Join Date: Jan 2010
Thanked 72 Times in 28 Posts
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The only thing keeping me away from spacers and really thick back tires is the fact that the outboard tires protrude rather far outside the fender flare. There's the asthetic side to it, some people think it makes the dually look awesome, others like myself tend to think "overkill" when they see it. Then there's the functional side, in which mud and gravel get constnatly flung up onto the side of the fender, other crap goes flying upwards because there's no wheel-well to catch it.
To each their own, but I've decided I want rear wheels that FIT under the wheel well and prevent debris from being flung up. With this in mind, I'm limited to a 255 series tire in back with NO SPACER. But, what I was trying to accomplish is make the front tires look equally impressive by beefing them up to wider unit. The "staggered" dimensions I mentioned earlier I think will work and prevent the pizza-cutter look up front. Either a 285/70R17, or a 305/65R17 would work if it fits on the wheel. Both are close enough in overall diameter to function.
I'm not sold on the fact you'd have to carry two sizes of spare. The same size spare for the rear tire would probably work up front just fine. Sure, one tire would be 1" wider the other one with the spare on, but who cares? The diameter is almost identical.
**Geeks only beyond this point**
(You've been warned). Lets run the math. We've got an open axle up front which means the tires can easily turn at different rates (4x4 owners here). Using the simple formulate C=Pi*D, we can calulate the difference in rotational distance if a rear spare was used up front on the staggered design. That number is 1.11", meaning the 255/85 tire used up front would move 1.11 inches further forward per full rotation. Divide that number by the overall circumferece of 33.062", and we get roughly 30 rotations. This means that for every 30 full rotations of the taller tire, the spider gears would make one full rotation in the opposite direction, allowing the wheels to turn at different rates.
Pushing the math further... we know that at 60mph highway (limp home) speed, we are traveling at 1056 inches per second. And we know becuase of our tire circumference of 103.8", that means the tire is turning roughly 10 times per seond, or 10 RPM. We stated earlier that we need 30 revolutions to make one full turn of the spider gears due to different tire diameters in our theoretical situation. That means the spiders will make one full turn every 3 seconds, at 60mph, with a 255/80R17 on one front wheel, and a 285/70R17 on the other front wheel.
ONE TURN EVERY 3 SEONDS is NOT ENOUGH TO HEAT UP OR "BUZZ" THE SPIDER GEARS, HENCE, YOU'RE FINE TO DRIVE ON IT!
-This house is clear, I have exercised the demons!!!
All i'm saying is that "to get somewhere if you had to", you might not have to carry two size spares for staggered tires this close in diameter. The only advange to this is a front tire that is a 285 series vice a 255 series, 30mm difference = just over an Inch wider up front. If you wanted 2" winder up front for the "dump truck look", then go with the 305/65R17.
-2010 MCSB DRW 4x4 Laramie 3500
SOLD!! Gone but not forgotten, anxiously awaiting my next Cummins purchase...