Originally Posted by BarryD0706
A lot of RVs do not come with them.
Due to damage caused by clueless (or tired/unlucky) users forgetting the bars and trying/succeeding to open the slide with them installed; I understand that some "helpful" dealers/back shop maintenance guys have just "forgotten" to include them during the PDI.
Also some have even suggested that they be used for clothes rods.
Electro/Mechanical Rack and Electro/Hydraulic (piston) slides need these. Electric motor/cable systems (like NORCO) do not.
The Electro/Rack systems have a motor clutch that can slip under side load (like a curb strike while turning), allowing the slide to start moving outward. Once the heavy slide starts moving, it can fully extend due to its own inertia overcoming the motor clutch. (you can hear the clutch sometimes when fully opening or closing the slide).
The lock bar does not actually "lock" the slide. It just pre-loads rack's pinion gear with a downward force and prevents "easy" movement of the rack outward.
The NORCO cable system does not need the bars because motor rotation is required to open or close the slide and the mechanical advantage works against the slide turning the unpowered motor.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW