We use High-Tensile TC-35 carbon for the majority of the lay-up. This gives the rim a very high strength with sufficient stiffness to cope with hard application of the wheels. So, rather than use a stiffer, but more brittle carbon type, we chose durability over ultimate stiffness. In some lay-ups we add some higher modulus sheets to increase stiffness locally.
All rims are molded with a process we call EcomTM (Equal Compression). This means that the rims are molded with a custom-made air bag that has the inner shape of the rim . This makes sure that the pressure/compression is equal on the entire inner surface of the rim. Result is a practically void less rim section and a smooth wall on the inside of the rim. Without voids, the carbon sheets are completely fused into one system. The rim structure is much better and you can make the rim lighter and stronger.
EcomTM also provides for a smooth inside (no wrinkles!) which is a great feature and not common for carbon rims. This is for instance very beneficial for the nipples. Just imagine how the force of the spoke tension is applied through the nipple seat onto the rim itself. If the nipple seat isn't smooth, the transition of the force isn't clean and optimal. This might cause spoke, nipple or spoke hole failure in future. FFWD rims are made with EcomTM which ensures longevity.
We actually use multiple layers of different types of carbon. Only the outer layer is made from a 3K weave. Underneath this layer are layers of UDF (Uni-Directional Fiber) sheets. A mixture of different angles to resemble a uniform material. Because carbon fiber can handle tension very well, we have to mix up the layers to make the rim stiff and strong enough. Pressure is not a great feature of a fiber. Just think of a string being pushed ). But when mixed correctly, the different angles interconnect through the resin to make it resistant to all kinds of forces .
The 3K has a slightly lower stiffness/weight ratio than UDF (Uni-Directional Fiber) sheets of equal fibers, but it makes up by giving the rims a bombproof feature. Why? Because when a strand (or multiple) gets cut in UDF, by crashing for instance, the sheet is compromised and the tear will expand through a larger part of the sheet at continuous workload. A weave will stop the tear because it is intervened by the crossing layer of strands .
Although it is not advised to ride with a 'hole' in your rims, situations can occur where you might not know of a damaged rim or it is not an option to stop right away. Then you have the extra safety of the 3K weave to get you home.
No, you can't!
There are two very important reasons for this.
1) The brake pads we supply with our wheels are for carbon rims only, because of the special compound of which the pads are made. This compound mix is not suitable for optimum brake performance on alloy surfaces.
2) It is also very important to keep the brake pads that are used for alloy rims separate from the ones you use on carbon rims. It is very possible that alloy splinters can accumulate on the pad when braking. And when you would use these pads on carbon rims, the splinters will scratch the carbon and possibly damage the fibers. This is an important safety issue which must be avoided. So, please think of your pads when you have different wheel sets.
The pads we deliver with every wheel is a specific compound, engineered to give the best performance in combination with our rims in every condition.
As long as the brake pads are designed for carbon rims you can use those as well. For instance, besides our own pads we also have good experiences with the Swiss Stop Yellow Kings.
You can find loads of information on the internet on this subject. And since tires change in specifications throughout the years, it is hard to draw definite conclusions. For instance, many people were convinced that a tubular tire had a lower rolling resistance than a clincher. Many are reconsidering that statement. There are very good clincher tires on the market now with 'tubby'like behavior.
There are a few general things we can say when comparing the two types.
Tubular / Clincher:
- lighter / heavier tire (in weight)
- mostly better ride qualities / mostly lesser ride qualities
- lighter / heavier rim (in weight)
- spare tire is heavy / spare inner tube is light
- changing a flat tire is mostly hard because of the glue / changing an inner tube is pretty easy
- small chance / big chance on running flat after a pinch (rim hits the ground and crunches the tire)
- more / less costly per tire
- smaller / wider range of choice as far as price and level
I guess the important thing is that you should make a choice depending on your specific use and budget.
But, in the end for every situation is a solution. For instance, are you heading out on your own for a long trip? You can use tubulars, but do take along a spare, a Pit-Stop container (or Stan's or Tufo's Sealant) and make sure the cement isn't fully hardened, so that you can pull of the tire with your hand. Or you can go out on clincher wheels and just take along a spare inner tube and two (plastic!!) tire levers.
FFWD Wheels does not recommend the use of adhesive rim tape for mounting tubular tires. Tubular tires are best fitted to the rim when glued with specific glue for carbon rims.
NEVER sand a carbon rim!! This instruction only applies to alloy rims.
NEVER use a metal tool to mount the tire!!
You can use a solvent like acetone to get the glue off. But if it is not much then you can glue the new tire on top of the 'old' glue. This will soften up when it comes in contact with the new glue.
NEVER use a sharp or hard tool to scrape off the glue. You could damage the carbon rim and endanger the structural integrity.