| Author | Message | ||
     Jon |
Jim, The title and subject of the thread is regarding brakes. That was thought by the detractors to be such a defect that it was worth it's own arguement. Now that that arguement has had a mudhole stomped in it's backside, suddenly it's not that important by itself. | ||
| Blake |
Alan, I commend you for recognizing the very real and very significant benefits to real world street bike performance that the innovative reduced mass Buell ZTL brake/wheel system provides over other more conventional configurations. I would certainly agree that many in the market for a motorcycle will be looking for different overall qualities than what the current Buell models offer. If one desires to ride around on a repli-racer superstock or supersport machine, a Buell is absolutely not the bike to be considering. The really interesting question might be... Would an R6/CBR600RR/GSXR600/ZX6R be a better street bike if fitted with a lightweight Buell ZTL front wheel/brake system? I say yes. Why? Well, they would be significantly lighter and would gain an improvement in front suspension performance (road handling). Lighter means that they would accelerate harder. That is a good thing. Braking characteristics would likely change. Certainly the braking power would remain more than adequate. Initial bite and feel and lever effort would probably differ. Whether those qualities would be better or worse often comes down to personal preference, most likely governed by one's own experiences/expectations, what one is most acustomed to. So of course there are a lot of subjective aspects to the issue too. One more thing... Lighter front wheel... easier power wheelies. That cannot be a bad thing, can it? What if you could drop another 8 LBs from an R6/CBR/ZXR/GSXR...? by reconfiguring the bike and putting the muffler under the engine? But then why isn't everyone doing that? I think Kawasaki is fixin' to do just that. Saw a pic posted here somewhere of a Kawi with an under-engine muffler. The Honda NAS concept bike had an under-engine muffler too. It even had its own innovative aspects that have been patented. Interesting stuff.  | ||
| Reepicheep |
Jon... Brakes that keep me from lowsiding when I am not on the brakes are better brakes. If a ZTL system can get me through a particular turn with a realistic threat scenario, but an identical bike with dual traditional rotors would lowside, then ZTL brakes are better. At least for what I want to achieve. And even in the most literal sense of this thread, I would happily put my XB9SX up against an R1 for shortest stopping distance on gnarley, bumpy, washboard asphalt. And I bet it would win. I think everyone is agreed though, "better" depends on what you are trying to achieve. | ||
| Blake |
Jim, Trust me on this, it is indeed possible to measure and quantify motorcycle handling performance. A Buell XB can lap a CBR600RR in a Formula Xtreme race too. Mike Cicotto lapped two of them at Laguna Seca last year. Pretty sure he was using the stock front brake too. What is your point? Using racetrack performance as the primary gauge by which to measure the value of a prospective road-racing bike makes perfect sense, but to use that same gauge to measure the value of a street bike is simply ridiculous for a host of reasons. As I recall it was just a few months after its introduction that an XB9R won the FUSA National Championship series Sportbike race at Loudon, NH. Apparently the Buell, on a tight technical track ain't so bad of a race bike. Kinda like the Suzukis in MotoGP at Laguna Seca. What Jon said. The topic is drifting. I think everyone is agreed that a lighter front wheel really is a good thing. It will be real interesting to hear all the comments if/when a MotoGP machine shows up with a perimeter braking system and a lighter weight front wheel. | ||
| Blake |
How about a rear wheel with a semi ZTL perimeter mounted drive sprocket (Blast) and a ZTL perimeter brake, maybe combine the two? How Buellish would that be, one part performing multiple functions. Take away another 8 LBs of unsprung weight? Dang, I should patent that! | ||
| Davegess |
What race track? Road America with that loooong HP straight or Blackhawk Farms? How about the Isle of Man versus Laguna? Not one of those places come close to a real road, IOM is closer but since they let you run at top speed for miles on end it is not a real world test. | ||
| Anonymous |
Jim, BS about the Honda lapping the Buells in FX. That has never happened, and in case you don't remember, Mike and Mike were really in the hunt last year. Mike C was outbraking the factory Hondas a number of times early in the races until the power of them got away, and Mike B finished fourth in one FX race. These bikes all ran single ZTL discs despite what BrianH lies about. Go look at pictures from the races. And I'll bet this type of brake does show up on Moto GP bikes one day, just like underslung exhausts will and are showing up. And the race track is not even where these brakes have their real advantage. Why does Buell have to be considered stupid? There are great engineers at Buell with radical American innovative thinking at work. | ||
