jvnixon
07-02-2007, 01:03 PM
Corsair Crown
http://www.sicklines.com/2007/06/27/corsair-bikes-crown-dh/
http://www.corsairbikes.com/
PDF Information attached and at
http://www.corsairbikes.com/downloads/COR_Crown_Dossier08.pdf
http://www.sicklines.com/news-images/corsair_1.jpg
http://www.sicklines.com/news-images/corsair_2.jpg
Finally as an overview, this frame offers;
• Ability to run single or dual shock system
• three degree adjustable headtube to maintain optimal geometry
• low mass swingarm for traction
• low stroke ratio
• idler pulley for efficient pedaling
• CenterBalance design for improved handling
• optimized axle-path for energy absorption
• high-end manufacturing and materials are used.
OK, there were comments and questions about weight, price, plenty of chain growth comments, does our design attempt to fix a problem that doesn’t exist, who needs the complexity and swingarm stiffness. Easy ones first;
Prices will be released at EuroBike and Interbike time period. I believe in offering value. But that doesn’t mean cheap. I suppose our products will fall into the highest 25% of the pricing spectrum.
I don’t know the exact weight of the Crown yet. What I do know is it will be among the lightest 25% of DH race bikes. To address the weight of the second shock; the weight of the shock itself is 175 grams (approx 6-7 ounces). Beyond that, it’s a bit difficult to say what would need to be there anyway, and what is there only because of the second shock. In the end, if a rider is utilizing the blow-off shock, we assume that they are doing so for a performance advantage which they believe outweighs the additional grams.
Giving further thought to weight and alternatives, lets also understand that as an alternative we could utilize a 10.5” e-e coil shock with a 3:1 stroke ratio to achieve a similar amount of travel. What does that weigh? We’d rather have a lower leverage ratio. And this would not be the optimum shock set-up for all race courses.
We are working on getting some additional pictures of the swingarm and surrounding assembly up on the website. The swingarm is mounted to press-fit cartridge bearings via an axle-less pivot. The swingarm bolts around the axle-less pivots and bearings in a clam shell manner much like a piston rod is attached to the crankshaft of a car. Our design uses very tight tolerances eliminating any mechanical play which can occur with traditional axle/spacer/nut configuration. Because of this mounting system, along with the relatively short length of our swingarm, the Crown’s swingarm offers excellent lateral stiffness.
For those of you who may not fully understand chain growth, it is measuring the length of the chain between the rear cog and the front chainring. As the swingarm on a bike compresses, it is typical for this distance to grow longer. As a result of the swingarm compressing and the resulting chain growth, at least two things happen; first, the rear derailleur needs to accommodate the chain which is being forced to span a greater distance and second, the chain may cause rearward pressure on the pedals, which is felt by the rider, and reduces pedaling efficiency.
As explained in that fine document on the website, because the Crown utilizes an idler pulley which is located on the swingarm, the chain growth is limited to 11mm at 170mm of travel and 26mm at the full 240mm of travel. These are world class numbers resulting in a bike that won’t snap off rear derailleurs nor cause inefficiency due to ‘chain pull’. Finally, as a result of the placement of the idler pulley, as well as the limited amount of chain growth, during pedaling there is actually an ‘anti-squat’ effect which improves pedaling efficiency. (always a benefit for a big bike)
Is the Crowns design and technology an answer to a problem that doesn’t exist? Well, there are plenty of good bikes out there. Sometimes the simplest design wins the race and sometimes the so-so design with the best marketing wins the race. (maybe it has something to do with the rider?) Racing is a dynamic environment. Courses and course conditions change from week to week and even hour to hour. In developing the Crown, we believe we have created a bike that can offer racers the ability to optimize their bike set-up for all conditions. No compromises, no excuses. In the end, we don’t see this bike as an answer to a problem that doesn’t exist, what we do see it as is an opportunity to raise the technology and performance bar in order to give riders the opportunity to maximize upon their personal potential.
