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Building a wheel (part 1)

Building a wheel (part 1)

For many people, making a bicycle wheel is a kind of magic. It is not very complicated or difficult. With the proper tools and patience you can do it to. To create a good wheel a number of things are important. First, of course, the quality of the materials used.

The better the quality the smoother hubs run. In the rims there is a clear difference in quality. A good rim is straight as you start truing the wheel  and therefore much easier. The spokes have to endure the most so it is important that they can withstand the forces over time.
 

The theory

Before you begin to make a wheel an understanding of the theory behind the building wheel can be handy. Bicycle wheels come in many types. The spokes convey a lot of different forces. In a rear wheel of course you want your pedal power to make you go forward. And when you brake you want to actually stops. Therefore, when making wheels there are multiple spoke patterns possible.

The main difference is the number of times the spoke cross another spoke. Most wheels are crossed 2 or 3 times. With small wheels and large hubs, such as an electric or rohloff hub is often only one time. Some front wheels have no intersecting spokes at all, this can only be done if you have rim brakes. Such a wheel in not very good at transferring the drive and braking forces. The choice of the number of crosses depends on the size and the type of use of  the wheel.

 

wheel radial spokepattern

radial

Wheel with 2 crosses

Wheel with 2 crosses

Wheel with 3 crosses

Wheel with 3 crosses

Another factor is the wheel dished or not. The rear wheel needs space for your cassette and the chain must clear your tire. Therefore, the spokes on that side are more upright than the ones on the left . This means that these spokes have a higher tension. Today, some front wheels are somewhat dished when they have a disk brake. This is done in order to have room for your brake.

paraplu gespaakt

Paraplu of niet

Spoke length

 

In order to make the perfect wheel the length of the spoke has to be spot on. But how do you calculate this length. There is a formula for this . It is as follow:

 

Length = √ {(R1 x R1)+(R2xR2)+(A x A)-(2xR1xR2xcos(Kx720/N))}

R1 = Half the diameter of the rim

R2 = Half the diameter of the hub flange

A = Distance to the center of the wheel

K = Number of times the spokes cross

N =Number of spokes in your wheel

That is quite higher mathematics. Fortunately, there are online programs that make it easier for. I usually make use of the Sapim one but the one by  DT Swiss is also working properly.

Both calculators you have to measure your hub and rim. This is best done with a caliper. The most difficult size to measure is the distance (A) of the flange up to the middle. Most of the calculators therefore ask for the distance of the dropout to the flange. For most of the wheels, this is not a problem. If you know that distance you can also calculate the distance to the center.

However, it goes wrong if your wheel is not centered between your dropouts . On Ice trikes for  example, the rim of the rear wheel is  about one centimeter more to the left. This is done to get a stronger wheel (less dish) and more space for the chain. In this case, you add this 10 mm offset  to the total width of the hub. And deduct this 10 mm from your measured distance on the left. In this way you make sure that the rim ends up 10 mm to the left.

At last

Are you enthusiastic and know the correct spoke length then you can of course they buy from us. I make all spokes on a special spokemachine made by Cyclus and use  Sapim stainless steel spokes and nipples. There are two types: spoke 14 and spoke 13/14. The difference is the thickness at the head. Spoke 14, the entire spoke is 2 mm thick, and spoke 13/14 is 2.34 mm thick at the head part. These thicker spokes are mainly used in high-load wheels such as the front wheels of a velomobile or a trike and wheels with an electric motor.

 

In the next part I wheel explain how to lace the spokes

 

1 thought on “Building a wheel (part 1)

  1. Saved as a favorite, I really like your site!

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