| Jima4media |
BS? http://home.ama-cycle.org/prorace/raceres/rr/lapchart.asp?type=F&cls=FE&rnum=1&s nct=p7235&year=2005 Pikes Peak - This year. http://home.ama-cycle.org/prorace/raceres/rr/lapchart.asp?type=F&cls=FE&rnum=1&snct=p7240&year=2005 Road American - This year. I'm not saying there aren't great engineers there, one of my riding buddies is an engineer there. I'm just saying Buell XBs aren't up to the level of a factory prepped Honda CBR600RR. I'll be waiting to see ZTL perimeter brakes on MotoGP bikes. Will that be on a Honda, Yamaha, or Ducati? (Message edited by jima4media on July 21, 2005) | ||
| Blake |
Jim, Pretty sure anony was speaking to the factory supported efforts of 2004. For instance, has Barnes riding for Kosko or Cicotto riding for Hals ever been lapped in an FX race? You really are being terribly disingenuous in some of the logic you are employing towards belittling Buell motorcycles. In order to be valid, the logic you see fit to promote imagines that all teams and racers are created equal or that they have no influence on the outcome of a race. Might want to rethink employing that type of logic. It doesn't do much for one's credibility. If you really want to honestly compare track performance of the Buell FX bikes to their competition, it's only fair that you do so for comparably matched teams and racers. | ||
| Steveshakeshaft |
Anony, Blake, et al- It is the engineering in these bikes that makes them so fascinating to own and ride and discuss. I bought mine in '97 simply because it was exactly the kind of machine I would have built myself given the opportunity. Long may it continue that Buell motorcycles lead the way in innovative solutions. | ||
| Bomber |
OK, gnets -- please help out a non-engineer, math challenged ex-tech writer, please I understand how the ZTL brake can shed pound off the wheel, as the braking force is tranferred more directly to the rim, and, therefor, the tire -- I get that part but, it seems to my uneducated noggin, that the force required to stop the bike remains the same (or, slightly lessened due to the overall weight loss realized through the ZTL system) so, there is less force (energy) going through the spokes from the hub to the rim/tire with ZTL, but it seems to me that there is still an equal (or analogous) amount of force (energy) going back from the rim/tire, through the spokes, to the rest of the bike now, given what I've read and heard (at the chalk talks duing homecoming, thanks for that, Erik), I realize my logic, such as it is, is flawed -- please help me understand where . . . . | ||
| Steve_a |
The force at the tire contact patch for a given deceleration for a given weight bike is constant. The braking torque applied to the disc to create that force drops as the disc gets bigger. A bicycle type rim brake would require the lowest torque, a tiny disc the most. The ZTL is light for a combination of reasons. First, its load path is very simple, allowing for a much lighter wheel. A standard disc brake applies force to the disc, which is then transmitted down to the wheel hub, then through the spokes, finally to the rim and tire. The hub has to be heavier, the spokes have to be heavier, the wheel is heavier. Secondly, because the ZTL disc is large, it allows you to get away with a single disc without overheating. My intuition (not knowledge) tells me that the heat dispersing capacity of the ZTL is larger than that of a conventional single disc, but smaller than that of most dual disc systems with 320mm discs. But it's enough to work on the Buell Formula Xtreme racers even on brake demanding circuits. In the end, with the ZTL, you have a lighter wheel assembly because of: 1) a lighter wheel 2) a single disc 3) a single caliper 4) very small parts count in spacers, brackets, etc. There are other benefits as well. Erik's point is that the benefit radial mount calipers really offer is that they're self-centering if you apply the brake as you tighten down the caliper bolts. The Buell design offers such a small tolerance stack that Buell can offer the same result without any care in assembly, because the care was taken in the design. | ||
| Bomber |
Gents – little help in understanding something (non-engineer, ex-tech writer, math challenged) – From all I’ve read and heard (including the chalk talk given at Homecoming this year – a big thanks for that!), I understand the weight loss in the ZTL system is due to the lessening of force (energy) going through the wheel spokes, due to the fact that the disk is attached to the rim, bypassing the old path from the disk/hub/spokes/rim & tire – Energy directly from the disk to the rim/tire -- I get that part Seems to me, though, that the energy (force) still has to go back the other way, from the tire&rim/spokes/hub/rest of the bike – clearly, there is force following that path while the bike is slowing I would think that the two forces would be similar if not equal – now, given the fact that there are a large number of XB series bike happily traveling the planet without falling on their front axles at the first application of front brake, my logic, such as it is, is flawed I’d be most appreciative if one of your smart folks to school me, and show me where I’ve strayed . . . . . . thanks | ||
