Rear End Swing. Or Tail Swing

[Gary RVRoamer]

I saw a RV Class nestle tip to the side of the pump this past week and when he pulled away and made a sharp left hand turn, his rear end bumped the pump. He was on the inside of the pump. He was clueless of watching his rear when turning which surprised me.

Would a tag axel have any impact on this very real scenario?

Almost surely NOT.



Some coaches has a longer rear overhang than others, i.e. a shorter wheelbase vs overall length. A shorter wheelbase is a cheaper chassis, so low end of special-priced models may end up with more swing. And some motorhome chassis have a sharper max wheel cut than others, enabling them to create swing situations such as you describe.


Gas-powered chassis also tend to have longer rear overhangs than DPs. The engine & tranny weight on a DP mitigate against longer overhangs.

[96 Wideglide]

Was once parked beside a fairly long, single rear axle, gas coach (can't recall the manufacturer). This thing had 4 full size basement bays, behind the axle !
Can't imagine the tail swing, and I wouldn't want to try keeping it in a lane with anything more than a gentle breeze!

[amosnandy]

Originally Posted by Stonehands

Hello Friends.

Our coach is a 2007 Fleetwood Revolution LE40E on a Spartan Chassis. Love it. It is single axel with no tag axel.

On the topic of rear end swing, how much is it reduced with a tag axel? Just curious. As a former truck driver I know the impact, no pun intended, of Ass Swing on a rear of a straight truck or trailer.

I saw a RV Class nestle tip to the side of the pump this past week and when he pulled away and made a sharp left hand turn, his rear end bumped the pump. He was on the inside of the pump. He was clueless of watching his rear when turning which surprised me.

Would a tag axel have any impact on this very real scenario?

I think as a truck driver you know the answer. Always calculate tail swing from the center of the forward most axel to the rear of the unit. Watch the guys with the split axel trailers. The front axel makes the turn while the rear axel just gets drug around the corner.

[amosnandy]

Originally Posted by Crasher

Most if not all tag coaches have the option of dumping the tag suspension and/or lifting the tag which eliminates 90% of any scuffing. The exception to this is the higher end coaches that have passive steering tags or active tags that steer opposite of the front steering axle to swing around a turn. Virtually no scuffing on the later.

Yes, most tags can be lifted. Quick story. While driving semi in a snowstorm came up a pretty good grade to find all traffic stopped. Old guy with a 45’ motorhome spun out, blocking all lanes and just sat and spun. Not much snow, a little icy. I walked up, he looked frantic, I asked if I could help. He let me get in, behind the steering wheel, it had a tag axel pressure gauge. I reached over, dumped and lifted the tag, backed up about 5 feet and drove right out of there. Never underestimate how much weight is on the tag.

[Ray,IN]

Originally Posted by amosnandy

Yes, most tags can be lifted. Quick story. While driving semi in a snowstorm came up a pretty good grade to find all traffic stopped. Old guy with a 45’ motorhome spun out, blocking all lanes and just sat and spun. Not much snow, a little icy. I walked up, he looked frantic, I asked if I could help. He let me get in, behind the steering wheel, it had a tag axel pressure gauge. I reached over, dumped and lifted the tag, backed up about 5 feet and drove right out of there. Never underestimate how much weight is on the tag.

Did you help him wipe the egg off his face??

[Stonehands]

Originally Posted by Gary RVRoamer

Almost surely NOT.



Some coaches has a longer rear overhang than others, i.e. a shorter wheelbase vs overall length. A shorter wheelbase is a cheaper chassis, so low end of special-priced models may end up with more swing. And some motorhome chassis have a sharper max wheel cut than others, enabling them to create swing situations such as you describe.


Gas-powered chassis also tend to have longer rear overhangs than DPs. The engine & tranny weight on a DP mitigate against longer overhangs.

Good points Gary. Thank you

[Stonehands]

Originally Posted by amosnandy

Yes, most tags can be lifted. Quick story. While driving semi in a snowstorm came up a pretty good grade to find all traffic stopped. Old guy with a 45’ motorhome spun out, blocking all lanes and just sat and spun. Not much snow, a little icy. I walked up, he looked frantic, I asked if I could help. He let me get in, behind the steering wheel, it had a tag axel pressure gauge. I reached over, dumped and lifted the tag, backed up about 5 feet and drove right out of there. Never underestimate how much weight is on the tag.

Great story and information. Thank you.

[Stonehands]

Originally Posted by amosnandy

I think as a truck driver you know the answer. Always calculate tail swing from the center of the forward most axel to the rear of the unit. Watch the guys with the split axel trailers. The front axel makes the turn while the rear axel just gets drug around the corner.

Agreed.

When driving, I have driven Reefer straight trucks of single and tandem axel configurations. 18 to 26 foot boxes. Semi's 36', 40' and 45 foot trailers. All Reefers. None ever had tag axels or air ride. The trailers all had fixed axels and yes you could spin them around and leave plenty of rubber on the road.

I felt bad for the guy tagging the fuel pump and he said he knew better and just had a lapse in judgement. We can all relate to that occurrence.

[Phantom13]

No, distance from rotation point is the deciding factor

[BruceDeville]

Originally Posted by Stonehands

Hello Friends.

Our coach is a 2007 Fleetwood Revolution LE40E on a Spartan Chassis. Love it. It is single axel with no tag axel.

On the topic of rear end swing, how much is it reduced with a tag axel? Just curious. As a former truck driver I know the impact, no pun intended, of Ass Swing on a rear of a straight truck or trailer.

I saw a RV Class nestle tip to the side of the pump this past week and when he pulled away and made a sharp left hand turn, his rear end bumped the pump. He was on the inside of the pump. He was clueless of watching his rear when turning which surprised me.

Would a tag axel have any impact on this very real scenario?

I have driven an Eagle (old Trailways) and a MCI-7 (old Greyhound) both with tag axles and no wagging tail.

In addition I have extensive experience driving things with long overhang behind the rear most axle.

With apologies if I offend any drivers but it is my OPINION that most tail wagging is driver induced.

If you find you are constantly making very minor steering corrections, you are inducing the wag.

[dizcom]

My gasser had way more tail swing than my current DP with tag. The tag can be dumped, and ours is also steerable. The rear tires going forward track in the same track as the front at low speed. In reverse, the tag is dumped. It turns amazingly sharp. Wheel cut makes a difference in ways I didn’t understand until I drove it. My 44 with tag turns tighter and is easier to maneuver than my 37’ gasser was. Look at all the factors of the coach you are interested in. A modern DP has modern equipment and features, but an older one will have the limitations of its time. It all depends.

[wildcatter]

[QUOTE=BruceDeville;5804806]I have driven an Eagle (old Trailways) and a MCI-7 (old Greyhound) both with tag axles and no wagging tail.

In addition I have extensive experience driving things with long overhang behind the rear most axle.

With apologies if I offend any drivers but it is my OPINION that most tail wagging is driver induced.

If you find you are constantly making very minor steering corrections, you are inducing the wag.[/QUOTE


Did you even read the posts? This is about tail swing when turning, not tail wagging when driving.

[GypsyR]

I was wondering. I've never seen a Trailways/Greyhound type bus with much overhang.

[Oucamptoo]

I believe tail wag is more noticed on gas models I installed a rear track bar and was very pleased with the reduction of tailwag. I immediately noticed a reduction steering input.