Help on new truck specs

[GeorgiaHybrid]

OK everyone, long post warning as I'm looking to spec out a new truck to see how it will price out vs a slightly used truck (200K or less). The used truck will need to be singled vs buying the new one already singled up. Yes, I know the furor I started on the other thread but I have decided to go with single axles.

Given that, there are a LOT of specs that I NEVER considered on a new truck and would like to ask you folks for a LOT of help on these. I am looking to spec out a logging/tanker style of frame with the lowered crossmember in the back already drilled for a pintle for towing plus a lot of other options to make finishing the truck a little easier.

First things first, it WILL have air disk brakes front and rear. The Kenworth spec I am looking at will also have a 20K AG230 rear suspension and 13K airbag front suspension to keep the weight at 33K or less (trying to avoid the FET tax and 33,001 and up will require that). For the T680 Kenworth with a 72" sleeper, it will have a MX13 Paccar engine with an Eaton 10 speed Ultra Shift Plus OD tranny.

I also want to set it up for a new Smart car that will be 106.1 long, 65.4 wide and weigh 1,800 pounds but will use ramps and not a loader for the car.

Those are the basics, here are the questions I need help with:

Single axle wheelbase is? I am thinking 235 or 236 inches would be about right but would like to hear your opinions on this.

Center of rear axle to end of frame? Would 72" here be about right? It will not be easy to change this once it is set due to the lowered, heavy duty rear cross member so I need to make sure that this will come in correctly.

Would the height of the tow hitch ball/bed bumper/rear bed mounting point at 24" from the ground be enough? I can set it at 1" increments.

Centerline of trail pin to the outermost point of the trail (with some clearance) would be 4'-6" Would this work OK?

What do you think a good length of the bed would be and roughly how much would the bed weigh out of 3/16" or 1/4 plate (need a rough idea for front/rear axle balance).

How far back would you place the 5th wheel hitch pin location? I will be using an ET hitch from Henry and they can prepunch the frame for the bolts and I am going to assume a pin weight of 6K for the axle weight check. They will also punch holes for the bed mounting.

We plan to have all the under sleeper area on both sides to be completely filled with fuel tanks and DEF tanks. Right now that appears to be a 150 gal on the right and a 110 gal on the left and they can add a bung in the tank for a ThermoKing or HP2000 APU on the passenger side rail as well as running engine cooling lines and power lines to the rear of the cab for that install. I will also have a weedburner exhaust instead of a stack.

I would also like to have an air suspension drop on the truck (real handy for a gooseneck...) and will have glad hands at the back of the cab and the rear of the frame as I plan on adding a Blue Dot air brake system to the trailer later.

I think an 18" deep Drom behind the cab would work OK but assumed the weight would be about 2500lbs. Does that sound about right for a steel drom loaded with stuff?

One more BIG decision to make is regarding the aux cab heating and cooling. A ThermoKing or HP2000 APU probably costs less to have installed and is going to cool in hot weather but there is another engine to deal with, more oil and filter changes, cab noise, and a big ol box the bed will need to be designed around.

The battery based KIMS system will require me to pre-chill the sleeper and then drive at least 4-6 hours the next day to get everything recharged unless I can get it setup to charge from shore power. The advantage is it is dead silent and you get a truck electrical system that they claim Jack would die for.......

The disadvantage to the KIMS is that I can't have the ultracap starting system with an Ultrashift together as they run out of battery terminals for the Ultrashift clutch. I also don't know ANYONE that has one of the KIMS systems on their truck so I am all ears on this as an option.... If I use a ThermoKing or HP2000 unit, I will get it with the invertor/shore power option but will use a factory invertor if I go the KIMS route.

[CDR]

GeorgiaHybrid;

 

You have me interested in the options of this setup! Do you know how much power needs to go back into the kims to fully recharge? I know Webasto make their "Blue" system that works on that same type of theory. Freightliner offers a similar system also. I feel using a ultra quiet small generator in conjunction with shore power, would give you a very quiet very efficient total package system!

 

Good to keep the wheels turning!

 

 

Curt

[CDR]

GeorgiaHybrid;

You have me interested in the options of this setup! Do you know how much power needs to go back into the kims to fully recharge? I know Webasto make their "Blue" system that works on that same type of theory. Freightliner offers a similar system also. I feel using a ultra quiet small generator in conjunction with shore power, would give you a very quiet very efficient total package system!

Good to keep the wheels turning!

Curt

I forgot to add these systems also have an inverter incorporated in their setup. Some inverter/charger!

 

Curt

[Jack Mayer]

Scrap would be a good judge of how the battery system works in that application. I think he had a truck with one. But my discussions with people with them is that they are "marginal" in really hot weather, and that they depend on the cab curtain being drawn in most hot weather. I have some experience with a DIY version which used a mini-split. But a min-split is challenged in the harsh vibration environment of the truck. So the battery system is "iffy" in my mind,at least currently. But if you are not going to use it for long durations in really hot weather it will likely be OK. Personally, if I intended to use the cooling a lot, or for longer time periods I'd go to the genset. You have the noise factor, but you also have a more reliable and robust cooling factor.

