Well, The Rear Wheel is Spokeless...
Nine mechanical engineering students at Yale created this pretty cool bike in their mechanical design class. It's only a prototype and their time was limited, so the front wheel has a more traditional design, it doesn't have a suspension, and the balancing isn't quite as good as it could be, but as a proof-of-concept it's really cool. Might never become more practical than a regular bike, but it's good to experiment with different designs, if only to learn more about what makes a good bicycle (and let's not forget that it's fun). More photos and details below.
Since there's no one better qualified to describe the bike than one of the people who built it, I'll just give you some excerpts from what he wrote (his username at Reddit is zhaolander):
"I'm not gonna lie, the number 1 reason we had for wanting to make this thing was because we thought it would look cool. But also, we searched online and couldn't find any actual physical human powered spokeless bikes. There are plenty of patents and concepts for spokeless bikes, and plenty of actual spokeless motorcycles, but to my knowledge no actual spokeless human powered bike."
"As you've probably noticed, only the back wheel is spokeless. This was done for several reasons: Manufacturing the rear wheel/rim was very expensive, so we only had one machined to see if it would work. We knew that if we could get it working for the rear wheel, it would definitely work for the front. But in the end, we ran out of time (class was only one semester long)."
"I just wanted to elaborate on why we went for the spokeless bike. First, it looks cool. Second, we only had a semester so we wanted to pick something that was both feasible and challenging. Also, you can do a lot of things with the space that opens up where the spokes use to be. You can stick an electric motor in there. You can install some sort of gyro balanced storage basket. Finally, the fact that we couldn't find pictures of a real spokeless bicycle online really sealed the deal."
"Also, this is the first prototype! We weren't even thinking about suspension and all that stuff. If you notice, we only have one brake installed. All we wanted to do was prove the concept of a human powered spokeless bike."
"The frame was water jet cut out of 1/8" thick aluminum"
"I don't know what the exact weight is. I don't think it's too much heavier [than a regular bike[ overall, it's just that it's balance is a little off. There's more weight in the last half of the bike because of all of the rim support. You can feel this most when you're turning.
It's a single speed setup. We used two cranks and two bottom brackets in the front to gear up the ratio. It goes from (IIRC) 53 to a 13, which is connected to the second crank and another 53 which connects to the rear hub. The rear hub is just a normal ratcheting rear hub that we mated to our belt pulley. Not sure if all these bike terms are right, but that's the general idea."
"The front wheel would be almost exactly the same as the rear wheel except that it could be a little lighter. Some of the aluminum can be shaved off since there's no powertrain to connect to."
"The wheel/rim itself is made from T6061 aluminum. The frame is made out of a cheaper aluminum alloy, I'm not sure which one exactly. I mainly worked on the drive train.
The tire that you see on the rear wheel is a normal bike tire so we did use a standard wheel size. I think we aimed for 26" initially but that might have changed."
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