What Should You Do When Your Truck Bed Bouncing/Vibrating

You can’t have a fun ride if your pickup truck is vibrating all the time. Moreover, it’s irritating and intimidating. I have seemed many truck owners complain about their vibrating truck bed. Usually, the problem surfaces after a few months of purchase. In this post, we will try to list out all the possible reasons for your pickup truck bed vibrations.

What is the primary reason for a truck bed to bounce or vibrate? There are multiple reasons such as an unbalanced or unaligned tire, warped rotors, bent rim, faulty axle, uneven weight distribution on the truck bed and among many others.

Here are Some Primary Reason For Your Truck Bed Vibration

1. Wheel balancing

There are many reasons why your truck bed might be vibrating, and one of the most common and often overlooked problems is wheel balancing.

You can know you have a problem in wheel balancing when you can feel your steering wheel vibrating. When your truck’s tires are out of balance, it will cause all kinds of troubles with a common symptom of shaking and vibrating. The severity of the vibration depends on how out of balance are your tiers.

Unbalanced tires lead to two peculiar problems called a static imbalance and dynamic imbalance, which happens at the same time. A static imbalance of the tire is when it bounced up and down during rotation. A dynamic imbalance is when the unbalanced tires shake side to side during rotation. Combine them, and you get a nasty vibrating truck bed.

Find Out if Your Tires are Out of Balance

A tire out of balance means the weight of the wheel is not evenly distributed around the circumference of the wheel. Some common symptoms include uneven tread wear, reduced fuel economy, and vibration in the truck which you will get in the steering wheel. It gets worse at higher speeds.

An evenly distributed wheel-tire will make it roll smoothly, where the tires wear out evenly and last longer. When the rear tires are out of balance, you will feel the vibration in the seat or the floor. Tires naturally get out of balance with everyday use. Sometimes, it could be a manufacturing defect. Most of the times, the tires and wheel will not have equal weight distribution; it would be heavier or lighter in some spots. Only an ounce of weight difference will create significant vibration while your drive at high speeds.

Unbalanced tires will also cause suspension issues as the bearing and shocks are continually affected due to bouncing tires which causes partial loss of traction. It may also cause cupping where tires wear out at a particular spot. This will further lead to more damages to your truck.

What Should You Do When Your Tires are Out of Balance?

Take it to a Mechanic

The technician will put your wheel-tire unit on a balancing machine. The machine would spin your wheel to find out stiffer spots at the same time measuring vibration. He will then apply wheel weights, usually made from aluminum or zinc, opposite the hard places. Most of the times, adding this weight is enough to fix your tire. However, they will also check for locking wheel lugs, which can add about 0.5 oz of weight to the side of the wheel, enough to cause vibration in your truck.

2. Bent Rim

You may have driven over a nasty speed bump or smashed into a pothole, and now you have a bent rim. A bent rim in the rear wheel will give you a wobbling vibration in the back. Furthermore, you will get uneven tire wear, road noise, cargo displacement, decreased gas mileage, and poor handling. It takes a simple fix; you only need to take it to a repair shop.

3. Hauling a Mountain Bike on One Side

Hauling a mountain bike on one side of the truck bed would cause uneven weight distribution and cause your truck bed to vibrate. This gets worse if the bike is not tied down fixed to a position. Let along mountain bikes, any cargo when placed unevenly in the truck bed and is not secured correctly, your truck bed will vibrate and bounce. Moreover, if you are carrying higher loads with the top heavy will cause your truck bed to vibrate or even slide off.

Make sure if you are carrying mountain bikes, make sure they are positioned to the middle of the truck bed. Hauling mountain bikes on hitch mounted racks, make sure they are secure and don’t move around when you drive.

While carrying wide plywoods, you need to tie up well and don’t bounce around while driving. An even distribution between the cab and truck bed could also cause vibration. If the load is too heavy the bed sags, you will get significant bouncing and vibration in your truck bed. On the other hand, if the rear is lighter than the front, it too will cause vibration in the truck bed.

4. Faulty Axles

Your truck’s wheel is constantly turning through the axle of the truck. Many times the axle is bent which could happen during a collision or sudden drop on a pothole. This bed axle will make an uneven rotation, causing your truck bed to wobble and bounce, especially at high speeds. It can be repaired with a full axle replacement.

Axle bearing could also fail to give a bouncing effect on your truck bed. The axle bearing holds the weight of the wheel and prevents it from touching the axle. If the bearing is broken, the two metals will rub each other and will cause vibration in that wheel.

