Kenworth K270/K370 and Peterbilt Model 200 4x4 Conversion and Misc Questions

[TheFlyHighKid]

Hi Y'All,

I'm coming from full timing in a 170EXT 4x4 Sprinter (now sold). I wonder if the big brains here can answer a few questions I have about possibly jumping to a DAF/Kenworth/Peterbilt COE chassis with a habitat box?

1. Anyone know who GXV uses to convert their Kenworth's to 4x4? I know that several companies CAN do this with these trucks, but I'd prefer to go with the one that has more experience.

2. Insurance: Has anyone DIYd one of these? No possible way I can afford a GXV build and I'm a fairly competent builder. If you've DIYd one, was the process of getting it certified/classified as an RV straightforward? Looks like about $2-3k/year for RV insurance on a build valued around $200K?

3. If you hired someone to mount the box (with suspension/flex), who did you use? ITB (International Truck Body)? Overland Adventure Truck? Cost?

4. How is freeway cruising in these? Anyone regularly cruise at 75mph? Too fast...better at 65mph? Noise vs a Sprinter or F-350?

5. Confirm MPG of around 8-9mpg?

6. Recommend M+S 22.5 duals or go to the MPT singles? I'm leaning toward keeping the duals since it would make travel and replacement abroad easier. And keep the max speeds up.

Thanks in advance!

 

[gregmchugh]

I think it is common knowledge now that Tulsa Truck Manufacturing has been doing the 4x4 conversion for the GXV Kenworth K-370 chassis.

We have the 425 size Goodyear G278 super singles on ours. The max speed for these tires is 68 mph and I cruise at 65 on the interstate and 55 on secondary roads. At our weight of around 28,000 lb we get 8-9 mph on the highway. It is definitely not overpowered at this weight and you will slow down on hills and be going slow in the mountains in the right lane with the loaded semis. We are retired and in no hurry so it works fine for us.

I have yet to see any other expedition trucks on the Kenworth, Peterbilt, or DAF versions of this current model chassis except for the ones from GXV and I don’t think DAF offers it in 4wd either.

 

[TheFlyHighKid]

I think it is common knowledge now that Tulsa Truck Manufacturing has been doing the 4x4 conversion for the GXV Kenworth K-370 chassis.

We have the 425 size Goodyear G278 super singles on ours. The max speed for these tires is 68 mph and I cruise at 65 on the interstate and 55 on secondary roads. At our weight of around 28,000 lb we get 8-9 mph on the highway. It is definitely not overpowered at this weight and you will slow down on hills and be going slow in the mountains in the right lane with the loaded semis. We are retired and in no hurry so it works fine for us.

I have yet to see any other expedition trucks on the Kenworth, Peterbilt, or DAF versions of this current model chassis except for the ones from GXV and I don’t think DAF offers it in 4wd either.

Thanks for this. Gives me a bit more info on which to make decisions.

I tend to drive at 70 mph, so it might take some getting used to, but the universal chassis and size benefits seem worth it. 68mph is a damn sight better than 55!

How's your insurance cost?

How are your rig's road manners after the 4x4 conversion?

Off to gather more info!

 

[gregmchugh]

Road manners are fine.

Insure through Progressive but cost won’t apply since it is insured for full replacement value at the GXV price.

 

[charlieaarons]

Regarding tires and speed, traction type super singles are speed rated at 55-68mph. I think you will find that being responsible for that much momentum and kinetic energy with a relatively high COG will discourage aspirations of driving 75mph. I know of no other country where one can drive such a heavy vehicle at over ~100kph, other than the US. Fuel consumption rises alarmingly at speeds >55-60 mph.
If travel outside the USA is contemplated I would recommend obtaining a CDL. The fact that “it’s an RV” doesn’t mean much in much of the world as far as driver documentation.
Also, outside the USA, particularly with super singles, recommend a mounted and another unmounted spare tire. Personal experience.

 

[charlieaarons]

A way to carry an additional unmounted spare.

 

[TheFlyHighKid]

Regarding tires and speed, traction type super singles are speed rated at 55-68mph. I think you will find that being responsible for that much momentum and kinetic energy with a relatively high COG will discourage aspirations of driving 75mph. I know of no other country where one can drive such a heavy vehicle at over ~100kph, other than the US. Fuel consumption rises alarmingly at speeds >55-60 mph.
If travel outside the USA is contemplated I would recommend obtaining a CDL. The fact that “it’s an RV” doesn’t mean much in much of the world as far as driver documentation.
Also, outside the USA, particularly with super singles, recommend a mounted and another unmounted spare tire. Personal experience.