http://www.sicklines.com/2007/06/27/corsair-bikes-crown-dh/
http://www.corsairbikes.com/
PDF Information attached and at
http://www.corsairbikes.com/downloads/COR_Crown_Dossier08.pdf
http://www.sicklines.com/news-images/corsair_1.jpg
http://www.sicklines.com/news-images/corsair_2.jpg
Finally as an overview, this frame offers;
• Ability to run single or dual shock system
• three degree adjustable headtube to maintain optimal geometry
• low mass swingarm for traction
• low stroke ratio
• idler pulley for efficient pedaling
• CenterBalance design for improved handling
• optimized axle-path for energy absorption
• high-end manufacturing and materials are used.
OK, there were comments and questions about weight, price, plenty of chain growth comments, does our design attempt to fix a problem that doesn’t exist, who needs the complexity and swingarm stiffness. Easy ones first;
Prices will be released at EuroBike and Interbike time period. I believe in offering value. But that doesn’t mean cheap. I suppose our products will fall into the highest 25% of the pricing spectrum.
I don’t know the exact weight of the Crown yet. What I do know is it will be among the lightest 25% of DH race bikes. To address the weight of the second shock; the weight of the shock itself is 175 grams (approx 6-7 ounces). Beyond that, it’s a bit difficult to say what would need to be there anyway, and what is there only because of the second shock. In the end, if a rider is utilizing the blow-off shock, we assume that they are doing so for a performance advantage which they believe outweighs the additional grams.
Giving further thought to weight and alternatives, lets also understand that as an alternative we could utilize a 10.5” e-e coil shock with a 3:1 stroke ratio to achieve a similar amount of travel. What does that weigh? We’d rather have a lower leverage ratio. And this would not be the optimum shock set-up for all race courses.
We are working on getting some additional pictures of the swingarm and surrounding assembly up on the website. The swingarm is mounted to press-fit cartridge bearings via an axle-less pivot. The swingarm bolts around the axle-less pivots and bearings in a clam shell manner much like a piston rod is attached to the crankshaft of a car. Our design uses very tight tolerances eliminating any mechanical play which can occur with traditional axle/spacer/nut configuration. Because of this mounting system, along with the relatively short length of our swingarm, the Crown’s swingarm offers excellent lateral stiffness.
For those of you who may not fully understand chain growth, it is measuring the length of the chain between the rear cog and the front chainring. As the swingarm on a bike compresses, it is typical for this distance to grow longer. As a result of the swingarm compressing and the resulting chain growth, at least two things happen; first, the rear derailleur needs to accommodate the chain which is being forced to span a greater distance and second, the chain may cause rearward pressure on the pedals, which is felt by the rider, and reduces pedaling efficiency.
As explained in that fine document on the website, because the Crown utilizes an idler pulley which is located on the swingarm, the chain growth is limited to 11mm at 170mm of travel and 26mm at the full 240mm of travel. These are world class numbers resulting in a bike that won’t snap off rear derailleurs nor cause inefficiency due to ‘chain pull’. Finally, as a result of the placement of the idler pulley, as well as the limited amount of chain growth, during pedaling there is actually an ‘anti-squat’ effect which improves pedaling efficiency. (always a benefit for a big bike)
Is the Crowns design and technology an answer to a problem that doesn’t exist? Well, there are plenty of good bikes out there. Sometimes the simplest design wins the race and sometimes the so-so design with the best marketing wins the race. (maybe it has something to do with the rider?) Racing is a dynamic environment. Courses and course conditions change from week to week and even hour to hour. In developing the Crown, we believe we have created a bike that can offer racers the ability to optimize their bike set-up for all conditions. No compromises, no excuses. In the end, we don’t see this bike as an answer to a problem that doesn’t exist, what we do see it as is an opportunity to raise the technology and performance bar in order to give riders the opportunity to maximize upon their personal potential.