| Author | Message | ||
     Benm2 |
Imagine, if you will, a Buell ZTL setup on a forged magnesium wheel, with carbon disc and titanium fasteners. | ||
| Jima4media |
Blake, That was just the weight of the wheel and rotors. No calipers. 3-4 pounds is not a lot of difference in my mind, especially when one of those bikes has 50-100% more horsepower or more. The weight of the rider comes into play more than the weight of the front wheel at that point. Go on a carbon fiber diet of 25 pounds and lose the weight of your front wheel.  (Message edited by jima4media on July 28, 2005) | ||
| Reepicheep |
How does more horsepower help a wheel with excessive upward inertia get back down to touch the track again? | ||
| Blake |
Jim, And the price of tea in China is?  Please, try to stay focused. We are talking about the merits of the ZTL design and whether or not it is as much lighter as it appears compared to the stock wheels on other sportbikes. (See Alan's posts above.) As to And that 4 pounds did not include the calipers or the caliper brackets or the spacers (Buell has none). Not sure if it included applicable hardware either (fasteners for disks/carriers). I can see the total difference in unsprung mass approaching 6 LBs. That is huge. Looks like I'll have to answer that pesky question that non of the Buell naysayers care to address. Many of the Japan Inc. repliracers downsized to 300mm disks on their repliracers in order to reduce unsprung mass and mass in general. How much did they save by downsizing from 320mm to 300mm diameter disks? They saved approximately a whopping 0.3 LB by doing so. You don't think saving four LBs would be a big deal? If so, I think your beverage must be stronger than what we serve here. As to the carbon fiber diet... that stuff is great, but man don't ever mess around with a broken piece of it. The splinters are virtually invisible and can plague you for weeks. The weight of the rider is not unsprung mass. In fact for most racers it is doubly sprung. Once by the suspension, and once by the riders legs and arms. | ||
| Blake |
Dam you Bill. One sentence said it all and here I typed a complete dissertation. Good one.  | ||
| Xb12rene |
Just to think about. Here is one of the lightest systems for streetuse with normal double rotors. Wheel: PVM (www.pvm.de) same as before only in magnesium (not recommend for street): 2.0kg  Rotor: Sicom(www.sicom-brakes.com, 310mm, 2 X 910g  Caliber: Sicom, 2 x 590g  Brake pads: Sicom streetversion 2 x 286g  tire: per Steve_a's post, 4.2kg So all together: 9.772kg = 21.5lb Is is around the same weight as the wheel of the Ulysses (thanks to Steve_a). To get the same weight as the buell frontwheel you have to spend 4797Euros = $5756! Rene | ||
| Jima4media |
Ceramic rotors - Comparative Brake Weight Stats (YZF-R1): Yamaha OE 320mm stainless: 3lbs 3.0oz at 4.5mm thick [1446grams] BrakeTech 320mm Iron: 2lbs 15.1oz at 5.0mm thick [1335grams] BrakeTech 320mm CMC: 1lb 1.2oz at 5.0mm thick [488grams] Commercial released Feb/March 2004 with pricing starting at $1600pr (plus pads). http://www.braketech.com/news.html These are what Jason DiSalvo is using on his bikes. The performance of brakes depends upon the total weight of the bike and the rider. That is why little guys like Duhamel, Zemke, The Haydens, and Jason DiSalvo on light bikes stop faster than heavier guys on bigger bikes. The other side of the equation is horsepower. 1 horsepower = 7 pounds of weight. A bike with no motor isn't going anywhere. A 320lb bike with a 250HP motor is going to be fast. Do you remember the uproar about the weight of Danica Patrick? She almost won the Indy 500 this year, but not just because of her weight. Skill is still the key ingredient in racing. Advantage: Armstrong, Schumacher, Rossi, Corser, and Mladin. (Message edited by jima4media on July 29, 2005) | ||
| Toadboy |
