Why Do Bikes Have Spokes? (Everything You Need to Know)

by Mario Claramo

Throughout your years of cycling, maybe you have wondered what exactly are the spokes for on your wheels? I know I did. I made some assumptions and moved on for a while, but eventually, the curiosity returned. Here are the reasons bikes have spokes.

The spokes on a Bicycle work to support and distribute the weight of the rider and also to transfer the energy created by pedaling from the hub of the wheel to the outer rim. These are the two main functions of bicycle spokes

So in short, the spokes on your bike are super important. Without them, your bike would not work nearly as well. I’ll explain the details below

The Reason for Spokes

Like I stated earlier, spokes play a very important role in the function of a bike and are the solution to an age-old problem. They provide consistent, light-weight support of the rider. And modern spoke patterns allow for the largest possible transfer of energy to happen when you are using your bike.

When you are pedaling your brains out, it’s nice to know that modern technology is on your side. Your spokes make sure your hard pedaling is not in vain. Yet, they are one of the most under-appreciated parts of the bike. I don’t think I have ever heard someone say, wow I like your spokes. It just doesn’t happen.

In my experience, the only time I even think about my spokes is when there seems to be a problem with them. NOw there are many factors that affect the efficiency and functionality of the spokes on your bike.

In order to help you understand what spokes are used for, let’s start at the very beginning.

 

The History of Spokes

Spokes inside of wheels have been around since the time people started using their brains. If you think back to any history book you have ever opened, now go to the time of the ancient Greeks or the Romans. What are you going to see? Chariots!

Somewhere around that time, spokes started to be a common thing to see. When wheels were first made, they were made round and solid. (Think Flintstones) These worked great, but the problem was weight. Those wheels weighed so much! There needed to be a better way.

They started by simply hollowing out areas in the wheel to try and make it lighter, but the structural integrity took a blow when they tried that.

Eventually, there was a model made with a rim with wooden spokes connecting from the rim to the point where the cart attached to the wheel.

This model became well known and was used for hundreds maybe thousands of years. Think about a pioneer-style wagon wheel. Its the same concept as a chariot wheel. Pretty cool!

So where do bicycles come in? In the early 1800s, the first bicycle was made. The first model of bike employed the use of spokes. In the early days, you would only see radial spoke patterns. Where the spokes attach directly to the hub straight out to the rim.

Now, following much innovation, we are more likely to see more complex spoke patterns.

Cross Zero Pattern (Radial)

The cross zero pattern is commonly known as the radial pattern. This pattern is where it all started. The very first wooden spokes on the wheel were arranged in the radial pattern.

The radial pattern was used at first because it was easy to figure out. It was obvious that there needed to be an equal distribution of weight across the rim of the tire, and so the space between the spokes was measured out and spokes were added in accordingly.

This method is in no way bad, but there are a few problems with it, mainly when using this set up on a bike.

Weight of the Wheel

The weight of the bike is a huge factor for cyclists. You can’t be riding a 100-pound bike. Yes, I suppose that would be good exercise, but if you are competing and your opponents are riding bikes that way 13 pounds, you are going to lose.

When the spokes are arranged in this pattern, there have to be fewer spokes because there is simply not enough room on the hub to add more spokes. Then the problem comes at the rim. If the hub only has space for 20 spokes, then the space between the spokes at the rim will be larger making the rim weak.

The only way to combat that problem was to increase the thickness of the individual spokes. And once you do that, you quickly increase the weight of the wheel.

Weight of the Rider

Now imagine our spokes, they are either thin and are unable to support a rider, or they are thick and heavy, making it difficult for the rider to ride.

Another problem with this pattern is that as the wheel turns, there will be a spoke that points directly from the hub to the ground. Once you put a rider on the bike, that single spoke is carrying the entire weight of the rider.

If the spoke doesn’t break right away, over time it will surely become weak and unable to support the rider.

Imagine placing all of your weight on a single wire, as thin as a spoke……yeah it didn’t work for me either.

Energy distribution

The third issue deals with bike performance. When you pedal your bike, you expect it to go forward. You know it will move forward because you are transferring energy from your legs to the pedals, to the hub, to the rim.

Transferring energy is something we can’t observe directly, but it has been studied and proven that energy is lost in this process. Energy loss happens when there is an inefficient part of the process.

On a bike, some energy may be lost between the crankshaft and the chain, or the chain and the gears or between the gears and the rim. When you maintain or replace parts on your bike you do that to decrease the amount of energy lost.

Radial spokes were tested and proved to provide poor energy transfer, because of their angle, so what did we do? We made a better pattern.

Cross Spoke Pattern (Tangential)

The cross spoke pattern was really an answer to the less efficient radial pattern. It is exactly how it sounds. Rather than having the spokes radiating out from the center, now thew “radiate” at angles.

These angles allow for greater rim support. They connect at the hub, but in a pattern that allows for more connections to be made. More spokes provide for more support. And since there is space for more connections, each spoke is thinner and lighter.

This pattern also decreases the chance of a blowout when you hit a rock or jump a curb. And since the pokes are at varying angles, less energy is lost while riding.

The pros of the cross spoke pattern definately outweigh the cons,but there are a few cons worth mentioning.

With so many spokes on each wheel, there is a chance that one could come loose and you might not realize it until it pops your bike tube. That happened to me about a month ago, and I had to patch up my rim liner and make sure my spokes were in order.

Another con is that the thin nature of the spokes leave them vulnerable to bending. Always be careful especially when you store your bike, that there is nothing putting pressure on the side of your spokes.

Happy Riding!

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