S was at the beginning of the serial number on the early lightweights. It's been written that the Sierra and High Sierra were produced by Giant. The placement of the S may or may not indicate who made the frame, Panasonic, Bridgestone, Giant, it's only an indication that the bike was built for Schwinn and it has nothing to do with the dating of the frame. Les's frame has a serial number that was machine stamped on the BB shell before that shell was used to build a frame, just as Schwinn did starting back in 1937. The serial BS367823 was stamped in February 1983. When the frame was made or when the bike was built in anyone's guess.

 

[LIFE OF SCHWINN]

There was never a head badge on this bike. The only way I dated it was the '83 stamped in the Diacompe levers, I believed to be original, along with all the SR parts. I sold the Araya7x on Suzue high flange hub wheelset. I am well informed about how Schwinn dated bikes. However, I have learned new things from responses here, well appreciated...
What's throwing me, is the loop? not only on this ATB, but the road frame I just picked up. If someone knows what company used that loop, mystery would be solved...

 

[J-wagon]

The serial BS367823 was stamped in February 1983

Good point decoding. The BS367823 has 6 digits after BS, and not 5 digits as in the 1981 format database:

Schwinn Serial Number Reference | All Things Schwinn

1948-1951 1952-1969 1970-1982

thecabe.com

@GTs58 decode as 1983 is consistent with 1983 catalog listing of mountain bike frameset part 29-265 / 29-266

@Les, this new info suggests your frame is not 1981 and more likely the catalog frameset

 

[GTs58]

Good point decoding. The BS367823 has 6 digits after BS, and not 5 digits as in the 1981 format database:

Schwinn Serial Number Reference | All Things Schwinn

1948-1951 1952-1969 1970-1982

thecabe.com

@GTs58 decode as 1983 is consistent with 1983 catalog listing of mountain bike frameset part 29-265 / 29-266

@Les, this new info suggests your frame is not 1981 and more likely the catalog frameset

Les's frame was definitely not made in 1981. That serial was Schwinn's format on these and it doesn't follow the regular format that Schwinn used on the Chicago built bikes or the Schmurray built bikes simply because the letter S is added. Giant's built bikes also had their format for the stampings on Schwinns. There was just a series of numbers for the serial and on the right drop out there was a 4 digit date stamping after the letter G. That wasn't even close to Schwinn's normal serial format! Les is making this way too complicated for some reason. If he wishes to not to believe what I have told him in PM's that's fine with me.
Another known fact, if the head badge has no date stamping the frame was sold as just a frame and was never built up by Schwinn, Giant Panasonic etc....

 

[J-wagon]

Yup, I think 1983 makes sense. Serial BS367823 indicating 1983 as you explained. So S for schwinn, and if remove S, BS367823 perhaps Bridgestone format, so bridgestone built for schwinn 1983. Also fork may not be og to catalog frameset, but period correct 3B indicates 1983. And frame listed in 1983 catalog. Serial and catalog documentation all point to 1983 frame.

Giant's built bikes also had their format for the stampings on Schwinns. There was just a series of numbers for the serial and on the right drop out there was a 4 digit date stamping after the letter G. That wasn't even close to Schwinn's normal serial format!

Yup, below pic of my 1983 schwinn high Sierra, giant built G1083 date code and other numbers on BB.

 

[GTs58]

Yup, I think 1983 makes sense. Serial BS367823 indicating 1983 as you explained. So S for schwinn, and if remove S, BS367823 perhaps Bridgestone format, so bridgestone built for schwinn 1983. Also fork may not be og to catalog frameset, but period correct 3B indicates 1983. And frame listed in 1983 catalog. Serial and catalog documentation all point to 1983 frame.
View attachment 1646496



Yup, below pic of my 1983 schwinn high Sierra, giant built G1083 date code and other numbers on BB.

View attachment 1646552

I like what is written at the bottom left of that catalog page. I've heard more than once that Schwinn imported frames and then built them up in Greenville. I never really believed that, but now it's believable they did at least import just frames. Never had the pleasure of seeing the serial on a three piece crank model from Giant. Thanks!

 

[LIFE OF SCHWINN]

The road bike frame has mylar sticker oval sticker badge and mylar downtube sticker. I've only ever seen these on CItoh. I can't say for sure, because it's been spray bombed, just as the ATB was? I know Bridgestone made bikes for CItoh, so now I have to figure whether Bridgestone had these crazy loop guides before the stops? As stated, I owned one of those grey Japanese framesets from '83-'85, but it had the three top tube guides. Still a mystery...