May 2004

By: Eric Stern & Dave Huntoon


Creating the Patrick Chassis

Patrick Chassis
Dan Patrick's shop 25 miles outside of Columbus, Ohio
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We recently took a day trip and visited Dan Patrick's shop to see where the famous "Patrick Chassis" is built. Dan has produced more Monster Truck chassis than anyone else in the industry, 64 to date. Dan's shop is located about 25 miles outside of Columbus, Ohio, out in the country surrounded by farm land, on a meticulously maintained plot of land in an unassuming building.  The building is large enough to have 4 to 6 chassis inside it in various states of construction or repair.

Patrick Chassis
Dan's shop can handle 4 to 6 chassis at one time
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Dan can provide a customer anywhere from a basic chassis, to a rolling chassis to a full turn key Monster Truck. It all depends on what the customer wants and how deep their pockets are.

Dan showed us the drawings for the chassis he builds and explained the construction process. The most important stage that has the most impact on the structural integrity of the chassis is the frame rail construction. It is very important to have these perfectly straight because everything is built off of them. The construction of the frame rail takes place on a specially build and plumbed steel topped table that is about 30 feet long.  Dan typically builds four frame rails at a time. Once he completes one rail a special holding bracket lifts it up and he builds the next one underneath the first one. This technique continues until all four rails are built.  This process take about 2 weeks.  A completed chassis takes about one month to build.

Patrick Chassis
Specially built table used to construct chassis frame rails
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Patrick Chassis
Four chassis frame rails are built at one time
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One of the important aspects of Dan's chassis is that parts are interchangeable. So it is very important that every chassis is built exactly the same. This might sound like an insurmountable task but Dan has developed special patterns and laser cut tools that ensure correct dimensions and angles are adhered to.

Patrick Chassis
Chassis component patterns located on back wall.
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Patrick Chassis

Patrick Chassis
Some of the custom laser cut tools
used in chassis construction
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As with any specialty there have to be techniques developed to ensure you get what you are trying to achieve. In this case, over the years, Dan has developed techniques to weld the components together to ensure when the welds and tubing cool they will not end up warped. Dan's early frame rails warped up to 6" from end to end and today, using his welding techniques, he has reduced this to 3/4". Even with these techniques there are limitations. To compensate for the inevitable warp Dan will build mating components such that they will have opposite warp thus canceling each other out.

As the frame construction moves along Dan will ensure that the motor, transmission and other major components, the customer will be using, will mount properly in and onto the chassis. He has a number of different manufacturer's transmissions, engine blocks and other components that he uses to fabricate and test with.

Patrick Chassis Patrick Chassis
Different manufacturer components are used as fixtures
to ensure proper fit in the chassis
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The typical axle used in a Monster Truck comes from a school bus. These axles have to be modified and strengthened to be used. Dan build a special jig where he makes these modifications and ensures that they are aligned and build dimensionally to specification.

Patrick Chassis Patrick Chassis
School Bus axles are modified and
precisely assemble
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Many of the Patrick Chassis come back for repair. When we arrived Dan was working on Grave Digger 14. This truck had suffered some front end damage at the Vegas Finals back in March and Dan was beginning to start the frame repairs.

Patrick Chassis Patrick Chassis
Grave Digger 14 was in the
shop for repairs
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Typically, the trucks sent to Dan need frame repairs which will require a section of the chassis cut out and a new piece put in place. This particular truck had previously been back for a repair from damage suffered in Rochester, NY that we reported on back in February. Dan explained how they cut out a piece of chassis, add an insert and reassemble and weld the new piece back in place. The new section is just as strong as the original piece when completed.  We found the cut out frame piece, from this truck, alongside Dan's shop.

Patrick Chassis Patrick Chassis Jason Childress Patrick Chassis

Grave Digger 14 had previously been in for repairs suffered at the hands of
Jason Childress back in January in Rochester, NY.
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It is rarely quiet at Dan's Shop.  If the phone isn't ringing off the hook or trucks are under construction someone is pulling up to drop their truck off for repair.  While we were there Kathy Winston and her husband Bryan brought Kathy's Team Suzuki truck in for repairs  [See Scott Bryant's article on Kathy back in our Nov '03 column].  Her truck was also damaged at the Vegas Finals. Quick repairs were performed so she could run in a couple of shows after the finals but now they were bringing the truck in for longer lasting repairs.

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Kathy brings the Team Suzuki truck in for repairs
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Patrick Chassis
Kathy Winston & the Team Suzuki chassis
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Dan is constantly working on improvements to his chassis. Today's Monster Truck is stressed significantly more than in the past and is asked to perform some freestyle gymnastics that were unimaginable only a few years ago. Not only are the trucks put under this significant stress the human body is also taking a beating as they bounce, jump, slam and crash. Over the years the Monster Truck Racing Association (MTRA) has developed safety regulations to help ensure the safety of the drivers and the fans.  Dan's chassis are built to meet all MTRA regulations.  In addition to this Dan has been developing an advanced racing seat specifically for use in Monster Trucks.  He reviewed this new design at the 2003 MTRA meeting in St Louis.  Since that time he has mounted this experimental seat in his Samson truck and ran it at a number of shows this past winter.  He is very pleased with the performance if this new seat.  Racing seats available today were not designed for use in a Monster Truck so, not only do they not last very long they do not provide good isolation of the serious G-forces the human body is subjected to.

Patrick Chassis
The new racing seat that Dan is developing
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We want to thank Dan for letting us visit his shop and ask him a thousand questions.  We hope this helped provide a good insight to what goes into building the "Patrick Chassis." For more information on Dan and his incredible history in the world of Monster Trucks check out his website at www.samson4x4.com.

Patrick Chassis
Dan Patrick and his Samson Monster Truck
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Last update: MAY 1, 2004