trading the long bed for a crew cab short bed this fall because my wife wants the back seat for the dog and a grandkid now and then. truck is a 2021 F-350 SRW, 6.7, the 6 3/4 ft box. trailer is a 2019 Keystone Montana 3121RL, about 13,800 loaded, pin weight near 2,600.
we run Billings to Yuma every november and back in april, 1,150 miles each way, a lot of it on I-15. the RV dealer says i need a sliding hitch. a fellow at the campground says a regular hitch clears a Ford cab with the 6.75 bed if the trailer nose is rounded. i would rather not settle this with a busted back window at a fuel island in Utah.
i pull a gooseneck, so salt to taste. but the geometry doesn't care what you pull. on a 6.75 bed with the Ford puck system the pin sits a few inches ahead of the axle, and the front corners of that cap swing in a circle around the pin. a 90 degree turn into a fuel island happens every day on that trip. i would want the slider or a pin box that moves the pivot back, the Reese Sidewinder type.
T
duramax_shop_tony
Rigshop truck: 2017 Silverado 3500 HD dually, L5P
Rank
Heavy Hauler
Posts
58
Joined
Sep 2025
From
Kearney, NE
#3
we have put in more of these than i can count. on a 6.75 Ford bed most people are fine going down the road, it is backing into a site at a hard angle where the corner meets the glass. a manual slider only works if you remember to slide it, and people forget. the automatic ones like the PullRite SuperGlide shift on their own but cost a few grand more.
don't go by anybody's guess, mine included. measure from the pin to the back corner of the cab, then get the front swing radius off the trailer spec sheet.
M
montana_winters_azOP
Rig2021 F-350 SRW 6.7, Keystone Montana 3121RL
Rank
Tow Rated
Posts
26
Joined
Sep 2025
From
Billings, MT / Yuma, AZ
#4
measured tonight. 48 and a half inches from where the pin will sit to the back corner of the cab. Keystone lists the front swing radius on the 3121RL at 66. the hitch shop in Billings says that is a no at full lock without something moving the pivot.
then that settles it. while you are at it, run it across a CAT scale loaded once, with you, your wife, the dog and the generator in the bed. first weigh is around 15 bucks and it ends every argument about pin weight and rear axle rating.
M
montana_winters_azOP
Rig2021 F-350 SRW 6.7, Keystone Montana 3121RL
Rank
Tow Rated
Posts
26
Joined
Sep 2025
From
Billings, MT / Yuma, AZ
#6
went with the pivoting pin box. cheaper than an automatic slider and nothing to remember at 11 at night in a dark campground. $1,380 installed in Billings.
scaled it at the Flying J on the way to the storage lot. steer 5,120, drive 6,840, trailer axles 11,240. the rear is under what the door placard says, not by a ton. we pull out november 8, i will report from Yuma if the back window survives.
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