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'21 3500 Rear Air Suspension - Smoooth Ride!

roegs

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As I put my order together for a '21 3500 SRW, I went back and forth on the air suspension. What surprised me was the number of vastly different reviews on how this truck rode empty with air suspension. Some loved it, and others regretted ever getting it. From test drives that I did, I actually preferred GM trucks, but RAM HD's are shorter and were the only trucks that would fit in my garage without a major re-organization. Magazine reviews all rave about RAM HD ride quality - including the 3500 air suspension. We're retiring and would like to do some traveling with a 5th wheel - but lets be honest, 80% of this trucks use would be DD getting groceries and Home Depot runs. In theory, the air suspension should make a big difference in ride quality. RAM basically takes a much lighter spring pack (I think it basically is there to hold the axle in place) and then uses air bags to assist once a load is applied and the rear of the truck lowers on the light spring pack. Anyway, that's my understanding.

Rolled the dice and ordered it.

The dealer I purchased from was about 45 miles away. After taking delivery of the truck, I pulled around the building and checked tire air pressures. They were all over 80 lbs. Lowered the front axle to 60 lbs. and rear to 50 lbs. Then proceeded to drive home. Mixed combination of backroads and freeway. It rode okay, but I was sure hoping for better.

Next morning I slid under the truck and poked my finger into the air bags. Passenger bag had no pressure in it, but the drivers was very firm. What! I figured each would be the same. I had seen a youtube video where a guy had adjusted the height sensors somehow, so I figured I'd take a look.

1. Each side of the rear axle has its own sensor. The photo below is not the best, but the sensor has a long arm that extends to a rod that attaches to the axle. The sensor itself is mounted to the frame with two bolts.
2. I measured the angle of the sensor on the passenger side (angle sensing app built into iphone's) and it was 4 degrees different than the drivers sensor angle.
3. I loosened the two bolts on the drivers side (where sensor bolts to frame) and the holes are somewhat slotted in the sensor bracket. Before loosening them, the top of the sensor bracket was parallel with the frame. Same for passenger side (top of the sensor bracket was parallel with the frame).
4. After loosening the drivers side bolts, I was able to turn the bracket clockwise. Look close at the photo and you can see that the bracket is no longer parallel with the frame. There is not a lot of play in the bracket holes, but enough for me to hear the bag on the drivers side deflate. Excellent!
5. At this point, I went for a drive - finally! It rode like I thought it should.
6. Not done yet though - went to the local recycle drop off and weighed my truck. Front axle, Rear axle, and combined.
7. Firestone Load Chart for our tires (I have 20" Longhorn rims) showed I could easily go down to 40 lbs in the rear when the truck is not towing. 60 lbs is good for the front axle (Cummins HO).

Between these two, my truck now has a beautiful ride.....to be honest, not a whole lot different than my '15 Eco with air suspension that I traded in.

My theory....(and I'd love to find someone with a 19+ RAM Service Manual to see how they recommend setting the sensors.)

1. I'm thinking that with an empty truck, the bags should have little to no air in them.
2. The sensors are very sensitive, and a small amount of rotating the drivers bracket was all it took for mine.
3. Based on my truck, I'm guessing the assembly line guys install the sensor brackets so both passenger and drivers are parallel with the frame. I suspect there are no further checks done to ensure sensors are both set the same.

I hope this works for others. These are spendy trucks and having it ride nice around town was the icing on the cake for me.


IMG_1021[1].JPG
 

Cpschevy

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As I put my order together for a '21 3500 SRW, I went back and forth on the air suspension. What surprised me was the number of vastly different reviews on how this truck rode empty with air suspension. Some loved it, and others regretted ever getting it. From test drives that I did, I actually preferred GM trucks, but RAM HD's are shorter and were the only trucks that would fit in my garage without a major re-organization. Magazine reviews all rave about RAM HD ride quality - including the 3500 air suspension. We're retiring and would like to do some traveling with a 5th wheel - but lets be honest, 80% of this trucks use would be DD getting groceries and Home Depot runs. In theory, the air suspension should make a big difference in ride quality. RAM basically takes a much lighter spring pack (I think it basically is there to hold the axle in place) and then uses air bags to assist once a load is applied and the rear of the truck lowers on the light spring pack. Anyway, that's my understanding.

Rolled the dice and ordered it.

