RZR Fact Sheet
FAQ
Every aspect of the RZR is designed for performance, with no short-cuts, and no compromises. Reynolds Composites Studio engineers created the lightest, strongest, most responsive production bicycle wheel on the planet. To make such a statement is bound to raise a few eyebrows–not to mention quite a number of questions. We’ve listed some of those questions below, along with our responses.
Q. “The RZR freehub body makes quite a loud clicking sound when freewheeling. Is that normal?”
A. The RZR pawls are designed to run “dry,” that is, they can operate without lubrication. The pawl mechanism is comprised of three individual pawls and three individual springs that pivot at an elbow, similar to Chris King and White Industries systems. The individual pawls with dedicated individual springs create a louder sound than DT Swiss or Shimano-style transmissions. The benefit of the individual pawl transmission style is that there is no single point of failure in the transmission system. The three individual pawls operate independently of one another. In the unlikely event of a spring failing or a pawl breaking, the transmission will continue to engage. The audible sound of the pawls as they engage the ratchet is amplified by the carbon-boron hub shell. The sound level of the pawl mechanism can be significantly reduced by packing the pawl chamber with grease. However, for reasons of weight and reduced speed of pawl engagement we do not recommend grease.
Q. “Does the O-ring seal have the potential to create drag and slow the wheel down?”
A. The RZR features an O-ring seal on the large flange (right) side that is designed to seal the pawl chamber from contamination. Friction between the cassette body and wheel hub due to O-ring friction is not a significant factor in wheel performance. Free wheeling means the cyclist is coasting, not applying power, and often has the intention of slowing. Therefore, free wheeling friction represents only a tiny fraction of the forces that cause a bike to decelerate. The second component of deceleration is brake application. From this perspective it is clear the O-ring seal plays an important role in minimizing contamination to the pawl chamber, but has no effect on the efficiency of forward acceleration. Conversely, when power is applied to accelerate a bicycle, O-ring seal drag is not a component of the overall mechanical drag influences acting to slow the bicycle.
Q. “How soon before there will be an RZR service center in the EU?”
A. We have already gotten comments on forums about this topic and need to make sure that our service course, even if in the United States, is the best it possibly can be. We are already in the process of setting up a European service center, but having one up and running will take about a year. We need to locate the most qualified technical personnel, train them on our technology, and indoctrinate them into the Reynolds “system.” However, a customer who invests up to 4000 € deserves to know that Reynolds is committed an identical level of customer satisfaction–no matter where they may live and ride.
Q. “There has been quite a bit of publicity lately concerning the failure of a MAVIC R-SYS in a race situation.
Since both wheels use carbon spokes, how can I be sure I would not have the same problems with the RZR as
were experienced with the Mavic wheel? “
A.Unlike metal spokes, bonded composite spokes can function in both tension and compression. This is true for both carbon (Mavic), as well as carbon-boron spokes (RZR). The failure mode for carbon tends to be compression because carbon is only one-third as strong under compression as it is under tension. Boron is equal in strength to carbon in tension. Boron is three times stronger than carbon in compression, making it an ideal material to function as part of a tension-compression system. A carbon spoke can function effectively in compression if the deflection of the spoke from an applied stress does not exceed its strain limit. This means that when the spoke is stressed in compression it must be allowed to bend before its maximum compression strength is exceeded (in other words, before it breaks). In the process of bending the compressive load is reduced and catastrophic failure is avoided, just as a steel column would under compressive forces. The performance of carbon-boron composite exceeds the performance of a carbon composite structure in compression due to the enhanced mechanical qualities of the boron fiber. If, when compression stresses are applied to a carbon spoke, the spoke is rigid, and it does not bend (like the concrete column), yielding to the load, the spoke will fail catastrophically. This is a significant concept for carbon spoke wheels.
The RZR spokes have been tested to yield and, under high compressive loads, are designed to bend (deflect) up to 125 mm without breaking. However, keep in mind that, in an intact wheel, it is not possible for a RZR wheel to create a spoke deflection of 125 mm. (A typical spoke deflection in extreme use is 4-5 mm.) This means that an RZR spoke will not fail catastrophically, and that under extreme conditions the RZR spokes are only stressed to 4% of their limit.
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