Worn out engine and transmission mounts could also cause your truck to vibrate. They are made up of metal and rubber which are prone to cause vibrations. The bracket that bolts to the transmission is covered in hard rubber, which acts as a cushion between the engine and the mounting area. When the rubber wears out, the metal bracket comes in contact with the truck frame, causing a nasty vibration. This condition is called grounding, and it can be fixed by replacing the mount.

5. Fault in Engine Vibration Dampers

Also called as torsional or crankshaft damper, it is fitted to the crankshaft that absorbs its vibrations. It also prevents the belt drive and other engine components from wearing out prematurely.

When the engine runs, the torque generated for each firing is transmitted to the crankshaft and gets deflected. This torque causes the crankshaft to vibrate and sometimes the torque, and the crankshaft vibration synchronizes causing excessive stress in the crankshaft. To avoid this condition, the manufacturers use vibration dampers in the engine.

However, due to frequent exposure to stress and heat the dampers wear out. A damaged damper will let vibrations to transmit outside the engine compartment causing damage to the other parts. If your vibration damper has worn out, you should replace it as early as possible and prevent your engine from further damages.

6. Fault in Driveshaft

If the wheels, rims, and tires are unharmed and the vibration persists, the fault could be in the driveshaft. This is a common problem in all rear-wheel drive vehicles such as pickup trucks. Typically it is caused by worn out U-joints, which can cause vibrations at just about any speed. It will typically clunk when the transmission is put to gear and may emit a cyclic chirp with an initial start. This cyclic vibration will cause an excessive driveshaft angle. This is a common problem about truck owners who have raised or lowered the stock ride height of the truck. When this U-joint runs at an angle, it causes cyclic vibrations in the shaft. A great angle means stronger vibration intensity.

7. Loose U-Bolt

A U-bolt is threaded at both ends supporting the leaf spring suspension. It keeps the spring leaves together permanently. These bolts go around the axle and hold the leaf spring bundle. Sometimes the leaf springs don’t have spring clips, which is where U-bolts become necessary. The leaf springs absorb the shock that goes to your suspension. During your ride, the shock is transferred from the axle to the leaf springs.

If the U-bolt comes to lose your rear end of the truck will vibrate. The suspension system and the U-bolts are frequently hammered with jolts and jerks when you are driving on rough terrain. When the bolts come to lose the bolt itself start hitting against the axle, which may lead to bolt breakage. Moreover, it may disassemble the leaf springs, causing even more damage.

8. Rear Brake Vibration

Brake vibration is also called has shaking or pulsation and is often caused by thinning brake rotor. When the brakes are slammed, the brake pad will be pressed by the calipers and on the uneven spots, giving short vibration. Rust and dirt could also build upon the rotor and cause some vibrations in the truck bed.

If the rotor’s thickness reduces by a few millimeters, the driver will get the vibration through the brake pedal. If the rotors are warped, the whole vehicle could shake when hitting the brakes.

A common cause of uneven rotors is the brake pads. The friction material doesn’t get fully released by the calipers when the brake is disengaged, thereby causing friction as the wheel rotates. If the pads drag on the rotors too long, it will damage the rotor causing mild to severe vibration.

For warped rotors, it can be a machine on a brake lathe to create a smooth even surface. It will take you to scrape off the top layer of the metal; however, if too much of the rotor thickness is removed, you will have to completely replace with a new rotor to stop the vibration.

Many trucks have drum brakes in the rear wheels in which the brake shoes are pressed outward against the wall of the drum. Here, the drums could wear out and become uneven to create mild vibration in the truck bed. It too could be solved by machining the braking surface.

9. Some Other Causes of Pickup Truck Vibration

There are a few signs to find out why your truck is vibrating. If vibration reduces while speeding up or slowing down, then the problem is in tire balance. And if vibration increases when you accelerate, you should check the transmission, torque converter or driveline. More one If it’s worse when you speed up the problem could be bad tires or driveline. When you find vibration while slowing down or slamming on the brake, you can assume it’s a brake problem. Somehow if vibration persists while taking turns, the problem could be in loose front-end parts. If tires are good, check the lug nuts. If the vibration is while revving the engine, you know it’s an engine problem.

Truck’s transmission can be a bigger problem for vibration. However, in most cases adjusting the driveline or changing tires solves the problem. If it persists, tighten the lug nuts and see if any front-end part has come loose. Sometimes, fixing the brake will also solve vibration issues.

Locating the cause of vibration is pretty simple if not accurate. If you feel a vibration in the steering wheel, your vibration problem is in the front tires. If you feel in the seat or the floor the problem is in the rear tires. When your truck moves laterally, side-to-side, the vibration problem is in the front, whereas hopping or bouncing movement indicates a problem in the rear.

