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How Do You Stretch A Semi Truck Frame? (Solved!)

Stretching a semi truck frame should be left to the professionals or at least be attempted in the presents of a professional.

We will fill you in on what tools and equipment you need.

Guide you on where to have the framework done and give you an idea of the resale value after you have had it done.

We cover the laws on stretching a semi truck frame and how much it will cost.

Here’s a short summary of How to Stretch a Semi Truck Frame:

To stretch a semi truck frame, remove all components until the frame is naked. Cut the existing frame using a grinder or a cutting torch. Measure the new frame piece, hold them together using clamps and axle stands. Weld cross members and brackets in place. Add bolts and finally replace components.

What does it Mean to Stretch a Semi Truck Frame?

It simply means extending the truck’s length to fit or/and carry more weight.

It is a common practice to lengthen the frame, especially when trucks are purchased cheaper.

It also strengthens the frame, particularly when you double frame it.

It is ideal to extend a frame when you would like to fit a lift box or add a sleeper into the cab that doesn’t have one, along with many other reasons.

What is the Point of Stretching a Semi?

There are two benefits to stretching the frame of your semi truck. One is to give you a smoother ride.

By stretching the frame of a truck you will reduce vibration caused by the surface of the road.

When the truck’s front axle passes over a point, it causes a chain of vibrations that is seriously reduced when the stretching of the frame moves the rear axle further away. It is more common on older trucks.

This option is not recommended as it is not cost-effective. The second reason is to fit a longer box or being able to carry a longer container.

It would be more beneficial for you to invest in the correct truck for your line of work in the beginning.

If you are not sure what length truck you need or you are in two minds about it, always go for the longer version.

You may end up paying a little more in fuel, but you can take on more jobs and not have to worry about the cost of stretching. 

What Equipment is Needed to Stretch a Semi Truck Frame?

The equipment needed to stretch a semi truck frame is not as complex as you might think and can be done to a professional level with a disc grinder, clamps, a few bottle jacks, or heavy-duty axle stands.

A straight edge, to measure the level is correct, a drill, a heavy-duty cutting, and a welding torch.

You will also need a sledgehammer and a tape measure.

If it is your first time you may want to have the assistance of a professional.

How do you Stretch a Semi Truck Frame?

The frame of a semi truck can be stretched using new or used parts.

The existing frame has to be stripped down completely and any components welded to the frame that is in the way need to be cut off.

Remove all air hoses and wires, as they will also need to be extended. Remove fenders, air suspension bags, and torsion bars if necessary.

Once everything is clear, the frame can be measured and then cut using a grinder or torch.

You may have to remove the fifth wheel, Battery box and any tanks that may be in the way, and the driveshaft.

When you have lined up the new frame with the existing one, hold them in place with clamps and jacks or/and axles stands.

After this, make some final adjustments and then use a straight edge or string to level it off.

Once you are happy with its position, weld the frames to each other and weld cross members in place. Bolt or revert fish and diamond plates in place.

Refit all the parts you removed. You may have to add additional suspension, wheel axle, and wheels depending on the style you are going for.

Here is a really cool video on how a semi truck frame was stretched:

Do you need to Double Frame your Semi if you Stretch it?

It depends on what you will be hauling and the length of the stretch you will be having done. A double frame adds stiffness to the chassis. You could get away with reinforcing the frame.

However, having a double frame welded will mean a more robust vehicle and the ability to haul heavier loads with ease.

It will be handy to have a double frame if your line of work is off-road.

The double frame can go from front to back or from back to just behind your cab.

Can you Stretch the Semi Truck Frame Yourself?

If you are a confident welder and cutter, there is no reason why you couldn’t do the job yourself.

Different states have different laws surrounding GVW limitations. Some have no restrictions regarding weight.

You could be stretching the vehicle out for agricultural work to be done on your private farm, which may also change what you can and can’t do.

Make sure you check the requirements before you go any further. If, for any reason, you do not want to carry the work out yourself.

There are many competent workshops out there to do the job for you.

Although it is a lot cheaper to do it yourself, it can be very time-consuming and stressful.

How much does it Cost to Stretch a Semi Truck Frame?

Stretching a frame on a semi truck can be expensive.

A good shop will generally charge anywhere from $4,000 to $8,000. It can be hard to choose the right shop. Asking fellow truckers is a great place to start.

You can get a good deal on a stretch, but it does depend on the length you want, along with where it gets done.

Where can you get your Semi Truck Frame Stretched?

There are thousands of workshops across the United States that specialize in semi truck frame stretching. It is best to do some research and ask around for any recommendations.

Although stretching a frame can be done by anyone with a welding certificate, it can be tricky to find the right shop for your needs. A good reputation goes a long way with a task like this.

Check with your local laws and laws for any states you will pass through to ensure you are getting the correct frame length. Each state can have different regulations.

Check out the Federal Motor Carrier Safety Administration (FMCSA) website for complete information surrounding vehicle welding and stretching laws.

How does Stretching your Semi affect its Resale Value?

Stretching the frame of a semi truck will add value to it. Provided it has been done professionally and hasn’t had any issues. The truck will be capable of carrying heavier loads.

And can haul larger boxes or longer trailers, therefore increasing its resale value.

That being said, it depends on the level of care the truck receives and the mileage and the condition of the truck itself.

It will also depend on the resale value of that particular brand of truck. In some cases, the truck has gained a resale value of $10k.

In another case, the truck neither gained nor lost resale value.

These figures do change with where and when you sell the truck, most people that stretch their trucks, do so with holding on to it in mind.

What does the Law say on Stretching a Semi Truck Frame?

The law is a little grey around the area of stretching a semi truck frame. What it does say is the following:

The frame or chassis of each commercial motor vehicle should not have cracks, be loose, broken, or sagging.

Bolts or brackets securing the cab or the vehicle’s body to the frame must also not be loose or broken and have no missing parts.

The frame rail flanges between the axles shall not be bent, cut, or notched unless specified by the manufacturer.

No parts and accessories can be welded to the chassis of the commercial vehicle except by the manufacturer’s recommendation.

Any welding repairs to the frame are to be under the recommendations.

No holes should be drilled in the top or bottom of the rail flanges unless it’s acceptable as per the manufacturer’s recommendation.

As long as you stay within these guidelines, you will be fine.

Happy Trucking!