Being pretty much a newb to the more technical aspects of motorcycles, I've been following this thread for a while. The 'arguments' for/against the ZTL system are all very persuasive. I'm curious about this latest statistical info that's popped up, with regard to wheel weighting and rotor sizing. Bear with me here on this: If, according to the braking stats presented in one of the first posts here, the ZTL system with 1 rotor is off by about 14 stopping feet from being in the top 10 in braking performance, a difference of about 13%. And, if the difference in weight between a dual rotor system and the ZTL is about 19%, would it be too much of a leap to be able to say that the ZTL system is just as 'efficient', if not more 'efficient', at stopping as a stock 2 rotor system. And if Buell came out with a properly tuned and calibrated dual-sided ZTL system, this efficiency would place it in the top 5 or 10 in braking performance, while still providing a bit (maybe a pound overall) of a weight savings? If so, then from a motorcycling perspective, even the single sided ZTL, with the ability to provide more-than-adequate stopping power in a more weight-efficient manner, is actually pretty awesome. Maybe not 'better' at absolute braking, but providing the most stopping power per lb. Or am I just oversimplifying? Don't shoot! I'm just a noob trying to wrap my brain around all this! | ||
| Anonymous |
Toad, your points are good, but not complete. The stopping distances in the tests above are all about the wheelbase and tires. If you put dual Brembos on the XB it would stop in nearly the same distance on a smooth test track. The real advantages of the ZTL come in on bumpy roads, cornering, etc. It's all about less unsprung weight and less inertia, which make little to no difference on a smooth test track doing a single straight line stop. But they make an enormous difference when you are actually riding. The simplifications come from the guys who think that this kind of a stopping test represents the entirety of the real world. Losing a small amount of single event test statistics in exchange for a huge advantage in the real world riding conditions is what the XB is all about. | ||
| Wyckedflesh |
XB front wheel shod with Dunlop 208 36lbs pressure no caliper using the comparison weight method (me on scale, then me on scale with wheel subtract difference) came out to 25lbs on the nose. Maybe later in the day I will get adventurous and pull the spare front brake assembly apart and weigh it with pads. | ||
| Jon |
Lately for me, getting "adventurous" means having a second diet coke dangerously close to bedtime. Just thought I'd share that. | ||
| Phillyblast |
Wycked, Is it 36 lbs or 25 lbs? I couldn't tell from your post. | ||
| Blake |
René, That is really interesting information. So with the Lightning and Firebolt wheel being around a pound lighter than that of the Ulysses, at 20.95 LB, even that exotic $5756 conventional setup is no lighter than a stock Firebolt or Lightning front disk/wheel assembly. And that is excluding the additional caliper support bracket/hardware for the dual disk setup. Jim, Are those weights for just the bare rotor or an entire disk/carrier/hardware assembly? Looks like a bare disk to me. Not much help unless you can find the carrier and joining hardware weights too. Where are the naysayers now?  | ||
| Dbird29 |
But what about the brake fluid?  Aren't we now arguing about angels on a pin? It appears that Buell designs for the real world and other manufacturers design for the spec sheet. I ride in the real world, so I appreciate Buell Engineering. | ||
| Jima4media |
Blake, That weight is for the entire rotor assembly. http://www.braketech.com/cmc.html With pictures. | ||
| Blake |
Whoa! That is cool! Only 1/3 the weight of stainless steel! That would drop the weight of a ZTL wheel down to around 20 Lbs including the tire. And a stock GSXR wheel weighs 24 LBs without tire? Wycked weighed his ZTL wheel + tire at just 25 LBs? Is this case closed or what?  | ||
| Blake |
The Buell ZTL is at least 6 LBs lighter than any other OEM front wheel/brake system and that is not including the calipers or the caliper support bracketry. Overall then, probably 8 LBs less unsprung weight in a Buell ZTL wheel/brake assembly versus the GSXR1000. | ||
| Jima4media |
