What Causes a Trailer to Bounce Up and Down

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Question:

I have a 30 ft cargo trailer weighing about 7000 lbs with 2 5000 lb axles. I am getting a lot of bouncing transfer to my 201’5 3500 making the ride very uncomfortably. The axles are leaf spring. Ideas?

asked by: Mike

0

Expert Reply:

The leaf springs on your trailer could be too far worn which is making the ride bouncy because they have lost their rigidity or it could just be how the weight inside of the trailer is positioned. If you are having any clearance issues with your fenders or the trailer is leaning to one side more so than the other then this would point to signs of worn out leaf springs. Aside from these instances it is rather difficult to diagnose a worn out leaf spring if there are no other visual cues therefore, if you can't recall the last time they were replaced then it might be a good time to do so.

In order to recommend the correct set you would need to take the weight off the axle and then measure the distance between the two eyes (double eye springs only). The new leaf springs you obtain will then most likely be up to an 1" longer than the old but the capacity should also help to narrow down the options. If you can give me your eye to eye measurement unloaded then I would be happy to recommend a set but if not I have attached our selection for you.

The other option you have if your leaf springs are not worn would be to install a set of shock absorbers, the Roadmaster Comfort Ride Shock Absorbers for Tandem Axle Trailers part # RM-2460 which will work for you so long you have 3" diameter axle tubes. The addition of these shocks to your trailer will be a night and day difference in ride quality and just might be exactly what you need.

expert reply by: Conner L

0

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Answer 1

There are a couple things that you can do that will help with the sway and bounce on your trailer when you are pulling it with your vehicle. The first thing you can try to do is tow the trailer level. If the tongue on the trailer is high, then the…

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Answer 2

Normally, the tongue weight should be somewhere between 10 and 15 percent of the loaded trailer weight. For your trailer it would mean somewhere between 780 and 1200-lbs. The #C17501 system is designed for tongue weight between 1,000 and 1,500-lbs so…

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Answer 3

Our trailer leaf springs are rated for dynamic axle load. Which means the capacity listed but in use on the highway under normal circumstances. Since your trailer is 2,200 lbs loaded you want to go for a spring capacity 2,200 lbs or slightly higher.…

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Answer 4

The issue with the leaf springs being too bouncy could be caused by a few different things. The first is that they are not properly rated for the weight of the trailer, they are worn down too far, or the trailer is being overloaded. Furthermore, a…

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Answer 5

For 1/2 inch trailer u-bolts that attach to axle the recommended torque value is between 45 and 70 ft lbs of torque.

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Answer 6

If the leaf springs are located under the axle then adding leaves will lower the trailer whereas if they are mounted on top of the axle then adding leaves will raise the trailer. That said, the amount of rise/drop is very minimal (most leaves are…

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Answer 7

Length-wise the leaf spring part #SP-210275 that you referenced is about right at 27 inches. Since your trailer only weighs 1,500 lbs though this is going to give you a somewhat rough ride quality. A better option would be #e77SR most likely as it…

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Answer 8

According to our FAQ on slipper springs, linked for referenced, the torque specs are as follows: Torque Ratings 1/2 inch Bolts: 45 ft/lbs - 70 ft/lbs 9/16 inch Bolts: 65 ft/lbs - 95 ft/lbs 5/8 inch Bolts: 100 ft/lbs - 120 ft/lbs The Replacement…

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Answer 9

Though I do tend to warn people about the ride getting stiffer when upping the capacity of their leaf springs, you are correct in that you will technically never be fully "unloaded". I do have to mention that this could still happen, but…

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Answer 10

If the U-bolts are 9/16 inch diameter, the torque specs should be between 65 to 95 foot lbs. If the U-bolts are 3/8 inch diameter, the torque should be between 30 and 50 foot lbs.

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Answer 11

We have kits for that but you would need to know the diameter of your axles to determine which kit you would need. If the axle diameter is 2-3/8 inch which is common for 3,500 lb axles the kit you would need is the part #K71-384-00. If instead you…

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Answer 12

You will want to choose the diameter size of U-Bolts you need by the axle type (round, square) and the axle diameter. The Redline 2 Inch Square Trailer U-Bolt, part #SP01-160, you have referenced is for a 2 inch square axle. It is a 9/16 inch…

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What Causes a Trailer to Bounce Up and Down

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