specking a new truck

[arch_stanton]

I have been running a dump truck business for 28 years in San Diego we haul dirt mostly and some demo. Used trucks have been how most small and even some large companies get replacement trucks, but with the new calif smog rules we have no choice but to buy newer equipment but, what I have learned hear and the horror stories from other buyers of trucks that should have been dependable, the new motors require more knowledge and maintenance to keep running.
This is what brings me to the decision to speck a new truck i have bought 1 new truck and was very disappointed in the support from the dealership, the truck itself is dependable and has worked well I did make a few mistakes when specking it and with a little help I want to get the next ones right.
I do have a good idea of what I need in a truck but one of the most important things is what not to speck and to that end I want your opinion of what to avoid.

I am looking at buying a Kenworth T880 at this time with an X15 485 hp 1600 torque with 18 speed auto shift 46,000 lb rears with 3.70 ratio on Neway ADZ46 suspension the front Axel is a 20K unit with 16K springs with a single 16K steering gear and 315/80/22.5 tires the rear tires are 11/22.5 16 ply well thats the basics.

I should tell you a little about the cost of my business fuel cost is 13 % of revenue tires are 2.6 % we only average about 200 miles a day Drive tires are heavy lug with a tread depth of 31/32 and they last about 40K miles I have tried regular tires and they only last about 25K the tires I run cap up to 3 times and we almost never have a blow out since switching to this style of casing so any body else into this kind of trucking

[Brock]

I don't do dump trucks but if I did I would spec 4:30 on 11r24.5. Better for stop and go traffic and getting out of mud plus when you are up to speed,you'll be running 1600 rpm getting the emissions warmer. Goodyear g741msd tires. Primax suspension. I would drop the 485 down to about 450, no xhance of snapping the driveline if stuck in the mud, engine will produce less emissions and would have a easier life due to the gearing.

I don't know if you pull a wagon or not. I'm also not sure of your operation so take my thoughts with a grain of salt.

[Hammerhead]

The X15 is basically an unknown quantity at this time. Based on Cummin's so called improvements with the 2250, then the 2350, I'm not willing to make a prediction at this time.

I agree with Brock on the gearing as well as the suspension.

The gearing having you run at 1600ish RPM is going to help you by creating airflow through the emission system, which for regional and or short haul applications such as yours will help ensure that passive regens get the opportunity to complete efficiently where RPM operations may inhibit good regens.

Neway is a very good Heavy Haul suspension, however Hendrickson's Primax suspension is a true 4 link design. If you were to go to any drag track and talk to them they will all tell you that the 4 link design suspension actually builds traction under power, which for off-road applications is an asset. I decided Primax over Neway in my truck and there have been times where I was sure that I would get stuck and didn't. In full disclosure, I will also assure you that Neway does have a better/softer ride.

Do you really need 46k rear ends? I know Cali allows that kind of weights on tandems under permit, so you very well may. The reason I ask is that a couple of years ago I had a drive wheel seal failure in San Diego, and El Cajon KW didn't have bearings in stock for Eaton 46's! I couldn't believe it with all the HH trucks around Cali, but they told me almost nobody around there runs them. I was fairly skeptical, but that's what the service Dept said, and waiting for parts for diffs is a real pain. I asked about the availability of reman out of curiosity, and he told me 3 days away. Anyhow, something we do in our HH application is we run 46k diffs with 52k suspensions. I know it sounds questionable, but think of this; almost all freight trucks run 40k rears and legal axle weights are 34k. Using an overrated suspension increases longevity and improves ride as you are not at the limit during loaded operation.

As for the front axle, anything over 14,600 and I am absolutely adamant that the truck has dual steering boxes. I know engineering will tell you that one is enough, but it's barely enough. Dual boxes are more stable, reliable, and run much cooler than a single. I did the single on this truck and I regret it. If you are running the big weight on your front end, I think you should seriously consider 385/65R22.5 tires. They do cost more, but if you are consistently running the weight, they will last longer enough to offset the cost. The other side to it is if you are on a soft site long enough you can deliberately under-inflate them allowing them to "spread" the weight across a larger surface area allowing for better control. I drop mine to 70-75psi in these conditions and it helps tremendously.

As far as tires go, you run way longer in warm temps than Brock and I do and it sounds like you've made some astute observations based on your application.

