Community Forums

marka · 07-22-2009, 01:55 PM

Howdy,

I've noticed when looking at lots of different hitches on class A motorhomes that most are either not rated at all for weight distribution mode or rated for the same weight as weight carrying mode... Meanwhile all the regular truck hitches I've seen are usually rated double for weight distribution mode vs. weight carrying mode...

Why is this? I'm going to be starting to tow my enclosed trailer behind our new motorhome and was planning on doing it with our normal WD hitch setup. Is that a mistake?

Thanks!

Mark

Gary RVRoamer · 07-23-2009, 06:53 PM

The only thing I can think of is that the spring bars on a WD hitch can't exert enough pressure to transfer any weight to the front wheels of a long and heavy motorhome chassis, i.e. can't really distribute much weight. Maybe a call to a hitch manufacturer could clear this question up?

LandHo · 08-03-2009, 01:53 PM

Quote:

Originally Posted by RV Roamer [Gary]

The only thing I can think of is that the spring bars on a WD hitch can't exert enough pressure to transfer any weight to the front wheels of a long and heavy motorhome chassis, i.e. can't really distribute much weight.

I was thinking the same reason. Mark, you didn't say what you MH is... a small class B/C or large A? I doubt that 400-800 lbs of tongue weight is going to raise the front end up on my 22,000 lbs MH... I've seen WD hitch on smaller class B units though...

marka · 08-03-2009, 02:15 PM

Howdy,

This would be for a '99 Dutch Star, so yeah a fairly heavy class A.

Maybe I'm just too used to doing the weight distribution bars... :-)

The thing that makes me wonder is the different weight ratings on the hitches themselves... Its normal for a class III+ hitch on a truck to have double the weight rating in weight distribution mode. I suppose that could be because of wheelbase & overhang or whatever, but I'd have figured the ratings for that would be up to the vehicle manufacturer, not the hitch maker. I.e. the hitch maker would rate the hitch for xyz lbs in either mode, and the vehicle maker would rate the different modes based on the wheelbase, overhang, axle weights, etc.

But I guess the load dynamic would be slightly different at the hitch to frame interface for the different modes... Weight carrying is going to try and pivot the weight around the front bolt with the rearmost bolt getting most of the load. Weight distributing seems like it's going to have the middle and frontmost bolt seeing more of the load I'd think?

Maybe I'll give Spartan a call and see if someone can explain it to me. I just want to understand the deal so that when I hook up my enclosed trailer, I'm doing it in the best way I can.

Thanks!

Mark

expectmuch · 08-03-2009, 11:24 PM

"Maybe I'll give Spartan a call and see if someone can explain it to me."

Mark, how'd you make out? I have a near identical setup on my Spartan chassis MH. Also, do you have trailer brakes wired up? I'm scratching my head on that one too.

marka · 08-04-2009, 07:38 AM

Howdy,

I haven't called them yet. I need to get around to that. :-)

I have trailer brakes wired up, but it was done by the RV shop. I talked to the guy who was doing it though, and may be able to offer some advice...

He ran a two wire line from the hitch to the front of the chassis, then up through a hole in the front firewall to the inside. One line provides the brake signal, one line provides power. He split the power line in the front, next to the generator, and tapped power from what I assume is the Spartan relay/electronics box. That provides power both to the charge line on the trailer connector as well as power to the brake controller.

He got the brake signal from a pressure switch in the left front wheel area. I believe that switch was already in place and used to turn on the brake lights, but I didn't see as much of that. I suppose I can crawl under there and check it out if you wanted me to.

I still need to actually install the brake controller in the cockpit. Soon. Last night was "install hard tie down points for my son's child seat" night... that only took about three times as long as it should have, though if I had to do it again it'd go a lot quicker. Seems like that's always the way. :-)

Mark