Danny mentioned Blackstone wheels a week ago, but they are worth repeating. http://www.blackstonetek.com/products.php Some of the advantages of the new BST RACE wheel: -- 11 lbs lighter than standard OEM wheels (GSXR 1000) -- 5 lbs lighter than forged magnesium wheels (GSXR 1000) -- Saving of more than 20% of Rotational Inertia over forged magnesium wheels -- Hubs are durable - high strength treated 7075 aluminum Weight saving on the BST wheels works like this: -- Outer rim affects 85% of the overall performance of the wheel -- Spokes affect 10% of the overall performance -- Hub centre affects 5% of the overall performance of the wheel. We have reduced weight where it increases performance most - a feat that only our wheels can achieve. Reduce weight in the right places and you save on rotational inertia - physics takes care of the rest - you cant help but perform better. Street CF Wheels (including 6000 series alloy hub, stainless steel fittings with bearings): Front: 4.62 lbs; Rear: 5.94 lbs. Race Only CF Wheels with 7000 series alloy hubs including 7000 series alloy hub, lighter wheel, titanium fittings with bearings : Front: 4.4 lbs; Rear: 5.28 lbs Your Price: $1,669.00 http://www.panteraproducts.com This is what Acid is running on his 24 pound front wheel dual brembo setup. Now match up the BST wheels with the Braketech ceramic rotors, and it is game over man! That is over $3,200 for a wheel and a set of rotors, plus the price of the Brembo calipers and master cylinder, and steel braided brake lines. Of course that is nothing if you are paying $3 million for a bike, and $25 million a year for a rider. (Message edited by jima4media on July 30, 2005) | ||
| Blake |
I wouldn't ever trust CF wheels. No way. | ||
| Jima4media |
Jason DiSalvo is using ceramic rotors from Starfire Systems and not BrakeTech as I said earlier. Some CF wheels have had problems in the past with breakage. The BST wheels have aluminum hubs and are quite a bit more reliable. Given enough force you can break any material. | ||
| Blake |
Are you telling me that all this time you were questioning the merit of the Buell ZTL brake on the track versus conventional brakes and the Superstock and Supersport racers aren't even using their stock brakes? Buell was using the stock brakes most races last year! Slam, bang, over and out case closed!  Pretty sure all CF wheels used metal hubs. The problem with CF and ceramic is that when they fail, they fail without warning and catastrophically. Metal will usually yield and not fail catastrophically, just deforming some as it gets stronger the more it yields, to a point. And the stuff some of the manufacturers are using for the CF wheels is the crap of the crop when it comes to CF/epoxy material. Really bottom of the barrel stuff. Easy to work with, but not anywhere near aerospace quality. That neat looking woven pattern looks pretty, but it is crap as far as structural properties go. I do the structural analysis gig, remember? B-2 bomber... earth station satcom antennae... remember? There is one thing no amount of force will fracture... the will of a stubborn woman. Can you cast that into a motorcycle wheel? | ||
| Blake |
But the real question is.. why was Mr. Disalvo, one of the smallest lightest racers on the grid using ceramic brake disks? Could it be.... to save weight, unsprung weight? I wonder, are F1 disks mounted to the hub or rim? | ||
| Steve_a |
The reason a light rider can outbrake a heavy rider is that his combined center of gravity (machine and rider) is lower. Take an extreme example, a 180 pound rider versus a 120 pound one on a light, 240 pound GP bike of some type. The machine cg is probably around 24 inches plus or minus a bunch, and the rider cg is probably around 36 inches (perhaps less, but this is just for example). The combined cg height for the heavy rider is 3/7*36 + 4/7*24 = 29.1 inches. For the light rider, the cg height is 2/6*36 + 4/6*24 = 28 inches. If the bike had a 52 inch wheel base and the cg located halfway between in both cases (not that it would, but we're simplifying here), the light rider could brake at about 26/28 g's or .93 g's and the heavy rider could brake at about .89 g's. Any more in either case and you get a brakie. This is an example with made up but not totally unreasonable numbers. It tells you that brake power isn't the limiting factor in motorcycle braking, but instead the overturning moment is. Given that the front tire has a lot more traction than can be used when braking straight up, you'd expect riders to use up a little more of it by carrying the brakes in all the way to the apex, loading the tire with both cornering and braking forces. And from what I understand, almost everyone who's fast is currently running Gary Nixon deep braking lines. Note also that this becomes more of an issue as bikes get lighter. For a 450 pound bike, the combined center of gravity is much more influenced by the bike c of g position than in this example. It also suggests that street bikes will outbrake lightweight race bikes. The smaller rider also has an advantage because he doesn't need as much leg room -- a bike designed around him can have the seat slammed as low as possible. | ||
