U500 crash, two firefighters killed

#46
So, what tires now?

That being said, then the Nevada Highway Patrol, Nevada DOT, the BLM and the D.A. are all wrong.
At this point, I agree with you from all of the information I have.
I am happy to see this discussion carry on. Erwin Z., I appreciate the interest and work you have put in, your info is valuable. I have not been privy to the Reports and am having a hard time getting any copies of the reports. Additionally, I think your info about the tire situation is also very well intended. So..... I am now at a loss as to what tire I can run on my U500. The 55 mph max rating is not a good thing, the U500 can travel at over 70 mph. Can you or someone viewing the page make a suggestion for replacement tires. My U500 was factory supplied with Michelin tires made in 1999. So when my Mog was new, the tires were already six years old! Please help, myself and other U500 owners need to know what to do. I spoke with Frieghtliner of Reno, they had no idea what kind or type of replacement tire is available.
One additional note; I inspected my upper, outer seat belt mounts, yesterday. The shoulder strap is connected to only the plastic corner pillars with one screw that is mounted into plastic. There is no way this attachment could survive a serious crash. The metal component in the corner post stops below where the mount is and does not connect to the belt.
Hopefully, the Families of the Fallen are finding some peace. Such a tragic loss, I am still shocked and and saddened by the event, last Summer. Thanks to all of you that have contributed to the thread.
 
#47
Did you contact Michelin? Or Continental (I think the MPT81's are rated up to 68mph?)

Not sure if this tire is available in the NA market but it's the right size, and is rated up to 110km/h (check the load rating to be sure it's right for your application, of course)

tires.jpg


Just because the U500NA goes 70mph, doesn't mean you have to drive at 70mph, if you have tires rated for 55, cue up some Sammy Hagar and enjoy the sights @ 55 ;)
 
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#48
Question about tires: I see lots of posts about speed ratings, they make total sense. But what about those rally trucks that can and do go well over 120km/h? Do they run on special tires?
 

dwh

Tail-End Charlie
#49
The speed ratings are variables. At X pressure and Y load, max speed is Z.

So maybe the rally guys are running at maximum pressure and minimum load, and then just taking their chances on the max speed.

Or...running special tires. :)
 
#52
The speed ratings are variables. At X pressure and Y load, max speed is Z.
Correct. If you want to dig into more information, take a look into E/ECE 324 standard Section 6.2 for Load/Speed Performance Testing.

So maybe the rally guys are running at maximum pressure and minimum load, and then just taking their chances on the max speed.
Highly likely and a decent assumption.

Or...running special tires. :)
In my opinion, this is highly unlikely give the cost involved with tire development and production costs for small lot runs of "special tires". Then again, it could be possible... It is more likely that these tires are run at much lower loads than they are rated for and never reach the limit of their duty cycle within a particular race or collection of segments before the tires are changed.

I think it is safe to say it is best practice to pay careful attention to the following when purchasing and operating tires for large vehicles like Mogs (or any tires in any application for that matter):
  • Do not exceed to push close to the limit on the load rating of the tire for a given application
  • Respect the speed rating specified by the tire manufacturer, especially when operating in the higher end of the load rating of the tire
  • Carefully inspect the condition of your tires before mounting or in particular on regular intervals while the tire is in service, replace when necessary
  • Use good judgement - a failed tire and possibly resulting in an accident is not worth saving a few hundred dollars by not replacing a unsuitable tire
 

kerry

Expedition Leader
#53
The fact that you discovered that seat. Belt mount justifies this thread. Are you planning to change it back to the original seat mount?
 
#54
The fact that 3 young kids in their 20's who while at work were in a wreck in a Unimog, 2 getting killed and one whos life will never be the same, justifies the thread.
Had that not have happened, this thread would not be here. That I would sooner have seen.
 
#55
Please help, myself and other U500 owners need to know what to do. I spoke with Frieghtliner of Reno, they had no idea what kind or type of replacement tire is available.
The 1st and 2nd report was clear.
Freightliner knows but didn't want to tell you.
Maybe call Germany and speak to Daimler directly ? The tire is not specific to the U500 but to many other Unimogs.
It makes me wonder with both reports done, who is contacting the owners ? What is Michelin saying ?

Maybe the answer is, when the tires need to be disposed of, the Unimog is too, and buy a new Mog and you get the new tires.
Unless someone can come up with a better answer.
 
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