Technology Improve Of Carbon-Bicycle Carbon MTB 650B Rims

After months past, most customers have feedback their ride tesing result on our carbon 650b rims & 650b wheels. And we also read some 650b review about our 27.5 carbon rim. We know there is a lot that needs to be improved.

And since last month, we have always been focusing on technology improve for 650b bikes rims. And we have done it well.

Please find as below five advantages of our new manufacturing process. And all the 27.5 mountain bikes rims & wheels we made from now on are pretty strong. We will not let most of our customers disappointed and will keep doing technology improvement. We will provide good 27.5 bikes rims & wheels for our customers.

1. For our original process & also other facotries, the carbon fiber is cut into 3 pieces, to make easy for layup process. Because one long piece of carbon will easy to cause wrinkle at some area. But cutting carbon layer into 3 pieces will make the strength weaker,also the weight will be added(because there are some overlapping area). Carbon fiber layer(prepreg) has maximum strength only along the lengths of the fibers. The new manufacturing, we have new way to use one piece long carbon, to cause no wrinkles and all the carbon fiber layers are continuous, only one area overlapping, the strength is also the strongest.

carbon 650B process

2. For all other factories and also our past manufacturing, we make one curing carbon ring first. Please see the picture(IV), then put it at the bottom of rim(at spoke holes area), and do the carbon layup for rims. Then put it in the mold and the whole rim shape is made after molding.If there is no curing carbon ring, the reinforcement carbon layers around spoke holes is easy to be offset(not at the center), this will cause the spoke holes wall thickness is not even(some area is too thin). But the curing carbon ring is cured first, it is will stay at the center area while we do the next layup process. This will ensure the spoke hole thickness.

But,this means the carbon ring is heated again. This will affect the strength, also if the surface of curing carbon ring is not clear enough, this will cause the layers around the curing carbon ring have small gap, and affect the strength around spoke holes. Also, the carbon ring is thick, this will make the weight higher.

For new manufacturing process, it is without curing carbon ring, we can ensure the reinforce carbon layers stay at the center, to ensure the wall thickness is even. It is our new manufacturing method. The wall thickness of spoke holes is thick enough. We make special carbon layup schedule to make the spoke hole area thick. After spoke hole tension test, we find the spoke hole tenstion is twice stronger than we using curing carbon ring. Also, it can save some weight.

650B rim carbon ring
curing carbon ring carbon fiber ring

Curing carbon ring

3. For all other factories and also our past manufacturing, there will be big square hole at rim bed, to make the air bags easily out after molding, then bond one carbon plate on the square hole. The square hole is big, after tire pressure, the rim width around square hole area will become much bigger than other area.

For our new manufacturing, there is no square hole, we make the hole in a small round hole to let the air bag goes out, and the hole can also be spoke hole on rim bed finally. This will make the strength much improved.

carbon rim square hole

4. For all other factories and also our past manufacturing, the rim cross-section is not very smooth. Please find as below, it is high lighted in red circle.

For our new manufacturing, our eniggners improve the layup schedule and make it smooth, and the strength is much improved.

650B carbon rim cross section

650B carbon rim cross section

5. To improve the system of quality assurance. All of our new 650b rims are done below test and ensure all the rims are good.

Test item Standard Remarks
Lateral stiffness 5mm↓ Testing weight: 4.72kg
Tire pressure 0.5mm↓ rim width formation Tire pressure 60psi
Spoke tension 300KG↑ No visible crack
Breaking test 300KG↑ No visible crack
Impact test 600mm/22.5KG No visible crack

Inspection item Standard
Inner width 23+/-0.15mm
Spoke hole diameter 4.5+/-0.15mm
Valve hole diameter 6.4+/-0.15mm
Appearance clean, even, no stain
abnormal noise Shaking, nothing left in the rim
Number of holes 24, 28, 32, 36…
Weight standard +/-15g
Flatness 0.3mm↓
Roundness apex – nadir ≦ 0.6mm

650b rim lateral stiffness test
650b rim lateral stiffness test
27.5er rim lateral stiffness test
27.5er rim lateral stiffness test
650b rims width check after tire pressure
650b rims width check after tire pressure
650b rim spoke tension test
650b rim spoke tension test
650b rims impact test
650b rims impact test

New Update : All wide 29er all mountain rim, 27.5er rim and New 26er DH rim(33mm wide & 30mm deep rim) are now all used new process. And For new process rims, only can be available for Carbon-bicycle. We haven't sold to any other local trade companies.
Learn more about: How to distinguish rims with new & old manufacture process

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