| Author | Message | ||
     Fstgo |
Finally got around looking thru the June issue of MotorCyclist Magazine, near the end in the MC Garage Ask the pro section pg.166 a reader asks: "why don't all manufacturers adopt the ZTL Braking System" James Parker replies: "No truly large benefits but no big problem on the street". My impression from the read was the only way it can become a great system if it wins superbike races. What were your impressions? | ||
| Disturbed |
Well the easy answer would be "because Buell has a patent that hasn't expired yet". | ||
| Obiewan |
Disturbed, who are you quoting here? You really think that's why? | ||
| Samiam |
Disturbed, +1 Sam | ||
| Buelltroll |
I read that about 2 weeks ago There IS science behind both arguments... They agree it does have SLIGHTLY more advantages on the track but... | ||
| Thepup |
Disturbed,Buell does not have a patent on the perimeter mounted rotor,only the mounting itself.If other manufacturers thought there was an advantage using the perimeter mounted rotor they would use it. | ||
| Rocketman |
I think the answer is much simpler than that. There are a number of reasons why Buell adopted this design of brake, and they all add up to one overriding reason. A perimeter brake can offer as good as performance as a conventional single disc brake set-up, if not better. A perimeter brake can be a lighter set-up than a disc brake set-up. A perimeter brake set-up can be made to offer less rotational mass. A perimeter brake looks different from disc brake set-ups. A perimeter brake could be considered aesthetically pleasing compared to a disc brake set-up. A perimeter brake could be considered more high tech than a disc brake set-up. A perimeter brake could be considered a contemporary design. A perimeter brake had not been used on a production motorcycle previously. One could conclude that the XB platform with its frame and swing arm appearance, and more conventional rear suspension set-up, made this Buell overall design appear more conventional as a motorcycle compared to the tuber frame model Buells it followed. Such would have a motorcycle company proud of its quirky designs look to areas where they could be seen rather than just explained in their marketing hype. It seems no one really cares how interesting it is to carry oil in the swing arm after all. There is little mention ever on BadWeB of the merits or design quirk of the oil in the swing arm design. XB owners are not looking to discard the design in favour of mounting an oil tank elsewhere, though I'm sure a debate or three could be raised about where the recirculating oil could be better placed, or the sometimes temperamental oil leaks could be avoided, or the shift of mass caused by circulating oil and its affects toward handling could be argued. So it is that the quirky designs on the XB platform are for the most hidden from sight. The fuel in the frame has the frame look very similar in appearance to a Japanese style beam frame. The air box cover actually looks like a conventional motorcycles fuel tank, and so it goes that something in the overall design needs to jump out at those looking. Be they motorcycle types or just the average Joe passing by an XB in the street. So you see, that is the overall reason Buell made the many years old perimeter brake system fit their XB platform. They needed something to entice people into the rest of the motorcycles design. A perimeter brake does such very well by sitting right at the sharp end of the motorcycle. Its mounting system might well be world leading, which may or may not reap other benefits, but the quirky brake system itself is absolutely certain to make motorcycling and non motorcycling people look again - which in turn will draw those watching eyes towards the rest of the motorcycle. So it is that the Buell perimeter brake is as much a marketing exercise as well as a feat of motorcycle engineering, if not more so. Clever engineering, clever marketing, but the jury's still out as to whether its benefits will ever see other manufacturers jump on the band wagon, but one thing's certain. Smoke and mirrors might well be involved in Buells use of this braking system, but it works well, seemingly in different ways, for Buell. Rocket | ||
| Court |