The dealer I purchased from was about 45 miles away. After taking delivery of the truck, I pulled around the building and checked tire air pressures. They were all over 80 lbs. Lowered the front axle to 60 lbs. and rear to 50 lbs. Then proceeded to drive home. Mixed combination of backroads and freeway. It rode okay, but I was sure hoping for better.

Next morning I slid under the truck and poked my finger into the air bags. Passenger bag had no pressure in it, but the drivers was very firm. What! I figured each would be the same. I had seen a youtube video where a guy had adjusted the height sensors somehow, so I figured I'd take a look.

1. Each side of the rear axle has its own sensor. The photo below is not the best, but the sensor has a long arm that extends to a rod that attaches to the axle. The sensor itself is mounted to the frame with two bolts.
2. I measured the angle of the sensor on the passenger side (angle sensing app built into iphone's) and it was 4 degrees different than the drivers sensor angle.
3. I loosened the two bolts on the drivers side (where sensor bolts to frame) and the holes are somewhat slotted in the sensor bracket. Before loosening them, the top of the sensor bracket was parallel with the frame. Same for passenger side (top of the sensor bracket was parallel with the frame).
4. After loosening the drivers side bolts, I was able to turn the bracket clockwise. Look close at the photo and you can see that the bracket is no longer parallel with the frame. There is not a lot of play in the bracket holes, but enough for me to hear the bag on the drivers side deflate. Excellent!
5. At this point, I went for a drive - finally! It rode like I thought it should.
6. Not done yet though - went to the local recycle drop off and weighed my truck. Front axle, Rear axle, and combined.
7. Firestone Load Chart for our tires (I have 20" Longhorn rims) showed I could easily go down to 40 lbs in the rear when the truck is not towing. 60 lbs is good for the front axle (Cummins HO).

Between these two, my truck now has a beautiful ride.....to be honest, not a whole lot different than my '15 Eco with air suspension that I traded in.

My theory....(and I'd love to find someone with a 19+ RAM Service Manual to see how they recommend setting the sensors.)

1. I'm thinking that with an empty truck, the bags should have little to no air in them.
2. The sensors are very sensitive, and a small amount of rotating the drivers bracket was all it took for mine.
3. Based on my truck, I'm guessing the assembly line guys install the sensor brackets so both passenger and drivers are parallel with the frame. I suspect there are no further checks done to ensure sensors are both set the same.

I hope this works for others. These are spendy trucks and having it ride nice around town was the icing on the cake for me.


View attachment 13337
This is great to know ! my 2020 ram 3500 is as you described with one air bag being firm and one feeling empty ? I thought they were tied together like my gmc 2500 duramax but obviously they are not . I have a 2021 on order so probably wont bother messing with this one but thanks for your insight so i can check the new one after it finally gets delivered ( If it ever does anyway since its been stuck at the body vendor since the 3rd of march with no updates ! )
 

Mat_HD

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Did you look at your side-side level before and after this change? Just curious.

This is good to hear, btw. I'm still waiting on my '21 Longhorn 3500 but I've been obsessing over the reviews for ride quality and scheming potential changes to the suspension and wheels/tires to ease my long, rough daily commute. This will be the first thing I look into, thanks for the info!
 

H3LZSN1P3R

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Interesting and good to know i had assumed they just had one level sensor and the bags paired together
 

Mat_HD

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Thinking more about this, it seems like this could be where some of the difference in opinion comes from, to a certain extent. I imagine some folks have theirs aligned "better" from the factory so that the bags have the same pressure in them, and others have their trucks like the OPs.
 

roegs

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Did you look at your side-side level before and after this change? Just curious.

This is good to hear, btw. I'm still waiting on my '21 Longhorn 3500 but I've been obsessing over the reviews for ride quality and scheming potential changes to the suspension and wheels/tires to ease my long, rough daily commute. This will be the first thing I look into, thanks for the info!
You'll love your Longhorn! I did the same as you obsessing over ride quality. I've not towed with mine yet (just picked it up Friday) but as a daily driver I'm extremely happy on how it rides. I'm guessing that different tires could also improve things. On my last HD truck, switching to Michelins made an improvement on how it rode.


