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inHaliburton
07-10-2007, 11:48 PM
I pumped up the trailer tires from 35 lbs. to 55 lbs. Now the trailer sways back and forth at speeds over about 40 mph.

Tomorrow I'll be letting air out until issue is corrected.

Any ideas why swaying occurs at higher tire pressures?

LindblomRJ
07-10-2007, 11:50 PM
How is the trailer loaded? Where is most of the weight and how is it distributed? What size is the trailer?

inHaliburton
07-10-2007, 11:59 PM
The trailer is 5 x 10 with the front wheels of the JD 737 about 2 feet back from the front of the trailer. Got to be at least 100 lbs. on the tongue.

procut
07-10-2007, 11:59 PM
Yes, check to make sure you don't have negative tounge weight.

KTO Enterprises
07-11-2007, 12:27 AM
Put the mower on the trailer backwards.

The Captain
07-11-2007, 11:57 AM
I pumped up the trailer tires from 35 lbs. to 55 lbs. Now the trailer sways back and forth at speeds over about 40 mph.

Tomorrow I'll be letting air out until issue is corrected.

Any ideas why swaying occurs at higher tire pressures?

Why are you running this much air pressure? The sidewall gives the maximum safe air pressure (usually around 35 psi). My first guess would be the tires can't flex up & down or sideways. Kind of like having wooden wheels on the trailer. You'll probably blow one of them when you hit a nice sharp edged pothole.

KTO, what are your thoughts?

SiteSolutions
07-11-2007, 12:42 PM
Why are you running this much air pressure? The sidewall gives the maximum safe air pressure (usually around 35 psi). My first guess would be the tires can't flex up & down or sideways. Kind of like having wooden wheels on the trailer. You'll probably blow one of them when you hit a nice sharp edged pothole.


My trailer tires say 65 psi. My truck tires say 80 psi. 35 psi is for passenger car tires or small utility trailers, where you are putting about 1500 - 2500 pounds per axle, not per tire.

That said, Captain is absolutely right that each tire should be inflated based first on what the sidewall says. If you've got tires designed for 35 psi on a smaller trailer, that's what you should run. If they say 50 psi, that's what you should run. If you're over or under, you can get all sorts of problems with handling, improper wear, blowouts, brakes not braking very effectively, and so on.

inHaliburton
07-11-2007, 05:56 PM
Appreciate all the feedback.

The sideswall says to inflate to a maximum of 50 lbs., so I'm over a bit. They are Carlisle (sp.) trailer tires. The reason I increased pressure was to make it easier to pull with my Ford Focus. Ofg course, it pulls just fine empty at 55 lbs. but with the mower it's terrible. Swings me all over the road. I'll try loading it backwards, too. That'll put more weight on the tongue. I'll try your various suggestions tomorrow until I get things right.

I may be pulling more weight than I should be. The mower weights about 1100 lbs. and the trailer weighs about 725, plus another 120 lbs. of other stuff.

This is the trailer I'm running: http://www.miskatrailers.com/product_details.asp?cid=25&pid=15

Thanks for your thoughts.

SiteSolutions
07-12-2007, 12:40 AM
The reason I increased pressure was to make it easier to pull with my Ford Focus.

I think we may have located the source of your troubles.

A Focus has, as my neighbor puts it, "a bad case of noassitol" (no-a$$-at-all)

That trailer weighs almost as much as your tow vehicle so it is going to manhandle it a bit... getting the balance right will be important.

I think underinflation helps mask the problem by making the trailer drag a little bit, which would tend to keep the trailer lined up straight behind you. With full inflation, the trailer rolls better and so it can swing around easier. Putting the mower on backward might do the trick. I'd like to hear back what happens.

Even my truck gets light in the rear if I load my CTL too far back on the trailer... very scary at highway speed!

inHaliburton
07-12-2007, 09:41 AM
I think we may have located the source of your troubles.

A Focus has, as my neighbor puts it, "a bad case of noassitol" (no-a$$-at-all)

That trailer weighs almost as much as your tow vehicle so it is going to manhandle it a bit... getting the balance right will be important.