| Reepicheep |
Wow. I am glad Steve answered before I did. He did a much better job. I won't quit my day job One other thing to consider is that a contact patch is only braking while it is in contact. Otherwise, it ceases to be a contact patch, and is just wishful thinking. So what controls if the contact patch remains in contact? For smooth pavement, nothing really. The front wheel of a motorcycle will just stay in contact until the bike stops or rotates around it's front axle and endos. No difference what kind of brakes you use, so long as they are strong enough to loop the bike. But what if you hit a bump? In this case, the compression of the tire will cause the unsprung mass to accellerate along the line of the bump. So far, so good, you are just adding force to the contact patch. But what about the downhill side of the bump? Your unsprung mass is now moving *away* from the road surface at whatever velocity resulted from the bump, but the road is suddenly moving the opposite direction away from the bike. This could be bad. This is where your suspension comes into play. One job of the springs in your suspension is to push the wheel back down onto the pavement when the pavement has gone away. What determines how quickly the suspension can get that tire back on the road surface? The force of the spring, and the weight of the unsprung mass. Assuming the spring rates are equal, the rate at which the tire can move back to find the asphalt again is directly proportional to unsprung mass. In other words, a lighter unsprung assembly (wheel, rotor, calipers, bottom of forks) will get back on the pavement sooner then a heavier assembly will. Perhaps a simpler analogy is the dip in the road that lowsided me and my Cyclone. The road opens up beneath the front wheel. The lighter the wheel, the faster suspension springs can push it down to touch the road again, and the sooner it can get back to work. If the tire is not touching the road, the front brakes are exactly 0% effective. | ||
| Reepicheep |
Ah. I think I answered a question you did not ask. Steve, fortunately, answered the question you *did* ask. Another way to think of it, on a bike braking near it's limits. Think hostile thoughts: Conventional Rotors 1) The road is trying to rip the rubber off the surface of the tire. 2) The tire is trying to spin around the rim. 3) The rim is trying to wrap the spokes around the hub. 4) the Hub is trying to rip the bolts from the rotor. 5) The rotor is trying to rip the surface from the brake pads. 6) The brake pads are trying to rip out of the calipers. 7) The calipers are trying to rip off the forks. Now consider the same "entropy map" for the ZTL setup. 1) The road is trying to rip the rubber off the surface of the tire. 2) The tire is trying to spin around the rim. 3) The rim is trying to rip the bolts from the rotor. 5) The rotor is trying to rip the surface from the brake pads. 6) The brake pads are trying to rip out of the calipers. 7) The calipers are trying to rip off the forks. We bypassed all the spokes / hub hostility. And what Steve pointed out that never even occured to me is the lever arm presented by the size of the rotor. Think about trying to stop a spinning motorcycle wheel by grabbing near the hub. Now think about stopping it by grabbing the outside of the tire. The second puts FAR less force on the rotor, the carrier, the bolts, and even the wheel. It sweeps this force through a much larger distance, so the ultimate "stopping power" remains the same, but the load presented to the rotor, bolts, and carrier, are far less. Very cool stuff! Brilliant! | ||
| Davefl |
Jima4media, am I wrong or is the factory CBR600RR's lapping non factory CBR600RR's and GSXR 600's, and R6's. Not sure what your point is. (Message edited by davefl on July 21, 2005) | ||
| Choptop |
It has yet to be proven that the ZTL system is lighter than any of the systems on those bikes (remember, Erik compared the system to an RC51 wheel ONLY, not the caliper and forks, JUST the wheel)... (Message edited by Choptop on July 21, 2005) | ||
| Blake |
Bomber, You are right. The braking force transmitted through the steering head to the axle via the forks is no different for a conventional versus ZTL configuration. As far as the wheel hub and spoke structure is concerned, that type of loading is no different than pushing down on each end of the axle with the wheel/tire resting on the ground. That loading imparts pure axial tension or compression loading through the hub and spokes. There is no significant torsional or shear loading that the hub and spokes must endure. So other than being greater in magnitude the ZTL wheel hub and spoke structural loading under braking is no different in its basic nature than it is for non-braking conditions. That is not the case for a conventional hub-mounted brake disk where the additional load of braking imparts into the wheel hub and spokes not only additional tension or compression, but also a significant torsion (actually shear for the individual spokes themselves) loading. That added loading requires more beef to safely support it. If you compare the design of a Buell XB's rear wheel's hub and spokes to those of its front wheel, you can see clearly the effects on structural configuration that said torsional loading has. The rear wheel must endure significant torsional loading imparted by its hub mounted brake and hub mounted drive sprocket. Anyone for a free body diagram (FBD)? | ||
