The heart of the wheel is the rim. The rim determinates the main characteristics of the wheel.
There are different types of rim. They differ in:
- dimension (diameter)
- material
- number of holes (for the spokes)
- rim section (single, double or triple wall)
- with or without lightening holes, that can be of different dimension
- with or without Eyelets
Rim diameter (dimension)
When we talk about rims we usually speak of their dimension in inch.
A 24-inch rim, a 20-inch rim, a 28-inch rim...., however, this is more a "commercial dimension" and is rather not precise and may lead to misunderstandings and mistakes.
The rim dimension tells us if the rim is big or small, furthermore it tell us which tires can be mounted.
The dimension in inch of a bicycle wheel tells us the approx. final diameter of the wheel including the tire correctly mounted and with the right pressure.
It progressively led us to indicate with the same dimension in inch (i.e. 26-inch), rims and tires having different diameters, but all with a very similar final diameter of the complete wheel.
Of course, if we try to mount on a rim a tire not of the right dimension, it will be not possible.
A 24-inch rim, a 20-inch rim, a 28-inch rim...., however, this is more a "commercial dimension" and is rather not precise and may lead to misunderstandings and mistakes.
The rim dimension tells us if the rim is big or small, furthermore it tell us which tires can be mounted.
The dimension in inch of a bicycle wheel tells us the approx. final diameter of the wheel including the tire correctly mounted and with the right pressure.
It progressively led us to indicate with the same dimension in inch (i.e. 26-inch), rims and tires having different diameters, but all with a very similar final diameter of the complete wheel.
Of course, if we try to mount on a rim a tire not of the right dimension, it will be not possible.
To overcome these problems the European Tire Rim Technical Organisation (Etrto https://www.etrto.org/Home) has adopted a measurement in millimeters and has indicated how this measure must be clearly identified so that it is possible to define rims and tires compatible with each other.
- the Etrto classification for the rims tells us the diameter in "mm". We will find the same measurement on the tire which is referring to the width of the tire.
An Etrto measurement will appear like this: 37-622 (mm), where 37 indicates the transversal diameter of the tire (the width) and 622 indicates the referring diameter of the rim.
There is also a French standard, which indicates the external diameter of the cover in mm, and its width with a letter at the end. This letter tells us the inside diameter of the cover and the rim.
- A French measurement will appear like this: 700x28C (mm), where 700 indicates the external diameter of the cover, 28 its width, and the "C" the internal diameter (in this case 622).

The rim diameter
If commercially the internal diameter of the rim in "inch" is the most common way to define it, the measure in mm given according to the Etrto standard is the most precise one. In our shop you will find both values, i.e.:
19" = 387mm
20" = 406mm
24" = 507mm
26" = 559mm
27.5" = 584mm
29" = 622mm
To be sure that the tire you are mounting on you rim is the right one, the code (in our example 622), must be reported on both, tire and rim.
To know the total height of your wheel you can simply add these values:
Tire diameter + internal rim diameter + tire diameter = total height of the wheel (approx. value).
19" = 387mm
20" = 406mm
24" = 507mm
26" = 559mm
27.5" = 584mm
29" = 622mm
To be sure that the tire you are mounting on you rim is the right one, the code (in our example 622), must be reported on both, tire and rim.
To know the total height of your wheel you can simply add these values:
Tire diameter + internal rim diameter + tire diameter = total height of the wheel (approx. value).
Rim width
Below an example of rim section:

Type of section
The rim can be single, double or triple wall (the last one is not so common and is heavier).

It can be with or without big lightening holes.
The rim can be "reinforced", i.e. without lightening holes, or with more or less big lightening holes.
With or without Eyelets
With or without eyelets mounted around the hole, in which the spoke is inserted. The eyelets are mounted to avoid the direct contact between Aluminum (rim) - Aluminum (nipple), but this is not our case. The nipples are in nickel-plated steel or in bronze.
All our wheels are built by hand in our factory in Italy and are without eyelets.
The eyelets do not simply make the wheel more expensive (it is a component having its own cost), they sometimes come off making your wheel unusable. Furthermore, a rim with eyelets cannot be re-anodized, this means you cannot change the color of your rim.
All our wheels are built by hand in our factory in Italy and are without eyelets.
The eyelets do not simply make the wheel more expensive (it is a component having its own cost), they sometimes come off making your wheel unusable. Furthermore, a rim with eyelets cannot be re-anodized, this means you cannot change the color of your rim.
Last tips and information before choosing your rim
- please check that the number of the spoke holes of your rim corresponds to the number of the holes in your hub !!
- In our shop you will find only ALU-rims of good quality. We speak of "quality of the aluminum" because there are different types of ALU on the market. If the ALU used is of poor quality the stiffness and robustness of your rim are not guaranteed... The strongest will surely be a double-wall rim without lightening holes.
In any case please choose the rim based on your needs, i.e. on what you plan to do with your unicycle. - in addition to the quality feature described above, let's consider also the look of your rim :)
All our rims are anodized in Italy in different colors, a bit different from the usual ones. They are limited editions and cannot be copied. We offer 13 different colors, you have simply to choose the one that most fits to your style!
Below an overview on the wheel sizes
203mm | 305mm | 355mm | 387mm | 406mm | 507mm | 559mm | 571mm | 584mm | 622mm | 686mm | 787mm |
12,5" | 16" | 18" | 19" | 20" | 24" | 26" | 26" | 27.5" | 28-29" | 32" | 36" |
trial with tire20x2.5 |
MTB | Race 650B | 700C |