you are dead wrong there.
replace single pivot with "rearward axle path" and you are ok, or even specify high pivot locations.
Corsair Bikes website update
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you are dead wrong there.
replace single pivot with "rearward axle path" and you are ok, or even specify high pivot locations.
Where is Corsair located?
yes, its acting like the upper link of a paralel link design, with the lower ling being the black part on the drawing, one pivot is the BB the other is the original single pivot.
what strikes me as a bit odd, is that if the design works like the animation would have it to be, the rearward axle path would only be achieved after 7 inches of single pivot travel have been used, ie not quite the situation when you care all that much about square bump compliance since you are bottoming out already.
hopefully its just that schematic thats oversimiplified, i think it has to be because it says it has an idler, said idler would be no good for the single pivot part of the travel since the main pivot is already in line with the chain, so idler could only be useful for the secondary pivot arrangement, and if those only are activated after 7 inches of travel, it wouldnt make much sense to use an idler since few people will be trying to pedal when the bike is that compressed, if at all possible due to pedals hitting the ground.
I know I can be surly, and I apologize. A fair amount of good natured banter can seem aggressive when typed. So screw you.
I'm no Sinister devotee, and I see what your saying about chain tug. Just seems like Sinister has a unique new idea that they showed off fairly early in it's development, so it's exciting to people.
I don't really understand where you were going with this entire paragraph, but 10 points for bizarre comparison and speculation.
All I was meaning when I used the term "replacement" was to move to a different place. Kinda' cryptic I know, but terms are bound to be a little weird when discussing a new idea like "travel area" as opposed to a traditional idea like axle path.
So, basically, the MTBR XC-riding computer jockies are the ones who will be using that bottom shock.
I know for me, I don't think that I'd ever get any travel out of it.
I know for me, I don't think that I'd ever get any travel out of it.
I laughed when I read your post. Yeah, I deserved that
I really, really hope that sinister can work the kinks out. They have a smooth, clean design that could hold the key to really opening up the axle area idea. I'm just a little taken aback at how people are all on the bandwagon when the only people to ride the bike are the ones that built it and the ones that won't buy any bike besides a sinister. The fact is that nobody knows how these bikes brake or pedal besides cannondale, and they abandoned the design entirely. I think it locks out rearward under braking, and forward under pedalling...so the question is how do you get around that. On a trail bike it's less important, but in DH, I like my floater.
I'm a big prononent of these bikes, I liked the BCD 2x4, and I dug the 2stage, but both of those bikes have a high pivot and low pivot, and since I already ride a bike with a high pivot, they really don't offer anything new. This corsair does just that by having a mid-pivot that can essentially move backwards an inch or two. Think of taking a commencal and being able to slide the pivot back and forth as well as rotating it in its travel. It could be a very cool design if tuned properly. All these companies keep pitching these bikes as "platform" bikes, instead of "area travel" bikes.
Hey - here's an idea. (I claim rights to any patent!)
Think of a GT Idrive pivot-in-a-rotating body type arrangement
Make the pivot the pivot of a swing arm (eg Turner)
Suspend the swingarm/activate primary shock somewhere/somehow... placement and linkage to suit geo. and required behaviour
Mount the rotating body at someheight above the bb
Constrain the rotation of the rotating body with a torsion spring (or similar, with damping)
Presto-chango
You've got a singlepivot that can wander.
I call it the wandering link. WL for short (also stands for the 'Whoops Link')
Think of a GT Idrive pivot-in-a-rotating body type arrangement
Make the pivot the pivot of a swing arm (eg Turner)
Suspend the swingarm/activate primary shock somewhere/somehow... placement and linkage to suit geo. and required behaviour
Mount the rotating body at someheight above the bb
Constrain the rotation of the rotating body with a torsion spring (or similar, with damping)
Presto-chango
You've got a singlepivot that can wander.
I call it the wandering link. WL for short (also stands for the 'Whoops Link')
Totally agree with you about the lack of knowledge. At this point it would probably be a lot easier to get the travel area design wrong than right.
Obviously this wouldn't solve any potential pedaling or pedal feedback issues, but I would imagine a simple telescoping floater arm could solve any braking issues. No?
A telescoping arm? Perhaps I've misunderstood, but a floating brake arm carries load along it's axis. A telescoping arm is just going to lock out as soon as you touch the brakes, regardless of what the suspension is trying to do.
thank you for catching that, my bad.
I can see a problem with this design.
If it has a wheel path area, then the leverage ratios are going to be all over the map while riding the bike.
Some hits will bottom it out, while others will not use as much travel.
I've tried designing this same thing, but came to the conclusion that leverage ratios would be all whacked, hard to get stiff rear end, and braking would feel inconsistant.
Regardless of my theory though, I would love to see how it rides! I'm sure it's pretty damn smooth riding on the small/fast stuff!
I'm surprised it's designed by Kiwi New Zealanders. Usually zee Germans get the reward for over-engineered uselessness.
If it has a wheel path area, then the leverage ratios are going to be all over the map while riding the bike.
Some hits will bottom it out, while others will not use as much travel.
I've tried designing this same thing, but came to the conclusion that leverage ratios would be all whacked, hard to get stiff rear end, and braking would feel inconsistant.
Regardless of my theory though, I would love to see how it rides! I'm sure it's pretty damn smooth riding on the small/fast stuff!
I'm surprised it's designed by Kiwi New Zealanders. Usually zee Germans get the reward for over-engineered uselessness.
no, you see, then you put rails on it, so that it doesnt lock out, and then you reinforce it some more and then it becomes a simple rail driven telescopic tension string reinforced floater brake control arm. simple, really.
Yeah, I see what you're saying.
