Input - HD front springs and Z71 Pkg.

MesaRat · March 12, 2020

I am about to buy my first GM truck and have spec'd out a 3500 4x4 SRW CCLB Diesel. I am about to pull the trigger on a distantly located truck that has the Heavy Duty Front Spring Package and the Z71 with 18" off road tires. Unfortunately the truck is 400 miles away so I can't drive it. I drove the 2500 (same config w/z71 and 18") off road and it was fine. I live 6.5mi down a semi-maintained dirt/gravel road, that has some bumpiness/washboards/etc. I cannot find a 3500 (diesel of any config) with in 100 miles of me to test.

Does any own or have experience with this configuration (3500, Z71, 18", heavy duty front springs) and if so what is your opinion, especially for offroad?

How much worse of a ride do you think the 3500 w/ HD springs/z71/18" will be than the 2500 z71 i drove?

Thanks

-MR

FirstAscent · March 16, 2020

I am about to buy my first GM truck and have spec'd out a 3500 4x4 SRW CCLB Diesel. I am about to pull the trigger on a distantly located truck that has the Heavy Duty Front Spring Package and the Z71 with 18" off road tires. Unfortunately the truck is 400 miles away so I can't drive it. I drove the 2500 (same config w/z71 and 18") off road and it was fine. I live 6.5mi down a semi-maintained dirt/gravel road, that has some bumpiness/washboards/etc. I cannot find a 3500 (diesel of any config) with in 100 miles of me to test.

Does any own or have experience with this configuration (3500, Z71, 18", heavy duty front springs) and if so what is your opinion, especially for offroad?

How much worse of a ride do you think the 3500 w/ HD springs/z71/18" will be than the 2500 z71 i drove?

Thanks
-MR

I’ve never driven one of them with the HD spring package but for what it’s worth the front suspension is the same on the 2500’s and 3500’s, unless you get the hd spring pkg of course.

There is a thread on here about snow plows, maybe ask one of them? I’d bet they have that option for their plows.

Oh, also the z71 pkg on these he trucks I don’t believe changes the suspension, it’s just skid plates and adds Hill Descent Control. The 1500’s it actually upgrades the shocks too.

Good luck!

FirstAscent · March 16, 2020

Delete - double post

MTU Alum · March 16, 2020

On this model, the torsion bar goes up one size and the front shock stays the same. The front ride impact is pretty small on this model.

Similarly the unloaded ride is a little worse on 3500 vs 2500. The first stage spring rates are the same but on 3500 the second stage engages sooner, rear shock has more force, and tire pressure is 80 vs 70.

#iworkforGM

MesaRat · March 21, 2020

thanks for the input. i pulled the trigger and took delivery yesterday - 3500 diesel, CCLB, Z71, with the HD springs. from what I read and can tell, the shocks are Ranchos on the HD too. However, the welds to the lower bracket don't look that robust to me.

Going down my bumpy road is not too bad and actually better than I thought. Logically, it is a bit stiffer than the 2500 I drove and on one washboard area the rear does get a little bouncy (unloaded). However, coming out of a F-250 with Fox OEM replacement shocks and 35" on 18" wheels is night and day.

Dealer said they can turn the torsion bars to raise the front an inch give or take and stay under warranty ($160). They believe the truck can then take 37" tires, but are confirming for me. I am hopeful that the ride will improve some more with big sidewall tires. I will post an update when I change out the tires, but if anyone has experience please chime in (couldn't find anything searching the site).

davester · March 21, 2020

Ouch. $160 just to turn up the torsion bars on a brand new truck (so it's not like the bolt in the key is rusted in place or anything).

MesaRat · March 21, 2020

It seemed a little high to me too. However, service manager said if they do the adjustment it will not void my warranty and GM will not try to deny any suspension claim (of course assuming I don't abuse anything, which I don't). Between turning the torsion bar and going to 37" (if i can) will raise my front end almost 3".

FirstAscent · March 21, 2020

It seemed a little high to me too. However, service manager said if they do the adjustment it will not void my warranty and GM will not try to deny any suspension claim (of course assuming I don't abuse anything, which I don't). Between turning the torsion bar and going to 37" (if i can) will raise my front end almost 3".

Does the $160 include an alignment? If so it’s not TOO bad. If not that’s ridiculous. They literally turn a bolt a few times and done.

If it doesn’t include an alignment I would do it yourself, if for any reason you did need any warranty work related to the front suspension take the 10 minutes and turn the bolt back down to stock height.

I also think they are getting more lenient on lifts. Dealers have plenty of 1500/2500/3500’s with lifts on their lots, brand new trucks too. I had a shop do a 6” lift on my 2019 1500 when I had it and it didn’t affect the warranty at all. My dealer said it more depends on what lift kit, so maybe it’s more dealer discretion?

Anyways, if they cranked it up an inch I think that’ll be pretty tight fit for a 37. But possible if your sticking with factory wheels (or at least the same size custom wheels) and not too wide of a 37” tire.

I think there was a YouTube vid of 37’s with a leveling kit

MesaRat · March 21, 2020

No alignment is included. However, I am getting one for free as the steering wheel is off center and it seems to have a slight pull to the right but that maybe the truck is sensitive to road crown. Local dealer is a satellite of a dealership 80 miles north in Colorado and don't have an alignment rack big enough for it.

