Overhang at Rear Axle??

[reubenray]

While looking at motorhomes I noticed some have longer overhangs than others. Some even appear to sag some at the rear.

Does the longer or shorter overhangs have any effect on the driving?

[Mike Canter]

I think if you look a little closer you will see that the motorhomes that have the long rear overhangs are front engine units and the ones that have a short overhang are rear engine diesels. One reason for the long rear overhang on a front engine motorhome is to loot the length of the driveshaft.

[RickO]

Overhang has a huge effect on handling and driving in general. I think they tend to be blown around more in the wind or by passing trucks and you really have to watch for "swing out" when maneuvering it tight places like camp grounds and gas stations.

I'm sure not an expert on this but I believe that some coaches with long overhangs are that way because the manufacturer put the largest box they could on a relatively smaller chassis.

Best of luck.

Rick

[LandKinaMoho]

I chose a tag axle system to cover a lot of potential issues.

[Oscar Mike]

I have about 12' of overhang on my 2010 Fleetwood Bounder 33U, and I can say that I take my time in tight places like fuel stops, campgrounds and so forth. I have noticed a bit of push when a semi blows by me...I have not yet had the experience of driving in a high wind, although I am certain that in high wind conditions, we'll just pull over in a safe place and wait it out.

[daveshan]

From everything I've read the long overhang does get more "wind steer" Our Alpine has 10' from center of axle to bumper in back and 6' in front. I have been through some serious winds coming up through NM and had no issues at all, don't even feel semi's passing on a 2 lane road at 60. Another thing the long overhang hurts is the ability to handle hitch weight.

[kenandterry]

Like others have mentioned........

With a substantial overhang as you call it, you have to be cautious of what is called "tail swing". The more vehicle you have behind the rear axle, the more "tail swing" will happen in the opposite direction as the vehicle turns. Just the nature of the beast. One you're underway at a decent speed it's not that much an issue.........but at slow speed with sharp turns, be aware.

Another thing to watch is your entry and exit of certain parking lots or gas stations where there is a significant difference in the height of the lot and the main road...........you could scrape the undercarriage. Especially watch out if you're towing anything too. Sometimes it's better to make the approach at an angle instead of straight on.

[CampDaven]

I have 12 ft aft, 3 ft forward in overhang on a 33 ft A. No wind or truck wash issues except a slight nudge with no movement with my WH chassis. 11.5 ft height helps in wind effect too I'm sure. And my 50 degree turning radius is pretty sweet.

Overhang not an issue as I have driven a small C and small A and various box trucks for a few 100 thousand miles. You get used to it, much like any truck or 5-er hauler.

Happy trails folks!

[Koop]

I have ~12ft of rear overhang. Tail swing is something to be aware of - especially leaving the gas pump. My MH is equipped with a rear track bar and steer safe on front. I don't have a lot of miles under my belt but have driven it in crosswind and also had several occasions at 55mph on two lane country roads where oncoming semi-trailers were hardly noticeable. How much of this is attributed to the suspension mods? I don't know, but I'm not concerned by the 12' of overhang.

[ga traveler]

The front end of the motorhome is the weakest. If you look at the front and rear axle weights, you will see the rear carries the most weight by far.
the designers leave a long overhang at the rear so that it will push down on the rear and take weight off the front axle. ( Of course this is on gas motorhomes,)

[SteveSkinner]

The wheel base length is determined by weight distribution.
So I would suspect that a manufacturer designs the motorhome first loads it in to a spreadsheet that then calculates where the rear axle needs to be.
Handling and overhang are then a function of the wheelbase and chassis.
As suggested above 3 axles are better than 2 as the overhanging is reduced by the tag.
Adding a tag axle seems to stabilize the ride - just my personal opinion . Certainly on the coaches that approach max axle weights.

[Mike Canter]

Steve, you don't think the tag is added for weight carrying capability or did I read you wrong?

With DPs the rear axle position is more determined by the length of the diesel motor plus the Allison transmission then by a driveshaft that is sufficiently long to maintain the correct pinion angle on the u-joints through the complete movement of the rear control arms. The tag axle was first added to motorhomes that went above the weight that a single axle could carry. The slides and length is what increased the weight. When the weight of the mh increased the size of the motor got bigger to push it so the weight got even greater. On front engine motor homes the length of the driveshaft restricted how far back the rear axle could be. It is very difficult to make a three section driveshaft suspended via bearings to stop from going in and out of harmonics and vibrate so most try and restrict driveshafts to a single section or a dual section driveshaft with a single hanging bearing. Since front engine MHs have the weight of the motor to hold down the front it was easy to move the rear axle forward and to keep the driveshaft short.

A non tag side radiator also results in less overhang than a rear mounted radiator non tag.

[GregOk80]

Hey everyone. Hope we all have a Happy New Year. Now as a Class A RV and truck driver for UPS. We are known as Feeder Drivers. You have touched on (TAIL SWING) but also while towing the tail swing can swing so fast that your (TOW) hits the corner of your RV because the swing pivots off the rear axle. A tow dolly with a short tongue can get you car (toad) and rv together faster then you think. I pull 2 48 foot trailer and I slid the rear axle back to slow the swing down . Just something to think about.

[Selah]

Tail swing is equal to the length from the center of the rear axel to the rear of the coach devided by four. In my case that's 3 feet, for most diesels that would be a foot less. For an equivelant length coach the added tail swing of a front engine is off set somewhat by the reduced off tracking of the rear weeks due to the shorter wheel base. I do think the diesels do handle the wind a bit better, tho I really don't have any complaints about my gasser.