Just curious if anyone out there knows the anwer to this. Why is it if you have dual tires running together (i.e. DRW) the weight rating on the tire drops compared to a single tire running (i.e. SRW). I spoke to a few of my tire reps, and every reason I was given, I could shoot the theory to pieces. Any thoughts?

 

the only reason i can come up with is the fact of the way the weight is distributed among the dual tires and the way they are side by side ???

 

Its due to the way a load (could,can &amp; will transfer its weight). Same as in wheel ratings themselves.<br>This only matters to dually owners.( training wheels)<br> Danny

 

Anyone know the biggest tires you can run on a daulie Im running Scorpion zero 245/70/16's

 

Yeah, but if the weight transfers, the tires receive the weight transfer via the axle, which receives the weight transfer via the frame. The same would occur on a SRW axle, but more weight % could transfer to one tire in a turn vs. a DRW axle because there is larger contact patch. There will still be a higher percentage or ratio of weight on the inner wheels (in a turn) on a DRW than a SRW. This is a result of how the weight is distributed to the frame, to the axles, to the tires. Does that make sense?

Don't get me wrong, I'm not trying to argue or be an @$$...just trying to understand. Any ideas or thoughts?

 

The tire rating doesn't drop, the rear axle can carry the same weight regardless of 2 or 4 tires. My DRW is rated at 7500 lbs. and a single rear would only be 6000-6500 lbs. Why only 7500 on the dually thats all the rear Dana 80 can safly handle. The 6000-6500 is all 2 tires can safly handle. Got It??

 

Regardless of what the axle can handle, what I don't understand is why the weight rating of a tire drops (from say 3,000 lbs to 2,700 lbs) when they are used in dual mode. Hypothetically, say you have a truck that has a 12,000 lbs rear axle. You have four tires that are rated at 3,078 lbs each and you put these four tires on that rear axle (DRW). Since the are being used DRW, the rating for each tire drops to 2,777 lbs each instead of 3,078 lbs when used SRW.<br><br>I guess it's one of those &quot;why is grass green...because it just is&quot; type things. Thanks anyway... [undecided]

 

J28: <br><br>Imagine a DRW rolling over a stone of about 4&quot; on the pavement. In that case the tire that rolls over the stone will have to support the whole weight of its side of the vehicle momentarily. <br>The safe load a tire can handle can be split up in the load it can handle momentarily and the load it can handle continuously under a certain pressure. The continuous load is determined by the heat the tire produces, and the momentary load is determined by the build of the tire. On a DRW you have the situation that the continuous load is taken by both wheels, but the momentary load is taken by just one tire sometimes. <br><br>A tire that can handle 5000# single @ 50psi is limited by the heat .<br>In a dual application we see the same tire rated at 4000#- because at 8000# momentary load the construction of the tire is at it's limit ( before reaching safety margins)<br>The rated axle load capacity has nothing to do with it- it's just that the weakest thing will break first. <br><br>Just my 2c<br><br>AlpineRAM