18 wheels on that semi or 10 ?????????????????????????????????

[QUOTE="semi" retired;4038608]Hi Richter, just one more thing (Columbo), just so you know, I like you, you make a lot of good points, you're not a an idiot and have a good head on your shoulders. I don't advocate anything that went on in the '70's, we paid a price for that activity, but I just like to remind people of how it was. I'm glad there are truckers like you now, we have come a long way, now,,, as for your spelling,,, just kidding, truck em safe, pal.[/QUOTE]

Yes, some paid a price, & a very high price. Yet in the years gong by there were times when one could drive fast yet be fairly safe, & not endanger others. The problem back them was we had some who drove fast anywhere & everywhere, even in heavy traffic & even on bad roads. Those type of driver I never tried to stay up with, I let them go on & paced myself safely.

Today most of the highways has so much traffic on them than in yesterday years so there not that many places that its safe to drive as in yesterday years.

I remember an incident between Fort Worth & Dallas one afternoon, I believe it was a Sunday. Another hand & I was coming east, the traffic was not thick, yet there were several on the highway. A Trailways bus passed us going quite fast, & right behind him came an 18 wheeler, they seemed to be racing. Going through a long curve to the left the 18 wheeler was passing the bus on the inside of the curve, he got the buses drivers side mirror, & both of us thought from seeing it from behind as it happened, thought we were about to see several people killed in a bad wreck between an 18 wheeler & a bus.

We had been running about 60 MPH, & they passed us like we were setting still, switching lanes constantly to pass the slower traffic.

I admit driving a truck & or a car is much different than in yesterday years, & its easier to wind up in a wreck if one is not extra careful today.

 

you need to be careful about what size the super singles are. Texas uses tire rating, most other states use width to determine how much you can carry. You can use a program like Legal Load to find the right size or rating. Usually, duals are overkill - I've heard some states don't allow super singles - at least for some loads

 

What? I have never heard of any law/state against SS's... Each tire, weather SS or Dual application has the rating right on the side wall. I assumed all SS's were the same width, am I wrong?

 

If your grossing 80k or less, no state has any laws against SS (i haven't checked Alaska or Hawaii.) For over weight and permit loads, some states have regulations against them. Some stated require duels regardless of size for heavy haul. If you got a specialized rim i didn't see any regulation saying you could run duel supper singles. I'm not to familur with over weght in all states so some may have with restrictions, but, SS are primaraly for normal trucks grossing 80k or less.


So no, they are not for every industry subset, but for the 90% of us that gross 80k or less they are 100% legal.

Some stated used to no allow them on trailers, but that has changed.

 

So the question I always have about singles is, why not go to single 315's? They will hold enough weight to get to the 34,000lbs. tandem, and you would have the same tire and rim on every wheel. Just one spare for the whole truck.

 

I'd guess maybe a stability issue.

 

A tire like the XAZ 2 energy is 315 80r. It can hold 9090 per tire at max psi which is 130. Many rims limit you 120 psi, so you may not be able to get the max out of the tire. Now I forget the exact number, but i learned from mike becket, those standard are at a certain temp and 55 mph. When it gets hotter or you plan to go faster you need to add psi. Since we are already at max psi (which is the same as min) we cant add more air. We will constantly be running under inflated since we need more then the min when in hot areas or faster. Also, at 9090 / tire we are able to lift 36360. We are maxing out this tore all the time. Its never good for tire life to always run it to it design max. A few bumps could expose that tire to more then the design limit of 36360 and cause problems.

Now lets go into why you need surface area. When the tire spins, its surface area on the ground keeps the truck moving insted of the wheel just spining. Thinner tire= less urface area, more likley to spin out and get stuck. braking would also be problematic. Have you ever locked up your wheels by mistake on a hard brake? What if there was less runner on the road slowing you down?

Now lets discus rolling resistance. the X one line energy d has an rr of only 89. The XAZ2 has 88. Only 1 point less. 1 point isnt going to make any measurable difference in MPG. It eill make a difference in grip, handling, and tire life. Why not buy the Super singles designed for the job.


EDIT, i got 36k and 34k confused. You would have 2k of wiggle room, (why was i thinking 36 on drives lol)....anyways, you would still be running the upper limit of the tire, just not as bad as i thought.

 

It is wishful thinking. If you get the correct rim, max PSI is achievable. Its the same as 12,500 on the steers all day every day, ran at max.

 

12000/2=6000

34000/4=8500

XZA2 energy comes in both sizes

275/70R 6940@130... 6000/6940= 86% of max capacity on steer
315/80R 9090@130... 8500/9090= 93% of max capacity on drive

So, its actually using 7% more of the tires capacity on the drive. So no, its not the same capacity ishue we have on the steers.

I ask again, why not use the super single that is designed for this. Your only sacrificing 1 rr point.

445/50R 10200@120...8500/10200= 83% of max capacity on drive

Don't forget, some truck stops cap off at 120 or so... topping off a 130 psi tire may be hard.

 

Richter,if you drive a few miles while loaded,you will allready be above 130psi as the heat off the tires will cause the air to expand thus raising pressure.