1975 serial numbers were a hand-stamped five number, individual frame ID. They begin at 10001 and continue until early 1976 when a revised stamp begins to include place of manufacture indicated with the letter 'C' ( for Chatsworth, California) followed. On BMX Products, Inc. Frames Identifying the serial numbers on the early Mongoose frames is actually quite easy and intuitive. For the most part the early Mongoose frames from 1975 and into early 1976 were done with hand stamped 5 digit numbers starting from 10000. For example, a frame from 1975 will have the numbers like 11994. If your bike has an 8 as the last digit of the three digit group it is a `78, a 9 is a `79, 0 is an `80. I'm sure there was some sort of carryover at the end of the year, so a bike stamped as a `78 could in theory be built up with `79 parts and sold as a `79. Mongoose Bmx Serial Number Decoder There is some inconsistency in Mongoose serial numbers, due to how the bikes were assembled. Welders were supposed to use the bracket tubes, where the serial numbers are stamped, in sequence, but sometimes they grabbed whatever tubes were handy.
Mongoose Bike Serial Numbers
Secondly, it looks like your building a 1978 model like the John George ad. If your frame is a '79 your looking for a totally different build, see my catalog scans in the museum. A '79 model has annodized 7C's, annodized low flange Shimano hubs with cassette rear, matching red or blue fork, Mongoose suede saddle, MKS BM-1 pedals, Mongoose headset, blue alloy bars and Mongoose shinwall snakebellies.
To properly match a 1978 Team Mongoose like the John George ad and the 1978 catalog you need need MKS BM-1 [again], non logo suede saddle, blue alloy bars, DeCoster fork and believe it or not, the 1978 catalog Team Mongoose has a Motomag decal on the down tube.
Mongoose didn't issue any stamped products [not counting pads] until 1979, then came grips, seats, headsets, bottom brackets, seat clamps and tires.
Team Mongooses came with 39t Shimano rings, both years.
We've talked about the fork already, but that fork looks to be a later model, like 1982/3 when they were putting the red or blue over silver powder coat instead of over nickel, your fork doesn't appear to match your frame shade.
Is the Shimano lever straight or pre-bent? Looks straight, need bent.
What are the date codes on the shimano products, hubs, brakes, cranks? I have the date codes if your as picky as me.
I'll finish with this, I love that bike, as I said I'm building a 1978 just like John's in the ad. I lusted over that ad in 1978/9 like nothing else, I finally got mine in '79 but I always like the 78's better, now I have one. I'm only being picky because I'm nuts about both years, yours, like I said is kind of a cross breed between the 78 and 79.