Maybe I will try myself and do what you said but to me I'm probably am OK with $160 and not have to worry about it.

From my understanding, if the dealers do or farm out the lift (or other modifications, accessories, etc.) and sell it with the truck as new, it is covered under warranty. This was Ford's policy. Unfortunately, this dealership is very small (and the only new car dealer in our area) and they don't do any lifts / leveling kits.

FirstAscent · March 21, 2020

No alignment is included. However, I am getting one for free as the steering wheel is off center and it seems to have a slight pull to the right but that maybe the truck is sensitive to road crown. Local dealer is a satellite of a dealership 80 miles north in Colorado and don't have an alignment rack big enough for it.

Maybe I will try myself and do what you said but to me I'm probably am OK with $160 and not have to worry about it.

From my understanding, if the dealers do or farm out the lift (or other modifications, accessories, etc.) and sell it with the truck as new, it is covered under warranty. This was Ford's policy. Unfortunately, this dealership is very small (and the only new car dealer in our area) and they don't do any lifts / leveling kits.

I’m in a VERY similar situation as you on the steering wheel. Just picked up my 3500 CCSB yesterday and noticed the slight pull to the right as well so steering wheel was off center to the left. I’ve driven it 600 miles so far all hwy and it’s been doing it the whole time so I think alignment is off.

FYI, Chevy will cover the alignment under warranty but not until AFTER 500 miles. I learned this today, luckily I was at 600 miles so just barely haha. So if you’re under 500 miles you’ll need to rack up some quick miles.

I stopped at a dealer that I was passing by and actually have the truck on an alignment rack right now as I type this, I’ll let you know the outcome and how it drives afterwards.

MesaRat · March 21, 2020

3 hours ago, FirstAscent said:

I’m in a VERY similar situation as you on the steering wheel. Just picked up my 3500 CCSB yesterday and noticed the slight pull to the right as well so steering wheel was off center to the left.

I stopped at a dealer that I was passing by and actually have the truck on an alignment rack right now as I type this, I’ll let you know the outcome and how it drives afterwards.

Please let us know. It kind of pissed me off. So much money and they can't deliver the truck so it tracks straight.

FirstAscent · March 21, 2020

Please let us know. It kind of pissed me off. So much money and they can't deliver the truck so it tracks straight.

Sorry for the delay, I needed a nap then wanted to get some miles in before getting you an update.

I just put 200 more miles on her after the alignment. Below is what the tech told me as well as my thoughts...

They said the alignment was maybe barely off but the steering wheel needed alignment. They did do a full alignment though.

It’s better, I think it’s good now but will continue to monitor it. I don’t think it’s pulling to the right anymore and I think the steering wheel is where it needs to be. Here’s why I’m hesitant to say it’s 100%.

I think these trucks may be extra sensitive to the crown in the road. I was on a two lane (each way) hwy. the left lane slanted to the left and the right lane was a little flatter but slanted to the right.

When in the left lane the steering wheel is slightly to the right, accounting for the slant. When in the right lane, it’s slightly to the left. When I think I’m on flat ground the steering wheel seems straight.

My other car doesn’t seem to be affected as much by the crown in the road so who knows if it’s just how these trucks are.

BUT, it is better than before, so progress! And I’m with ya, rand new trucks I don’t want to be dealing with alignment problems. Just make sure you’re at 500 miles or they won’t do it under warranty and they will charge you.

MesaRat · March 21, 2020

Thanks FA. I'm glad to hear you got some if not most resolution. Mine is doing exactly what you described. i am 100% certain road crown is a big influence. I live very remote so can test it out on long stretches of highway, in different lanes etc. when i go to the left (on coming lane) it veers to the letf. however, it seems a bit more eager to veer to the right in right lane. supposedly camber adjustments can help but i don't know if that is something they can adjust on these trucks. my steering is off as you described.

i am at 500mi but i brought it up on the test drive a day before i took delivery. they couldn't align locally and it has to go to their main dealership in CO.

my F250 did this constantly and i was able to dramatically improve by installing a Fox IPS 2.0 steering stabilizer with air adjustment. wound up keeping it at ~100psi. dealer did install camber and caster shims but really couldn't get it were i was satisfied.

i might of been wrong on the alignment for adjusting the torsion bars (I looked up the process and didn't realize an alignment is needed) and suspect it does include an alignment for the $160, will talk to service next week if they don't mandate shelter in place here. however, since they are going to align it for free and I have to drive into Colorado, I will try to get it included. it is so simple I laughed.

MesaRat · April 2, 2020

had my torsion bar adjusted two turns by the service department. on normal pavement i cannot tell a difference. on my 7mile dirt road it is much much worse. kind of surprised me. even worse the tech said he really couldn't see a difference and i couldn't measure a difference in front ride height.

now discussing putting a set of Kryptonite or cognitio A-arms and fox shocks or setting it all back to stock. i wonder how much the HD front spring (torsion bar) is playing into this.

MTU Alum · April 3, 2020

Cranking the torsion bars the little you did shouldn't change the ride. One crank changes the suspension height 4 to 5 mm. Cranking the torsion bars does not change the spring rate but it changes the check height of the spring. If you crank the torsion bars too high, you will eventually decrease your rebound travel too much.

#iworkforGM