Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!
41 - 60 of 69 Posts

·
Registered
2021 3500HD GMC Denali
Joined
·
101 Posts
So I actually ended up getting a set of 2020 Silverado 2500 torsion bars on ebay. These are the stock bars that would have been in my AT4 had I not bought one with the snowplow package. Measuring the diameters and calculating volume they had 7 or 8% less volume than the snowplow bars. I installed them, (super easy) and the ride is notably better. However, what I'm learning is that the relationship between the jouncers and the control arms are VERY important. Interestingly also, there are 4 jouncers on the front end of the truck. I'll call them extreme forward and middle forward, not to be confused with the rear jouncers above the leaf springs. The extreme forward and middle forward jouncers do not meet the control arm at the same time. In other words as you lower the rake of the truck the middle forwards will touch the control arm before the extreme forwards. I"m guess there is maybe 1/8 to 3/16 of an inch difference in when they touch the control arm. I have found through experimentation that squishing the middle forward jouncer just a little to allow the extreme forward jouncer to just kiss the control arm results in my best ride so far. If I raise it up from there where the middle forward jouncer kisses, and the extreme forward jouncer is about 1/8 inch above control arm, this has a noticeably worse ride. Obviously the higher the rake from there the worse the ride gets. ( I do drive the truck aggressively over bumps after every adjustment before I even check measurements or jouncer positions)

As far as tire pressure: I reached out to Goodyear and received the documents to account for different psi allowable under different loads. I'm assuming my truck carries 60% of its weight on the front wheels and 40% on the back. Assumption is based on multiple weight reports that show a 57/43 % split, albeit on older duramax trucks. And just for daily driving (not towing or hauling) a very comfortable figure of 9500 gross weight (full gas tank, myself, wife, and two kids, and 400 lbs of whatever else I put in the truck) allows me to go down to 55psi in the front and 40psi in the back. I've got 56 in the front and 46 in the back right now. Interestingly I had 56 in front and 50 in back and the ride seemed better than when I dropped the rears to 46. I'll continue experimenting there, but at least I know I'm 100% safe running those lower pressures now that I have the tire docs. Just can't forget to inflate before I haul. And I won't.

If anyone has any thoughts or concerns for me that don't include "why would you buy a HD truck and then bitch about the ride" I'd love to hear them. By the way, I've improved the ride already without compromising the handling or towing capacity or payload. From what I can tell so far using the stock non-snowplow torsion bars reduced my forward axel allowable weight from 6600 to 6000 but this has zero implication for towing or hauling at the levels I will be using it for.

If I still cannot get satisfied my next step will be upgrading the Rancho shocks, moving to an 18 inch wheel vs the 20 I have. Because I test drove a SLT 2500 non-snowplow with 18 inch wheels and it felt so much better than my AT4. But it didn't look as cool Lol.
Hello, can you possibly forward or post that tire pressure info please??? I lowered the TMPS warnings to 50psi, I’m learning really quick these are a PITA, I don’t know why GM cannot figure out how to automatically relearn the tmps like my other vehicles in the family.
Right now my pressures are at 55 front, 65 rear, the ride is not as harsh as the factory tire pressure settings when I first bought the truck.
Does anyone know of a cheap TMPS relearn tool that can be purchased??? I have a second set of tires and rims for winter.

Coming from a ram, I do not believe the GM rides any better than a solid front axel, I’m running lower tire pressures than I used to in my ram but that truck had 17” rims, maybe it’s the 20’s on my Denali that’s compromising the ride quality that I’m noticing?

I had also noticed the torsion key adjustment is tighter on the drivers side, I’m thinking This is because of the fuel tank and DEF tank being on that side of the truck???
Thanks


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
19 Posts
Hello, can you possibly forward or post that tire pressure info please??? I lowered the TMPS warnings to 50psi, I’m learning really quick these are a PITA, I don’t know why GM cannot figure out how to automatically relearn the tmps like my other vehicles in the family.
Right now my pressures are at 55 front, 65 rear, the ride is not as harsh as the factory tire pressure settings when I first bought the truck.
Does anyone know of a cheap TMPS relearn tool that can be purchased??? I have a second set of tires and rims for winter.

Coming from a ram, I do not believe the GM rides any better than a solid front axel, I’m running lower tire pressures than I used to in my ram but that truck had 17” rims, maybe it’s the 20’s on my Denali that’s compromising the ride quality that I’m noticing?

