Wilsons Sandbox

> Quick question. Is the tool used for adjusting the rear spring preload a > Kawi-specific piece or can I use the hooked deal I've seen at auto parts > stores? > > Thanks, > > Jim Jackson II > A13 - South Carolina

> -----Original Message----- > From: Kurt Simpson [mailto:ajax@...] > Sent: Monday, June 19, 2000 12:18 PM > To: Jim Jackson; DSN_klr650@egroups.com > Subject: RE: [DSN_klr650] Rear Spring Adjustment > > > > Quick question. Is the tool used for adjusting the rear spring > preload a > > Kawi-specific piece or can I use the hooked deal I've seen at > auto parts > > stores? > > > > Thanks, > > > > Jim Jackson II > > A13 - South Carolina > > Jim it takes a 10mm socket on an adapter... > > Kurt

----- Original Message ----- From: Jeffrey L. Walker To: Klrlist (E-mail) DSN_klr650@egroups.com>; Weaver, Mark ; Jim & Shannon Morehead Sent: Monday, June 19, 2000 1:06 PM Subject: Re: [DSN_klr650] Tire cupping, revisited and complex for non-engineer types NKLR > > > I never claimed that there isn't a POINT of instantaneous zero velocity, > > just that the entire contact patch does not have zero velocity relative to > > the pavement. > > > > Nope, just the great majority of it, where the tire is flattened to the > pavement. There is an "entry region" and "exit region" where their will be > some slippage between the two surfaces, but this is very small in comparison > to the area of the contact patch. Consider this extreme example of a > similar system; a tank's tracks. All along the bottom of the track where it > is flat their is no relative velocity between the surfaces. Also, bear in > mind that as an element of the tire (a differential mass if you will) enters > the contact patch, it is not only translating, but rotating, therefore moves > up or down rather rapidly, so the amount of time that it slips is very short > in comparison to the amount of time that element spends in the contact > patch. > > Yes, the slippage that occurs is a wear mechanism, but I don't think that > you have described why tires cup. This wear mechanism you describe would > provide even wear on the tire, not uneven wear. > > I consider the dynamic system like this; With vulcanized rubber and > pressurized air in the tire, there is a coefficient of restitution, or > spring constant for the system. There is also a damping constant, (which I > have no clue as to what it is, but it must exist and offhand I'd say the > system is underdamped.) The normal force between the tire and the surface, > and the force due to static friction contribute to the forcing function. > (Alternating stresses on each side of the contact patch, compression and > tension.) Therefore, this is an oscillatory system. I don't know how many > degrees of freedom. I do know that the natural frequencies of the system > are influenced by the rotational velocity of the tire, and the tire tread > pattern. Perhaps it is then a "beating phenomenon" that creates the tire > cupping, or simple resonance. This I don't know. As Tom pointed out, this > is a very complicated dynamic system, so I'm sure I don't have much hope > creating a mathematical model, even with finite element analysis. So you > see, it is because of the zero velocity point that tire cupping occurs, as > this is the point at which the forcing function occurs, and my original > explanation is valid, with refinement. > > Mr. Morehead, I might respectfully suggest that you check the validity of > your own arguments before you make disparaging allusions to the intelligence > of others. I am not infallible, and I do appreciate corrections to any > theory I might propose, as this is a very important part of the learning > process and I still have much to learn. However you came across as rather > unprofessional. If you have any doubt as to the professional conduct and > ethics of an engineer, then I refer you to the National Society of > Professional Engineers Code of Ethics: > > http://www.nspe.org/ethics/eh1-code.asp > > More specifically: > > Engineers shall: > > 6. Conduct themselves honorably, responsibly, ethically, and lawfully so as > to enhance the honor, reputation, and usefulness of the profession. > > and > > 7. Engineers shall not attempt to injure, maliciously or falsely, directly > or indirectly, the professional reputation, prospects, practice, or > employment of other engineers. > > > Respectfully, > > Jeff Walker >