[GeorgiaHybrid]

Jack,

 

I am leaning towards a gen set and I know that Thermoking will work well but it does butcher up the cab a lot to install it. The HP2000 just requires two small holes for the coolant lines to enter the cab. It is also a very quiet unit but reviews on them seem mixed. I do have a very good friend that installs and services them locally to me however so I will probably go that route and take a chance on it. as far as the pin location, I know that I will have a 18" drom, the smart car and I know the distance from the fiver pin to the edge from straight ahead to 90 degrees from the truck. I would like some advise about how much clearance everyone runs between the drom and the car and between the car to the fiver. I also don't have a clue as to how far the bed needs to extend behind the pin to be able to bolt in one of Henrys ET hitches.

 

I was guessing at 6 to 9 inches of clearance between everything but I'm not positive about that and have NO IDEA about how far behind the hitch pin to end the bed and leave room to bolt the bed down, clear the ET hitch and add the class IV receiver hitch to the heavy duty rear cross member.

 

Thanking everyone in advance for the help...

[MrSeas]

If you have a chance check out these YouTube videos.... lots of ideas are shared and explained. Might give you some answers....http://www.youtube.com/playlist?list=PLiJ8IVlm34GAF54yUkHlvGc26H0hp0EoP

[noteven]

Have your KW sales person check out code 8190005 - pre-wire and coolant lines for customer installed APU.

[Jack Mayer]

My measurements are HERE.

 

Add the 5" for a new smart though.

[GeorgiaHybrid]

Have your KW sales person check out code 8190005 - pre-wire and coolant lines for customer installed APU.

 

 

Thanks for the heads up on and Scrap had sent me a PM about it also. That option even has a bung welded into the right fuel tank in addition to the coolant and wiring runs to the back of the cab. Seems like a nice option and will be added to the spec.

[GlennWest]

My measurements are HERE.

 

Add the 5" for a new smart though.

Are you also allowing for fairings on your back of cab to center pin of hitch measurement?

[peety3]

I'd ask your dealer if they have any as-built weights for as comparable truck as they can dig up. A little time with a spreadsheet should allow you to verify weight/balance estimates as in-range.

[Jack Mayer]

Are you also allowing for fairings on your back of cab to center pin of hitch measurement?

Yes, that is included in those measurements. And in my case I have the extenders on, which makes the total vertical cab fairing right around 18" +/- .25". My 18" drom sits behind the fairing "line"...done on purpose for "looks".

 

I left around 3-4" between my drom and my typical load position for the smart. Bear in mind that the loaded smart is NEVER in the exact same position....it can vary by more than an inch or so.

 

My distance between the trailer nose and car on a 90* turn on a relatively flat road surface is only a couple of inches. Kinda close. If doing it again I'd give myself another couple inches. And of course, I screwed up and did not figure in the 5" for the new smarts. A new one would fit, but barely. I'd have to snug up against the drom more, but it "could" work. But it would not be ideal.

[GlennWest]

I am planning on a 630 so I should have more to allow for. Thanks, Jack.

[Chad Heiser]

I found this tonight. It is a pdf build spec sheet for Kenworth T680/T880 trucks. Pretty much everything you ever wanted to know about what build options are available.

[Chad Heiser]

Oh, and also Kenworth has launched the mid roof sleeper option in the T680/T880 trucks as well. Now there is a truck to fall in love with. I would love to have one of these as my RV hauler.

[GeorgiaHybrid]

Chad & Jack,

 

Thanks for the links and the dimensions. I have been a little busy here at work this week and hope to be able to sit down with the wife this weekend and figure everything out. The build spec sheet helps a lot but didn't have the larger sleeper info included so I need to figure out a few things to finish that up.

 

Overall, I am starting to really like to possible layouts for some items along the rails.

[Scrap]

Well here's some numbers for you guys. I screwed up and let the "battery apu" truck die flat dead over the last month. So at 10AM I put a 100A charger on it. It finally (unhappily) cranked at 4:30 PM. Right now at 8PM the dash gauge says 72% main battery and 94% aux batt. So I guess I get another hour of OT to read the forum and watch it charge... If I milk it right it'll need to regen for another hour after all this idling!

[GeorgiaHybrid]

That is why I was afraid of the battery APU option...... I'm still leaning towards a Thermo King Tripac or an HP2000 split system. The HP2000 only puts 2 small holes in the cab for the refrigerant lines and is the way I'm leaning. You could always take a trip over the mountains to the tri-cities area instead of just sitting there idling...Lots of nice vineyards out that way.

[tyates007]

Oh, and also Kenworth has launched the mid roof sleeper option in the T680/T880 trucks as well. Now there is a truck to fall in love with. I would love to have one of these as my RV hauler.

Me too

[Scrap]

LOL I just got back from Walla Walla yet again.....but I took the ICON 900 that was parked next to it instead! The concrete sniffer is going to keep having dead batteries as long as the big dawg is in town!

 

Last day to order an ICON 900 is Friday!

[noteven]

I found this tonight. It is a pdf build spec sheet for Kenworth T680/T880 trucks. Pretty much everything you ever wanted to know about what build options are available.

 

Chad's link is to the T680/880 Body Builder Manual - for public use by second stage body and equipment installers. Lots of information there on suspensions, dimensions etc. This is additional public information to the data books and spec'ing software that are licensed to dealers for their use with customers.