In order to determine which replacement lead leg you need on your 2005 Keystone Challenger, you'll need to know the model of the landing gear on your trailer (we have no way of knowing what you have), and measure it's outer tube length.
For example, if you have a Venture, Lippert, or Stromberg Carlson landing gear with legs that measure 33-1/2 inches you can replace the leg with the Replacement Lead Leg for Stromberg Carlson Landing Gear # LG-177202 and the part # LC122533 is 29-1/2 inches.... view full answer...
The Replacement Lead Leg # LG-179013 and Follow Leg # LG-179014 referenced in your question are direct replacement legs for the Stromberg Carlson # LG-1, # LG-3, and # LG-183708 Landing Gear Systems. They can also be used with many systems from Atwood, Venture, and Lippert.
I am not sure of the exact system you have installed on your Keystone Challenger, so your best bet is to take a few measurements to see if these replacement legs will fit with your existing brackets. They have a leg... view full answer...
I spoke to my contact at Lippert and he told me the correct hydraulic cylinder replacement for your 2009 Keystone Challenger Fifth Wheel is the Lippert Replacement Hydraulic Cylinder for RV Slide-Out - 53" Long
# LC342328. view full answer...