| Imonabuss |
Jima4, Match up a ZTL wheel in CF and the ZTL rotor in ceramic, and the game is REALLY over. With comparable materials, the ZTL wins every time. You can't break the laws of physics, no matter what you spend. And you know what if you did the ZTL in CF and ceramic it would be cheaper than the heavier dual set-up! | ||
| Xb12rene |
I would say now 7 pages later it is proven that the Buell's ZTL front wheel is significantly lighter as any other stock setup on sportbikes. This is exactly what Erik said or did I understood that wrong? The only conventional setups matching or succeeding the ZTL setup are too expensive (for my taste) for normal streetuse. Rene | ||
| Blake |
Yep, case closed. Excellent point bussman on the reduced cost of manufacturing a composite ZTL wheel. You know, I'd be a LOT more inclined to put a CF ZTL on my bike than a conventional CF wheel. The high risk braking failure mode of the spokes or hub exploding is eliminated. | ||
| Jima4media |
Harvey (McQueen), Agreed. You can't break the laws of physics, but you can apply them to your will, if you are smart about it. Lower the CG, lengthen the wheelbase, and give rid of that sucky telescopic forking front end and replace it with a wish-bone Hossack design. Front end dive is bad for braking and cornering. Who is going to build this ceramic ZTL brake? Not Buell, that is for sure. Braking could do it, I suppose, but I doubt customers are beating down their doors asking for them. | ||
| Anonymous |
Jim, Oh, yeah, the wishbone Hossack front end featured on all MotoGP bikes. That so many riders complain about on BMWs. Wasn't that the logic against ZTL? I now see your engineering complaints are based on whether its a Buell design or not. Buell=Bad, Import=Good. Hard to argue with this logic. | ||
| Court |
Gotta tell ya.....I looked at my riding partners brakes on his Hayabusa today. I didn't count them, but it looks like there are about 712 parts and pieces to go fritzy....I keep thinking about the poor guy who has to, I see the tolerances in his service manual, line all that stuff up. WOW....they are amazing simply by virtue of the fact that they work. They work, it would appear, largely due to the planrtes (or parts in this case) being aligned. Wouldn't it be simpler if you used less parts? Call me a simple construction worker....but less complicated at least brings it down to my level. | ||
| Jima4media |
When we look at a comparison of braking between the BMW K1200R and the Buell XB12S, the first stops in 121 feet, the second bike stops in 123 feet. OK 2 feet is not a lot of difference. The XB12X is only 2 inches longer than the XB12S, but it does have a higher center of gravity, and the higher ride position puts the riders cg higher also. I would suspect the stopping distance for the XB12X is going to be longer. The K1200R is $14,500 or $3,000 more than the XB12X, but for that price you get 135HP at the rear wheel. For that amount of money you also get a shaft drive, and no-squat rear end. For another $1,000 you can get ABS brakes on the BMW. The dive problem in telescopic forks have been a problem for all bikes, not just for Buells. The Hossack-type front end is one of the only designs that addresses this problem. Who has complained about the Hossack front end on the K1200? All of the reviews that I have read have been very positive. NIH syndrome will keep most manufacturers from trying new and more effective front ends. Buell has been more innovative than most companies with reducing parts counts, mass centralization, frame rigidity, and lowering the unsprung weight of the bike. Fuel in the frame and oil in the swingarm are worthwhile design ideas also. Buell isn't the only company that is innovating, is what I'm getting at. Jim (Message edited by jima4media on July 31, 2005) |