That's "kinda" true . . . 6 or 7 other folks have previously patented, back to a couple guys in New Jersey and some fellows in Japan, the perimeter rotor system 20+ years ago. What Buell did was MAKE IT WORK. The others, as had been observed in some of the magazine tests, kinda developed a bullet but never figured out the gun. Without the mounting system, the benefits are nil. The prior attempts took a new and innovative part and then got back inside the box when it came to thinking about the mounting system. Honda, some of you have seen the NAS, which was kinda their stab and "what we see the future of technology being" was onto the perimeter rotor until Buell effectively checkmated them. You'll be seeing if from Honda in a couple years. I, for one, am hoping they introduce it the same year they "invent" the underslung below the engine muffler. That was in the NAS and estopped from production as well. It's a neat system which not only works well but looks awesome. Interesting how I can park an XB in NYC and a person who knows nothing about motorcycles will immediately comment on how interesting the brake looks.  | ||
| Disturbed |
"Disturbed, who are you quoting here? You really think that's why?" Well since I guess Obiwan will not share his knowledge with us, just his questions, we are forced to fend for ourselves. LOL ^_^ Obi, gimmie some insight man! I guess all the other guys forgot how with the ZTL system the braking force isn't transferred through the wheel, thus allowing the use of a much, MUCH lighter front wheel and rotating assembly. It's on my bike, I like it. I didn't buy the "other guys" bike for lotsa reasons. I was quoting a picture I saw somewhere on Buell's site with a patent number. LOL  Here's a little light reading for ya. Feel free to share it with the "other guys". http://a1264.g.akamai.net/7/1264/1354/c5095239a838 50/www.buell.com/en_us/buell_way/buelltech/pdf_010 2_2003.pdf (Message edited by Disturbed on June 09, 2007) | ||
| Altima02 |
Its on Honda's prototype http://www.sportrider.com/bikes/146_01_honda_nas/ (Message edited by altima02 on June 09, 2007) | ||
| Altima02 |
With dual calipers  | ||
| Rocketman |
Thank you for that thoughtful counter Court. Such scribblings are all I have argued for for ages, lol! Rocket | ||
| Disturbed |
Looks like they are using dual calipers to a total of 4 pistons. :/ | ||
| 07xb12scg |
There are pros and cons to everything in this world...EVERYTHING. This perimeter braking system is a good example. The perimeter rotor offers better leverage than a smaller diameter rotor. The downside to this is that it has a larger moment of inertia. What does this mean? Well it means that it takes more energy to accelerate and decelerate this rotor in comparison to a smaller diameter rotor. Plus, this perimeter rotor also has more of a gyroscopic effect than a smaller rotor because of it's larger diameter which makes it harder to change directions. There was an interesting article comparing Buell's ZTL to standard dual disc brakes. I can't find it right now, but I'll look in my history on my work comp and hopefully find it there. As far as the oil in the swingarm goes - I've always thought that was a bad design. I'd even call it a flaw. Anybody who knows anything about cars or motorcycles knows you do everything in your power to reduce unsprung weight if you are trying to make a great handling machine. The oil in the swingarm adds unsprung weight and on top of that it's constantly sloshing around inside. Bad idea. | ||
| Ridrx |
07xb12scg, How much oil do you think is in that "flawed" swing arm? Capacity is only 2.5 qts. for the entire system. When you start the engine a portion of that 2.5 qts is circulating through lines and passages in the engine. This leaves only a fraction(don't know exactly how much it takes to "fill" the oiling system) of the original 2.5 qts in the arm, which is "wrapped" around the pivot of the swing arm. Not like your totin' 4qts in the rear axle. Wonder how the jap bike pilots are able to control 2-3 gallons of sloshing fuel mounted way up high? Flawed?...please. As for the ZTL, I will agree the larger diameter reacts more slowly oz. for oz...thing is, the total reduction in weight achieved on the Buell's f. wheel(Something like 5lbs?) likely offsets any negative side effect of the large diameter rotor. I'll keep my ZTL thanks. That NAS front suspension is cool looking...but, ya' think "stiction" would be an issue? The dual calipers are neat too, wonder how well that arrangement works? Who's gonna be the first to mount dual 6 pistons on an XB? LOL (Message edited by RidrX on June 09, 2007) (Message edited by RidrX on June 09, 2007) | ||
| Ft_bstrd |
Where is the exhaust can on the Honda prototype?  Looks like an updated Firebolt to me. I sure hope Buell's new "Firebolt" makes production what Honda touts as a prototype. And then 6 steps better. | ||
| Court |