I had also noticed the torsion key adjustment is tighter on the drivers side, I’m thinking This is because of the fuel tank and DEF tank being on that side of the truck???
Thanks


Sent from my iPhone using Tapatalk

I'll try to forward the Tire Data. I don't know anything about the TMPS except that mine always reads 2 to 2.5 pounds lower than actual pressure. I've tested with 5 different gauges / different brands, digital analog. Right now I just accept the annoyance of the warning. I'm running 54 cold front, and 48 cold back.

With regard to Torsion keys and ride:
Couple things:

1.) Don't try to gauge the degree of torsion bar tension (adjustment) based on what the torsion key bolts look like under the truck. Mine are notably lopsided looking, and they are set perfect. Look at the distance between the control arm and the forward jouncers (parked on very level ground). After much pain and suffering (and looking at dozens of stock trucks on the dealership lot) I've deduced that about 3/16 inch clearance (give or take 1/8 inch - eyeballing it) tween control arm and jouncer is right where it should be, and both left and right should match (a good flashlight will help you see this gap) I also called the parts dept and he went through the various rake positions for these trucks and they all fell right at about 1.2 inch difference between back and front. If that rake is set true to form it will give the jouncer/control arm gap I've previously mentioned.

NOTE: ((( I had previously posted that letting the control arm barely ride on the jouncer gave the best ride - I was wrong. Through exhaustive experimentation, I eventually found the stock gap between jouncer and control arm to be the best ride )))

2.) If your truck is brand new, give it some time. I noticed after about 4000 miles on my Racho shocks, the truck started feeling better. I confirmed this because I swapped out to just regular OEM, non -4x4 package shocks, and the truck felt stiff again and then in another few thousand miles it started feeling better again. And after breaking them in I do feel like the OEM GM shocks are softer than the Ranchos.

Let me work on that tire data sheet. Standby.
 

·
Registered
Joined
·
298 Posts

·
Registered
2021 3500HD GMC Denali
Joined
·
101 Posts
Try this tool. It works with GM or Ford vehicles and I find it super easy to use on both my Ford and Chevy.
Cool, thanks


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
19 Posts
Try this tool. It works with GM or Ford vehicles and I find it super easy to use on both my Ford and Chevy.
So it for sure worked on your 2020 GMC HD?
 

·
Registered
Joined
·
121 Posts

·
Registered
Joined
·
298 Posts
Yes, and it worked training my Airstream trailer tires to my 2020 2500HD. It also trains the tires on my Ford Raptor when I rotate them. Doesn't work with other brands - just Ford and GM.
 

·
Registered
2020 GMC Sierra 3500 HD Denali
Joined
·
67 Posts
Try this tool. It works with GM or Ford vehicles and I find it super easy to use on both my Ford and Chevy.

I have this tool. Are you saying in will learn new sensors to the truck? I have only used it to relearn TPMS position after rotation (shop forgot to do it).
I have a new set of sensors showing up today for a new set of wheels. I would like to be able to swap the wheels out for summer/winter and just learn the sensors at the house. I know the tire shop has a tool that can do it. I have seen it done when a guy swapped on his summer wheels
 

·
Registered
Joined
·
121 Posts
I have this tool. Are you saying in will learn new sensors to the truck? I have only used it to relearn TPMS position after rotation (shop forgot to do it).
I have a new set of sensors showing up today for a new set of wheels. I would like to be able to swap the wheels out for summer/winter and just learn the sensors at the house. I know the tire shop has a tool that can do it. I have seen it done when a guy swapped on his summer wheels
This is exactly what I do with this tool and it works great.
 
  • Like
Reactions: Caper11 and kylant1

·
Registered
Joined
·
298 Posts
It depends on new sensors. Some have to be programmed with a professional tool used mostly by tire shops because the sensor frequency can be changed according to the vehicle they are used in. If you're careful, you can buy sensors made just for your application and this tool will do the job. I bought the sensors for my trailer tires from a GM dealer online and had them installed locally. The tool worked flawlessly with the truck. It took just a few minutes to pair them.

Yes, they will allow you to have two set of tires and wheels and do the relearn when the wheels are changed seasonally.f

1090999
 

·
Registered
Joined
·
19 Posts
So I bought this tool, and I get it to honk around each wheel and a double honk at the end. But I'm confused about how to make the truck accept a lower pressure and not cause the warning and the pressure to show in yellow? Is this tool just for learning positions and not for resetting what the truck views as LOW Pressure? Thanks!
 

