20K steer w/ multiple pusher chassis

Anytime you specify a 20,000 lb. rated steer axle, and you’re adding lift axles, you need to think about creep rating or site rating.

Both of these terms refer to the manufacturers acceptable overload that occurs with lift axles. Lift axles in the down position take burden from the stationary axles, but when they come up you are overworking the components.

Axle and suspension OEs allow for around 40% more weight in this condition. Other components do not provide for this. One thing to be cognizant are the steering gears (yes, hopefully plural). The front axle load with the lift axles raised can make turning a challenge, especially at low speeds. Make certain you are specifying the largest gears available to mitigate this situation.

These axles should require the dual TRW TAS85 or SD110 Sheppard gears. Typically, OEs will guide you on a new truck. But plenty of people install lift axles in the aftermarket.

One example: most truck manufacturers will not install 2 lift axles rated at 20,000 lbs. each.

Reason… creep ratings are dangerously high for the components involved. Some people elect to do this locally. Just be aware of the potential for park steer performance issues before you go down this path.