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The philosophy behind our rims
The philosophy behind our rims
This section is about some basic concepts of product design that we have developed through our manufacturing experience.
We need to maximize the advantages of our materials for different purposes.
Some things are universal and some things are unique.
All is about how to optimize weight, strength and stiffness, and aerodynamics when applies.
Hookless & Medium Hook & Clincher
All mtb carbon rims have a hookless bead design.
Hookless rims have a solid round head that allows the carbon fibers to stack smoothly and maximize strength.
This is ideal for off-road rims to handle the various impacts of rocks and forests. For different MTB terrains, our engineering team customizes the hookless bead structure accordingly. These adjustments include thickness, shape, height, etc.
As more and more tubeless tires are mounted on Mtb wheels, the tire pressure is getting lower and lower. This is another friendly improvement for hookless design in bicycle rims. As a manufacturer, we can improve the strength and shock resistance of MTB rims without giving riders flat tire problems.
Why do we develop the middle hook?
It was originally developed for on-road and off-road disc brake road carbon wheels. The focus of the product is very similar to the MTB rim: tubeless, wider tires, lower pressure, lighter and more shock resistant.
It is a mix of on-road and off-road.
The mid-hook design is designed for this purpose.
It adopts the hookless and tubeless design of off-road wheels, but retains the ability to use tubes.
However, this design is more tubeless and the recommended maximum tire pressure is 90 PSI.
We retain the traditional clincher design on all of our rim brake rims.
Because the tire pressure is very high and there are still many riders who use clincher tires with tubes. And we make all rim brakes carbon rimss wider and tubeless compatible.
HOW TO FIND A COMPROMISE BETWEEN ASYMMETRICAL PROFILE AND AERODYNAMICS?
We have to admit that we continue to strive for perfection and the beauty of simplicity, but we also keep compromising.
Asymmetrical profile design is good for making a stiffer wheel, but not good for aerodynamics.
Aero-dynamic wheels reject asymmetry on principle, which would lead to unbalanced crosswinds.
To the best of our current knowledge, we have no better solutions.
Asymmetry still has the tiny disadvantage that the impact resistance differs between the offset and non-offset side.
Based on these findings, our engineering team applies different profile designs for different rim series.
For rim brakes bicycle rims, we maintain symmetrical profile designs to maximize aerodynamics;
For disc brakes bicycle rims, we have developed two series, one with an asymmetrical profile and medium hook design, mainly for off-road and gravel use.
The other is a standard symmetrical profile and clincher design, mainly suitable for road riding.
Of course, there is no longer a strict division, many riders are open to both profiles. For MTB rims, the asymmetrical design is widely used.
Only for downhill mtb rims, where the best impact resistance is important, we still use the symmetrical design.
ALL YISHUNBIKE CARBON CLINCHER RIMS ARE TUBELESS COMPATIBLE
There are a lot of advantages for tubeless tires over traditional clincher tires. Many brands and manufacturers have clearly stated these and riders also support.
We are also one of those supporters. Our engineering team has come up with the perfect tubeless design. Several points make up this perfection: Tire mounting, inflation, anti-leakage and tire burping air.
To make mounting the tire as easy as possible, the depth of the tire channel is the key point.
Too shallow or too deep would make tire installation difficult and even damage the rim. It would also affect the inflation of the tire.
The tubeless tire would get the hassle of tire burping air if the tire pressure is too low and the tire is squeezed.
So we make a slight bump between the drop channel and the outer bead seat. With this bump, we could make sure a hassle-free ride for low tire pressures.
To stop leaking air, we have designed a smooth tire bed surface to fit tubeless tapes.
Nipple hole takes the tension from spoke, also the impacts from the ground.
We have developed a one-piece pre-mold reinforcement for balancing weight and strength on the nipple holes.
Many manufacturers do similar efforts, but there are many variations during manufacturing.
For example, the actual thickness would be different from the initial design causing strength loss and wheel-building difficulty, and failure.
This reinforcement demands a new mold and more costs, but greatly increases the production efficiency and stability. This solution still offers two options.
One is for lightweight rims, more costly; the other is for standard weight rims, more economical.
HOW TO ANGLE DIFFERENT FAW FABRICS AND HOW TO BE LAMINATED TOGETHER
Carbon prepreg is made by UNDIRECTIONAL ( UD ) fibers.
It means that the material benefits are effective in just the lateral direction.
But the products need to tackle tension and power from many different directions.
So our engineers have to work out different material angles for different parts of a rim with different FAW fabrics.
For example, on the nipple hole, the main tension is from the spoke, where force keeps trying to break the structure.
Here, we need to consider how to angle the fabric to resist this big tension.
The rim belly, tire bed, and the bead, all need different angled fabrics to be laminated together to combine a strong and stable structure to handle the different challenges.
Also, we need to consider how to laminate tens of layers of fabrics together. Again all about how to balance weight, stiffness, and strength for a carbon fiber product.
This work demands plenty of experiments, tests, and analysis to accumulate correct knowledge and experience. It’ s a long story about time and money, we need to keep trying, testing, and improving.