Serial Numbers. Many manufacturers use a date-code as part of the serial number. For example, a Brompton uses YYMMXXX as their serial code, so a Brompton with a serial number of 1306 123456 was manufactured in 2013.06 or June 2013 Surly is another manufacturer who uses date codes, this time in their stamped frame numbers.

• Dyno Bicycle Parts

Hi guys,
I happened to see this bike on eBay a bit ago and the seller had it advertised as an '89 Dyno Compe Survivor' based on the serial number on the dropout he was able to read. Upon looking at his pictures, I could instantly tell that it appeared to actually be a '90' model instead because of the decal set and the straight forks Dyno went to beginning in 1990.
When I looked at the serial number in the picture, is where I started to get really confused. It shows 'DH8912XXX'. Is it then really a 1989 model as he states? Or a 1991 because of the '91'? I know Dyno didn't switch to the cutout/flare-back drop out (and again to the straight forks) until the 90s which would make this a 1990 at the earliest. I know there are those who will say you can see this type of drop out in the '89 Catalog, but as far as hitting the showrooms, I don't think these appeared in their Production bikes until the 90s. Dyno switched decaling in 1991 as well, with 'Dyno' and 'Compe' literally switching places on the bars.
Then I went to my storage shed and pulled out two old Dyno frames I've had for a while, and the same debate continues on these as well. I have an original 1987 Dyno Detour and a 1988 Dyno Compe. These are both factory original and have not ever been repainted or redecaled.
To prove these are structurally different frames, I illustrate in this next picture where I've laid the smaller 1987 frame over top of the 1988 frame. You can see that the blue frame is about an inch higher in the back tubing as this was changed from '87 to '88.
You can also see in this picture that the support plates around the seat tube on the 1987 Detour are completely open (basically two separate 'Dyno' stamped plates, one turned upside-down and welded opposite, hence the logo on the bottom side too). On the 1988 Compe it's one solid piece bent back on itself with two holes drilled out for brake cables.
The difference in the rear of the frames are illustrated here. From the bend at the top of the rear tubes above where the rear brake mounts, is an entire inch different between the '87 and '88.
So now here's where it gets weird. It may be hard to read, but the serial number for the 1987 Dyno Detour on the left is [DH8873426] and the serial number for the 1988 Dyno Compe on the right is [DH8803278]. Also notice that the '87 drop out doesn't have the Dyno 'D' stamped in it, but the '88 does (another physical feature that began to surface in 1988 distinguishing any previous models).
So here's the debate... the black bike decaled as a 1987 DOES have '87' in the serial number at positions 4 and 5. However, with that same logic, then the blue bike decaled as a 1988 would be an '80' model. If you base it on positions 3 and 4, then they would both be '88's (which they're clearly not) and making the chrome bike at the top an '89'. Three separate bikes, three totally different designs, structures, and decals... yet no clear logic to the numbers.
Any one have any input on this? I think it's up for debate on how to read these serial numbers and/or even if they matter if there's no consistency.

Last edited by Dynotherium (2014-06-09 7:58am)

How Old is My Bike?

Unfortunately, exactly dating a Peugeot earlier than the late 1970s is an art rather than a science, and is often an estimate at best. Even original owners have a hard time remembering the year that they purchased the bicycle. That said, it is possible to date a bike within a couple of years with some confidence based on frame features and components. See the 'Frames, Headbadges and Decals' webpage for a pictorial timeline of frame features, and the 'Parts & Accessories' webpage for information on when specific components were found on 'U' bicycles.

Older bicycles have a serial number on the underside of the bottom bracket. If the number has six digits the frame was probably made in the 1960s, seven digits in the 1970s. Sometimes, the first digit indicates the year within each decade that the frame was made. For example, 1940481 and 2400884 represent 1971 and 1972, respectively. However, there are many cases when the first digit suggests a frame production year that is older than the actual age of the bicycle. For example, the serial number 1355592 on a 1975 bicycle. The reverse has not been documented, so it is likely that bicycles are no older than the first digit in the factory serial number, but could be younger. Sometimes local bike shops etched serial numbers into the rear dropout, but this number may or may not match the original.

It is helpful to compare the serial numbers of older bicycles with dates that are sometimes found on the rims, hubs and derailleurs. Although my 1972 AO8 has DEA rims and a Simplex Prestige rear derailleur clearly marked '1972' and '72', respectively, these dates also cannot be used alone to determine the age of a bicycle. For example, my 1973 UE8 came equipped with a 1971 derailleur. If your serial number and component dates match, you are probably in good shape. If not, the bicycle is no older than the latest component, but you will have to estimate the age (e.g., early 70s).

Dyno Bicycle Parts