I think underinflation helps mask the problem by making the trailer drag a little bit, which would tend to keep the trailer lined up straight behind you. With full inflation, the trailer rolls better and so it can swing around easier. Putting the mower on backward might do the trick. I'd like to hear back what happens.

Even my truck gets light in the rear if I load my CTL too far back on the trailer... very scary at highway speed!

I think you are right on the money, SiteSolutions. I'll be rearranging the load today until I get it right. Will let you know.

mverick
07-12-2007, 11:25 AM
Usually,

You need more tounge weight when this happens. But, your car isn't designed to do what your doing anyway. And probably won't take the tounge weight that's needed.

talldaddy
07-12-2007, 02:03 PM
Many years ago when I had a travel trailer I read in the owners manual that you need a minimum tongue weight of 10% of the total trailer weight and the ideal tongue weight was 15% of the total trailer weight.

Total car weight vs total trailer weight being near equal should not be a problem other than the car not being equipped to tow very much weight. I have a 1994 toyota pu that I tow a pretty heavy built short trailer with an exmark on it. I also have a 2003 GMC 2500HD with D/A and I know the truck weighs around 6800 lbs and I tow loads of hay that weigh around 10K gross. Both setups tow great with the proper amount of tongue weight.

Hope this helps. *:)

mverick
07-12-2007, 02:09 PM
Many years ago when I had a travel trailer I read in the owners manual that you need a minimum tongue weight of 10% of the total trailer weight and the ideal tongue weight was 15% of the total trailer weight.

Total car weight vs total trailer weight being near equal should not be a problem other than the car not being equipped to tow very much weight. I have a 1994 toyota pu that I tow a pretty heavy built short trailer with an exmark on it. I also have a 2003 GMC 2500HD with D/A and I know the truck weighs around 6800 lbs and I tow loads of hay that weigh around 10K gross. Both setups tow great with the proper amount of tongue weight.

Hope this helps. *:)

When ya tow the hay. Does that trailer have trailer brakes?

talldaddy
07-12-2007, 05:28 PM
Yes my larger trailer has brakes on both axles.

mverick
07-12-2007, 07:11 PM
Yes my larger trailer has brakes on both axles.


Mine do also. But, I'd be willing to bet the trailer he's towing with doesn't. Or it isn't hooked up. So, stopping a 2500lb car with a 2000lb trailer is gonna be a fun ride. Or not.

Comparing your truck towing 10000lb and his car towing 2000lb is a little more then just the weight.

Your truck was designed to tow. You have a long wheel base. You have trailer brakes and a brake controller.

A Ford Focus doesn't have a long wheel base or a brake controller and was NOT designed to tow.

inHaliburton
07-12-2007, 10:12 PM
Hi Guys, things have settled down considerably. I reduced the air pressure from about 55 lbs. to 40 pounds and the swaying was completely elliminated. I've tried the mower in various positions on the trailer after each cut today and could not get the trailer to sway no matter what the tongue weight happened to be. I'm finding that the preferred position is with the mower backed onto the trailer with the rear wheels positioned just ahead of the axle.

You are correct re braking, none on the trailer. The owner's manual states that the car can pull a maximum of 2k lbs.

The next time I'm in a gas station that has an air pump, I'm going to try increasing the tire pressure to 45 lbs. to see what happens.

SiteSolutions
07-12-2007, 10:30 PM
I picked up a nail in my right rear trailer tire sometime today.

Unfortunately, the reason I am aware of this is because that tire blew out when I was a few miles from home this evening; doing 65 mph on the highway. That tire was only a few months old.

Fortunately, I was only about a mile from my tire dealer when it happened, and it was not quite 5:00, so he was able to get me fixed up.

I don't think 45 psi is dangerously underinflated, but I check my pressures pretty regularly, just to try to avoid this type of thing. I would say keep them at or durn near whatever it says on the sidewall. Today I was a slacker and it cost me money and time. It could have been worse.

btw, the new tires are radials with a 10-ply rating... 80 psi... I am going to check the tire pressures on everything before I go to bed.

inHaliburton
07-13-2007, 09:44 AM
Glad you didn't end up stranded, SiteSolutions.