What do you do about the hub when maintaining your bicycle?

The hub is the central axis of the bicycle's wheel, where the spokes gather.

You probably don't think much about the hub on a daily basis, but it's a very important component for a bicycle. So I'd like to inform you about it, and also discuss hubs for carbon-spoked wheels.

The Importance of Bicycle Hubs

The hub is located at the center of the bicycle wheel, bundling dozens of spokes.

At its center is an axle, and between the axle and the wheel are ball bearings.

These ball bearings are key to the smooth rotation of the wheel.

There are two types of hubs: those with direct-contact balls and those with standardized cartridge bearings. Both have pros and cons, and neither can be said to be definitively superior.

In hubs with direct-contact balls, the hub itself also acts as the bearing housing, which reduces the number of parts and makes it lighter. However, if even one ball is lost during maintenance, all the balls will need to be replaced.

In hubs that use standardized parts, the entire unit can be replaced, and ball bearings are relatively inexpensive, making maintenance easier.

On the other hand, specialized tools may be required for replacement.

Also, since the bearings themselves have housings, the number of parts increases, adding a slight amount of weight.

Most hubs use different parts for the front and rear wheels.

The front wheel can rotate both forwards and backwards.

The rear wheel, if it has gears, incorporates a ratchet mechanism, so even if you pedal backward, the power is not transmitted to the wheel.

The hub has the function of holding the spokes to prevent the wheel from bending, and most importantly, the function of smooth rotation.

If foreign matter such as dirt or dust gets into the ball bearings mentioned above, the rotation will become rough.

In that case, if not removed quickly, the ball bearings will be damaged, leading to permanent poor performance.

Hubs for Carbon-Spoked Wheels

For carbon-spoked wheels, the hub may also be made of carbon.

This requires precise machining, so wheel manufacturers and hub manufacturers are often separate entities.

In other words, even companies that manufacture their own wheels often purchase and use hub components from hub manufacturers.

Looking at ICAN's carbon wheel lineup, you'll see DT SWISS and NOVATEC, but it seems they also have some in-house products (OEM).

Chinese Carbon Wheel Buying Guide

You might be concerned about the strength of a carbon hub, but as mentioned in another article, carbon is three times stronger than iron.

Its weight is about 30% that of iron.

When using aero spokes, the spokes are flat (wide).

They may not pass through regular holes, but aero hubs have special holes, called "daruma holes," which are larger than the diameter of the hole, allowing aero spokes to pass through easily.

Wheel Precision

Some people might think it's cheaper to assemble wheels themselves, so they buy the hub, spokes, and rim individually.

Honestly, I personally don't recommend it much.

Determining if each part is balanced requires considerable specialized knowledge about components, and it can cost a lot of money to find the optimal solution.

It's not just a matter of cost.

The biggest problem is precision.

When you fix the axle and rotate the wheel, both lateral and radial runout occur.

Making this perfectly zero is almost impossible, I believe.

However, it is common practice to set a certain standard (tolerance) and ensure that the runout falls within that range.

For reference, if you have it adjusted at a regular bike shop in town, the lateral runout is typically ±2-3 mm.

When the wheel rotates, the wobble is visible to the naked eye.

At a local bike shop, they are not specialists, so you cannot expect such precise adjustments.

Also, since it's not a new wheel, if the rim is already bent, this might be the limit of adjustment.

Specialty shops often adjust it to within ±0.5 mm.

Of course, this won't be achieved if the frame is bent, but the pure adjustment itself is done with considerable precision.

ICAN does not disclose its tolerance.

(I looked it up, but I couldn't find any other company that discloses the tolerance for wheel runout.)

However, I found an amazing video.

It shows the adjustment of an ICAN carbon wheel, and you can see a dial gauge being used.

A dial gauge is a measuring instrument that can measure lateral runout in micron units.

I also use it for post-assembly checks of equipment that requires ultra-precision, such as semiconductor manufacturing equipment.

Looking at the values on the dial gauge in the video, the needle consistently points to zero while the wheel is rotating.

This means the runout is within 1 micron.

Since 1 mm is 1000 microns (μm), converting that to mm gives 0.001 mm.

It's even less than that, so it can be considered zero.

*This is the author's impression after watching the video, so ICAN wheels are not claiming to have zero runout. Please be aware.

Although it's new, it far exceeds the adjustment range for an amateur.

If you actually try it, you'll realize it's quite difficult.

Personally, I believe you'll get a better product if you leave it to professionals.

If you buy a set, you don't need to worry about the balance of each part.

Considering the adjustment precision, it is undoubtedly the optimal solution.

Unboxing Review

I'm curious about the condition it arrives in when purchased.

I looked it up and found an unboxing video.

It's reassuring to know in advance how it will arrive, isn't it?

In the video, the Aero40 is being unboxed, and the front and rear set weighs just over 1300g.

That's light!

Watching the video made me grin.

I really want it.

External writer: Koichi Okuno