Roadmaster

Good question, it really depends on the set up of the airbags and brackets attached to the bag itself. If the airbag set up sits directly over top of the leaf springs, it is less likely to be able to fit with an RAS because of interference. From what I have seen, most of the bag setups that sit inboard of the leaf springs are less likely to interfere with an RAS setup.Obviously set ups are different for each air bag manufacturer, and further for each truck.

My advice: to improve the chances of an airbag working with the RAS, find a style that sits inboard of the leaf springs that do not have adjoining brackets within 3/4" from the u-bolts. I am aware multiple instance where an RAS and air bag set up were ran side by side, generally speaking, leave pressure in the bags less than 30lbs for best results.

Hope this helps!

TomTruck55

I've read all the comments on this thread & couldn't find the answer to my problem. I have a 2014 F-150 SCREW 4x4 5.0. Built in January it sat in Pittsburgh until I bought it in August. Off the dealer's lot it had what felt like a jittery suspension or bouncing rear suspension. Slight shudder off the line (normal acceleration) but at about 48 to 58 mph it felt like bad tires. Dealer road force balanced all 4 wheels but could not improve on the recent re-balance I had done elsewhere.

I feel like Bucket Man in that I hate driving my truck & feel like jumping out of it going down the road because of the incessant shaking or bouncing. I refuse to accept that a $47,000 is within "specs". The dealer told me that there is no fix.

All the comments here appear to have addressed the the off the line vibrating/shaking or whatever everything else people are calling it by installing the RAS system but I didn't see anyone comment about the higher speed problem like 50 to 60. I did see RAS worker state that the system probably won't stop that higher speed problem but has anyone have a fix for it? I am totally stressed about this problem as the truck only has 3,500 miles on it! The jittery or bouncy ride at higher speeds is felt in the seat bottoms as well as the seat backs, no shake at all in the steering wheel.

Today I went down a steep hill & had to stop at a red light. When it turned green I felt a shudder like the brakes were releasing too slow or the drive line was settling back down which caused me to think that the axle was unwrapping.

To me it feels like every imperfection in the road is causing the rear axle to constantly bounce up & down. I put Bilstein 5100's on the rear but it did not make any difference.

The very last thing I told the dealership before I left was it will be a cold day in hell before I buy another Ford product if they don't fix my problem. This is my fourth F-150 & the fifth Ford product. The previous trucks were regular or super cabs & had no ride problems. Yes, they rode like trucks but I accepted that.

If people want soft riding trucks, why not buy something more car like & let us buy our stiff riding trucks? Does any one have a fix or a suggestion for me?

BucketMan

I feel your pain.
Do you have the 6.5' bed? I feel that due to having the 5.0 that your vibration is likely different than mine and others that have the 157" WB Ecoboost, however I'm sure yours is equally frustrating.

I had a highway vibration as well. I had my tires re-balanced multiple times with no luck. I hated the GY SRA's and replaced them within a few months of owning the truck and the highway vibration went away. Maybe I had a bad set of tires, maybe the Ford tech's can't correctly balance tires, or maybe the GY tires are just flat out junk. I think it was a combination of all 3 personally. However after replacing them with BFG AT's that were correctly balanced by a tire shop all is well at highway speeds.

After 3 years I have pretty much grown accustomed to the take off shudder, although I'd say between the RAS and the bump stops in the leg springs I had eliminated about 95% of it, now I'm just used to it.

I certainly appreciate shelling out $900 or more isn't a great thought after dropping all that money on a new truck, but that is what honestly resolved my highway speed vibration.

Also, I'm a fellow Yinzer (although relocated to Virginia) so I'll do my best to help ya aht 'nat.

fcancer

WOW,your right ,I think i'll go trade in my soft riding Platinum and get a car.

MCDavis

iTrader: (1)

Bringing this one back to the top for some recent rear shock changes.
I added BOSS rear shocks not long after this RAS install. I then increased the tension in the RAS to compensate for some of the height increase I netted with the coilovers. That extra tension created some unpleasant ride characteristics when unloaded...I'm talking about almost zero weight in the bed. The rear of the truck was jittery and choppy. It walked a bit at highway speeds if the pavement was broken or uneven.

F150lifts worked with me on replacing the BOSS with another set. Ran those for a few thousand miles and pulled them. Same ride quality. I put the stock shocks back on and some of the chop went away. This got me thinking about shocks/valving/compression and rebound...so I began researching like crazy. I'm not talking about just a quick search...I'm talking about months of reading and emails with suspension/shock manufacturers.
What I learned is that most shocks are progressive or linear on compression and rebound. The opposite is digressive, and very few shocks use this valving. So with my questions, and a very helpful manufacturer's sales team, I came to the conclusion that digressive shocks would aide in my efforts. Here's the problem, the only shock I could find that is digressive on both compression and rebound are the Icon 2.5" resi's...and they're $1300 a pair. That's outta reach.

