Shorter WB give's you more maneuverability, better for working in tight spaces, but with the longer WB you have room for overhang on the front if needed.
It's give and take, each has advantages and disadvantages.
In decking you try to make it as flexible as you can in terms of where you might travel and what you might haul.
In nasty weather in the mountains a long WB is probably safer than a shorter WB, a little more control and time to react if the trailer decides to pull out and pass you.
About the engines.
It's more about the driver than the engine.
The DD and X15 are different engines, yes, but not so different otherwise, the same logic apply's to both.
It doesn't matter which, but I'll use the X15 for an example.
If you have 2 X15's, physically identical except one is set at 500 hp and the other is set at 600 hp your first thought might be that the 600 hp engine will be less fuel efficient.
The answer to that is, not if you don't use that extra 100 hp.
If the 600 hp truck followed the 500 hp truck all day long and didn't pass it, they should both use the same amount of fuel because they are both using the same amount of hp to propel the trucks down the road or climb hills and etc.
Any truck you might name is using X amount of hp to propel it down the road at any time, regardless of engine brand, probably 200 to 250 hp an the flat with no wind.
The less hp you use the less fuel you burn.
The different brands of engines may vary slightly in fuel consumption, but not a whole lot, they're all pretty close, 13L to 13L and 15L to 15L.
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I put some old iron through loads that defy reason, Broke a scale in virgina (And fell through to the steel frame designed to save lives a foot down) at 134500 with a box heavier than that. (That was a very bad day, 7 months from school no loading training in box count, weights, capacity etc. All I did was tell the court juvie hall lumpers (5 of them) these meat boxes fill that box until redline on wall up there.) *Bangs head... such stupidity. I understand that box got to Europe and I understand that old mack got totaled. (And I crossed one walkersville bridge that was set formally to be dynamited in 2 to 3 weeks time. If i had to drop a bridge I chose that one.) It took the load.
All that on a little 200 something horse two stroke engine. No problems. Just redlined for oh... 11 hours. Gauges quit having any meaning, pyrometer stayed at 1350-1450 most of the day. creeping towards 1550 and touched 1650 a couple of pulls which I think is probably the molten steel point. I don't know. I got scared then when that thought hit. But she took it. Thank god. (Pryo has a peg at 1650F and a warning, no more than 5 minutes. HA... Try 3 hours total....)
Today's trucks? ech..... But... they have become marvelous. Get in set in the air plush ride everything. Push a button and go. everything else is done for you including propaganda make work fritter on satellite.
UGH.MACK E-6 Thanks this.
Why does that KW have what looks like 24.5 on the steer axle and 22.5 on the tandems?
For better ride, cool factor?
What's the deal, did the dealer swap out a set of 24.5's on the tandem to lower the gear ratio for the previous owner?
I would want to know and have them change the steer tires to 22.5, or better in my opinion, 24.5's all around for the ride and forgivingness where curbs are concerned, also gives you a little more clearance if you wind up loading or dropping freight in a field or a farmyard somewhere and less likely to get stuck.
The bigger tires would take your ratio from 3:36 on 22.5 to an equivalent of about 3:25 on 22.5 which should still be no problem if you never exceed 80k or 90k.
The ground would have to be pretty soft to make that engine grunt in the basement gear with an 18 spd.
I drove a truck with a 550 Cat with 3:25 rears and a 13 spd on 22.5 rubber pulling a reefer from time to time and that truck rumbled along all day at 68 mph @ 1350 rpm with cruise engaged and every once in a while it would start to grunt a little on a hill and you would hear the turbo start to sing and feel the torque coming on and from time to time you might split one gear down on a longer steeper hill, which gave me a boner because I really like shifting gears.
One of these W9's as a matter of fact.
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