The Unicorn 36" Carbon Rim and Its Tire Fitted

Recently, some remarks on the Internet have questioned the professionalism of our newly developed Unicorn 36" carbon bicycle rim. The main argument is that the popular NightRider tires on the market cannot fit the Unicorn 36" rim very well, so it is questioned that the Unicorn rim does not conform to the design standard. In view of this, we have made precise analysis, measurement and testing for reference.

As we know, according to ISO (International Organization for Standardization), the BSD (Bead Seated Diameter) theoretical value of 36-inch rim is 787mm, reference link: https://www.sheldonbrown.com/tire-sizing.html

We strictly abide by international standards at the beginning of designing the Unicorn 36" carbon rim, and the actual measurement is also accurate. The measurement picture is as follows.


Actual measurement of outer diameter: 798.26mm (standard 798mm)

Actual measurement of bead height: 5.49mm (standard 5.5mm)

Actual measurement BSD: 798.26-5.49x2=787.28mm (standard 787mm)

There is an error of 0.28mm between the actual measured value and the theoretical value, which is completely within the allowable range. It can be concluded that our products meet international standards.

As far as we know, there are two common types of tires for 36-inch rims on the market, one is Vee Monster, the other is NightRider. Unicorn 36" rim has been selling for more than half a year. There is no problem with the use of Vee tires for Unicorn 36" rim. One of the customers from Iowa in the United States purchased 14 Unicorn rims and mounted with Vee tires, all ran quite normally. The picture is as follows.


The only negative feedback we've received about the Unicorn is the possibility of the NightRider tires falling off. To pinpoint the problem, we purchased a NightRider tire for actual testing. When installing the tires, we found that the tires were mounted too easily, which is completely different from the installation feedback we have tested on other rims with other brands of tires. We have reasons to believe that the BSD of NightRider tire is unreasonable, which leads to the fact that a small number of customers fall off the tire when riding.

However, since NightRider is still a mainstream 36-inch tire, in order to be more compatible with this tire, and also in response to some customers' preference for hook 36-inch rims, we designed an additional hook model for Unicorn. Among them, the height of the small protrusion (bulge) at the rim bead has been increased from 0.2mm to 0.47mm for hook model, which makes the installed NightRider's tire not easy to fall off due to its large BSD size. The hook rim lip could also hold the tire bead more securely. We tested a NightRider tire on a Unicorn hook rim, picture as below. 


To this end, we recommend:

1. Either the Hook model or the Hookless model of Unicorn 36" rim, the Vee Monster tire can be used without any problem;

2. If NightRider tire is preferred to use, the hook model is highly recommended, and be sure to use inner tubes. 


In addition, some customers would like to run tubeless on Unicorn rim. As we have to know, running tubeless needs to meet two conditions:

1, rim is tubeless compatible,

2, tire is tubeless tire or at least meet basic BSD standard.

No doubt, our Unicorn 36" rim is tubeless compatible, but there are basically no 36" tubeless tires on the market. According to actual tests, NightRider's BSD is not precise enough to meet the basic requirements for running tubeless.

As for the Vee Monster for tubeless, we are not completely sure yet. While, since the Vee Monster tire is in line with international standards, theoretically it can be used for running tubeless, just needs to add sufficient sealant. 


NEXTIE Team

2022 / 01 /19