But, I thought of a different way to do it specific to the Corsair. What about mounting the floater so it sits at a mid-point in the chain growth with a long brake mount arm to allow for chainstay growth, like a longer derailer would allow for a greater range of gears.
Also, unless this theory has a hole I'm missing, it could be applied to any "travel area" design, given that the arm was long enough to allow for total freedom of movement.
Hi, this is Doug from Corsair Bikes. We will reply to many of the questions and comments in the next day or so. But I'd like to point out that maybe some people did not see the tech brief icon at the top right of the web page for the Crown. It offers a fair amount of information concerning why we have done certain things with this design. For those interested in looking at axle paths on a computer screen, in the medium future we will be enhancing the website to show that as well.
Sweet first post. Welcome to the jungle Doug
Keen to hear more about your bikes.
Keen to hear more about your bikes.
That bike looks so friggin' good!
No tech questions here, since I am a people person I am just wondering if this Pablo dude (the designer) is the same guy that used to hang out with Robin Balloochi a lot and David K, the guy that said he had a FS bike in his head but was just trying to make it happen?
Looks like him anyway.....
Looks like him anyway.....
Yea, it's who you are thinking of... Pablo Tafoya.
looks like its a two piece link to give the swingarm another anchoring point, similar (but completely different) to what cortina does on their monopivot dh bike.
Wow, very cool to see his dream come to fruition!
looks like there is a bunch of e-arguing on the tech front, but the bike looks cool and the website looks nice too... so best of luck to him.
think they were grossmann project..i think? will as my german mate
That is a goofy design. The point of adding those links is to make the back end resist twisting. The wheel twists along the plane from the main pivot to the rear axle. The farther you move from that plane, the more leverage you have to twist or resist twist. The links Cortina has are maybe 2" from that plane, and will barely add any stiffness. By adding them, they compromised the chain stay and the main pivot. I would bet money that bike is flexier than a well designed single pivot.
It would be alot better bike if it had a complete tubular chainstay that triangulated the main pivot. And the link at the top of the rear triangle.
It kind of folds out as the bike delves into its travel...I've seen the flash animation, it's wiggety-whack. I think it's supposed to work kinda like a Horstie? Not sure.
yeah, good for him, i know pablo. looks like he is making another stab at it.
for all the other guys wondering about pedal feedback.
looks like he has it covered till the second bottomout shock
where esentially it goes from big ring pivot of 3'' above the bb
to like 12'' above the bb and pivots from the rear shock eyelet.
it will have hella pedal feedback then, but who pedals then. designs
with this amount of chain growth need a lot of extra chain which
slaps around a ton. on the 2x4 i had to run a long cage to handle it.
only way to have no feedback is concentric like the 2x4. est 1998
i saw this bike in whistler today. i wondered what it was. now i know evidently.
Hi Everybody,
Pablo and I have been monitoring a few sites (lurking) and have gathered up a number of questions and comments that we would like to comment on. I will post this to all of those sites. As I said previously, if you havent read the tech download at the site, you might want to do that. I tried really hard to make that document a pretty complete reference for this frame model. The address is;
http://www.corsairbikes.com/downloads/COR_Crown_Dossier08.pdf
One thing you will discover as Corsair rolls out its new product line is that we are not married to any single suspension design. For those of you who read my earlier post, you will remember me saying that, in my opinion, it was rare for suspension designers to stand on their soapbox and proclaim that their designs were perfect or the best. That being said, suspension designers often dont run companies, and many companies, through their marketing activities, do make some pretty strong claims about the suspension designs they have chosen to develop or use. Im OK with that. Alls fair in love and war. What you will see from Corsair is that we will develop and use a number of different suspension designs that we believe best fit the type of riding the bike is designed for. While this might disappoint a few of you who might want to see a whole line of frames like the Crown; I guess my reply is that if you like the Crown, I think you will find the other models to be equally compelling.
OK, there were comments and questions about weight, price, plenty of chain growth comments, does our design attempt to fix a problem that doesnt 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 doesnt mean cheap. I suppose our products will fall into the highest 25% of the pricing spectrum.
I dont 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, its 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? Wed 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 Crowns 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 wont 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 doesnt 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 dont see this bike as an answer to a problem that doesnt 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.
OK, enough said for now. Ive got to save a bit for next time.
Pablo and I have been monitoring a few sites (lurking) and have gathered up a number of questions and comments that we would like to comment on. I will post this to all of those sites. As I said previously, if you havent read the tech download at the site, you might want to do that. I tried really hard to make that document a pretty complete reference for this frame model. The address is;
http://www.corsairbikes.com/downloads/COR_Crown_Dossier08.pdf
One thing you will discover as Corsair rolls out its new product line is that we are not married to any single suspension design. For those of you who read my earlier post, you will remember me saying that, in my opinion, it was rare for suspension designers to stand on their soapbox and proclaim that their designs were perfect or the best. That being said, suspension designers often dont run companies, and many companies, through their marketing activities, do make some pretty strong claims about the suspension designs they have chosen to develop or use. Im OK with that. Alls fair in love and war. What you will see from Corsair is that we will develop and use a number of different suspension designs that we believe best fit the type of riding the bike is designed for. While this might disappoint a few of you who might want to see a whole line of frames like the Crown; I guess my reply is that if you like the Crown, I think you will find the other models to be equally compelling.
OK, there were comments and questions about weight, price, plenty of chain growth comments, does our design attempt to fix a problem that doesnt 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 doesnt mean cheap. I suppose our products will fall into the highest 25% of the pricing spectrum.
I dont 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, its 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? Wed 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 Crowns 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 wont 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 doesnt 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 dont see this bike as an answer to a problem that doesnt 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.
OK, enough said for now. Ive got to save a bit for next time.