Trailer to Bed Clearance and Trailer Angle?

[SLVRBLT]

Hey all you guys with 5er's and 4x4's, I need some advice.



Just bought a 5er, 1st one, and got the hitch, brake controls, wiring done. Hooked it up today and went for about a 20 mile "maiden run" to check brakes, lights, etc. With the weight of the trailer on the truck, 5 gal of fuel in regular tank, about 40 gal. of fuel in the aux. tank, (90 gal. capacity) the truck sits about level. The trailer is slightly nose high, but when the truck is full of fuel, another 80 gal. , it will probably squat a little and the trailer will be closer to level. It still may be a touch nose high, don't know yet?



In this condition, I have 8" of clearance between the trailer and the top of the bed. When I fill the truck up (both tanks) and if the trailer is still a little nose high, is this OK? I can lower the 5th wheel hitch one hole and drop it about 1-1/4". This will lower the clearance between the truck and trailer to an estimated 6-3/4". Should I lower the hitch and go to less clearance or leave the clearance alone and pull it slightly nose high?



I appreciate any advice on this. This is my 1st 5th wheel.

Thanks,

Dave

 

[TR7110]

KEEP IT LEVEL

Dave,

From everything I have read on this site and several others. Your 5th wheel should be as level as possible. Towing nose high or nose low will effect the wear of your trailer tires and could result in premature failure. It also seems that between 6 and 7 inches clearance is just right. My 5th wheel used to sit a little nose high. Did some adjustments and now it sits level. Seems to pull a little easier, but I don't have any factual data to back up that claim.

TR

 

[Big John]

It is always best to have the trailer level, but a little nose high does not hurt anything. Most hitch and trailer manufacturers say to have 4. 5 to 6 inches of clearance between bed and trailer. I have run with as little as 4 inches, but this can be a little close unless you stay on fairly level ground. I shoot for 5 to 6 inches. This is plenty on all but the most severe angles.



Big John

 

[swamp rat]

I can back up some of what TR said about the tire wear and being easier to pull with some HS physics. The reason the tires wear faster when the trailer doesn't sit level, is the load way out of balance across all tow vehicle and trailer axle tires, which cause more rolling resistance on one or more tires/axles, and less on others. This in and of itself makes it harder to pull. Excess Rolling resistance= excess friction=heat=excessive tirewear



BTW Skinny tires offer less rolling resistance than fat monster mudgrips, hence one of several reasons the fatboys wear out faster, and provide slightly less fuel mileage.



Add to that the Loading or Unloading effect the trailer has on the towing vehicle's suspension and the problem can be compounded drastically. Worst case scenario, can actually cause loss of steer or drive wheel control and braking.



Try doing an emergency stop with the front of trailer angled upward more than the optimum, and I bet you'd most likely jacknife. Front end of trailer down, and your straightline braking distance is increased because the steer tires are not loaded to the optimum, and drive tires are sligthly overloaded. Just the right amount of upward angle of the trailer allows for a good weight transfer in straightline breaking.





When both vehicles set as level as possible, you are more likley to have equal loading across all axles and tires. Basically thats what a weight distributing hitch is supposed to do with a Class IV ball hitch. It helps load up all wheels and axles a little more evenly to provide less wear and tear, and better overall traction.



End of Physics 101.

 

[Big John]

Yeah, wwwwwhat he said.

 

[midnight1black]

Clearance and Trailer Angle

If your trailer is level then leave it. if you get below 4-1/2" you will start having problems your trailer will rub on the bed of your truck when you pull up a small hill. been there done that ! if your trailer is not level and you need to go higher you may need to flip your axles on the trailer so you can get the clearance you need.

 

[SLVRBLT]

Thanks for the Replies!



Thanks to everyone for all the feedback. Swamp Rat: I've had physics, but it's been ages, so the refresher course didn't hurt a bit! Forgot to mention in the 1st post that the axles have been flipped. The guy I bought it from was pulling it with a 4x4 Chebby.



Went out this morning to unhook the trailer and do a little more measuring. Before I read your replies, I had already decided to drop the hitch one hole, which is about 1-1/4", which should put me a lot closer to level. This should still leave me with 6+ inches of clearance which I agree with you guys is enough.



As I said in the orig. post, a full load of fuel in the truck, 125 gal. , should squat the sweetheart a little more. Going out right now to drop the hitch a hole.



Thanks again for all the info. You always get good feedback on this site.



Dave

 

[swamp rat]

Dave I don't dare mention how long it has been since I last sat in a Physics class. Suffice it to say it has been a long, long time.

 

[SLVRBLT]

Update





swamp rat: I'm 54 and didn't take any physics in college if that tells you how long it's been for me. Guess that kind of dates me, huh? However, some of that stuff actually sticks with you and you retain it, especially if it is useful.



Lowered the 5th wheel hitch one hole, 1-1/4". Man, thank God for air tools! Didn't think it would make that much difference, but it sets so darn close to level that I'm not touching it anymore. Got the wheel bearings packed, checked the brake linings, torqued the lug bolts back on, and the sucker is ready to travel. Didn't think that just a 1-1/4" would make that much difference, but it did and clearance between the bed and trailer is 6+". I am a (or will be?) a happy camper now.



Looked at the springs on the Dodge today with the trailer attached and still have lot of spring capacity to use. With the trailer pin weight, weight of aux. fuel tank full, it will still have plenty of capacity. I'm really glad I bought the camper package! Man, I love this truck!



Thanks to everyone for the advice. This was much easier than learn by experience or "hit or miss". This site is awesome!



Dave