Here are some common causes:

Driveline problem – Check the U joints, yokes, drive shaft, bearing and balance weights
Brakes – Check if the brakes are balanced, there is no excessive wear and are center mounted
Check if the lug nuts are torqued properly
See if the suspension is defective
Check the shocks or shock mounting to see any defects
See if the steering gear is loose
Check for drive train alignment

The most common vibration troubles in the truck bed come from either unbalanced or unaligned wheels. Here are some best practices.

Your pickup truck wheels should be aligned because the wheel angle changes over time. It could happen when various rubber bushings are deformed or wear out in the vehicle suspension. It could also happen due to sagging of the springs. Moreover, wheel alignment should be checked after you hit a deep pothole or speed bumps and also after collisions.

Will Adding Weight in the Back Decrease Vibration and Increase Traction?

Many truck owners add a couple of sandbags near the wheel well to reduce vibration. But does it work? To get better traction, you need a greater amount of the truck’s weight pushed over the drive wheels. So, should you add weight or not depend on your truck. If you have a rear-wheel-drive truck, do add weight in the back. If you have a front-wheel-drive truck, don’t add weight in the back. Also, avoid adding weight in the back if you have an all-wheel-drive truck.

When there’s snow on the road, and you are struggling to keep your truck on track, it’s a sign you need some weight in the back of the truck to increase traction, considering the fact that your truck is an RWD.

When you are driving your truck with an empty bed, your rear axles are not getting enough load that they are designed to carry. Trucks are designed with payload in mind. So, your truck needs some load at the back for more balanced handling. Here, you can use two sandbags each on either side of the truck bed wall. This will prevent vibration that could have caused due to unbalanced load and will also increase traction.

However, if your truck is already loaded with cargo, you don’t need those extra sandbags to keep things stable. If you are not a fan of sandbags and need something more professional, you can buy traction weight kit which will give you 300 lbs of extra weight to the bed.

Here is the suggested traction weight that you could add to your truck bed:

Half-ton pickup – 240-300 lbs.
Three-quarter-ton pickup
One-ton pickup – 300-400 lbs.

Does Added Weight Affect Truck’s Stopping Power?

Many truck owners think that adding weight in the back may take the truck longer stopping distance, due to the added momentum; however, in reality, it doesn’t make much difference with just an extra 300 lbs. On the other hand, the weight flattens out the tires, increase its contact areas on the road. This gives you tire more gripping power, which in turn helps to slow down your pickup truck faster.

What are your options?

The most popular ones are the tube-shaped sandbags which weigh around 60-70 lbs and cost just about $5. Other than that, you could use drainage gravel or potting soil for weight. Many also choose to spread rock salt around their truck bed. And keep their 5th wheel hitches attached to the bed during winter, which adds roughly around 250 lbs. Many purchase water-bladder traction aids which are typically made of woven nylon mesh. They will cost you under $200. Another simple way is just to keep your gas tank full, which will easily add around 100 lbs of weight.

Here are some best practices

Avoid using plastic mesh or plastic bags as they wear out quickly and may cause rust if the bag collects moisture.
Prefer double-wrapped bags to keep your weight sealed, as they would last several seasons
Avoid using snow to provide weight. They will fly away when you drive and cause visibility problems for fellow drivers

Where should you put the weights?

If you are using sandbags, you should center its weight over the rear axle. So, place those sandbags next to the wheel wells in a pickup truck. Moreover, it is advised not to wedge it against the tailgate as it would lighten the front, causing handling problems.

Don’t add weight to FWD and AWD trucks

For a front-wheel drive, most of the weight of the engine is over the front axle, giving a strong grip to the tires on the road. If your trucks have the same tire pressure on the rear, it will increase friction between the road and the tires, giving solid stability to the truck.

On the other hand, adding weight to the truck on an FWD truck will cause more damage and good. It is especially true if the truck is already loaded with your family members and luggage. More weight in the rear of an FWD truck will make the front lighter, giving your truck poor grip on the road.

For AWD, if there’s any slipping or skidding the engine will spend most of its power to whichever wheels with a better grip on the ground. In such case, if there’s more weight in the rear, it will lighten the front, cause poor traction. Then the engine will send more power to those wheels, causing them to spin.

Some symptoms of unaligned wheel

Vibration in the truck
The truck pulls to one side when driving
Truck feels unstable and wanders side to side
Tires wear out unevenly
Tires screech when turning

Conclusion

There are be various reasons that can cause your truck bed to shake, vibrate or even bounce. It is one of the most common problems faced by truck owners. I hope the points mentioned in this post helps you solve the issues. Have an excellent trucking experience.

What Should You Do When Your Truck Bed Bouncing/Vibrating – A Complete Guide