2019 Keystone Hideout 281DBS Bucks When Towing with a 2005 GMC Sierra

Question:

hi multiple question, have a 2005 sierra duramax dually when pulling or new 2019 hideout 281dbs 32foot 5th back from dealer it bucked very bad and long going over road imperfections/bridges. 5th was empty, on 1st trip out with about 1k of load did much better but still there, and on both trips my fuel mileage dropped almost 2 mpg on . ive pulled my 38foot enclosed with 12-15k and never had either issue. could run all day at 68-70 with ac on and get 10.5-11 mpg and never feel it back there, same with my old 29foot wilderness and it is lifted and has a high overhead. 1st is it has 10inch of clearance between bed and trailer, truck is stock height and overall hooked up trailer sits maybe slightly up,but not 4inch dont know if its even 2inch high, going to do trailer level measurements to hitch my 1st thought is to move pin box up last 2 holes to lower front-what is max nose down to consider. could the high bed clearance be causing the bucking ? and affecting air flow over nose, and causing drag affecting mileage? trailer stock sits high from factory. and only weighs in at 8k with 1.6k at tongue, truck doesnt even budge/squat when hooked up. my thoughts are to see how level it actually is before moving pin box, or maybe install a moryde pin box, or as a last result entire trailer to change drag and get closer to a 6inch bed gap. have put 2200 miles on and tires are not wearing uneven. i can tackle about anything auto/rv related and have been towing 5th and goose for 20+years with over 200k miles. all recommendations you have are greatly appreciated

asked by: Bdk

Expert Reply:

There are a few different things to check out when you are experiencing bucking while towing your 2019 Keystone Hideout with your 2005 GMC Sierra.

Be sure that you have your trailer sitting level when hooked up to your Sierra like you mentioned. You need to have 5" - 6" of clearance between your truck bed rails and your 5th wheel (see attached) so if your clearance is 10" and your 5th wheel is sitting nose-high then that would definitely contribute to bucking. You should be able to adjust both the height of your 5th wheel hitch and your pin box to help make your 5th wheel level. If not we have 5th wheel hitch options that have height adjustments that should fit your needs.

Another major contributor to bucking is a 5th wheel that is using an entry level 5th wheel hitch like the Pro Series # PS30093 which uses a slide bar jaw as opposed to a dual jaw system like the Reese # RP30047. Dual jaws make 360 degrees of contact with the king pin and keep it steady whereas a slide bar jaw has some wiggle room.

Aside from that you need to make sure you are loading your 5th wheel so that it maintains a pin weight that sits around 20% of the loaded weight of the trailer.

There are suspension and pin box upgrades upgrades for trailers to help with the ride quality, like the E-Z Flex # K71-652-00 or Center Point # LC1565391, or an air ride pin box like a Trailair (similar to a MORryde), but it is better to make sure you have your 5th wheel trailer setup properly for towing first before adding enhancements.