Needed a replacement 700C front wheel for my commuter bike after the old aluminum rim exploded like a looney tunes cannon. It’s hard enough to find the right size when there are 3 competing tire/rim sizing systems currently in use, it doesn’t help when the people selling the wheels have no idea what the numbers mean either! All of these examples are from separate storefronts at the big online store. Ended up buying the wheel identical to mine from my local bicycle shop at the same price as online and with no shipping fee or delivery time.
The 3 systems in use are the American customary inch fraction notation like 26x1+3⁄4 (which is NOT interchangeable with American customary inch decimal notation like 26x1.75), the French metric notation like 650x45C, and the ISO 5775 metric notation like 47-571. I found the wikipedia conversion tables and Sheldon Brown’s tire size chart invaluable.
700cm
I wanted to go with this, but had to go even bigger. The largest mine truck according to the wiki is BelAZ 75710 (as seen in the picture) which has “59/80R63” tires that are merely 402.7cm big.
You know there’s only one thing to do now, right? You have to make a 7-meter-tire tall bike.
(Don’t blame me; I don’t make the rules.)
The fact that everything from heroin to cocaine was found in everyday products in the Victorian era is the only explanation I can come up with for the penny-farthing bicycle to not have been a one-off idea that everyone dismissed as ridiculous.
If anyone finds themselves in this position, you should ignore everything else and just look at the ERTO size, which should be on the tyre itself. This is a standard way of measuring tyres and wheels, and is much better than the old ways
I’d love to use ISO sizes, but even if I know that I need a 40-622 wheel, there is no way to search for it on the storefront if every single seller made gross mistakes in labeling their product! I have to ignore the specs shown entirely and make educated guesses based on title alone. For example “WHEEL AL 700 FRONT ALEX AP18 QR Silver UCP” in the picture is almost certainly a 700C wheel and NOT an 18-inch wheel. The “18” in the title probably stands for 18mm rim width, which means that this wheel will fit my bike and tire, but is a bit more narrow than ideal 23mm. The sellers must be copying the title verbatim from the manufacturer, and then haphazardly filling out the specifications without knowing or understanding the actual numbers. The ISO size is not mentioned at all.
and this is why i basically ignore online shopping except for a few things, it’s utter nonsense and almost certainly completely automated with chatgpt at this point, you might as well donate to the church and pray that god puts your desired item in the mail before sunday.
700C is dang hot, are you building a rocket or something?
To be fair, when I was little I too was guessing that “C” stands for centimeters or something metric. Now I know that “C” in “700C”, the most popular road/hybrid wheel size, stands for the third size in the French “ABCD” notation, where sizes “700A”, “700B”, and “700D” are obsolete and are no longer manufactured.
Try purchasing wires or electronic components from Amazon. Same shit, only worse.
For components and wires that are made to a spec, I feel far more comfortable buying from CPC or Mouser.
Amazon sellers just feel like a coin flip if the guy is going to ship you CCA 24 AWG instead of OFC 23, in the hope you don’t notice or bother complaining.
I’ve experienced this sort of thing with my car. it’s a old 50s car that had a engine swap and a few mods before I got it. so one one hand everything is universal but on the other hand I don’t know what is stock. I only know what sizes are currently under the hood. which wouldn’t be a problem if the guys at AutoZone or O’Reilly’s knew what the different sizes ment. Before I finally figured out what car my engine came from. id just measure the part I need. come in and tell them the part I need, and they would just sit confused until they just asked me what car is this part going into. sometimes the part happens to be stock bel air size, but sometimes they weren’t and the guy would have to bring the used part to the back. until they found something the right size. Hell even when I ordered online id have to wonder if I’m going to be fighting the “guarantee to fit your car thing.” because I don’t know if stock will work. Here at least you can navigate if you managed to find a conversation calculator. My measurement standards don’t matter no matter what unit I use.