Wow. . . let me (in my 4 minute break from yard work) take a crack at this. >>>Its on Honda's prototype Has been for years. Had one on display at a little party a friend and I threw for some visiting moto-pals . . 4 years ago.  >>>that it has a larger moment of inertia. Actually no it does not. That is one of the things that had tripped folks up for years that Buell solved. The big news, when Buell rolled out the ZTL system, was not the perimeter brake that got all the attention, it was the wheel. Go back and read the review Reg Kittrelle did of an after market perimeter brake system and you'll find a concise summary of the moment of inertia problem. Bear in mind that "moment", although taking into account "finite" elements ultimately is the result of the performance of the entire system. You have to take progressively (call it the inverse of the square) more weight from the inner (smaller diameter) portions of the wheel . . which Buell did in elegant fashion. >>>>>The oil in the swingarm adds unsprung weight and on top of that it's constantly sloshing around inside. Bad idea. Oopppps. . .bad facts Will Robinson. Apparently the perception is that all these M.I.T. (Hurda and Anderson) and UC Berkeley (Askenazi) Ten years ago, after completing his Masters Thesis at UC Berkeley on the Dynamics of Single-Track Vehicles, Abe sent out a single job application. Erik Buell kindly responded with an offer that allowed Abe to become Buell Motorcycle Company's first full-time Analysis Engineer. degrees were obtained clipping coupons in Popular Mechanics. You may have missed Abe's Masters Thesis . . . anyway. The oil neither adds unsprung weight (go back and work that moment equation and review the concept of zero and the associative multiplicative principle prior to your review. Take the weight of the oil (I'd break it into several "chambers" along a line) and multiply it by the moment arm. The oil does not slosh. Next question. Are you going to be at Homecoming? I may have to arrange another "remedial engineering for laymen" class. . . I, as a lowly construction worker, found the last one quite enlightening. Could happen. Court P.S. - Seriously, if you are going to be at Homecoming, I'd be pleased to arrange to have one of the folks who developed this system sit down with you one on one. Buell folks are like that. | ||
| Blake |
"Buell does not have a patent on the perimeter mounted rotor, only the mounting itself.If other manufacturers thought there was an advantage using the perimeter mounted rotor they would use it." Pretend for a minute that Buell had been able to patent the way pneumatic tires are mounted to wheel rims. Silly notion I know, but for the sake of discussion assume it is the case. Would you then find it reasonable to state state that "Buell does not have a patent on the rim-mounted tire, only the mounting itself. If other manufacturers thought there was an advantage using the rim-mounted tire they would use it." Meaning, that if you can't find a way to mount a tire to a rim without violating Buell's patent, you won't be using a rim-mounted tire, will you? Answer: No, you will not. The same scenario is true for the perimeter-mounted brake rotor and Buell's patented mounting scheme. If you cannot get the perimeter-mounted rotor to work on account of you cannot figure out a mounting system that will allow it to perform well and reliably through its entire design life, then you won't find any advantage in using a perimeter-mounted rotor, will you? Answer: No, you won't. Additionally, if you fail to recognize that a perimeter rotor allows you to significantly reduce the weight of the front wheel/brake assembly, then you won't recognize a major advantage in using a perimeter rotor, will you? Answer: No, you won't. Prior/existing commercial variants of perimeter-mounted rotors had the rotor mounted in harm's way outside of the rim and they failed to take advantage of the ability to significantly reduce the mass of the front wheel. Thus, folks, customers, the marketplace evaluated that much inferior perimeter-mounted brake scheme and found it of no significant benefit. Whereas the Buell ZTL brake/wheel scheme offers very significant benefits, not all of which I've yet listed herein. There is also greater simplicity and much improved reliability/availability (reduced likelyhood of failure). ZTL Wheel Patent ZTL Rotor Mounting Patent} And BTW, a couple of reportedly very smart and accomplished former Formula-1 racing engineers have put out a design concept for a super-lightweight new Superbike. It uses a perimeter-mounted ceramic front brake rotor, reportedly to reduce weight and front suspension unsprung mass. No word on if they've come up with a new mounting scheme that avoids violating Buell's patent or if they intend to license the brake rotor mounting scheme from Buell. | ||