Thinking more about this, it seems like this could be where some of the difference in opinion comes from, to a certain extent. I imagine some folks have theirs aligned "better" from the factory so that the bags have the same pressure in them, and others have their trucks like the OPs.
Exactly...I'm thinking the same, that mis-adjustment could be the reason for different opinions. I'm still hoping to get a copy of the air suspension section from a Service Manual. At this point my statements about the bags being equally deflated when the truck is empty etc. are just assumptions on my part.
 

roegs

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Did you look at your side-side level before and after this change? Just curious.

This is good to hear, btw. I'm still waiting on my '21 Longhorn 3500 but I've been obsessing over the reviews for ride quality and scheming potential changes to the suspension and wheels/tires to ease my long, rough daily commute. This will be the first thing I look into, thanks for the info!
I did and wish I'd remembered to write the measurements down. If I remember right, there was 3/4" difference between left / right wheel well heights when I started, and 1/4" difference after the sensor adjustment. That said, due to tolerances etc. there is almost always differences in height between the two sides (at least with trucks I've owned). I'm not sure if the air assist is designed to make up for this. In a way, I'm not sure if I'd want it to do that. I wish I could find more RAM docs on how this system is supposed to work.
 

Mat_HD

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You'll love your Longhorn! I did the same as you obsessing over ride quality. I've not towed with mine yet (just picked it up Friday) but as a daily driver I'm extremely happy on how it rides. I'm guessing that different tires could also improve things. On my last HD truck, switching to Michelins made an improvement on how it rode.



Exactly...I'm thinking the same, that mis-adjustment could be the reason for different opinions. I'm still hoping to get a copy of the air suspension section from a Service Manual. At this point my statements about the bags being equally deflated when the truck is empty etc. are just assumptions on my part.
Really is encouraging to hear. Now I'm even more excited to get the truck and see if I have the same findings as you!
 

Hez

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I had the same experience. Just picked up my truck on 3/12 and noticed it didn’t have the smooth ride like the one I test drove earlier this year. After adjusting the tire pressure down from 92psi, I noticed a sizable difference ... but still seemed quite firm in the back. I just checked my airbags and the driver side was really firm and the passenger side was squishy. Made the adjustment per roegs above and now they are balanced. Headed out to dinner now and I’ll report back on the results.
 

H3LZSN1P3R

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I did and wish I'd remembered to write the measurements down. If I remember right, there was 3/4" difference between left / right wheel well heights when I started, and 1/4" difference after the sensor adjustment. That said, due to tolerances etc. there is almost always differences in height between the two sides (at least with trucks I've owned). I'm not sure if the air assist is designed to make up for this. In a way, I'm not sure if I'd want it to do that. I wish I could find more RAM docs on how this system is supposed to work.
I can see them being a little out but 3/4” thats wild its like they just slap em on no checking em lol
 

SFAngus

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As I put my order together for a '21 3500 SRW, I went back and forth on the air suspension. What surprised me was the number of vastly different reviews on how this truck rode empty with air suspension. Some loved it, and others regretted ever getting it. From test drives that I did, I actually preferred GM trucks, but RAM HD's are shorter and were the only trucks that would fit in my garage without a major re-organization. Magazine reviews all rave about RAM HD ride quality - including the 3500 air suspension. We're retiring and would like to do some traveling with a 5th wheel - but lets be honest, 80% of this trucks use would be DD getting groceries and Home Depot runs. In theory, the air suspension should make a big difference in ride quality. RAM basically takes a much lighter spring pack (I think it basically is there to hold the axle in place) and then uses air bags to assist once a load is applied and the rear of the truck lowers on the light spring pack. Anyway, that's my understanding.

Rolled the dice and ordered it.

The dealer I purchased from was about 45 miles away. After taking delivery of the truck, I pulled around the building and checked tire air pressures. They were all over 80 lbs. Lowered the front axle to 60 lbs. and rear to 50 lbs. Then proceeded to drive home. Mixed combination of backroads and freeway. It rode okay, but I was sure hoping for better.

Next morning I slid under the truck and poked my finger into the air bags. Passenger bag had no pressure in it, but the drivers was very firm. What! I figured each would be the same. I had seen a youtube video where a guy had adjusted the height sensors somehow, so I figured I'd take a look.

