| Author | Message | ||
     X1glider |
Really? So, why are moto GP bikes, AMA super sort, stock and FX bikes not running single discs? Why are the Buell FX bikes having so many problems with their ZTLs?
Do you really know "what" the roll axis is and "where" it is? How it affects handling? This is funny:
"For braking maybe...Hmmm...what else could the brakes have been designed for? Unsprung mass is our enemy? Do you know why? Did Erik tell you it was so? Do you really think it's necessary for "everything" to be "sprung" weight? What about rotating mass? You have to have both, which would you prefer to have less of? Oh and what does the brake have to do with absorbing mid corner bumps? Did Erik invent a suspension brake when I wasn't looking? Not trying to belittle the XB's innovativeness. Different doesn't mean better anymore than typical meaning better because eveyone does it. But I am finding it funny that so many have so much hero worship for Erik Buell that they've fallen for Erik Buell's BS design principals and ideas. I don't believe he's the first to think of such things and I also don't believe he's correct on a certain number of things as well. What he has done is fool a lot of people into believing his hype. Pretty soon I'll be reading posts of a group of Buell owners committing mass suicide from drinking too much Koolaid. There's a lot of talk here about roll axis, cg, unsprung weight, how a dual brake setup is heavier so it must be inferior... Lots of armchair engineers here. Not that I'm a bike engineer either, but I probably have a distinct advantage over quite a few here when it comes to understanding the truth. How many actually know the principals behind the buzzwords? Sounds like quite a few need to go to engineering school, get some real world experience, then try to wade though the BS to discover the truth. Buells are cool. Buells are not the best, however. There is no best. (Message edited by x1glider on September 13, 2004) | ||
| Hootowl |
"Um they intended it from the start. The fuel in the frame concept ( the first version) was applied for patent in 1989 and approved in 1991." Not according to the interview with Erik Buell on Buell.com It was a way to solve a problem, it was not an end unto itself. | ||
| Bomber |
glider -- yessir, I do -- I am alos not an engineer, but I do have some understanding of the terms, their applications, and, luckily, have spent some time talking over their application to bike on the stredet and track with those who ARE engineers (sounds like we share that) as for why race teams may or may not use any one of a nuymber of leading edge technologies, racers are pretty conservative, and tend to go with what works (duh!) -- most often, this translates into things with long development cycles behind them -- you'll see peripheral brakes on race bikes (again) when their advantages outwiegh their costs on the racetrack . . .. . same reason non-fork front ends will come back to the race track (again) when they've had sufficient development and, fully agreed, there is no "best" . . . only a series of compromises that lead, one can hope, do an acceptable outcome | ||
| Spiderman |
I'm not sure I'm clear on your assertion. Please explain. What specifically is the "only one opinion on this board" to which you refer? If I had to explain you wouldn;t understand  }Not according to the interview with Erik Buell on Buell.com I have also seen said interview and he has said it multiple times to. But take a gander on the patent website. And yes I do belive the ZTL is better than all the Radial 4 pots I have ridden. I am not just a Buell enthusiast I am a sportbike enthusiast with mutiple brands ridden under my belt.} | ||
| Uwgriz |
Unsprung mass is our enemy? Do you know why? Did Erik tell you it was so? It's not because Erik said so, it's because it is so. Srung mass is mass that can be accounted for and tuned for, unsprung mass just is and the more of it there is, the higher the percentage of vehicle mass that can't be tuned for in the suspension. Oh and what does the brake have to do with absorbing mid corner bumps? See unsprung mass. And before you say it, I am an engineer and have taken several courses in vehicle dynamics. | ||
| R1DynaSquid |
Dual discs just look so right & cool tho. I love the looks of the dual black aftermarket rotors on an X1. But I was also able to do stoppies at will with the single rotor, so I doubt duals would have stopped me any faster. Maybe the amount of heat per rotor would be less since each one only has to do half the amount of work so brake fade would be less of an issue? I think anyone who claims they really can feel the difference is just fooling themselves. I have state of the art dual Radial calipers & while they look trick & certainly do the job of stopping the bike from subsonic speeds, I personally cant detect any difference between them & a conventional setup. | ||
