12V on-board air project

[prfleming]

I wanted to add on-board air to our 2016 Roadtrek 210 and used the space available underneath the bed at the left rear - approx 18" x 18" x 8".

So, I put together a low profile compressor based on the ExtremeAire high output continuous duty 12V compressor. This model has a 3/4 hp motor and draws 50 amps. By mounting the compressor sideways and using a small 1 gallon Viair tank I was able to fit it in.

I wired it to the 2500 watt inverter 12V power posts. I made it to be portable, and have a set of jumper cables with the mating winch connector for use outside of the RV. Also I carry about 100 feet of air hose.

[markopolo]

Great use of that space and very handy to have on-board air.

[prfleming]

We tow a double axle horse trailer - 7000 lbs and 900 lbs tongue weight (use weight distributing hitch and electric trailer brakes).

With the on-board air I can air up tires if needed on a cold morning. With the trailer, I watch my rears pretty closely. The Chevy Express has a dash tire pressure display, very handy.

[booster]

Originally Posted by prfleming

We tow a double axle horse trailer - 7000 lbs and 900 lbs tongue weight (use weight distributing hitch and electric trailer brakes).

With the on-board air I can air up tires if needed on a cold morning. With the trailer, I watch my rears pretty closely. The Chevy Express has a dash tire pressure display, very handy.

How are you on your gross and axle weights? With a 210, you don't have all that much capacity to start with, and that is a big trailer.

[prfleming]

Right, we compared all the Roadtrek chassis options and the Chevy Express 3500 was the only one that would handle our trailer. The 210 spec sheet says tow capacity is 7650 lb / 1000 lb tongue weight. Pic is measuring the tongue weight with a bath scale and lever beam. With trailer tack room loaded and water tank full I measured approx 900 lbs.

The 210 has a 12000 lb / 1200 lb tonque rated Curt distributing hitch. I use a 10000 lb / 1000 lb tongue rated Equal-i-zer distributing hitch head (pic). I measured the hitch height unhooked, then I set the load bars so with the trailer on, the hitch height is the same.

Would be interesting to roll on a truck scale to measure axle weights sometime.

[booster]

IMO, you do need to get to the scales.

The Roadtrek specs, especially for 210s can be very misleading at times. Here is a link to a discussion of the topic, which we had here a while ago.

http://www.classbforum.com/forums/f5...bels-5844.html

[BBQ]

.

IIRC, RT welded an extension to the frame to make the RV longer.

ie the Chevy Express 3500 factory spec on tongue capacity might not apply.

[booster]

Originally Posted by BBQ

.

IIRC, RT welded an extension to the frame to make the RV longer.

ie the Chevy Express 3500 factory spec on tongue capacity might not apply.

The 210 is extended by Roadtrek, and they supply their own weight label on it. The problem is the new label design, and how Roadtrek lists the specs in their literature. Confusing and misleading to be sure.

In the link above, there is a scan of an older Chevy Roadtrek 210 that shows only #410 of total cargo capacity, which is going to be less than the OP has for just tongue weight.

If the OP's trailer is at 7000# and the van at max of 9600#, he will be over on combined weight also, as that is 16000#.

It is highly likely that he is going to be over on van gross weight, and probably even more over on rear axle weight. Rear tires will likely by the most critical spot as they are the limiting factor on the rear axle rating.

The rating on the hitch may turn out to be a non-issue simply because you can't use it with that much weight anyway do to other issues. The added overhang certainly is an issue with the 210 in relation to towing.

[prfleming]

Originally Posted by booster

It is highly likely that he is going to be over on van gross weight, and probably even more over on rear axle weight. Rear tires will likely by the most critical spot as they are the limiting factor on the rear axle rating.

Interesting discussion guys . With the under-hood generator (aka 300 amp house alternator) and without the Onan generator, there is some rear weight savings there - right - say 100 lbs or so?

With the weight distributing hitch set properly, there should be no added weight on the rear axle - right - as verified but measuring no change in the hitch height?

By my calculations, the tongue weight is distributed to the trailer wheels and the van front wheels - 43% or 387 lbs to the front wheels and 57% or 513 lbs to the trailer wheels - if I stepped off the distances from the hitch correctly.

[BBQ]

.

at least the 210 frame extension is not as long as those Xplorer extensions.

[booster]

Originally Posted by prfleming

Interesting discussion guys . With the under-hood generator (aka 300 amp house alternator) and without the Onan generator, there is some rear weight savings there - right - say 100 lbs or so?

With the weight distributing hitch set properly, there should be no added weight on the rear axle - right - as verified but measuring no change in the hitch height?

By my calculations, the tongue weight is distributed to the trailer wheels and the van front wheels - 43% or 387 lbs to the front wheels and 57% or 513 lbs to the trailer wheels - if I stepped off the distances from the hitch correctly.

I am not a WD hitch expert by any length or measure but have always heard you wanted even amount of "squat" front and rear when distributing the load to the tow vehicle. I looked around today, and some of that seems to have changed in newer rules and recommendations, which seem to mostly recommend only transferring load until the front is the original height (and load) that it was before the trailer was put on. That would leave the tongue weight to be distributed between the rear axle of the tow vehicle and the trailer, so rear axle weight will go up. I have never heard anyone say to keep the rear height and load the same, and put it all on the front and trailer, but some may have.

This guy has a pretty good description, and vehicle specific recommendations, but it is the internet so use your own judgement.

RV.Net Open Roads Forum: Towing: Travel Trailer Hitch Set-up Procedure

To keep the front the same height your 900# would be divided between the rear axle and the trailer center by the ratio you had used, I think.

[prfleming]

Yes, I like the "even front and rear squat" idea, seems to make sense to spread the tongue weight with a WD hitch. When the snow melts I'll take some fender height measurements.