[arch_stanton]

Brock the gearing suggestion is very interesting I normally run 3.90 or 4.11 but was trying to improve fuel milage and was going to the 18 speed to get the 14.4 low gear to compensate for the 3.70 we usually run a 13 speed or C model 10 speed that both have about 12.5 low gear. Does the air temp hear in San Diego help keep the emissions temps up ?
As far as mud goes its a 10,000$ fine to track mud on a street so there is no work when it rains and sometimes for a few days after, they fine the contractor not the trucker.The Goodyear G741 msd tire is very interesting I just looked it up it has 2/32 more tread depth, I currently run Yokohama LY053 drive tires and MY507 all position everywhere else the casings are the same and run well together when capped.The Hendrickson Primax is a similar designer to the ADZ and I like the design of both but ride quality is more important than a little more traction and I was lied to by Hendrickson when specking the HN462 suspension on a new truck, I ended up removing it and sent it off as metal scrap. The ride was brutal and it would get stuck very easy when unloaded so I won't buy from them unless the are the only choice.For HP both of the ratings are 1600 ft lb so a don't think the drive line will see the difference HP is achieved at higher rpm.
We do pull a pup trailer some of the time, I am actually building a super 10 and I did not mention that before, the truck will have a Watson Chalon 8K self steer drop Axel just ahead of the drive axels the spread on the tridum is 9 feet with that we are allowed 42500 the truck will pull a trailer but will be limited to a max GVW of 80K as a super pup or 56500 as a super 10

[Brock]

Well it sounds like you got it packed down pretty good. I was curious why the 18 speed but that makes perfect sense. I'm a fan of the 18 no matter what though. Those tires you use are great! Similar rolling resistance to the xds2 so they aren't as bad as they look.

Another thing that may help you out is the turbos on these newer isx. I own a 2008 but right now I am driving a 2014 while my one trucks being worked on. I call this thing "the whistling retard".... this turbo spools like mad before I even give it throttle. I can start in 2nd with 140k of I wanted too. It's a dog once up in the higher gears compared to my 871 but starting off this things a beast!

[Brock]

Oh....... and a half mpg worse on fuel despite being geared for fuel mileage better.

[arch_stanton]

Hammerhead for the motor I really don't have much of a choice but to roll the dice and hope that Cummins has in fact improved the X15,we only run about 45k miles a year so by the time issues show up Rawze should know a fix for it.
On a good day we run 4 loads going down the freeway a normal day we run 6 loads or so on city streets with a little freeway on a shitty day we run 12 loads around a neighborhood and then we get the ass kicker days 50 plus loads on a job site all day,luckily we don't get many 50 load days so regen's are going to have to be managed and maybe done at the shop by the mechanic I'm hoping the wireless connected diagnostics will help me track when regen's are due.i don't know if I should even try to gear for passive regen's given how we run the trucks but I'm going to ask some other guys in my type of operation how they deal with it.

I don't really need the 46K rear ends but we break the DS405 ring and pinion, axels, through shafts way to much and the one truck I bought out of Canada with 46k drives has never broken anything in 15 years I was looking at going with the 44K axels but it looks like they are just 40's with a heavy wall housing and a snubber bolt on the ring gear anybody know more about the 44k axels.
Inland Kenworth in El Cajon is the best dealership in San Diego they have only been there about 5 years, you may have noticed all the peterbilt's in there for service, Peterbilt is the most popular truck in this area and it's all I have, but Rush Truck just pain sucks to deal with I have heard other Rush truck centers are better than ours.
I hope Adam or John called all the local parts houses to help you but because of inventory tax in California nobody can afford to have parts in stock that don't move regularly there are at least 2 rebuilders in San Diego area that should have had parts but they may have after market parts and LA has everything I have had to drive up there to get parts the same day.
The 16K front springs and steering box is an upgrade to the 14.6k that we have been running for years with no problem with the addition of the drop Axel we will see about 16K max on the front end legally and only get to 18K if the rear Axel gets to 50K or 8K over weight.
I am hoping that running the 315's will allow me to reduce the tire pressure down to 85 psi to improve the ride, we currently run 120 psi on the 11/22.5's
I do know a few guys running the 385,s but it seems to really hurt the Turning radius.

what are your thoughts on disk vs drum breaks ?

[Brock]

The stopping power of discs is amazing compared to drum but off road guys have had issues with them. One company I was leased to was doing brakes every couple months but they were 100% off road in the muskeg logging roads.

[Hammerhead]

10-4! Stick with the 46's then. You answered the only answer that I could think of to justify the question for your application. Just don't break a 46, they are WAY more $$ to fix than a 40!
I've been to Solar Turbine in SD quite a few times and kinda wondered about the whole mud tracking thing, since I've never seen it there and assumed it was that way. Actually, I have a buddy loading there Tues.
I never needed a whole diff when I was there, but I didn't like the wear pattern on one of the bearings when I looked at it which was why they got changed. When they didn't have bearing for 46's I was quite stunned, which lead me to ask the question of availability. I'm naturally curious why people do things differently and I'm always interested to see if I can find a better or alternative way.
I wouldn't run 85psi in 315's, I don't think they are bigger enough to run that low, but I'm not in your application, so take my opinion with a grain of salt.
I understand your outlook of Hendrickson, and Neway is a fine option. Since you have the stated "can't work in the mud" option traction is not as much of a factor as it would be in other locations.