Each "answer" should address a different way to determine the manufacturing year of a bicycle. To some extent, these will also help you narrow down the model as well as it will tell you what distinguishing features to look at. Cottered cranks vs square tapered or splined cranks and bottom brackets. Style of shifters brifters, triggers, "Dating specialized bikes." A previous owner could have replaced or upgraded components on a bicycle, so this guide only applies to original equipment.
There is a delay between the introduction of a technology such as indexed shifting and when manufacturers start selling products that use it. Low-end manufacturers may continue using technology is severely outdated such as one-piece cranks, freewheels, or quill stems because it is cheaper to do so.
A number of bikes are built in a Retro style, but with modern components. Dutch bikes, trendy coffee cruisers, and beach cruisers may be modern but appear to be s styling. These tend to have modern rims and brakes as a giveaway. How much your bicycle is worth depends on the location of the buyer and Dating specialized bikes, how much the buyer wants the bike, etc. Bicycles except children's bicycles are almost always required to have a frame or serial number.
Many manufacturers use a date-code as part of the serial number. Surly is another manufacturer who uses date codes, this time in their stamped frame numbers.
However, many bicycle manufacturers don't use date codes and so you can't easily decode their serial numbers. Some of these manufacturers will provide their own serial number lookups on Dating specialized bikes websites. Some of the other ones have been reverse-engineered by their rider communities.
The best way to find out is to google " manufacturername bicycle serial number date of manufacturer.
If a bicycle has indexed shifters, then it is model year or later -- assuming that the shifters and derailleurs haven't been replaced. The "Dating specialized bikes" Shimano Di2 electronic shifters were introduced on a production bicycle by Giant in A simple thing if you're receiving a bike is to ask the person selling it.
Take their info with a grain of salt though - some sellers may lie to increase the perceived value of a bike. However if someone gives you a bike, they might say "I remember my dad riding this to work in the 80s while I was at school". So this information may be authoritative, or it may be an indicator to be combined with other factors.
I managed to date my old Raleigh by finding scans of old catalogues online. That model was only sold in one particular year, but more often you'd get it to within a few years this
There are many old cycling documents at Veteran-Cycle Club Online Libraryincluding plenty that can be accessed for free. Searching for a brand and plausible year with "catalogue" can often turn up sites dedicated to scans of that brand's literature; you may need to check more than Dating specialized bikes such site for good coverage.
This will only really work for a major brand that has a bit of a following, as it relies on someone uploading the catalogues. You also need a rough idea e. Bikepedia is also useful, mainly for confirming when you think you know a year, and only goes back to Downtube or handlebar mounted friction shifters were common on bicycles until the early s when indexed shifting was introduced by Shimano in see Indexed Shifting.
Brifters combination brakes and shifters on road bikes were introduced in with the Shimano Total Integration STI system. If your bicycle uses a cassette freehub for the rear sprockets, then it was likely made in the late s or later.
Shimano came out with the first commercial freehub in in the Dura-Ace series, but it took about a decade for it to make significant inroads.
The Dating specialized bikes of cottered cranks was popular on bikes until the mid to late s until they were replaced by square taper and splined bottom bracket designs.
Raleigh, for example, introduced square tapers on some models in and phased cotters out on all their models around Like many things, the shift to square tapered and splined brackets took some time so there were still some mainstream bike companies still using them in the early s.
However, a cottered crank is generally a good sign your bike is pre In some factories in "Dating specialized bikes" and that are still working off old blueprints, cottered spindles may still be in use in the manufacture of new bikes.