Hi all, brand new to the forum, looks like I got real lucky and found the right place for GMC info.


Anywho...I have been looking at buying a new diesel truck to be used for pulling a 26' 7500 lb toy box for my jet ski's. I have shopped all around and found what I want...(2500HD 4x4 4door SLT) The thing is I have noticed at least in the So Cal area that some of the dealers put 6" lifts and bigger tires on them. It looks REALLY nice but my question is...How does the lift kits and bigger tires effect the towing of the truck? Does it really hurt the ability to tow a heavy load? fuel mileage? stress on suspension parts?


Any info you experienced towers have will be great. I have never owned a diesel before or pulled a big trailer like this. Thanks in advance for all your advice.

6" lift and tires will decrease your mileage by quite a bit. And because you're putting bigger rubber on, your towing power will drop a bunch too, because now you've increased your rotating mass by quite a bit as well. And as for the stress on components, yes, any time you go to bigger tires, you get more stress.


What alot of guys do, and myself eventually, is buy a programmer/chip like the Edge juice or something to regain that power that you lost with the lift and tires.


Your truck will still tow the trailer, just not as proficiently as before.


Hope this helps!!


-Zorganov

I have a 4" Ranch lift and have run almost every size tire in a 16" up to a 305 and 19.5 as well. I have towed to 33,000 GCVW with the 305's, but most of the time my towing is about 23,000 to 25,000 GCVW. Your fuel mileage will fall off considerably with the taller tire both with trailer or without. Your running gear may shudder on take off with a heavy load. The higher stance of a lift usually causes more wind drag and thus helps cut fuel mileage. Dropping back to 285 increased my fuel mileage about 1.5 mpg unloaded. My lift gave me more ground clearance which I needed, but it did hurt the mileage dept.

I disagree with Zorg (sorry). givin what you are towing you will not notice the difference. these trucks have a plenty of torque and even without using my chip I can out run and out accel most stock blue ovals and sheepheads . . . If this were a problem GM would offer 4.10 gears for these truck but they don't and are not needed (only offroaders would benefit).


However, I would recommend a chip http://www.dieselplace.com/forum/smileys/Big Smile.gif they are so http://www.dieselplace.com/forum/smileys/Cool.gif and a lot of fun. you should go to a truck fest/drag race and see what can be done with even a singe chip. http://www.dieselplace.com/forum/smileys/Clap.gif

Thanks for info guys. I think I am headed for an 04 that is not lifted, at least not with a 6" lift. Maybe I will go stock and add a 2 or 4" later on. and just a tad bigger tire and wheel. May also just wait a few months for a 2005 and see if they are still having problems with the darn injectors.

yeah towing with a lifted vehicle can be a pain some times. The only problems I every have with my truck. Is the fact that my 35"x13" tires are so squared off the that they like to follow tracks in the road and when pull a trailer that can be kinda annoying. plus with a lifted hd you have to have atleast an 8" drop hitch. and those get exspensive when you wanna buy one that will hold more then 5-6000lbs. I know the putnam I'm gonna get is about 75-80 dollars. it an adjustable 10" drop. that holds 14,000lbs if I'm not mistaken. as far as power goes. I'm not worried about that. I've never pulled anything with my truck in stock form. always had the mod on it.

I have the big Putnam drop hitch. It is expensive, damn heavy to lift, but it works. I've had over 18,000 lbs behind mine. Great quality.

But I am guessing that ANY kind of 5th wheel is out of the question if lifed even just 2 or maybe 4 inches instead of 6.


I ask because with all the great info here I have considered a 5er because they seem to tow a bit easier. Now that I know I can get a good setup for a shortbed truck and be able to take it out when not using it so I don't loose the bed when not towing it might be another option.


DAAAAYUM...I LOVE THIS BOARD :)

I don't have any personal experience. but if you just cranked the torsion bars up in the front about 1.5" and put a 31 or 32" tire on the truck. you shouldn't have a bit of problems. because that would put you up that about the stock height of the new 4x4 dodges. so I don't see any harm in that. but a 4" would proably be a little to much once you did a larger tires and a 6" is definatly to big. hope this helps.


-Chad-

I bought a 2004 Hd 2500 duramax long bed. I was thinking about a 4" lift from rancho but I heard the ride is stif. Worse than stock! I plan on pulling a 5th wheel. I was told you can put a 4" lift with 33" tire and still pull a 5th wheel. Any help would be great.

You heard wrong about the Rancho!! My truck, with the 4" Rancho, BFG 285/75R16s (33 inchers), and RS 9000S shocks rides better than it did stock with Bilstein shocks. It also is more stable on the road and handles better.


