Tireman9 wrote:
OK I'm gettin confused. I don't know what the question is and now I have to set my alarm cuz I am no longer retired :-(
I can shed a little light on the speed rating of the Mich Rib. I have been told by Michelin "All current XPS Rib tires have a Q speed rating" the Q stands for 99 mph so the web page that says 75 is wrong and I have pointed out the error to Michelin. I will advise what they say or when they will make the change.
To those that want DOT or TRA or ETRTO or RMA to update their standards I can only advise that you not hold your breath. This is not just a technical question but it involves lawyers. If a standard changes the load spec on a tire the first thing that will happen is trucking companies will conplain because they can't carry the load they want on the tires they own so costs will go up. Next the lawyers will sue the tire manufacturer because every future tire failure, even the ones with a railroad spike through the sidewall will be blamed on defective design which overstated the tire capability.
Trust me, they really do ask "When did you stop designing defective tires?"
I also know that the standards orgs have been working for at least 10 years to "rationalize" existing published standards but the legal implications seem to be a major roadblock.
So continuing to question the formulas or existing tables is a waste of electrons on the internet.
Finally, Would it be possible for those with specific application questions to re-post their question along with the information needed i.e. actual and complete tire size, placard info, actual speed you drive and actual individual tire loading. so I can consult my reference books?
This is about 15% of my ref material.
I think Barry's main point of this thread was to answer a bunch of technical questions around the design and construction of LT versus ST tires and their general application, not a "I have trailer xxx and need new tires -- what should I buy?" type thread. If someone has that type of question, they should post a new topic and provide the data you have requested, along with my request for the GAWR also. There are a number of good sources of information, and you can certainly put yours to good use in aswering those. What we are interested in here is the continuing flow of the "why" type information that you and Barry are sharing. The whole LT vs. ST debate had been the same here, as far as I can tell, going back to at least 2008. This thread, and Barry's other thread that got closed are the first ones to bring new information and understanding to the issue. This has been very informative and much appreciated by those of us who aren't engineers but care.
Keep up the good work guys (and no, I won't try to coax you, Chris, or Calvin out of retirement, and I won't try to hire Barry away from his current employer. ERS Tire and Rubber Company Limited is a figment of my imagination that will only exist here in rv.net cyberspace).:D