| Mikej |
"Think about trying to stop a spinning motorcycle wheel by grabbing near the hub. Now think about stopping it by grabbing the outside of the tire. " So then, apart from wet weather performance, why are bicycles going to hub mounted disk brakes? Motorcycle brakes moving to the rim, bicycle brakes moving to the hub. (Okay, that's about all I've got to throw into this thread, sidestepping back to the sidelines....) | ||
| Bomber |
Blake- thanks for the explanation (without formula, even, so I could follow it!) I think I'm getting it now -- I stared at the FBD in Fuell some time ago until drops of blood appeard on my forehead and I heard Jimi playin the Star Spangled Banner, but it didn't answer the question (for me, lacking the engineering background required) I was gonna ask the question at Mr Buell's chalk talk, but everyone else seems to be smiling and nodding, and I didn't wanna be sent to the corner with a pointy hat Mike -- I'm thinkin overall weight on a pushbike is of supreme important, and braking performacne less so (on a relative scale), so a hub mounted disk doesn't affect the weight as much as a rim mounted -- sides, you can still use the same tooling for the rims | ||
| Blake |
Alan (Chop), The Buell ZTL is significantly lighter than any conventional front wheel/brake assembly on any repliracer. That you indignantly demand proof of that does not alter the truth of the statement. I have no way to prove it other than to ask that you compare the structure of the two wheels in the hub and spoke areas. And I suppose I can try to explain why it is intrinsicaly true. I'll do my best. But I am curious. How do you imagine that the conventional front wheels/brakes of Japan Inc. sportbikes have magically shed multiple pounds in the past six years? How? Where? A wheel hub and spokes that must endure the torque imparted during braking must be significantly more massive than those that are not subject to that severe loading. Example: The front wheel must be designed to safely stop the bike at 100% GVWR. For convenience, let's use a nice round 800 LBs GVWR for todays repliracers. Let's also assume a maximum braking performance of 1g. So the front brake and wheel must be able to not only support the entire vehicle GVWR, but also an equal amount of loading in braking/decelerative forces. Okay, as confirmed for Bomber above, the GVWR gravity and decelerative loading is no different for a ZTL versus a conventional front wheel. What is different is that in a conventional wheel setup the internal torsional loading due to braking must be passed from disk to hub through spokes to rim through tire to pavement. The ZTL internal torsional braking load skips the hub and spokes and goes directly from disk to rim through wheel to pavement. So what are the torsional loads imparted by braking to the hub and spokes? That's fairly simple for a structural analyst to figure. Braking load of pavement acting on tire is 1g x 800 LBs which is conveniently 800 LBs. How much torque about the hub/axle does that load impart? Since torque is equal to the force times the distance it will be equal to the 800 LB force times the tire's radius, about 12 inches in round numbers. So the torque about the axles imparted by maximum GVWR braking is 800x12=9,600 LB*IN. How does that translate into loading of the hub and spokes? Internal loading of the hub and spokes due to braking induced wheel torsion increases from rim to hub as you move closer towards the disk-carrier connection. The calculation is a simple one. Torsional shear loading, call it "Vt" equal the torsional load in LB*IN divided by the radius from wheel center. So at just 4 inches radius the shear loading would be... Vt=T/r=9,600/4=2,400 LBs! In the ZTL wheel, that hub and spoke load does not happen. The only loading that the ZTL hub and spokes see is the GVWR plus the braking decelerative loading. Those are comprised of pure tension and compression in the spokes and hub. The ZTL hub and spokes do not see any of the 9,600 LB*IN torsion. That loading goes directly from the disk to the rim to the tire. I can't imagine that a repliracer with a ZTL front wheel/brake would not be a better street bike. On the track, the jury is still out. I'm curious though and no one seems to care to offer an opinion on why the repliracer engineers decreased the diameter of their front brake disks? (Message edited by blake on July 21, 2005) | ||
| Blake |
