Bought a 17 leveled with aftermarket wheels/tires, help!

[SilverGhostD]

HI guys, new the forum..found it when doing some googling on my issues. I read a number of threads on here but wanted to post up my exact problem/situation and try to get some help!

 

I bought a 2017 Denali 2500 HD Duramax from a dealer a couple weeks ago with 4K miles on it.

 

The truck has 305/55/20 Toyo AT's on it, with Rockstar KMC wheels. Since the tires are on the wheels, I cannot get an exact measurement of width bead to bead, but being a 305 tire, they must be either the 20x9 or 20x10's. Given how far these stick out past the fenders, they must be a negative offset as well...so looking at 8x180 pattern on these wheels on Rockstar's website, they would be either -12(9" width) or -24(10" width) offsets per their spec sheet.

 

Here's the issue. I was told the truck has a leveling kit up front, but not so sure this is the case. This thing rides AWFUL. Front end bounces like mad. The main issue is when I'm towing my 29 foot Fountain Fever on a triple axle trailer and there's some load on the rear...then the front end bounces so bad on dips in the road its just brutal to the point of unloading the steering and giving us sore necks on longer pulls. Bit of reading I've done makes it sound like aftermarket keys wouldn't produce this bad of a bounce? Looking under there its hard to tell if they used keys as claimed or if they just cranked the living piss out of the stock stuff and re-aligned it. I'm leaning towards option 2, the front suspension just feels SO stiff and has no travel.

 

I am pulling my boat 8 hours end of next week down to Lake of the Ozarks shootout from Chicago, and really want to sort this prior. My first question is if as a short term solution, I drop the front end back to stock, do you guys think these tires will clear ok? I've seen some of you saying a wide 33" like these will clear with stock ride height. I'm assuming the negative offset on these wheels would further help that situation since it would be getting the tire away from the inner fenders. Given my shortage of time, I'd probably want to just do that for now to get the ride quality safe for towing, then figure out the right way to level the truck back out and not have it ride like poop and sag in the rear while towing.

 

I'll attach a pic of the truck as it sits, with my boat hooked up. Thanks alot in advance for your help!

[8lugCT]

Check your torsion bars.. probably cranked up to the max

[SilverGhostD]

Check your torsion bars.. probably cranked up to the max

yes, they appear to be. what I can't tell is if they installed aftermarket keys/leveling kit as claimed. I've read that with aftermarket keys you don't need to crank the bars to the moon as bad and the truck shouldn't ride this brutal.With how it rides, my guess is no leveling kit and they just cranked the piss out of the stock stuff.

[vinemann12]

First,, Cool truck & boat combo...

 

Short Term / Easy Stuff..

 

* Investigate suspension mods, brand, type as well as wheel part number to find it true size and offset..

* What shocks on truck at this time, factory, aftermarket, adjustable?

If they can be adjusted, set for max firm.

* Crank down bars just enough to clear front 305's, or close to rubbing.

* Adjust tire pressure to minimum 45Psi for towing,, this may help firm up ride..

* If possible, check torque of all suspendion components to validate no lose bolts, etc..

 

Long Term, find good suspension shop to help you map out future chassie set-up for towing and fun..

 

Cheers---K

[SilverGhostD]

First,, Cool truck & boat combo...

 

Short Term / Easy Stuff..

 

* Investigate suspension mods, brand, type as well as wheel part number to find it true size and offset..

* What shocks on truck at this time, factory, aftermarket, adjustable?

If they can be adjusted, set for max firm.

* Crank down bars just enough to clear front 305's, or close to rubbing.

* Adjust tire pressure to minimum 45Psi for towing,, this may help firm up ride..

* If possible, check torque of all suspendion components to validate no lose bolts, etc..

 

Long Term, find good suspension shop to help you map out future chassie set-up for towing and fun..

 

Cheers---K

I've seen a few people on here in other threads saying that a wide 33" tall tire like this WILL fit on stock ride height on a 2500 HD, thoughts? But otherwise yeah I was thinking crank it back down as far as it'll go and still clear otherwise for now.

 

45 PSI. All 4 tires or just rears when towing?

 

Shocks/suspension are all stock as far as I know. I was not told otherwise by dealer, and don't see anything under there to make me think anything is aftermarket either.

[SMiller]

Simply crank the bars down and test drive.

 

22mm socket and a couple minutes and you are good to go.

 

You need aftermarket upper control arms to keep from hitting the frame stops if you want to keep the front end height otherwise crank it down until you are happy and the tires don't rub, get a allingment and you will be good to go.

 

 

I would do a quick check to also make sure someone did not install wheel spacers.

[SilverGhostD]

the GMC dealership I bought it from is saying they are happy to drop it back down and re-align it free of charge, so I'm going to start there.

 

I'm not that super interested in having some big ride height. I've seen mention of using shackles in the rear to remove the rake that way instead of raising front. Anybody have some info/tips regarding this method?

[geektoad]

minimum 45psi? that's insanely low for towing...your TPMS should be going crazy on you. My tire pressures for towing my toy hauler are 70 front, 80 rear. Do you run a WD hitch? If not, get one.

 

my setup: 305/55-20 Nittos, suspension maxx key kit, Bilstein 5100 shocks.

