Learning trucks! Single axle vs tandem or double axle truck?

Well,I think the other guy is accurate.Believe its 32,000 max in a 53'. Ive drove single and double axle.Frankly,double axle tractors ride a lot better on the road and are more "controllable" in the wind on washboard or "rutty" roads. Usually slightly better fuel mileage out of a single,but with a light load in the wind you find yourself babysitting the wheel and will keep you compensating a lot. Singles are great for crazy back ins in tight parking lots. Prefer a double for ride quality.Also singles suck for slick mountain passes,barely any traction and will "break traction super easy".Put it in interlock with a double axle and chains and you're golden. That extra set of axles helps tremendously. I dont really care for single screw tractors. JMO

 

We run 9 S/A sleeper trucks nationwide, trucks are Cascadias with 410 hp, we also run 53 trailers. We lic. for 54,000 so my combo works out to 12,000+20,000+ 38,000 (we run an 8' spread axle, so we pick up 4,000 on the spread) The reason we run more axle than we reg. for is because of what we haul, we can not usually shift cargo, slide axles or slide 5th wheel.

With that said, we will be going to a 3 axle setup soon, 12,000_20,000_20,000, BUT the new trailers are lighter than what we are running now, so I think we can pull it off.

I personally like the S/A tractor, better mileage, less weight, less rolling res. less tire cost, less maint. less tolls, better turning, etc.etc. As far as traction being better on a twin screw, it depends, remember something, IF you have a bottom, hard packed surface you actually have MORE weight per tire on that S/A (at max weight) that you will on that twin screw.

Also remember, MOST twin screws run an interlocker, BUT they don't run locker rears, so on a very slippery surface, even in diff lock, you ONLY have two wheels turning, give me a S/A with a true diff locker and I will go places that will make your head spin.

Now if you have no hard surface, sand deep mud etc. then yes the twin screw will have better flotation. As far as weight, my Cascadias are 60" sleepers and are hard loaded, APU's, power everything, AMT's reefers, swivel seats, etc, they weigh 16,000 I think you could get one down to 14,800 pretty easy.

Hope that helps?

 

I'm wondering have you talked to a dealer who can see your operation and help you make a good informed decision?

Normally they would be the first one to talk to seeing that they can see what you are hauling and how it is being hauled.

 

Well, let's start with the weight first, because if you can't scale or axle it, nothing else really matters,

Let's say you get S/A tractors that weigh 15,000 and let's say your trailer weighs 15,000 (I'm guessing here, any idea what your trailer weighs) that puts you at 30,000, even if your trailer is a bit lighter you still have fuel, driver, etc.

So if your combo is 30,000 ready to roll empty and you add 40,000 you will be at 70,000 gross, can not gross that on four axle "conventional" dry van, because you will be 12,000+20,000+34,000= 66,000, so at MAX weight on every axle you will still be 4,000 short!

Now, you "could" run a spread axle trailer on a 10'1" and that would look like this,

12,000+20,000+20,000+20,000= 72,000 you could make weight with this setup, HOWEVER, you would have to be almost perfect on your weight distribution, you would need a sliding 5th, and if you get a heavy ended load you could still be in trouble.

So I guess you "could" do it, but you are probably going to have a hard time finding a spread axle dry van, AND if you are local del. you really don't want a spread axle, you would spend more on trailer tires than you would save by having one less axle on your tractor.

You could say, OK, so I will limit my loads to 33,000 that would be doable with sliding 5th and sliding tandems, but now you are into diminished returns, how many loads will I have to split or give up at that weight?

Just from what you have told me I am not sure it is a feasible endeavor, JMHO.

Stan

 

a dealership can help you spec what you need, but also understanding things first isn't a bad idea. A couple things to keep in your head, though there are of course permutations for each but this is a start:
single axle with single wheels on it(steer axle) 12,000 lbs
single axle with dual wheels 20Kklbs
tandem axle (two axles very close together, with dual wheels) 33K
spread axle is weighed as two single axles so 40K

underCDL straight trucks have lighter axles and are usually 10K and 16K, they tare at roughly 15K lbs
our single axle daycab tractor and single axle pup trailer scales at 25K with a little equipment on board. GCVW for that combo is 52K