Alan, Pretty sure Erik's comparison was for the entire wheel and brake assembly including calipers. If not, the weight advantage of the ZTL would be even more pronounced, one 6 pot caliper versus two four pot ones. I doubt that there is any significant diff in Showa fork slider masses between Buell XBs and other sport bikes. | ||
| Danny |
I'm curious though and no one seems to care to offer an opinion on why the repliracer engineers decreased the diameter of their front brake disks? Allright. Because with radial mounting the caliper deflection normal to the rotor was reduced. They were able to transfer the same amount of force to a smaller rotor because more of the hydraulic force was transferred toward the rotor when it couldn't move the caliper body away from the rotor. I think. (Message edited by Danny on July 21, 2005) | ||
| Jima4media |
Q: I'm curious though and no one seems to care to offer an opinion on why the repliracer engineers decreased the diameter of their front brake disks? A: As materials have changed over the past 10-20 years, you can get better braking torque with lighter and smaller rotors. Duh. Carbon-carbon and ceramic, CNC'd billet aluminum and beryllium are doing wonders for braking capacity and performance. In racing the brakes probably have the smallest impact on lap times. The skill of the rider is way up there. Valentino Rossi would drive a Buell XB to its limits, but Buell couldn't afford to pay him $25 million or more a year. Honda spends millions on prepping the factory 600 bikes for Formula Xtreme, and hires top riders like Zemke and Duhamel to put their bikes on the podium. A Formula Xtreme race is never going to be won by a bike with the brakes as it's best feature. You don't have to employ logic to figure out the winner of a race, you need a stopwatch. Who is going to win at Mid-Ohio this weekend? Either Zemke or Duhamel, you can bet on it. Are there going to be any Buell XBs in this race? Will they finish? Two items not discussed yet - The additional gyroscopic force of a perimeter brake near the outside of a wheel, versus the smaller rotors near the center of the wheel, will actually decrease cornering ability at high speeds. Single points of failure with a single brake system. Brakes don't fail very often, but when they do, it is nice to have a backup. Two brakes spread the risk. Just ask Wayne Gardner and Eddie Lawson who have crashed with braking problems at Laguna. On bicycles, if you bend the rim, your rim brakes are shot. With a center rotor, it is unaffected. (Message edited by jima4media on July 21, 2005) | ||
| Bomber |
until bikes have dual systems, a failure in either front brake will equally affect the other (with the exception of a disk failure only, which will likely impact the wheel, rendering the discussion pretty moot) . . . . | ||
| Anonymous |
Jim, you are so right that a Formula Extreme race is unlikely to be won by brakes, unless the two vehicles competing for the win are equal in every other way. Power and total vehicle weight are extremely important. However, the ZTL system does more than provide equal braking with less weight, see below. I still drastically disagree with many of your points. At first glance the larger rotor might look like it would have more rotational inertia, but as part of the whole ZTL wheel system it has less. This was shown on a chart at the Laguna dinner. Also less steer inertia about the steer axis. We have measured the competition, and the difference is significant. I virtually cannot think of a braking scenario where the back-up disc would give an advantage. I know exactly what the Laguna brake failures you mention were, and it would have made no difference with one or two. Most brake failures are fade, or a broken part. Fade is simply a matter of proper heat dissipation, no matter what system you use. In the case of broken parts, any failure causes an accident, no matter whether there are excess parts there or not. And, in my experience, the more parts, the higher the chance of a failure occurring. KISS. If there were a complete dual sysytem with seoarate master cylinder stages for each caliper, that could help in some scenarios, but no bikes have that. Other points: Lighter wheels with lower rotational inertia allow the bike to accelerate and decelerate faster. And, the really big factor with lighter wheels is keeping traction over pavement discontinuities. Not just during braking, but during cornering. This absolutely can win races, as it not only affects. Any of the exotic materials you mention will work on any system, therefore, if you can make smaller rotors with ceramics, you can make thinner ZTL rotors with narrower pad width. So, once you have an inherently simpler design, you have an advantage. Now on a race track, you can be beaten with horsepower, etc., but our brakes are superior, and more so on the street. | ||
| Jon |
I'm really enjoying this thread.  | ||
| Blake |
