normadist, from your photo....it appears that the rollers could be removed and replaced with roller, using the same roller base/frame. I’ll get a photo or two of mine, tonite !
I was incorrect on the class c roller length ,it’s been awhile since I was under there. The roller is only 24”, with roller diameter approximately 4 1/2”. It is secured to the receiver outer frame same as your rollers. If you wanted longer, the roller mounting brackets could likely be mounted to the rv frame. If done this way, it would make the roller approximately 18” longer, giving greater coverage. If mounted to the RV frame, the roller would still run beneath the receiver hitch frame, helping prevent it from connecting pavement or getting hung up on something.
The photo was taken from beneath the rv, looking toward the back. It’s rather tight under there, I hope that the photos will offer some help! memtb
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Our 5th wheel roller runs from frame rail to frame rail. The roller is 70” in length, giving nearly side to side coverage.