sway with a 16" scamp

[Roger H]

Originally Posted by Dawn HSV

Thanks for all your help and suggestions! We got it figured out, didn't realize that you used different tire pressures for towing. When the hitch weight was higher it increased the sway so figured it wasn't a hitch weight problem.
Rear wheels were at 29psi when they should have been 41psi.
It makes all the difference!
The weights I gave and our test runs have been with everything loaded for camping.
Now no sway.
We will still looking into a new tow vehicle but fell very comfortable doing things locally while we save up.

Yep, tire pressures are key, and the first and easiest thing to correct. Soft sidewalls will let all kinds of wiggly things to go on. Good job!

[Carol H]

Originally Posted by Dawn HSV

We have just got a "new" to us 16 foot scamp with side dinette (weigh in at 2340 loaded for light camping, including the hitch weight (195lb))
Our tow vehicle is a Subaru Forester (rated at 2400lb and 200lb hitch weight), so we are only just inside our specs
We have a class II hitch and a sway controller bar
between 55 and 60 we get a sway, any suggestions?
we love the 16 foot and the Subaru but thinking we may have to go with a 13 foot or a new tow vehicle.

I found having pulled a 16' with a Subaru you need at least 10% of the total trailer weight on the tongue to avoid sway - with a 2340b total weight it needs to be 230lbs so the 195lbs on the tongue is a little light which will be the reason for the sway at over 55mph. I actually found I needed 240lbs on the tongue for stability when traveling at speeds over 55 mph.

Highly recommend you read your manual in regards to the WDH suggestions. When I asked Subaru's head office directly why they do not recommend the use of a WDH they indicated they have concerns that under certain driving conditions the use of one can interfere in a not so good way with the full time all wheel drive system they use. As you know the full time all wheel drive system they use is unique to Subaru.

[redbarron55]

I have towed my Scamp 16 with my VW Sportwagen and I can tell you the tire pressure is important.
Low trailer tire pressure and rear tires will cause problems.
With the proper tire setup and the tongue at the max per VW it tows quite well.
The setup is very stable in all conditions.


Sent from my SCH-I605 using Fiberglass RV mobile app

[Wayne Collins]

Originally Posted by Roger H

Wayne, I'm not sure how much towing experience you have, but your statement isn't entirely accurate. While the hitch does have weight, of course, but when properly set up it also spreads tongue weight evenly across the two frames and subsequently the axles, taking it off the back axle of the tow vehicle. That's why most pickups' class III hitches have a dead weight limit of 500 lbs and a WDH tongue weight limit of 1,000 lbs.

Would towing since 1987 to present, from our base in Iowa to California, Alaska, Florida, Newfoundland & Labrador qualify as experienced? the Alaska Trip alone was 11,000 miles over 2.5 months.
We started with a VW camper van and 13 ft Scamp, traded for a 2000 Scamp 16 ft, which we still have. Upgraded the TV to Honda Oddysey's (3), then a Highlander hybrid 4WD, and now a Highlander 4WD.
wc

[Roger H]

Originally Posted by Wayne Collins

Would towing since 1987 to present, from our base in Iowa to California, Alaska, Florida, Newfoundland & Labrador qualify as experienced? the Alaska Trip alone was 11,000 miles over 2.5 months.
We started with a VW camper van and 13 ft Scamp, traded for a 2000 Scamp 16 ft, which we still have. Upgraded the TV to Honda Oddysey's (3), then a Highlander hybrid 4WD, and now a Highlander 4WD.
wc

Yep, sure would! I sent you PM.

Roger

[honda03842]

Dawn,

I would keep my trailer tires near max air pressure, typically 50 psi. You want stiff side walls on the trailer. Typically on a Scamp tires need to be near max to support the Scamp 16's weight and provide some margin.

Higher pressure typically reduces tire flexure and reduces heat build up.

It's the tire flexing that produces heat. That flat patch the tire makes on the ground when sitting becomes round each rotation, it's this flexure that produces most of the tire's heating. The deflection is not just in the outside radius but also the sidewalls which must deform for the bottom to flatten.

When we travel we tend to drive early in the day when it's cooler. As well slower speeds reduces tire temperature build up due to fewer tire rotations per unit time.

[Glenn Baglo]

With all the discussion on tire pressure, I don't recall anybody asking what tires were on the trailer in question.
This is where web advice goes awry.