Danny, WTF? You sound like an engineer.  All right. Because with radial mounting the caliper deflection normal to the rotor was reduced. I don't see that. Can you show me a free body diagram illustrating the lateral loading you are saying has been mitigated? And regardless, would not simply beefing up the caliper mounts whether for shear (conventional) or tension (radial) type mountings reduce lateral flexing?. Interesting factor to consider though; the ZTL avoids lateral flexing since the caliper mounting bracket is co-centered with the disk. And the disk certainly has a much more direct more rigid load path to the rim. They were able to transfer the same amount of force to a smaller rotor because more of the hydraulic force was transferred toward the rotor when it couldn't move the caliper body away from the rotor. Not convinced of the increased rigidity of the radial mount in and of itself. But even so, I'm pretty sure all clamping force gets transfered directly into the rotor, and once set during braking no more flexing occurs. So with caliper/bracket flexing only occurring upon initiation of braking, feel *might* be affected, but not braking power. Note that to achieve the same braking power with a smaller rotor(s), the pressure exerted on the pads would need to increase by the ratio of the old larger diameter to the new smaller diameter of the disk(s). In other words,in order to maintain the same braking power when disk diameter shrinks by 10%, brake caliper pressure or clamping force must then increase by 10%. But really, you didn't answer my question as to "why" the Japan Inc. folks spent to much money changing their brake system? You offered and explanation of how they could do so. But why did they do so; what was the motivation to shrink the diameter. Why not keep the same diameter and simply use the radial mount? Jim, Same for you. You offered how the engineers could get smaller rotors to perform okay. But why did they see a need to reduce rotor size? Not "how", tell me "why" the repli-racers all downsized their front brake disks. I actually worked through the math on the issue of gyroscopic forces of the ZTL versus conventional wheel/brake configurations. I found that the tire by far governs the magnitude of gyroscopic effect that tends to hinder high speed turning/handling. If you look at the availability analysis for a dual brake system, I'm pretty sure you will find that rather than a redundant configuration where one serves as a backup to the other, you have a serial configuration where failure of either side of a dual brake disk/caliper system will cause the entire system to fail. All else being equal, a dual system is then little more than half as reliable as a single disk system. The fact that a single lever and master cylinder is employed for each configuration puts the dual system above half the availability of a single system. Do you like the fact that that the intense heat generated by the small brake disks is in such close proximity to the wheel bearings? Might it be better to keep that intense heat further away from the wheel bearings? "On bicycles, if you bend the rim, your rim brakes are shot. With a center rotor, it is unaffected." Might want to take a look at where the ZTL disk actually attaches to the wheel. Not quite anything comparable to bicycle brakes is it. If you manage to bend that, having front brakes are likely going to be the least of your worries. You likely won't have an inflated tire or sufficient seal to re-inflate it. Or were you speaking to mountain bike brakes? If so, never mind. Good observation. Eight pound reduced mass. Hard to not like... for most folks. Here's some illustrations. One for a conventional wheel/brake system, one for the Buell ZTL type configuration. Green arrows are gravity/weight forces and reactions. Blue arrows are the forces of deceleration. Red arrows are the brake disk frictional loading and reaction. Note that the magnitude of the red forces times the distance between them must equal the magnitude of the blue forces times the distance between them. Take special note of the relative magnitudes of the red brake disk forces/reactions for the conventional versus the Buell ZTL style wheel/brake. All forces must sum to zero and all moments about any point must sum to zero for equilibrium to exist. Right Danny?  Conventional Wheel/Brake FBD  ZTL Wheel/Brake FBD I did neglect a small detail or two of the physics in this case. Anyone recognize it/them? Anyone care to cut away the rim and tire from the diagrams and see what they come up with for FBDs? That is what will clearly show how a ZTL wheel/brake can be so much less massive. Simple stuff... all forces must sum to zero, and about any point, all moments must sum to zero. Congratulations you now know Statics 101. | ||
| Bomber |
phew -- well, having recently humped both a wheel/disk and wheel/disk/tire round, I can back up Blake's assertion that the tire is the largest contributing factor in the gyroscopic affect dealie -- BIG difference in weight (I was surprised) I'm off to update my training records to show my mastery of both physics and Stats 101 - I'm sure to get that promotion NOW smile oh, and for the record, I, too, am enjoying the tech aspects of the thread -- thanks to you smart folks for sharing your hard earned knowledge | ||
| Reepicheep |
Nice touch with the open spokes and hub on the second drawing. |
