On this page we go into technical details of unicycle parts.
Brakes
Disc Brakes
There are generally two ways of mounting a disc brake on a unicycle:
Brake disc mounted on hub
A unicycle hub with a mounting base for the brake disc is required for this:
If no such hub is available, it can be retrofitted. For this purpose, the impeller must be spoked again and new spokes are usually required for this. Thus, in addition to the new hub, there are additional costs of approx. EUR 60 for the conversion.
Advantages:
- All cranks can be used, even without a disc mount
- The disc is a bit better protected as it is behind the fork leg
The brake disc is always on the left-hand side in the direction of travel and requires a unicycle fork on which the mount for the brake is on the left-hand side. Kris Holm forks cannot be used because the brake mount is on the right-hand side.
Brake disc mounted on crank
This requires special cranks such as the Kris Holm Spirit. Here the right crank has a mount for the brake disc:
Such cranks can be used to equip unicycles with disc brakes that do not have a hub with a disc brake mount.
Advantages:
- All hubs (e.g. Schlumpf gear hubs) without disc mounts can be used
- The impeller is laced symmetrically, all spokes have the same tension. The impeller is therefore somewhat more stable
The brake disc is always on the right-hand side in the direction of travel and requires a unicycle fork on which the mount for the brake is on the right-hand side.
Unicycle forks without a disc brake mount can be retrofitted with a Nimbus d'Brake adapter. The fork must have milled bearing shells for this. Since the perforation of the fork and d'Brake adapter must also match, not all forks with milled bearing shells can be used.
There are two types of disc brake mounts (sockets):
IS2000 - As can be seen in the picture, the mounting holes are perpendicular to the direction of travel:
An IS2000 adapter is always required. This is available for the respective brake disc size 160mm, 180mm and 203mm and must be selected appropriately:
Postmount - As shown in the picture, the mounting holes face backwards.
The post mount base is prepared for 160mm brake discs on unicycles and does not need an adapter for this size:
If larger brake discs such as 180mm are mounted, the postmount base must be expanded with a postmount adapter:
For a brake disc inside the fork (disc mount is on the hub), the socket must be on the left.
For a brake disc outside of the fork (disc mount is on the right crank), the socket must be on the right.
The socket must always point backwards. It is not possible to turn the fork so that, for example, a right socket moves to the left! The base would then point to the front!
A brake lever mount is required for the saddle to mount the brake lever. This is available with 2 or 4 holes for mounting on the saddle handle:
Choosing the right brake:
Unicycles are always delivered with a cheap standard brake (usually Shimano). These brakes are already doing their job. Hardcore downhill riders should use better (unfortunately also more expensive) brakes. Shimano XT or Saint, for example, are suitable here. All disc brakes available are designed for two-wheelers. However, cyclists generally have a different braking technique. The braking here is usually shorter and harder than with a unicycle. Unicyclists drag the brakes more. The brake does not have time to cool down and gets hot. Good brakes can dissipate heat better and remain stable for longer.
An absolutely recommendable accessory is the brake lever extension like the KH Starfigther shown here. With this, the lever of the brake handle can be pulled much easier and safer.
The KH Starfigther is a universal brake lever extension and fits all brake levers:
The predecessor of the KH Starfighter was the plastic KH Spooner. This only fits for Magure rim brakes:
Tires
There are two sizes for tires: ETRTO and inches.
ETRTO: e.g. 50-406
1st number = width of the tire (approx.)
2nd number = tire inner diameter / rim diameter
Inches: e.g. 20 x 1.95 inches
1st number = tire outer diameter (approx.)
2nd number = width of tire (approx.)
Tires for Trial-/Street-/Flat-Unicycles:
For example, a trial tire with the size 20 x 2.5 inches / ETRTO: 67-387 does not fit on a normal 20 inch rim with the ETRTO size 406! The rim would be too big. Sometimes one speaks of 19 inches because of the smaller rim.
Tires for 28/29 inch Unicycles:
In the size ETRTO 622 (rim diameter 622mm) there are two different sizes in inches: 28 inches and 29 inches.
The rim size is the same for both inches. The inch specification should reflect the outside diameter in something. 29 inch tires are "thicker" than 28 inch tires.
The manufacturers specify the inch specification quite arbitrarily. 55-622 is 29 inches for one manufacturer, while 60-622 is still 28 inches for another manufacturer. So in this comparison the 28 inch tire would be thicker than the 29 inch tire.
Conclusion:
Tire widths in ETRTO or inches are not accurate and are not a good way to determine if a tire will fit in a fork or not. When it comes to tires, everyone talks about the customs specifications. With 20 inch trial tires and 28/29 inch tires, however, this is completely insufficient.
Inddor Tires:
Indoor tires are tires that leave no traces on a hall floor. These are all white and colored tires. Black tires are very often not allowed in halls.
Tires for IUF track races:
Two rim sizes are used for 24-inch races:
24 inch - ETRTO (i.e. rim diameter): 406mm
26 inch - ETRTO (i.e. rim diameter): 559mm
Since the diameter of the rim has no meaning in the regulations, but only the actual outer diameter of the wheel, 26-inch rims are also used in the "24-inch" class. However, the remaining space between the rim (559mm) and the permitted maximum (618mm) is very small and only very thin/narrow tires can be used: 26 x 1.0 inches or ETRTO: 23-559. Bigger tires overshoot the mark.
With 24 inch rims (ETRTO: 406mm) thicker tires are used to get to the maximum diameter. This goes well up to about 24 x 2.0 inches (50-507) or a bit thicker, depending on the tire.
Air pressure:
In Germany, air pressure is given in bar. Abroad it is very often in PSI (1 bar = 14.5 PSI). The maximum air pressure is usually of interest. This should always be embossed or printed on the tire. A tire must not be inflated above the maximum air pressure.
The air pressure to be used depends on the volume and the purpose of the tire. The thinner the tire, the more air pressure has to be filled in order for the tire to be hard. A 1.0 inch (23-559) road bike tire is only hard from 5-6 bar. A thick 3.0 inch (75-504) tire becomes hard much earlier, e.g. at 2.5 - 3 bar.
If a unicycle is to roll easily (racing bike, freestyle, etc.), then the tires should be as hard as possible.
If the tires are supposed to be springy (tours, trials) or have a lot of grip on bad ground (Muni), soft tires are also used.