| Thepup |
Blake,there is not a significant amount of weight savings.There may have been 6 years ago,but Buell wheels have gone unchanged unlike other sportbikes. This warrants correction. The accurate version of the above commentary is as follows: "There is (Message edited by blake on June 09, 2007) | ||
| Blake |
Court, What?! No math! I'd fine you if I could. Great explanation though.  Leverage matters. I can't help but add to your already concise explanation. I just love this stuff.  To put it most simply, the three pounds or so of oil in the front of the swingarm produce the same effect on the suspension action as would a few mere ounces of unsprung mass at or near the rear axle. This is due to two factors. One is the much lesser lever-arm length (measured from swingarm pivot) of the mass (in this case that of the oil) acting about the swingarm pivot axis. The other is the doubly reduced kinematic effect where at the axle, unsprung mass travels much farther and faster (and must accelerate more rapidly) than it does nearer the swingarm pivot point. What?! No math!? | ||
| Blake |
I saw that extremely lame column in Motorcyclist. The author made no mention whatsoever of the benefits of reduced unsprung mass resulting from Buell's revolutionary ZTL brake/wheel system. | ||
| Court |
>>>>there is not a significant amount of weight savings. Uh . . . let me say that's not a statement I have a different opinion of. . .that's just flat WRONG. There is a HUGE weight savings. That was the joke at the time. Honda had introduced some new wheel for their factory racers and was touting the weight savings that they'd gotten for their $1,000,000 of research. Damn thing weighed like 2 more pounds than the XB wheel.
No math . . I'm on summer break and running wild! | ||
| Thepup |
"Uh . . . let me say that's not a statement I have a different opinion of. . .that's just flat WRONG." Seems some people weighed a XB wheel and a R1 wheel and there was a 1 pound difference,take off the rotors from each one and the R1 wheel was lighter. | ||
| 07xb12scg |
Court: I was talking comparing the moment of inertia of one perimeter disc to one "normal" disc, not the complete wheel and brake assemblies if that's what you were assuming. I was just giving general pros and cons of perimeter brake systems and not necessarily pointing out the ZTL system. According to Motorcyclist "the Buell's front-wheel assembly was 4.5 pounds lighter than that of a Yamaha YZF-R6, their MoIs were identical-the huge weight savings is offset by the Buell's larger single disc and heavier rim area." So you are right in saying that the complete assembly doesn't have a higher moment of inertia, but I stick with my statement about the rotors themselves. I also will say that "normal" perimeter braking systems in which the wheel hasn't been made substantially lighter will have a higher moment of inertia than a typical small disc wheel assembly. For example, take a normal dual disc setup and compare that to a perimeter rotor on the exact same wheel. The perimeter brake wheel assembly will have a higher moment of inertia. You keep referring to yourself as a "lowly construction worker", but obviously you aren't. Either you're an engineer or you've done a ton of reading or something. I won't be at homecoming, but I wish I could make it. That's too far away from me. | ||
| Anonymous |
Anyone who says what thepup just quoted about weight is flat out lying. We weigh the latest and greatest of the competition, and we kill them in unsprung weight. 5 - 7 lbs is the norm, it's even a bigger gap on adventure touring. Rotating moment of inertia we are about equal with the best in the sportbike world, and well ahead of most. Turning MOI (rotation about steer axis) we beat them because that includes the weight of whole wheel brake rotor, forks, calipers, etc. BTW, the GSXR1000 is lighter than the R1. We have the numbers for these, the 999, the 600s, whatever. Why hasn't anyone else done it? Think patents, and think saving face. All Buells since 1985 have had an underslung exhaust. Watch the next four years of Japanese sportbikes. | ||
| Ducxl |
Hey guys' i just found this interesting.I'm going to weigh my brand new Blackstonetech carbon fiber wheels and Braketech ceramic rotors i just paid $5500 for.They'll be going on my Ducati.Do you think they may be in the ballpark with my XB wheels/rotor assembly? They do feel remarkably lighter than the stock 996 assembly. | ||
| Court |