Based on what I have heard about the new 5th wheels, I think I could find one is tall enough for my truck. After all, a 4" lifted Dmax is only a couple inches taller than a stock Ford or Dodge, by then again I have heard that the Fords and Dodges have problems getting under some fifth wheels, especially the older ones. However, please be aware I have not yet thoroughly researched the issue of fifth wheels and my 4" lifted truck. If it doesn't work out, I'll just get a tag, which I am inclined to do anyway.


You might check out my two threads on lift kits and installing the Rancho:


http://dieselplace.com/forum/forum_posts.asp?TID=6842&PN=1


http://dieselplace.com/forum/forum_posts.asp?TID=5288&PN=1Edited by: afp1

Blaine,


Thanks for your help!!

Blaine,


Can you raise Gmc hd 2500 2004 in the front to level it out without causing wear on front end components ? Someone in the forum said to use


http://www.central4wd.com/store/itemdetail.asp?ID=8736
<H2>Chevy/GMC HD P/U, Suburban 99-04 3/4 Ton 8 Lug 4wd Leveling Kit.</H2>


It seems any way you go there will be parts that wear out faster than they should. I hate to say it but I may keep it stock so I have no problems with the 5th wheel hook up and I don't have to replace front end part .What's your thought?

I'm with Blaine all the way! I also have a rancho 4" on my 01' extra cab with a Predator programmer and a 4" turbo back exhaust. My ride actually got better. It was not stiffer at all. Think about it, most lifts just drop all your original components. You don't change rear springs or torsion bars, so the only thing that you change that can soften or stiffen things up is the shocks. Just get a good quality shock and you'll be fine. I'm only running the rancho 5000's and it still rides good. I'm running 295 tires also. As for fuel mileage, my city hasn't chaged at all. Heres the trick though, it's all driving style. I got 17mpg before my lift and programmer. This is all hand calculated mind you. After the lift, and driving easy (staying at 2100rpm or lower), I still got 17mpg. If I drive heavy footed it drops to only 16mpg. I got 20mpg on the highway before lift, but haven't been highway since, so i'm guessing i'd be close to that. It all depends on what you intend to use your truck for. If your never really gonna be off road in the rough stuff, you may just want to crank the torsion bars and put on some 265's or 285's. Maybe even get a set of green keys. If your going off road more and need the clearence, then you may want a lift. I did a lift cause I hunt and needed the clearence. I also got torsion bar relocators too so the bar cross member doesn't hang down after the lift. Hope that info helps.


Ken

Here is an excerpt from my "Lift Kit Summary" thread and leveling the front end as you are describing. The biggest downside I see is the truck will squat in the rear if the nose is raised.


Cranking the Torsion bars

There are both higher lift factory keyways and some aftermarket keyways (like from Hill 4WD and Central 4WD) that will allow up to 3" of lift in the front. At 2" of lift and below, the ride is very good and the CV axles are not at too bad of an angle. Many guys have run 60-100,000 miles with their HDs lifted this way.

However, as you go over 3" with the torsion bars, the ride gets choppy. This is not because we are loading the torsion bars more. Raising them simply resets their "zero" point. Their spring rate does not change, though effort the a-arm exerts on the t-bar does increase a little bit whenver the a-arms are not horizontal. Also, as we raise the nose of the truck, we are getting the shock absorber too far from the center of its travel and it doesn't dampen as well when we do that. The increased effort exerted by the a-arms on the t-bar, along with the shock getting out of it's ideal dampening range, winds up providing a noticable change in ride quality .

I currently have 2" of torsion bar lift and my ride is excellent. Part of this is because I have Bilsteins, but another reason is that I have a 1" spacer under the top shock mount which puts the shock closer to its center of travel.

While I did think of trying a 2" spacer and maybe getting 3" of torsion lift, I decided against that because I did not want to limit the travel of the shock anymore than I already have. Bottoming/topping out a shock is a bad thing.

Yes, if we could use a shock 3" longer than stock, we might be able to get 3" of torsion lift with a good ride. We probably wouldn't even hurt our CV axles, as this amount of change is well within their operating limits. However, no one makes such a shock. I also imagine that at 3" of torsion lift we'd want to flip our tie rods.

Interestingly, the droop travel of our trucks is limited by the shock absorber. With a stock length shock, the front end can be in the air and the CVs will not bind. However, longer shocks can allow the suspension to droop to the pint where the CVs bind. There is a metal pad on the frame that contacts the upper a-arm, and it needs to be about 3/4" higher to keep the CVs form binding.

I really don't like having my torsion bars cranked. While it doesn't hurt the CV axle itself, it does cause the folds of the CV boots to constantly rub against each other, which has to incease wear a bit. When the C

I am so glad i found this forum. I don't know much about diesels and this forum helps people with any problems or projects you may have with your truck. Thanks for all your help and great advise. Sorry for the rookie question. If anybody needs any advice with gas rigs or vw buggies, I am the guy you want to talk too. I have baja and two sand rails.