Identifying a straight bar, cantilever, and DX frame
Since Schwinn first introduced the balloon tire bike in 1933 there have been a number of different frames used. The very early frames were of the motorbike or camel back style. The Aerocycle had a unique frame and there was a double bar roadster frame as well as a camel back in the later style frames as well.
This article is not going to cover all the varieties of frames Schwinn built through the years of which there are many. Essentially there are three basic styles; the straight bar, the DX, and the cantilever frames. Many different models were built on these frames. I am not going to try and associate the models to the frames because both straight bar and cantilever frames were used for Autocycle models and trying to explain Motorbike, Cycleplane, Standard, Super Deluxe, etc… gets complicated. This article will not cover either girls or juvenile models. The girls frames were pretty much the same and were differentiated between model lines largely by paint schemes or equipment e.g. tank, light, or rack. The juvenile models mimicked the adult models to a large degree. In the prewar years Schwinn offered their boys 26” tire models in several different frame sizes (16”, 18”, and the so-called ‘tall frame’ 20”). After the war all boys 26” tire frames were 18”.
While this may seem obvious the first thing to do is to make sure you are looking at a Schwinn frame. This is not as simple as it sounds because nearly all manufacturers made very similar frame styles. You will need to pay attention to paint schemes and colors, seat binding posts, drop outs, serial number structure, font, and size, welding construction, and other ‘tells’.
Prewar frames discussed here will have the following characteristics: rear facing dropouts (Fig. 1), no built in kick stand provision, and the head tubes on boys models are shorter than girls models which means the forks will not interchange. There are other differences between pre and post war frames but these are the main characteristics.
Post war frames will have front facing dropouts (Fig. 2), the head tubes are the same size between boys and girls bikes which means the fork whether an Ashtabula, truss, or springer will interchange. Except for some low tier ‘50s models all bikes will have a built in kick stand (Fig. 3). Middleweight frames (tire size 26” x 1 ¾”) will be narrower than balloon tire bikes.
A quick way to determine whether a frame is a balloon tire or middleweight (cantilever or straight bar) is the “three finger method”. An adult male with average size hands should be able to get three fingers comfortably through the rear seat cluster triangle on a balloon tire frame (Figs. 4, 4-1). Not so on a middleweight frame (Figs. 5, 5-1)
The serial numbers will schwinn a numbers numbers the second position representing the month it was produced, dating a number codes the third position bikes the year. Take the date of production gathered from the serial number, number model printed on the bike itself, and the overall visual design and compare it to a Schwinn pricing table like.
Sep 17, 2017 - Vintage Schwinn serial number lookup. Enter your Schwinn serial number in the box and click button to see what date and year your Schwinn bike was made. Schwinn bicycles are easy to identify by the Schwinn logo displayed on the bike. But you can also look for the serial number to identify an authentic Schwinn bike. The serial number will also indicate when it was made, which can help you estimate the value of the particular Schwinn bike. Search for bikes that have been registered on Bike Index. The non-profit bike registry Sign up ☰ Search bikes. Serial WE19070616; Primary colors Silver, gray or bare metal. Schwinn World Sport Serial gm612263; Primary colors Black, Red, and Yellow or Gold; Stolen 2020-12-05T15. Register your Schwinn bicycle with us for up to date information on your model and, if your bike is ever lost or stolen, we can provide you with key information that can help you recover your bicycle quicker and easier. Product registration is quick and easy. Please fill out the form here.Register Product.
As previously mentioned the first balloon tire bikes had either a motorbike or camel back style frame. Starting in 1935 Schwinn introduced a new style frame. The first design straight bar frame is generally called a ‘double diamond’ due to the straight seat stays which create a triangle or diamond shape to match the front part of the bike (Fig. 6).
For 1936 the straight bar frame had curved seat stays and this feature would remain through the end of production of the straight bar frame (Fig. 7).
Vintage Schwinn Bike Serial Numbers
In 1938 Schwinn introduced the iconic cantilever frame (Fig. 8). Since its introduction the cantilever frame has been copied by nearly every bicycle manufacturer.
In 1939 Schwinn introduced a budget minded line called the DX. At first glance the DX frame (Fig. 9) looks very similar to the straight bar frame. Upon closer inspection however you will notice that the bottom bar (underneath the top tube) has a slight curve to it. For this reason the tanks between a straight bar and a DX will not interchange. The first year frame (1939) shown in Fig. 9 has built in drop stand ears. 1940 and later DX frames will not have these ears and look like Fig. 1. This is one of the few Schwinn frames to ever have this feature. The DX frame was only used until 1953 which is before Schwinn introduced its middleweight line so all DX frames are balloon tire bicycles.
By identifying whether or not a frame is pre or post war along with the style it will aid in potentially narrowing down the model of bike even if it lacks other identifying features such as a name on a chainguard which is never found on prewar bikes. As mentioned above there are many other differences on these frames, Besides the different sizes the straight bar and DX frames may have straight or curved down tubes and the tanks for B and BC straight bars will not fit C model straight bars and vice versa.
Armed with this information you should be able to determine whether you have a straight bar, DX, or cantilever frame. Enjoy the ride!
All bikes1all have unique serial numbers.
Finding a bicycle serial number
Most bicycles have their serial number engraved beneath their bottom bracket, but sometimes serial numbers are found in other places. Here are some examples of where and what to look for:
The bottom bracket (where serial numbers are typically located) is circled.
A serial number on the underside of a bottom bracket.
Another serial number beneath the bottom bracket, aligned parallel to the frame.
Rad Power bikes have their serial number on the head tube. This is on the front of the bike.
Some Schwinn bicycles also have the unique identifying number (their serial number) on the head tube.
A serial number located on a rear dropout. Some BMX bikes and a few Schwinn bicycles place the serial on the rear dropout. On older Schwinns there are numbers stamped on both the drive side and non-drive side rear dropouts; the one on the non-drive side dropout is the serial number.
Some bikes have multiple serial numbers.2When adding a bike to the Index, it's best to enter all the groups of numbers and letters separated by spaces.
Hopefully you can find the serial number on the bicycle you're looking at - email contact@bikeindex.org if you're having trouble.
Searching serials on Bike Index
Finding bicycles by serial number on Bike Index is a critical part of our functionality. When searching for a serial number, use our serial search bar - it's the second bar on our search form.
We've done a few things to make it more likely that you'll find the bike you're looking for.
- Certain numbers and letters are difficult or impossible to distinguish between (e.g. 0 and O, S and 5). We treat all these numbers the same way - a search for
005LLLwill match a bike with the serialOOS111. - We split bike serials up by spaces and store each separately. If you see multiple numbers on a bicycle - such as in the photo of the Look bike above - try searching for just one of the numbers at a time. Searching for either
M4106I9CA1or200910427-2Awill find the bike. - We do close serial matching - bikes with serial numbers that are close to the serial you entered are shown below the matching results under the heading 'Serial Numbers Close to...' - given a search of a serial number with a couple numbers/letters that are different or missing.
- We do not currently do partial serial searches. If you search for
1234, you will only find bikes with serial numbers of1234and serials close to that - not a bike with serial number of12345689.
Schwinn Bike Serial Number Lookup
- Okay, fine, so maybe there are a few bikes without serial numbers, but this is rare and typical only on hand made bikes or really old bicycles.↩
- In this picture 200910427-2A is a manufacturer number and not a serial number. However, to make bikes as easy as possible to find, feel free to enter all numbers you encounter.↩