Frame Inserts

Inserted frames (also known as liners) are usually required with multiple pushers, and/or long wheelbase vehicles, tied to steer axle rating.  Wheelbases of 280” or more will probably require an insert or the largest single rail the OE provides.  Fifth wheels that breech beyond the suspension area will most likely need some form of insert. The only way to know for sure is to contact Engineering so they can run the frame strength program.  

If your M.O. is to copy other OEs specs, be aware that all OEs evaluate frame strength differently. You may well be over-spec’ing, or under-spec’ing a chassis. Neither case is in the customer’s best interest.

Don’t spec an insert if not required, they limit potential payload capability and provide a harbor for corrosion. You will NEVER get a call from Engineering suggesting a lower capacity or downgraded component. If the order calls out an insert unnecessarily, and the chassis can be built with a double rail, then it will be.

If you modify trucks on the ground, keep in mind what the OE would have required for the vehicle application. No one wants to put a truck into service with a major oversight. And now......

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