| M1combat |
"Why are the Buell FX bikes having so many problems with their ZTLs?" I don't seem to remember hearing that they are... Of course, I'm no insider by any means. Are you? Pray tell. "Unsprung mass is our enemy? Do you know why? Did Erik tell you it was so? Do you really think it's necessary for "everything" to be "sprung" weight? What about rotating mass? You have to have both, which would you prefer to have less of? " Yes, I know why... No, I think it would be bad for everything to be sprung weight... One, it's not possible. The definition says that there is a spring... 1/2 of said spring is unsprung weight. Beyond that... Sure, I'd love to ride a completely rigid bike with steel tires... "what else could the brakes have been designed for" When Erik and Co. took the task of designing the XB they looked at all the parts and tried to find a way to use them for more than one purpose. That's sort of the beauty behind the ZTL brake. It works easily "good enough" compared to the best brakes in the world AND reduces unsprung weight by a great deal. Why do you suppose that other manufacturers spend zillions of dollars to shave ounces off the brakes on their systems? To reduce unsprung weight... The nice thing with the ZTL is that it floats, works AND brings back some of the rotating mass that was removed from the rim. Face it, it's a brilliant and out of the box solution. "Oh and what does the brake have to do with absorbing mid corner bumps? Did Erik invent a suspension brake when I wasn't looking? " Uhhhh... hmmmm... Screw it - Thank you, drive through. In a word, sort of  . Pay better attention next time. "I also don't believe he's correct on a certain number of things as well." And exactly what would those be? If you're going to slam the guy that you feel we hold in hero status at least bring some tech instead of baseless and down right humorous •••-clownery. Thank you, drive through. "Not that I'm a bike engineer either, but I probably have a distinct advantage over quite a few here when it comes to understanding the truth. " Yeah, you probably do have an advantage over most here... But not all of us . Buzzwords uncovered - 1. Roll Axis - The axis around which a bike will roll... It's based upon the location of the contact patch and the CG. It will generally be above the CG on a bike and below the CG on cars. Have you ever heard of roll-center migration? How about Instant Center? 2. CG - well, that one's pretty obvious... 3. Unsprung weight - In our application... The wheel, tire, rotor, caliper, a good deal of the brake lines and fluid, the fork tubes (lower portion and all that is attached to the lower portion) and half of the spring. The reduction of unsprung weight will cause a reduction in the amount of inertia that is generated when the tire is attempting to travel over a bump. The tire will deform less on the face of a bump, and will travel down the back of the bump with more conformity. This will give you a more stable jounce and more traction in rebound. It also allows a different tune that will affect the chassis less. This is a good thing. 4. "how a dual brake setup is heavier so it must be inferior" - See unsprung weight. It's better for handling and the same or better for braking. It's not JUST the location of the rotor though, it's also the fact that you can build the rim lighter because the torque doesn't have to travel from the rotor, to the hub, turn 180 degrees, travel through the spokes (this is the important one), then through the tire. It's got 90% of that trek completed at the outset and the spokes can be designed a LOT lighter. Have you ever held the front wheel assembly in your hand at the same time as a dual disc heavy assed wheel conventional setup? 5. You missed one - a. Mass Centralization - Go find the definition of "Polar Moment of Inertia". Have a nice day. (Don - Still not an engineer, but learning) "Instead of fixing a broken bike, just buy another one. " What exactly is your philosophy on preventative maintenance Glider? | ||
| X1glider |
Reducing unsprung mass is fine in a four wheeled vehicle because the tires are flat on the ground due to the design of the control arms and all the vehicle's weight is on top of the tire's contact patch. The body rolls in turns but the tires stay flat. The rolling adds downforce to the outside tires for better traction too. It's a bit different on a bike. Sprung mass' problem is that the mass moves. Yes, it can be tuned. A bike loses traction when the suspension becomes unsettled. It becomes unsettled when all that mass is moving towards the contact patch. That's a lot of kinetic energy to be absorbed and controlled by the suspension. The suspension works best when upright. Sprung mass is absorbed through the suspension and ultimately is transfered to the unsprung mass then to the pavement. Leaned over is the big problem. When all that mass is moving, trying to go in a different direction than where the bike is pointing, it is also trying to rebound in yet another direction. Makes a lot of sense to limit how much of the bike is moving in directions you don't want it to go and keep the weight on top of the contact patch as much as possible. | ||
