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Old 10-02-2017, 04:42 PM   #1
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15" wheels to 16" wheels, How much lift?

I am looking at ways to lift my trailer. Can anyone comment On how much lift you got in going from 15" wheels to 16" wheels?

I already have purchased a shackle kit to install this winter and I will drop the springs to the lower hole. I will still be towing "uphill".

My biggest problem is the high rear of the truck, with back end of the box hitting the bottom of the rig. There is a 1" height difference between the back of the box and the side of the box at the 5th wheel. I am thinking about getting the torsion bar "keys" that pick up the front end of the truck.
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Old 10-02-2017, 08:42 PM   #2
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15" wheels to 16" wheels, How much lift?

The wheel size doesn’t necessarily provide any lift. What tire sizes are you comparing/looking at?
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Old 10-03-2017, 08:11 AM   #3
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Swapping out wheels/tires to a bigger size is not a cost effective to address a height problem. Why is your truck so much higher than other trucks?
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Old 10-03-2017, 08:25 AM   #4
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I believe that it is a stock 2500HD long bed extended cab 2WD unit. The front end "sag" is very common in aging (2011) GM pickups.
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Old 10-03-2017, 08:27 AM   #5
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The wheel size doesn’t necessarily provide any lift.
I don't understand that statement - at minimum the bottom of the rim is 1/2" further from the center of the axle.
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Old 10-03-2017, 09:01 AM   #6
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1/2" is not a notable lift on RV's of around 30ft. Go to other methods suitable to your particular model or a sub frame bolted to your existing frame.
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Old 10-03-2017, 09:50 AM   #7
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Aging gm truck - 2011??? I have a 2010 2500 HD Silverado and it looks and drives like brand new. Never heard of a "sag" issue with these trucks.

I don't believe that is your problem unless there has been some type of front suspension failure. If that were the case then fix that problem rather than try to retro fit the 5er.

These aging gm trucks are a common tow vehicle. Get yours fixed and get on down the road.
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Old 10-03-2017, 09:52 AM   #8
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I don't understand that statement - at minimum the bottom of the rim is 1/2" further from the center of the axle.
Bigger rims does not necessarily equate to a taller over all tire. That depends on the tire ratios along with the bigger rim.
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Old 10-03-2017, 10:24 AM   #9
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The issue is not the wheel but the tire size. A larger wheel can accommodate a larger tire size. While the wheel is larger it is the tire size that will affect any height difference and load rating. If you have a 225/75/15 tire on a 15 inch wheel the tire diameter is 28.2 inches a 235/80/16 tire on a 16 inch wheel is 30.7 inches in diameter so you gain 2.5 inches in diameter which equates to 1.25 height increase. If you were to put a 225/75/16 tire on a 16 inch wheel there is a height difference but it might be 1/2 an inch so not worth doing generally speaking.

One thing you want to make sure of is that you have enough wheel well clearance ie from top of tire to bottom of trailer. On my trailer I could not go to a larger tire without raising the trailer as there was just enough clearance for the tires that were on there. My trailer has the cre3000 suspension which is supposed to have 3 inches of suspension travel I only had 3.3 inches of clearance meaning I had .3 inches to spare. Enough for the tires that were on there but not enough to increase the tires size more than .6 inches. So I raised the trailer 2 inches via a subframe which cost me $750. I then bought 16 inch wheels (5 of them to include the spare and 5 new tires in a larger size) So I ended up gaining 1.5 inches in height from my new tire/wheel combo based on the tire size I elected to use. The larger tire size also allowed a higher load rating. So the 1.5 inches from the tires and 2 inches from the sub frame gave me a total of 3.5 inches of lift at the trailer axles.

That does not mean you will gain 3.5 inches at the truck bed. You will gain some of that but not near all of it. Reason is the hitch is a fixed point it is not being raised. If you want to find out how much it will affect measure from hitch pin to center of trailer front tire at ground level, measure from hitch pin to rear of bed, Get string that long, mark string at that bed measurement. Secure string to ground with nail or whatever on both ends, mark on ground where the rear bed mark is on the string, move the trailer axle end of the string in an arc the distance of your proposed height increase and secure it. Now compare the mark on the string for the rear of bed to the mark you made on the ground of where it started out at. The difference between where the string is now and your previous mark will show you how much will translate to bed clearance.

Also raising the front end of the truck is not going to lower the rear it will just lessen the rake meaning that 1 inch difference between the front and rear of the bed will be less than the 1 inch currently but the rear will remain the same.

In addition to a subframe to raise the trailer, or larger wheels and tires to raise the trailer, there is also the correct trac system which is supposed to raise the trailer 2 inches. You can also think about lowering the rear of the truck sometimes much easier said than done in reality. Are you running over sized tires on the truck, any lift on the truck going back to stock size would help if either is the case. I know on my old truck I ran 285 tires vs the 265 tires that came stock. That meant over an inch of height difference. Now on my old truck the trailer worked ok a bit tight but it was ok, the new truck did require me to lift the trailer some.
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Old 10-03-2017, 10:54 AM   #10
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Just for clarification, I am not "planning" on going to 16" wheels, I was just wondering about the effect of 16" wheels for comparison.