[Dawn HSV]

I checked the max pressure on the tires, 50psi on the trailer, so have it just under
car tires were rated to 50psi as well so put in 41 on the rear and 34 on the front
it tows great now

[Mike Magee]

Wow, that's a high psi rating on those car tires! I'm surprised. Yep, when sidewalls can flex too much it can let the trailer push the rear of the car from side to side on those squirming tires. Sometimes a lower profile tire (less sidewall) can help with this; but you already got it under control.

I would still recommend looking to see if your drawbar can be positioned deeper in the receiver (moving the ball closer to the bumper) by drilling a new hole for the cross-pin. This can be an additional aid for better handling and it costs little.

[Glenn Baglo]

You would be advised to look at the vehicle manual for correct tire pressures, or on a sticker in the door frame.

[Carl V]

When towing I don't inflate the tow vehicle's tire to the sticker pressure. Sticker pressure is a balance between comfort and handling within the tire's load capacity, which is good for day to day driving. When towing, much more performance is required from the tires. I inflate them to the max pressure indicated on the sidewall (35 psi in my case). This ensures maximum tire stiffness and load capability. Also they run cooler and offer less rolling resistance. Same with the trailer's tire.
Since I tow most of the summer, my tires are always kept at their max pressure. The drawback is a little stiffer ride when not towing, the benefit is I don't have to adjust pressure every time I tow, and probably some gas saving.

[Borrego Dave]

Originally Posted by Glenn Baglo

You would be advised to look at the vehicle manual for correct tire pressures, or on a sticker in the door frame.

That's good info Glenn if you still have the OEM tires. I haven't replaced any tires with OEM's in 50 years and the PSI's have always been different with each set. Also seems that the recommended working pressures for my truck tires over the years have gone up by 10 PSI. I remember when radials first came out, folks thought that their tires were low on air pressure because radials had a flat look to them at 30 to 32 PSI. The last few sets I've bought call for 44 PSI, both car and truck. I do run the Casita's tires at the 50 PSI they call for and have never had any problems....so far.

[honda03842]

Originally Posted by Mike Magee

Wow, that's a high psi rating on those car tires! I'm surprised. Yep, when sidewalls can flex too much it can let the trailer push the rear of the car from side to side on those squirming tires. Sometimes a lower profile tire (less sidewall) can help with this; but you already got it under control.

I would still recommend looking to see if your drawbar can be positioned deeper in the receiver (moving the ball closer to the bumper) by drilling a new hole for the cross-pin. This can be an additional aid for better handling and it costs little.

Hi Mike.

I"ve had my CRV rear tires in that range 38-41 and had no problems and no sway. They are rated for 44 lbs cold. Towing tire pressure has nothing to do with mfg. suggested tire pressure.

We kept the front tire pressure about 4 lbs less.

[Mike Magee]

Yes Norm, I have vehicle tires rated for 44 psi also. But 50 psi rating, in a tire that fits a Subaru, still surprises me!

I usually run mine around 37-38 psi when towing. Nothing wrong with going to the max, though, as long as it doesn't cause the tire tread to wear more in the tread's center than at the sides. That comes down to the weight the tire is supporting.

[redbarron55]

The rated pressure on the tire related to it's load rating.
The air hold up the weight the tire is made to hold the pressure that it takes to carry the load.
If you reduce the tire pressure less than the rated max the amount of weight it will carry is reduced as well.
Sway is related to the resonant frequency fo the trailer, car and the combination.
Stiffer springs raise the resonant frequency of the system. If the resonance of the load is higher than the damping from the car then it will be unstable.
Slack tires, weak shocks and rear loaded trailers get worse.
Moving the tongue weight up helps until the rear end is overloaded and the system becomes unstable again.

[Ttocs M]

I agree with bpfick....I easily pull a 13 ft Scamp with a 3.6 Subaru Outback. While I'd love a 16 footer, I'd have to forgo a Subaru and get a tow vehicle with even a bigger engine to pull a 16 foot trailer.

Info from a Subaru web site: "Towing Capacity:
If you have heavy things you tow around, opt for the Outback. The 2.5i Outback has a maximum towing capacity of 2,700 lbs, while the 3.6R Outback can haul 3,000 lbs. The 2015 Forester has a maximum towing capacity of 1,500 lbs."

Sorry, guess you have to make a choice.

[Glenn Baglo]

It's not just towing capacity you have to consider.
Low tongue weight capacity is a problem with Subaru.

[Dawn HSV]

the older foresters (ours is 2006) have a 2400 lbs load rating
and we got it loaded for camping under 2400 lbs and at 200 lbs hitch weight
sway is gone completely and we are very happy