| M1combat |
"I think anyone who claims they really can feel the difference is just fooling themselves." Mostly... It's not about the stopping power any more. It's about the feel at the lever. The ability to correctly modulate. The Buell brake excels in this. "Maybe the amount of heat per rotor would be less since each one only has to do half the amount of work so brake fade would be less of an issue? " Sort of... The Caliper has to do twice the work, but one must remember that the surface area of the ZTL rotor is MUCH greater than a standard rotor, so it cools itself better than one small conventional rotor. Probably not as well as two conventional rotors, but I don't think fade is an issue in our application with todays technology. | ||
| M1combat |
"The body rolls in turns but the tires stay flat." Exactly which type of suspension keeps the tires flat (Which is NOT an optimal configuration)? Aside from the fact that this is NOT what you want, it's impossible because you are working with two control arms that NEED to be non parallel. This gives you FVIC's and SVIC's. They need this because you need Caster and Camber Gain. Camber gain allows for a thing called "Camber Thrust" and Caster allows the wheel to try to gently center itself AND allows you to dial in some Camber gain on the outside tire, while dialing OUT camber on the inside tire. the only system I can think of that keeps the tires flat would be a perfect four link setup with a TA and Watt's link (This would be one of many stick axle designs). Even then, it would only be "perfect" for a VERY limited range of it's travel, and still never gives camber curve so it's not optimal for what makes things corner. "all the vehicle's weight is on top of the tire's contact patch" Are you familiar with corner weights? "Leaned over is the big problem. When all that mass is moving, trying to go in a different direction than where the bike is pointing, it is also trying to rebound in yet another direction. Makes a lot of sense to limit how much of the bike is moving in directions you don't want it to go and keep the weight on top of the contact patch as much as possible." Which has absolutely nothing to do with the reduction and benefit therein of unsprung weight. "The suspension works best when upright." The suspension is always upright. At a 45 degree lean angle, a 2" bump makes a 4" bump. It still causes the suspension to travel upwards relative to the bike. Hence, the suspension is always upright. It's the reduction of unsprung weight that allows the suspension itself to absorb most of this 4" as opposed to transferring it to the chassis. It's more stable because there is less inertia trying to keep the unsprung mass where it's at. The bike will not compress the pavement (much) so all 4" have to be absorbed. You want the unsprung mass to absorb all of it. That being impossible, we'll settle for as much as we can get. | ||
| X1glider |
Several race sites around that have reported this and quoted from the pits.
They spend all that money shaving ounces off the brake so that the wheels will spin up faster for better acceleration. Also one of the reasons for going to 16.5" wheels. Having rotating mass is fine for cruising at steady speeds, but hinders acceleration and deceleration. A few of the problems with floating rotors is that it contributes to vibration, adds complexity and weight to the design and causes the rotor to walk side to side against the pads creating perpetual friction and forcing the pads outward which means you have to grab more brake when you need it. A properly shimmed caliper will keep the rotor centered between the pads.
Nothing has been said to prove the statement. Please explain then.
Who said I was slamming him? Contradicting, yes.
I love a challenge! I'm not as quick to jump to one as Blake is,  but I accept, if that's what you're after.
No need to define them for me... I know what they are.
Sounds a though you've read an article by Erik in Fuell. It's a good idea. BMW meets Erik and everyone else halfway for that reason. It's a good compromise. My beef is where Buell place that weight. That gyroscope makes you fight the bike to lean it over, keep it leaned over and then flick it if need be. Not a good handling property IMO. Ride some other bikes to experience the difference. My FXDX and BMW do not have that problem.
wasn't my intention to mention every physics related principal in every book.
Bob - M.E...always learning.