I am a lowly construction worker. >>>>I stick with my statement about the rotors themselves. You are right about the rotors themselves. Go remove the forks, tires, wheels, hardware and so forth from your bike and try to ride it. Buell took "laboratory smart" and made it "street useful". . . you can't ride hypothetical around the block. In terms of the physical properties Buell is light years ahead in the world of braking. One of the metrics I use to evaluate a system is "piece count". I have a keen familiarity with probability and statistics and the mathematics of system reliability. Each and every part added adds another element to the reliability equation. Just as there is "stacking" error is the good looking but dated dual brake systems there is a similar effect each time you add a piece. For those of you who are not lowly construction workers, let me take a stab at a layman's explanation of "stacking error". Each part in the incredibly part heavy dual front brake system has some tolerance such as +/- .005". Nothing is made perfect and there is a range calculated, generally in SD) standard deviations that is acceptable. In the instant case, say a spacer was IDEALLY 2.0". . . the .005 tolerance would mean I'd accept anything in the range of 1.995" to 2.005". I know some folks may not deal with Boolean postulates and series and serial system reliability but work with me here for a moment. Say we have TWO of those 2" parts, each with the same tolerance. You can see that we could accept two parts, each at one extreme end of the acceptance window. . . a 1.995 and a 1.995. It gets long winded when you start to take into consideration how parts relate to one another. If one part depends on another you maybe has a series system where you multiply reliability . . a parallel system, well you'd add reliability. Hey . . here's the old simple standby. Say I am making a ruler out of 12 - 1" pieces and I tell you that I'll accept pieces that are 1" +/- 1/4". I could end up accepting a ruler that was 9" long (.75 x 12) or 15" long (1.25 x 12"). Okay . . you're with me know. It gets more fun, and I'd be please to post copies of some of my work here, but it gets really fun when you have something like. Machine A is 95% reliable. Machine B is 90% reliable. Machine C is 60% reliable. I can make widgets with A and C running or A and B running but B and C won't cut it. What is the % reliability of the entire system? Brakes systems are similar and each piece you add to a braking system has a pronounced impact on the motorbike. Buell did something stellar with this mounting system and it has squat (a term usually reserved for suspension) to do with weight. Look closely at your XB (you new guys all have milk crates right?) and look VERY CLOSELY at the seat where the perimeter rotor sits and the machined face of the hub that the bearing sits in. Notice anything . . . go look and we'll continue our little chat. Although Buell pretty well kicked ass in terms of nominal weight (an easy magazine stat that you toss around) it is not weight that provided Buell with the benefit. It's a bit of genius that makes it damn near impossible to make a Buell wheel that's not perfect. . . while those silly folks using conventional rotors and machines that come in an out of spec, rely a hell of a lot more on luck than they'd like to admit. We'll talk more . . . I've got some construction work to do and we get breaks every hour. | ||
| Court |
Duc: If you got the Blackstone RACE wheels I'm sure those will be lighter than the Buell. Their street CF may be about the same. I'm betting that the ceramic rotor makes a difference too. Even if it didn't, the ceramic is an excellent material. We looked at Ceramic brakes when the SCU was buying her last car . . very TRICK STUFF!  | ||
| Court |
Hey . . . I have a question I like to ask fellow construction workers. Ever seen the MTBF (Mean Time Between Failure) on the lightbulbs you buy. . . says something like a gazillion years. Then you take the sumbytch home, pop it in the socket and a week from Wednesday . . . POOF just as yer coming in the kitchen rubbing your eyes. How the heck to you think they got that MTBF number? Yeah, they followed the govt's rules. . . but I'm curious to see if you can tell me why the numbers are pretty much meaningless. You're going to thank me for arming you with the cognitive battle gear you need to laugh off your IL4 riding buddies. . . they'll never make a sneezer of you again. | ||
| Asym50 |
"You are right about the rotors themselves. Go remove the forks, tires, wheels, hardware and so forth from your bike and try to ride it." Court, thanks for pointing out the purpose of motorcycles. Its the total XB package that I'm so crazy about. The individual pieces are great, its the sum of all those pieces that sends shivers when I'm on the XB. |