·
Registered
Joined
·
121 Posts
So I bought this tool, and I get it to honk around each wheel and a double honk at the end. But I'm confused about how to make the truck accept a lower pressure and not cause the warning and the pressure to show in yellow? Is this tool just for learning positions and not for resetting what the truck views as LOW Pressure? Thanks!
That's correct, this tool can only learn sensor position. You may be able to convince a dealer to make pressure warning changes but apparently most won't do that.
 

·
Registered
Joined
·
19 Posts
Gotcha! Ha, I beat the system. I simply programed the TPMS to think the back tires are the front, and the front tires are the back. (CANT FORGET I DID THAT) The threshold for the TPMS warning is higher for the back, so now I can run indicating 53 front and 43 back with no warnings or yellow annunciators!

Also as an aside, remember I told you that my Truck TPMS reads 2.5 to 3.0 psi lower than actual. So in truth I have 56 front and 46 back, which is well safe for Zero load daily driver. I'd love to hear if ya'lls TPMS reads lower than ya'll gauges. I've used 3 different gauges. Stick gauge, Dial, and digital. All 56 / 46 psi. Truck TPMS reading 53/43 COLD / 90 degrees in the garage.
 

·
Registered
2021 3500HD GMC Denali
Joined
·
101 Posts
A tire shop will lower the pressure warnings. I had mine lowered to 50psi.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
1 Posts
So I actually ended up getting a set of 2020 Silverado 2500 torsion bars on ebay. These are the stock bars that would have been in my AT4 had I not bought one with the snowplow package. Measuring the diameters and calculating volume they had 7 or 8% less volume than the snowplow bars. I installed them, (super easy) and the ride is notably better. However, what I'm learning is that the relationship between the jouncers and the control arms are VERY important. Interestingly also, there are 4 jouncers on the front end of the truck. I'll call them extreme forward and middle forward, not to be confused with the rear jouncers above the leaf springs. The extreme forward and middle forward jouncers do not meet the control arm at the same time. In other words as you lower the rake of the truck the middle forwards will touch the control arm before the extreme forwards. I"m guess there is maybe 1/8 to 3/16 of an inch difference in when they touch the control arm. I have found through experimentation that squishing the middle forward jouncer just a little to allow the extreme forward jouncer to just kiss the control arm results in my best ride so far. If I raise it up from there where the middle forward jouncer kisses, and the extreme forward jouncer is about 1/8 inch above control arm, this has a noticeably worse ride. Obviously the higher the rake from there the worse the ride gets. ( I do drive the truck aggressively over bumps after every adjustment before I even check measurements or jouncer positions)

As far as tire pressure: I reached out to Goodyear and received the documents to account for different psi allowable under different loads. I'm assuming my truck carries 60% of its weight on the front wheels and 40% on the back. Assumption is based on multiple weight reports that show a 57/43 % split, albeit on older duramax trucks. And just for daily driving (not towing or hauling) a very comfortable figure of 9500 gross weight (full gas tank, myself, wife, and two kids, and 400 lbs of whatever else I put in the truck) allows me to go down to 55psi in the front and 40psi in the back. I've got 56 in the front and 46 in the back right now. Interestingly I had 56 in front and 50 in back and the ride seemed better than when I dropped the rears to 46. I'll continue experimenting there, but at least I know I'm 100% safe running those lower pressures now that I have the tire docs. Just can't forget to inflate before I haul. And I won't.

If anyone has any thoughts or concerns for me that don't include "why would you buy a HD truck and then bitch about the ride" I'd love to hear them. By the way, I've improved the ride already without compromising the handling or towing capacity or payload. From what I can tell so far using the stock non-snowplow torsion bars reduced my forward axel allowable weight from 6600 to 6000 but this has zero implication for towing or hauling at the levels I will be using it for.

If I still cannot get satisfied my next step will be upgrading the Rancho shocks, moving to an 18 inch wheel vs the 20 I have. Because I test drove a SLT 2500 non-snowplow with 18 inch wheels and it felt so much better than my AT4. But it didn't look as cool Lol.
Thanks for the helpful info. I have 46k on 2020 2500 with x31 and heavy duty front springs and the Titan 56 gallon tank. The ride almost killed me in the pothole riddled streets of Richmond after dropping off my son and gear at college. And I like a stiff ride.

Any update?

Almost thinking of driving my 2008 2500 diesel rather than 2020 as it rides much better over bumps.
 
41 - 60 of 69 Posts
Top