1. Each side of the rear axle has its own sensor. The photo below is not the best, but the sensor has a long arm that extends to a rod that attaches to the axle. The sensor itself is mounted to the frame with two bolts.
2. I measured the angle of the sensor on the passenger side (angle sensing app built into iphone's) and it was 4 degrees different than the drivers sensor angle.
3. I loosened the two bolts on the drivers side (where sensor bolts to frame) and the holes are somewhat slotted in the sensor bracket. Before loosening them, the top of the sensor bracket was parallel with the frame. Same for passenger side (top of the sensor bracket was parallel with the frame).
4. After loosening the drivers side bolts, I was able to turn the bracket clockwise. Look close at the photo and you can see that the bracket is no longer parallel with the frame. There is not a lot of play in the bracket holes, but enough for me to hear the bag on the drivers side deflate. Excellent!
5. At this point, I went for a drive - finally! It rode like I thought it should.
6. Not done yet though - went to the local recycle drop off and weighed my truck. Front axle, Rear axle, and combined.
7. Firestone Load Chart for our tires (I have 20" Longhorn rims) showed I could easily go down to 40 lbs in the rear when the truck is not towing. 60 lbs is good for the front axle (Cummins HO).

Between these two, my truck now has a beautiful ride.....to be honest, not a whole lot different than my '15 Eco with air suspension that I traded in.

My theory....(and I'd love to find someone with a 19+ RAM Service Manual to see how they recommend setting the sensors.)

1. I'm thinking that with an empty truck, the bags should have little to no air in them.
2. The sensors are very sensitive, and a small amount of rotating the drivers bracket was all it took for mine.
3. Based on my truck, I'm guessing the assembly line guys install the sensor brackets so both passenger and drivers are parallel with the frame. I suspect there are no further checks done to ensure sensors are both set the same.

I hope this works for others. These are spendy trucks and having it ride nice around town was the icing on the cake for me.


View attachment 13337
Do you know if this would work for a DRW? My understanding is that the duallies have so much more support from the leafs, that the air doesn't really do anything until there's a load on the back.
 

heavyg603

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Ok, glad I saw this thread. I have a 2020 3500 Tradesman with the air suspension. My ride is way to firm even with 650lbs in the back to offset my plow. I’ll need to look at this soon and see if I can save my spine a little. Having access to a service guide on this would be awesome.


Sent from my iPhone using Tapatalk
 

Hez

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Made a big difference!! Seemed to take a few miles before it settled down but after that it was much more like a 2500 ride
 

roegs

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Do you know if this would work for a DRW? My understanding is that the duallies have so much more support from the leafs, that the air doesn't really do anything until there's a load on the back.
I'm still learning as I go so take my comments with a grain of salt. I would think that when sitting level and unloaded both bags should feel the same - preferably very soft. With my SRW level and unloaded one bag was firm and the other soft. My thinking is that the bags should basically be empty when the truck is unloaded - the thought would be that the lighter spring pack does the work when the truck is empty.
 

SFAngus

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I'm still learning as I go so take my comments with a grain of salt. I would think that when sitting level and unloaded both bags should feel the same - preferably very soft. With my SRW level and unloaded one bag was firm and the other soft. My thinking is that the bags should basically be empty when the truck is unloaded - the thought would be that the lighter spring pack does the work when the truck is empty.
Ok, thanks. I appreciate the advice. I poked around under there today, and one side felt harder than the other, but not dramatically so. (I'm also a newbie at this, because this is my first dually, and my first air suspension truck). I'm going to see if I can adjust the bracked like you did, although I'm not sure that I fully understand how to. I'm checking out youtube right now to see if there's any videos on it.

Thanks!
 

Mat_HD

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I know it hasn't been that long, but has anyone who's done this adjustment put a decent load in the bed or hooked up a trailer to see if both bags inflate to what feels like the same pressure?
 

Xflight29

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I have found that if you hit the dash button to engage the air bags even though you have no weight in the bed it equals out the air-bags.
Seems like it wakes it up after not towing with it for a while.
 

JcLeiva

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As I put my order together for a '21 3500 SRW, I went back and forth on the air suspension. What surprised me was the number of vastly different reviews on how this truck rode empty with air suspension. Some loved it, and others regretted ever getting it. From test drives that I did, I actually preferred GM trucks, but RAM HD's are shorter and were the only trucks that would fit in my garage without a major re-organization. Magazine reviews all rave about RAM HD ride quality - including the 3500 air suspension. We're retiring and would like to do some traveling with a 5th wheel - but lets be honest, 80% of this trucks use would be DD getting groceries and Home Depot runs. In theory, the air suspension should make a big difference in ride quality. RAM basically takes a much lighter spring pack (I think it basically is there to hold the axle in place) and then uses air bags to assist once a load is applied and the rear of the truck lowers on the light spring pack. Anyway, that's my understanding.