I did find though that Bilstein is linear on compression and digressive on rebound...this got me thinking about rebound as this is when the RAS is working as it pulls the leafs back to an arch. I found a stellar deal on a pair and pulled the trigger on a set of Bilstein 5100s. They have been on the truck for about 300 miles so far, but that's a mix of in town and highway, from cobblestones to expansion joints and I'm pleased to say that the 5100s have almost completely taken out the jittery feeling in the back of the truck. It's a drastic improvement over stock and the BOSS rear shocks. I'm very happy with this experiment.

Hopefully this will help others who might be in the same boat. During my research I was troubled by finding very few instances where the RAS was paired with anything other than stock. Maybe my research will help the next guy.

Wannafbody

RAS looks to me as if it essentially preloads the spring.

MCDavis

iTrader: (1)

In essence yes. Similar to the Hellwig helpers in that regard. Definitely helps with sag during loads and keeps axle wrap at bay. It's a great addition honestly and I'm very pleased now with the addition of the 5100s. I wish I'd added them earlier.

badtziscool

I'm looking to get some RAS after reading the many reviews and how everyone says it helps stabilizing the rear. Thanks for being so thorough with your review MCDavis! Your truck configuration is eerily similar to how I am looking to configure my truck. Can you elaborate on the progressive/digressive shock valving? I am thinking that progressive valving means the faster the shock is worked, the more resistance it will provide and vice versa for digressive valving. How would you compare the stability of the rear between the 5100 with RAS, stock shocks with RAS, and completely stock rear?

MCDavis

iTrader: (1)

I'll share with you some resources that lead me towards finding a shock that was digressive over progressive. I'm not an engineer, so I have to rely on other findings to base my decisions.

Helpful article:
http://www.dvosuspension.com/blog/su...essive-curves/

Here is an email chain, newest to oldest, that I had with the folks at Icon suspension about their shocks...Hopefully this pastes well, and I inserted my Forum ID in place of my name.

Scott Spiva
12/28/15

to MCDavis
No problem MCDavis. That is only the case for out 2.0 and 3.0 shocks. All of our 2.5 Series shocks are digressive on both sides of the piston. Fox traditionally uses linear pistons and I’ve read that Bilstein uses digressive, I haven’t opened to many Bilsteins up to have a ton of firsthand experience though. Bilsteins are excellent shocks but are usually not rebuildable like other brands.

There is often some misconception about linear/progressive pistons, many people describe linear pistons as “progressive” when they are really linear. Digressive shocks have much better low speed control characteristics than linear and improve the handling of the vehicle while reducing body roll when cornering.


From: MCDavis
Sent: Monday, December 28, 2015 9:22 AM
To: Scott Spiva
Subject: Re: New submission from CONTACT US


Scott thanks for the speedy response.
I wasn't aware that compression was linear and the rebound was the digressive valving...thank you for that. I hadn't seen it broken out before.
Out of curiosity, is that the same for Fox and Bilstein? Are they linear compression with Fox being progressive and Bilstein being digressive? I'm shopping the three brands right now in hopes of finding the best application for my truck with the RAS.

Thanks again

On Mon, Dec 28, 2015 at 12:10 PM, Scott Spiva wrote:
Hi MCDavis,

The shocks are tuned to complement the factory leaf springs so while it should be an improvement over your stock shocks, I can’t say that it would be 100% ideal right out of the box. Since the shocks are revalveable you should be able to tune them to complement your particular set up.

Our 2.0 Aluminum Series shocks are digressive on rebound but are linear on compression. All of our 2.5 shocks are digressive on both compression and rebound, which will give you more control. So if it’s within the budget a 2.5” shock would be my recommendation to complement the active suspension system.



From: MCDavis
Sent: Monday, December 28, 2015 7:22 AM
To: info
Subject: New submission from CONTACT US

I have a question about rear shocks on my '13 F150. I'm looking into your 2.0 Alum series shocks.
I have added the Roadmaster Active Suspension to my truck, and while I love what it provides for the truck (payload handling and ride control) it gets a bit twitchy over uneven pavement/potholes/broken roads.
I'm curious to know if the digressive valving on the 2.0 would compliment how the RAS works. Do you have any experience with a setup of this kind, or have any input on the matter?

Thank you,
MCDavis




RAS and the stock shocks were ok. RAS and the BOSS left me wanting something more. RAS and the 5100s has been pleasant for sure. The truck corners very well for weighing 6100+ pounds and sitting a few inches higher thanks to the BOSS up front and the RAS out back. I'm pretty happy so far.

Wannafbody

Most OEM Bilstein shocks are crimp top and not rebuildable. I'm under the impression, that most aftermarket Bilstein shocks are rebuildable.