In what context was that quote taken from me and where? Nowhere in this conversation. I don't doubt you that I said it somewhere, but probably out of fun. | ||
| X1glider |
Sure does. Makes a difference in handling. You don't want the suspension moving around fighting with itself while cornering. Next time you low side, you may understand. | ||
| X1glider |
We agree on this. Fade still is an issue as is overheating the brake fluid. Brake modulation is paramount. I can't think of a modern bike whose brakes will not slam you head first into the ground. Feel is where it's at and if it feels good you'll know it. If it feels bad, you'll know that too. | ||
| Uwgriz |
The rolling adds downforce to the outside tires for better traction too. And takes away from the inside tires. You're better off limiting that roll because the loss on the inside tires outweighs the gains of the outside. Hence anti-roll bars. (Message edited by uwgriz on September 13, 2004) | ||
| M1combat |
"A properly shimmed caliper will keep the rotor centered between the pads." What about a rotor that's mounted with springs pressing it against it's keepers? Sounds even BETTER to me as it will allow a centered rotor under no braking AND flex during breaking... :P. "They spend all that money shaving ounces off the brake so that the wheels will spin up faster for better acceleration. Also one of the reasons for going to 16.5" wheels." You don't hink it has anything to do with better mechanical advantage? Sure, reduction of rotating mass is good for a little acceleration, but I think the REAL reason for 16.5" is better mechanical advantage. It also allows the engine more revs at the same speed so you have more HP to work with... "Nothing has been said to prove the statement. Please explain then. " I was kind of hoping I wouldn't have to go over it again... Less inertia helps the suspension move w/o affecting the chassis. Therefore... It's more stable over bumps in a corner (and in a straight line, but I don't really care too much about that). "My FXDX and BMW do not have that problem. " But neither of those bikes are as stable over mid corner bumps. Just FYI, the XB's are extremely flickable... Mid-corner line adjustments are very precise and easy to do. "Instead of fixing a broken bike, just buy another one. " You have that in your profile. "Sure does. Makes a difference in handling. You don't want the suspension moving around fighting with itself while cornering. Next time you low side, you may understand." This sounds more like you are trying to talk about polar moment of inertia... The amount of un-sprung weight has little or nothing to do with the REACTION of sprung weight due to rider input. It has more to do with the REACTION of the sprung weight to the forces that make it through the unsprung weight. I don't think you understand what you are talking about... I've read you statment a few times. I'm willing to say that maybe I'm just not comprehending exactly what you are saying with this quote... "Leaned over is the big problem. When all that mass is moving, trying to go in a different direction than where the bike is pointing, it is also trying to rebound in yet another direction. Makes a lot of sense to limit how much of the bike is moving in directions you don't want it to go and keep the weight on top of the contact patch as much as possible." Please state that more clearly... | ||
| R1DynaSquid |
"My FXDX and BMW do not have that problem. " But neither of those bikes are as stable over mid corner bumps. Just FYI, the XB's are extremely flickable... Mid-corner line adjustments are very precise and easy to do. Supposedly from what I have read BMW's front end setup..tele lever or some deal like that is extremely stable over bumps while turning. | ||
| Rick_a |
Back to the subject, I believe Buell is building innovative streetbikes, marketing them as such, and racing them. Other manufacturers are building upon proven sportbike platforms for the purpose of marketing them for their track worthyness. Just different approaches, as I see it. | ||
| Blake |
Bob, If you cannot recognize the advantage of reduced unsprung mass on a motorcyle I'd have to wonder about your qualifications as an engineer. To put it simply, less unsprung mass improves the ability of the suspension to keep the tire firmly planted upon the road. So that is the answer to your flippant question about how a brake can improve the action of the suspension. Less mass is better no matter from where it is taken. "But I am finding it funny that so many have so much hero worship for Erik Buell that they've fallen for Erik Buell's BS design principals and ideas. I don't believe he's the first to think of such things and I also don't believe he's correct on a certain number of things as well. What he has done is fool a lot of people into believing his hype. Pretty soon I'll be reading posts of a group of Buell owners committing mass suicide from drinking too much Koolaid." I'll freely admit that I highly respect the achievements of Erik Buell and appreciate his genius. Not sure anyone characterizing as "BS design principals and ideas" or "hype" the major innovations and design philosophy developed and implemented by Buell will have any credibility on this discussion forum or as an engineer. Are you certain that you know what you are talking about? I have my doubts. | ||
| Blake |