Rolled the dice and ordered it.

The dealer I purchased from was about 45 miles away. After taking delivery of the truck, I pulled around the building and checked tire air pressures. They were all over 80 lbs. Lowered the front axle to 60 lbs. and rear to 50 lbs. Then proceeded to drive home. Mixed combination of backroads and freeway. It rode okay, but I was sure hoping for better.

Next morning I slid under the truck and poked my finger into the air bags. Passenger bag had no pressure in it, but the drivers was very firm. What! I figured each would be the same. I had seen a youtube video where a guy had adjusted the height sensors somehow, so I figured I'd take a look.

1. Each side of the rear axle has its own sensor. The photo below is not the best, but the sensor has a long arm that extends to a rod that attaches to the axle. The sensor itself is mounted to the frame with two bolts.
2. I measured the angle of the sensor on the passenger side (angle sensing app built into iphone's) and it was 4 degrees different than the drivers sensor angle.
3. I loosened the two bolts on the drivers side (where sensor bolts to frame) and the holes are somewhat slotted in the sensor bracket. Before loosening them, the top of the sensor bracket was parallel with the frame. Same for passenger side (top of the sensor bracket was parallel with the frame).
4. After loosening the drivers side bolts, I was able to turn the bracket clockwise. Look close at the photo and you can see that the bracket is no longer parallel with the frame. There is not a lot of play in the bracket holes, but enough for me to hear the bag on the drivers side deflate. Excellent!
5. At this point, I went for a drive - finally! It rode like I thought it should.
6. Not done yet though - went to the local recycle drop off and weighed my truck. Front axle, Rear axle, and combined.
7. Firestone Load Chart for our tires (I have 20" Longhorn rims) showed I could easily go down to 40 lbs in the rear when the truck is not towing. 60 lbs is good for the front axle (Cummins HO).

Between these two, my truck now has a beautiful ride.....to be honest, not a whole lot different than my '15 Eco with air suspension that I traded in.

My theory....(and I'd love to find someone with a 19+ RAM Service Manual to see how they recommend setting the sensors.)

1. I'm thinking that with an empty truck, the bags should have little to no air in them.
2. The sensors are very sensitive, and a small amount of rotating the drivers bracket was all it took for mine.
3. Based on my truck, I'm guessing the assembly line guys install the sensor brackets so both passenger and drivers are parallel with the frame. I suspect there are no further checks done to ensure sensors are both set the same.

I hope this works for others. These are spendy trucks and having it ride nice around town was the icing on the cake for me.


View attachment 13337
I’m curious, I had a terrible ride with extremely bouncing on any little imperfection on the road. After replacing my two rear tires, the problem when almost completely away. It’s still pretty rough but it’s expected from a 3500. I had a 1990 Dodge W350 with a Cummins and the ride was a little better so that’s where my disappointment came in.
What angle did you measure exactly? Mine seems to be the same but the eyes play tricks on you if it was only 4 degrees for you. The only thing is that both of my bags seem to be deflated. I can push them in a good amount and I figured the resistance that I’m feeling is the thick rubber.
I want to just change all my tires to a different brand but I may be looking into just changing my rims as well (for cosmetic purposes).
 

roegs

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I’m curious, I had a terrible ride with extremely bouncing on any little imperfection on the road. After replacing my two rear tires, the problem when almost completely away. It’s still pretty rough but it’s expected from a 3500. I had a 1990 Dodge W350 with a Cummins and the ride was a little better so that’s where my disappointment came in.
What angle did you measure exactly? Mine seems to be the same but the eyes play tricks on you if it was only 4 degrees for you. The only thing is that both of my bags seem to be deflated. I can push them in a good amount and I figured the resistance that I’m feeling is the thick rubber.
I want to just change all my tires to a different brand but I may be looking into just changing my rims as well (for cosmetic purposes).
The angle I measured was the arm on the electronic sensor - this is the arm that runs from the sensor to the ball stud which in turn connects to the rear axle. But regardless of the angle, the key for me was having both bags soft to the touch (deflated) when the truck was empty. It sounds to me like you are already there. As you mentioned, the rubber itself is stiff as you push the bag in. Did you also try tire air pressure changes?
 

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