All fair points...thanks! I am hoping to avoid the CDL. Used to have my commercial class B but let it go a few years back. Any more detail on how/where someone might check my DL in central/south america?

L

 

[TheFlyHighKid]

Road manners are fine.

Insure through Progressive but cost won’t apply since it is insured for full replacement value at the GXV price.

Thanks!

I'm going to have to go drive a Kenworth/Peterbilt now to check the manners for myself. I remember reading that, after the GXV conversion, an upgrade to "King shocks" was a worthwhile investment. Any input on upgrading?

L

 

[gregmchugh]

All fair points...thanks! I am hoping to avoid the CDL. Used to have my commercial class B but let it go a few years back. Any more detail on how/where someone might check my DL in central/south america?

L

Our 33,000 lb GVWR GXV is titled as a motorhome and has been registered in Michigan originally and now Florida. Regular drivers license is legal to drive motorhomes of any weight in those two states which would make it legal in all states where you drive. Have no idea what happens anywhere else except Canada where it is legal to drive if you are legal in your US state.

 

[gregmchugh]

Thanks!

I'm going to have to go drive a Kenworth/Peterbilt now to check the manners for myself. I remember reading that, after the GXV conversion, an upgrade to "King shocks" was a worthwhile investment. Any input on upgrading?

L

Not sure driving a bare 2wd chassis is going to tell you much since without any weight it is not going to ride very well and the front suspension and tires will be nothing like the final build.

Maybe you could take a GXV for a test drive at GXV if they have one available.

The 4wd conversion has gone through several phases. Ours was the 3rd one delivered and has had several suspension upgrades and also new seats to replace the OEM ones. Not sure about changes in the last two years. Ours had the following upgrades as they became available: King Shocks, front airbags, and added leaf to front springs. Along with the seat upgrades this made the ride very acceptable on the highway and off the highway. We also have the manual front hub locks which were not available on the first builds.

 

[charlieaarons]

Regarding CDL: nobody nowhere has actually asked for my CDL. But a CDL is definitely legally required for >7.5 metric tons for UK, EU, Australia, etc. RVs included.
Regarding “”King shocks” in Montrose Colorado: stay away!!!! They’re totally incompetent. Fortunately, I think they went out of business. I refer to “Road King”, definitely not King Shocks, the mfg of off-road racing and small 4x4 shocks. They aren’t incompetent; they just don’t respond well to inquiries about their truck shocks.
I think Road King just stole the name of the more legitimate company. I got burned by them.

 

[gregmchugh]

Regarding CDL: nobody nowhere has actually asked for my CDL. But a CDL is definitely legally required for >7.5 metric tons for UK, EU, Australia, etc. RVs included.
Regarding “”King shocks” in Montrose Colorado: stay away!!!! They’re totally incompetent. Fortunately, I think they went out of business. I refer to “Road King”, definitely not King Shocks, the mfg of off-road racing and small 4x4 shocks. They aren’t incompetent; they just don’t respond well to inquiries about their truck shocks.
I think Road King just stole the name of the more legitimate company. I got burned by them.

This is the King that makes the shocks on our GXV Kenworth...

King Off-Road Racing Shocks, Bypass Shocks, Adjustable Coil Over Shocks, Air Shocks, UTV Shocks, Jeep Shocks, Pre-Runner Shocks, Adjustable Shocks, and Bump Stops

King Shocks and King of the Hammers go together for far more reasons than a common name. For one, there’s no better place for The Leader in Off-Road Shock Technology to prove the performance and reliability of the world’s premier off-road shocks than one of the most grueling off-road races in...

www.kingshocks.com

 

[charlieaarons]

That King is ok , I think.

 

[gregmchugh]

That King is ok , I think.

No issues with the shocks so far in 3 years and 50,000 miles...

 

[waveslider]

Ditto. Ours have been fantastic.

With shock technology coming along, I'm wondering when/if on-the-fly adjustable shocks will become a reality and whether it will be something that improves ride quality and varied terrain of expo sized vehicles.