 

While I have a level kit, i'm not maxed out on it, probably could have done the amount i did with the stock keys, but i wanted the spacers for the diff that came with it.

[Buckshot556]

I'm willing to bet they cranked the bars all the way or got aftermarket keys but did not bother with shock extenders or aftermarket control arms. This will give you harsh ride up front as there is no more downward travel for your suspension to absorb bumps and dips.

[gearheadesw]

the GMC dealership I bought it from is saying they are happy to drop it back down and re-align it free of charge, so I'm going to start there.

 

I'm not that super interested in having some big ride height. I've seen mention of using shackles in the rear to remove the rake that way instead of raising front. Anybody have some info/tips regarding this method?

 

 

 

Do this, get the selling dealership in on getting you satisfied with the truck that they sold you. You seemed to have already talked to them, and for free, that's the ticket right there.

[SilverGhostD]

minimum 45psi? that's insanely low for towing...your TPMS should be going crazy on you. My tire pressures for towing my toy hauler are 70 front, 80 rear. Do you run a WD hitch? If not, get one.

 

my setup: 305/55-20 Nittos, suspension maxx key kit, Bilstein 5100 shocks.

 

While I have a level kit, i'm not maxed out on it, probably could have done the amount i did with the stock keys, but i wanted the spacers for the diff that came with it.

I'm not the one that said that, I was responding to the person above that did. I currently tow my boat with 65 front and 70 in the rear. I don't run a WD hitch, I've looked into it. Not sure its really necessary for a boat /trailer combo that can't weigh more than 8k lbs though?

 

you have the same size tires as me. How does the truck ride compared to stock with the key kit and 5100 shocks?

 

Also does your rear end sag at all with this setup when you are pulling your toy hauler? as you can see in the pic, my truck currently sags some with the boat on the back.

[geektoad]

I'm not the one that said that, I was responding to the person above that did. I currently tow my boat with 65 front and 70 in the rear. I don't run a WD hitch, I've looked into it. Not sure its really necessary for a boat /trailer combo that can't weigh more than 8k lbs though?

 

you have the same size tires as me. How does the truck ride compared to stock with the key kit and 5100 shocks?

 

Also does your rear end sag at all with this setup when you are pulling your toy hauler? as you can see in the pic, my truck currently sags some with the boat on the back.

 

 

The sag in your pic is what made me suggest the WD hitch. Even though your trailer might not be that heavy, the tongue weight is probably pretty high.

 

My truck rides as good as stock if not better with my set up, but I'm nowhere near maxed out on the keys. I didn't go for perfectly level but just to minimize the rake as much as possible. I've still got about 1.5" of rake when empty. When the bed is loaded up and the hauler (which is about 10k) is hooked up i'm nice and level and it rides great. we use towed NH to WI last month.

[pogrelis97]

Sounds like it's probably cranked up as far as they could get it and the upper control arms have no downward travel before hitting the bumpstops. new upper control arms would probably make a huge difference IMO.

I have the drop shackles on the rear of my truck and love them. I also installed sumosprings and with my gooseneck and skid loader behind it it rides level.

I'm headed to the shootout next Tuesday staying across from PBC, flag me down if you see me!

 

 

[SilverGhostD]

 

 

The sag in your pic is what made me suggest the WD hitch. Even though your trailer might not be that heavy, the tongue weight is probably pretty high.

 

My truck rides as good as stock if not better with my set up, but I'm nowhere near maxed out on the keys. I didn't go for perfectly level but just to minimize the rake as much as possible. I've still got about 1.5" of rake when empty. When the bed is loaded up and the hauler (which is about 10k) is hooked up i'm nice and level and it rides great. we use towed NH to WI last month.

Thanks for info. I'm going to see what it looks like once they drop it back down, get myself through the LOTO trip then figure out what I want to do next. Will see how it looks with the boat on back without the front suspension jacked to the moon also. Tongue weight shouldn't be that bad, I mean the weight of a go fast boat like mine is primarily in the rear where the engine and drive is, but who knows. Guess we'll find out soon. Tomorrow is when they are dropping it down and re-aligning it at GMC, and I'll be grabbing my boat off the lift right afterwards to pull it down to the city for Chicago Air and Water show this weekend. So I'll know alot more tomorrow night.

 

Seems like the FOX 2.0's have alot of positive reviews from folks, but they sure seem spendy compared to the 5100's. Being a sled guy, I'm a FOX fan, their tech in sled shocks has always been real impressive.

[SilverGhostD]

 

Sounds like it's probably cranked up as far as they could get it and the upper control arms have no downward travel before hitting the bumpstops. new upper control arms would probably make a huge difference IMO.

I have the drop shackles on the rear of my truck and love them. I also installed sumosprings and with my gooseneck and skid loader behind it it rides level.

I'm headed to the shootout next Tuesday staying across from PBC, flag me down if you see me!

 

 

 

Drop shackles def interest me. I'm not that concerned about trying to have a truck with a big ride height. Step 1 I guess tomorrow will be seeing how far the dealership is able to drop the front and still clear these 305/55/20 Toyo's that are on this thing. If they are able to get it down to stock ride height, then will for sure be considering dropping rear instead of raising front.