I'd sure like you to tell us all which if any of Erik Buell's design principles are "BS." I'd also be interested to know upon which "things" you "don't believe he's correct." How has he fooled us? Did you believe that we bought our Buells thinking they were the fastest racing motorcycle made? Would be tough to fool a lot of us, as we took a Buell for a test ride before deciding to purchase one. For me, my '97 Cyclone is still the best bike on the face of the Earth. | ||
| Newfie_buell |
Sorry Blake, YOUR WRONG - All Wrong The S1 is the best bike on the face of the earth!!! Just thought a little humor here would help!!! | ||
| Slaughter |
I'm not necessarily a blind fan but I do hold and deal with patents from time to time as an engineer. Here are some points you are free to take exception to (from the US Patent and Trademark Office) - search by number or inventor http://patft.uspto.gov/netahtml/search-bool.html PAT. NO. Title 6,773,077 Lightweight motorcycle wheel 6,672,419 Motorcycle front brake rotor mounting 6,609,585 Motorcycle swingarm having integral oil storage compartment and caliper mounting 6,601,667 Motorcycle engine cooling system 6,575,259 Motorcycle swing arm having removable section to facilitate removal of flexible drive member 6,561,298 Motorcycle front brake rotor mounting 6,516,910 Motorcycle swingarm having integral oil storage compartment and caliper mounting 6,484,837 Motorcycle frame having integral fuel storage unit and break-away steering head 6,267,193 Motorcycle muffler 6,213,240 Motorcycle engine and transmission mounting system 6,213,238 Motorcycle sprocket assembly D440,190 Footpeg support unit 6,105,701 Motorcycle with cooling air channels 5,577,790 Shock absorbing seat mount 5,435,584 Cycle rear suspension with shock absorber built into frame lug 5,332,246 Single sided cycle rear suspension system with vertical wheel mounting means 5,303,795 Motorcycle luggage carrier 5,295,702 Single sided cycle rear suspension system 5,226,674 Cycle rear suspension system 5,209,319 Motorcycle front suspension 5,205,572 Cycle rear suspension system 4,989,696 Motorcycle front and rear disc brake system 4,964,484 Motorcycle fairing 4,951,774 Combination motorcycle frame and fuel tank 4,776,423 Motorcycle chassis with uniplanar motor vibration isolation 4,568,101 Automatic suspension system 4,488,761 Wheel disc brake 4,058,181 Motorcycle suspension systems 4,049,090 Brake discs (Message edited by slaughter on September 13, 2004) | ||
| Crusty |
I'm not an engineer, I'm just a guy who rides motorcycles a lot. I've owned motorcycles from Great Britain, Italy, Germany, Japan and the U.S.A. I've been riding for 35 years. I roadraced a bit, back in the '70s. I used a motorcycle as my only transportation for several years in the Greater Boston area. A few years ago, after one problem too many, I was going to get rid of my Buell. The only reason I didn't was because I couldn't find anything that made me feel as good while riding it. Then I dove in, installed all the upgrades and have had a reliable and extremely rewarding machine ever since. I think that it's interesting that people have a need to come to a Buell enthusiast's site and tell us how bad our bikes are. I don't go to other marques enthusiast sites and badmouth their bikes of choice, even when I think that they're pieces of over rated junk. Anyway, I'm quite happy to ride my "BS design principle" on a daily basis. BTW, Blake and Newfie, you're both wrong; the S3-T is the most beautiful motorcycle ever made. | ||
| Doughnut |
Are you all drugged up? The S2 is the purtiest.  | ||
| Blake |
Newf, Now you gotta bring your S1 to Texas and prove it to me.  I'll tell the chiggers, fire ants, snakes, and spiders you're on your way.  | ||
| Xb9er |
Thanks Crusty, I think you speak for many of us. Mike. | ||
| Easy_rider |
If a Cyclone leaves Texas at full throttle and at the same time an R1 leaves Chicago at 3/4 throttle..... | ||
| Paulinoz |
Is that the African or European R1 you are talking about. | ||
| M1combat |
How about if the R1 were carrying a coconut husk? | ||
| M1combat |
I think I'm getting a sticker for the side of my frame... "BS Design Principle..." Too bad that's too long for a license plate. Anyway - Suspension geometry is one of my favorite topics. I'll certainly not say I know much about the subject, but a whole lot of the XB design platform is frickin' spot on for what I like in a bike. My favorite roads around here (where I have probably spent about 6000 of the 8500 on my 12R) are either very technical or constant 115 MPH sweepers. I try to keep it under 100. The XB just plain WORKS in that environment. I truly believe that there is hardly anything out there that is stock that will run around mountains as nicely. I've had it about 6" in the air and it seems to land very well too. I did break a belt on one landing, but it had developed a hole from having a small rock pushed through it. I was pretty much just waiting for the belt to break, and didn't treat it any different until it did. It took ~4500 miles. | ||
| Sandblast |
Dyna- To go back to your post way up there, they say the radial mounted brakes are that way so they can easily install or remove spacers for the caliper mounts, so that they can change rotor size easier for different race tracks. Apparently that is important to racers. I don't think it is meant to offer a real braking advantage other than that. ( I only know what I read...) |