Here is my current plan:
1. Raise the trainer axles (go to the lower mount on the spring bracket)
2. Lift the front of the truck by installing after-market torsion bar keys.
3. lower the 5th wheel hitch one hole (it is currently in the top hole)
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Old 10-03-2017, 11:17 AM   #11
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Where did you come up with the GM sag theory?? Haven't been able to find anything that even mentions that as an issue on trucks 5 - 10 years old. Also a rake front to rear is not normal for your truck. On level ground, my 2010 bed is almost perfectly level. If what you are describing is true, there is an issue with your truck. If that is the case, you should be able to level it out with a conventional repair without the need to go to any after market products.
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Old 10-03-2017, 11:35 AM   #12
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Look what I found: Rear axle lowering shackles

https://www.amazon.com/2011-2017-Che...+drop+shackles

Sounds like an easier installation and a more direct effect - it lowers the hitch 2 inches and also reduces the bed angle at the same time. They claim you can do it in your driveway without a lift...

Maybe I could actually reach into the bed...
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Old 10-03-2017, 11:38 AM   #13
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Where did you come up with the GM sag theory?? Haven't been able to find anything that even mentions that as an issue on trucks 5 - 10 years old. Also a rake front to rear is not normal for your truck. On level ground, my 2010 bed is almost perfectly level. If what you are describing is true, there is an issue with your truck. If that is the case, you should be able to level it out with a conventional repair without the need to go to any after market products.
The rear suspension looks stock - just one helper spring and no air bags. But that Eagle HT barely lowers it at all. Maybe I just need a heavier trailer...
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Old 10-03-2017, 11:44 AM   #14
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Where did you come up with the GM sag theory?? Haven't been able to find anything that even mentions that as an issue on trucks 5 - 10 years old. Also a rake front to rear is not normal for your truck.
From the first page of a google search:

Why Do Trucks Come From Factory With Nose Dive? - 1999-2006 & 2007-2013 Chevrolet Silverado & GMC Sierra 1500 - GM-Trucks.com
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Old 10-03-2017, 12:21 PM   #15
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My old truck had torsion bar front suspension. You could raise up the front end for a "level kit" type deal by just cranking up the preload on the bars. Make sure you count the number of turns of each bolt and do the other side the same. You'll need an alignment after.

Could it be that the Eagle HT was designed for half ton ride height and not 3/4 ton?

I think if you raised up your front end, got bigger tires on the trailer and flipped the axles you would have more than enough compensation to sit level.
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Old 10-03-2017, 02:33 PM   #16
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Good find but this link speaks to the 2wd trucks coming from the factory with a slant down in the front, no sag with ageing. I think it explains that the slightly higher back end is to accommodate a load so that when loaded the truck doesn't point its lights into the trees. I have a 4x4 and they apparently come level front to rear. Sounds like your HT [half ton] doesn't place enough weight on the hitch plate to level out the truck.
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Old 10-03-2017, 02:52 PM   #17
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"sag" was a poor choice of words on my part.

It looks like they call it "rake".
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Old 10-03-2017, 04:25 PM   #18
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"sag" was a poor choice of words on my part.

It looks like they call it "rake".

Good to know. My belly doesn't sag, it has a rake.
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Old 10-04-2017, 06:58 AM   #19
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So, yes, increasing the wheel size can make a pretty big difference. Last I looked if I went from the 15" to 16" wheels and got the larger tires it made a 5" difference in diameter. That means a 2 1/2" lift. If you also move the trailer springs to lower holes that is another inch. So you can get about 3 1/2" that way.

Ours rides about 5" high in the front. It is mostly due to the 4WD configuration for our 3/4T truck. Truck bed is high. To put in perspective it is 2" higher than our Toyota Tundra (2WD). One of these days I will raise the springs and put on 16" wheels and tires. Right now it does fine so I just run with it nose high.

The truck used to 'sag' a lot until I put Timbrens on it. I did not like hitting the bump stops all the time so added the helpers.

I am more concerned about bed clearance than how much nose high it is. I like having 6" of clearance between the bed sides and the bottom of the trailer. I will suffer with a nose high trailer to make that happen.

If you only need another inch or so you can put blocks between the springs and axles (using longer Ubolts). If you need more than that then you can have a sub-frame welded up and installed. IIRC it is a bit less than $1000 for that kind of mod.
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Old 10-04-2017, 09:45 AM   #20
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I am more concerned about bed clearance than how much nose high it is. I like having 6" of clearance between the bed sides and the bottom of the trailer. I will suffer with a nose high trailer to make that happen.
This is exactly my issue. The bed clearance at the rear of the bed is about 4 inches, with about 5 1/2 inches at the front of the cap. I have already hit the bottom of the trailer twice (slow learner) transitioning onto/off-of side slopes.

I already have the wet-bolt kit to install this winter. I will go to the lower holes when I install them, so that is one inch. After yesterday's discovery (drop shackles), I now plan to install the 2-inch drop on the pickup rear axle. That should put me nearly level with about 6 inches of clearance.
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