** YOUNG FRANKENSTEIN ** The truck Chevrolet should have built.

[drewskiren]

Originally Posted by oldman3

Tried to size this so it could be read, but no luck, anyhow here's the pic...Jim

AWESOME!!!

The girls and I are so stoked to be in the biggest magazine of hot rod car culture in the world!

[NewType72]

what an awesome writeup and i actually got to see my first quadrasteer vehicle the other day lemme say that pickup put my short bed single cab to shame hahaha

[mcbassin]

Originally Posted by drewskiren

AWESOME!!!

The girls and I are so stoked to be in the biggest magazine of hot rod car culture in the world!

Congrats on some more ink, I told you there would be some coverage, just a matter of time.

[jb1016]

Mine was in the mailbox today; I couldn't set it down until I found the picture. Congrats Drew!

[TennesseeZ]

Originally Posted by drewskiren

AWESOME!!!

The girls and I are so stoked to be in the biggest magazine of hot rod car culture in the world!

Originally Posted by mcbassin

Congrats on some more ink, I told you there would be some coverage, just a matter of time.

Originally Posted by jb1016

Mine was in the mailbox today; I couldn't set it down until I found the picture. Congrats Drew!

Got mine today too, of course I went straight to page 79. Congratulations on the coverage Drew, you deserve it, and much, much more for your hard work, craftsmanship, and vision displayed in Frankie. I'm glad to see you and your family having fun with it, and enjoying it. I'm still waiting for the full spread on it, tho, kinda suprised HRM didn't approach you about it. I look for a dedicated "truck" mag to get with you soon.

[RatRod68]

Oh. My. Gawd.

This truck is a true work of art. I am going to pick up my donor for a Crew Cab dually build today. You may get questions.... ok, you WILL get questions. Ha!

Lot of time, money, and sweat equity went into this thing (holy cow 139 pages!) and the end result is nothing short of amazing.

[Scott Webster]

Just got my mag yesterday and that sir is awesome. They should a huge write up in there for you! Me -..... my wife - . She doesn't get why I get so excited

[slammed427]

I gotta say Drew, the truck turned out beautiful. If I had built her, the only difference would have been the 4th door.

Stellar sir, stellar!
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[Dieselwrencher]

Congrats on the coverage Drew!

[Big Block 454]

I've been rummaging through this thread for the past few days and tonight I was reading my current Hot Rod magazine and saw your truck. Very cool.

[drewskiren]

Originally Posted by slammed427

I gotta say Drew, the truck turned out beautiful. If I had built her, the only difference would have been the 4th door.

Stellar sir, stellar!
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Thank you, Thank you, but a 4th door wouldn't have been period correct!

[drewskiren]

Saturday night picture time!

I dumped all the air out for one last set of pictures before a little revision surgery. It seems our patient's creator (me) was unhappy with the lack of a smooth ride.

Bottom edge of the fender lips are 29 inches here. Rears are the same 29 inches.

[VA72C10]

that's such an awesome stance for the truck....guessing though that it's the last we'll see it that low...

[drewskiren]

Over on the suspension board I posted questions early on in my build about how an air bag suspension rode. I was hoping for and looking for answers that said it would be smoother than the factory suspension. Maybe I wasn't listening well enough, or people just want to make themselves believe, or maybe a bagged truck would ride better than a worn out 40 year old suspension. I soooo wanted to have an even smoother ride than available from the factory. Turns out that my 2002 chassis rides pretty darn good just the way it was. WAS. Now that I bagged it, it stinks. I'll be honest, it is a mistake to think you can improve the ride of a newer truck.

Also, if you're wondering, I tried all combinations of air pressure on the front air bags. I got all the way down to 60 psi, but the bag was nearly totally deflated and was running on it's own internal bumpstop. 85 to 90 psi seemed to be my sweet spot - it wasn't very sweet.

Just recently, I've been back over on the suspension board looking for answers and I'll reprint a few of my posts from that thread:


I feel like I know the basics, but I'm hoping someone makes a lightbulb go off.

Yes this is my Crewcab truck.
I have about 3 inches of rear down travel with sleeve type bags which supposedly ride smoother. They do.
I have about 2.5 inches of down travel in the front with big Firestone double convoluted bags.
In the front I have a factory bumpstop which is very squishy and I actually am in contact with it at rest.
The rear shocks are pretty soft and the truck will drop a lot when you have a seat on the tailgate.
I don't think I have a problem with the rear ride, it is clearly softer than the front. Although I think a lot of trucks are softer in the rear? My 2002 Sierra squats down about the same as my 72 Crewcab when I plop down on the tailgate. (not very scientific)
The front shocks are very hard to compress by hand to install them. I took them off to see - hoping it would be a drastic difference. It wasn't. Better, but not near my 2002 Sierra ride.
Without the shocks I can get the front end to bounce some by pushing on the bumper. Not as bouncy as the rear, but then again the tailgate length acts as longer leverage for me for me to push down.
Air pressure in the rear bags is around 90 psi. 80 psi - on the bumpstops, 100 psi - sky high.
Air pressure in the front is 92 to 95. Much less, you are too low and fully riding on the squishy bumpstop which finally gets firm when fully compressed. 100 psi starts getting pretty stiff and high. 105 -forget about it.
I am riding on 20's, but they are take-offs from a 2007 Suburban - 55 series and those new burbans ride pretty nice. But my 2002 Sierra is riding on 17's and that is my main comparable. I might swap them and see if it helps.
I mounted my body with part of the rubber mounts from the 2002 truck, but it is not completely isolated by rubber. There is rubber between the frame and body, but the head of the bolt touches the cab and the nut touches the frame. This effectively means a direct metal connection, even though it doesn't seem like much.
I'm willing to do most anything to get it to ride like a new truck. It should since that's what it is - until I bagged it.
Would factory coil springs from the junkyard with tired factory shocks ride smoother? I'd be willing to swap back and use a dropped spindle to lower it a little.

I pulled the bumpstops out of the front and maybe it is better??? It has to be, because anything holding the truck up makes it stiffer. Now with no front shocks and no rubber bumpstops in constant contact I can really get it bouncing in the front. Seems a little better, but still not as smooth a new truck.

And the last post:


Quote:
Originally Posted by SCOTI View Post
Re-read the info shared.... The shocks & bumpstops were removed only to try & isolate the cause of the rough ride quality.

Drew, I can't remember. Did you also install drop spindles? If not, I think I'd try the OE coils trimmed as required & dropped spindles. It appears that for whatever reason, the bags are limiting your ride quality within the pressure/height requirements for optimal operation.

First, thanks for answering the previous 2 posters.

Second, I think you are right on. Today I spoke with a crew chief friend of mine and he and I came up with the same answer. Rolling sleeve bags ride pretty nice and are not very progressive in respect to their "Spring Rate". However they must travel in a straight line and cannot be used on a front suspension that travels in an arc. Double convoluted bags can ride smooth over small bumps, but by their design they get firm real fast - their spring rate ramps up very quickly and they become very stiff over medium and larger bumps. When double convoluted bags are installed on a long lever (rear control arm) this problem is lessened because the bag can stay in its sweet spot for a longer amount of actual wheel travel. In my front suspension the bag is near the actual wheel and is less leveraged which means with medium sized bumps my bags get compressed a lot which gets them into their stiff zone.

Another thing of interest: We hear lots of talk about all 18 wheelers ride on air bags now for a smoother ride. This is true, but look at what type they use - Rolling Sleeve type. Also it was pointed out to me that on an 18 wheeler, air bag suspensions weigh a lot less than those huge leaf packs. The manufacturers are shaving weight for better mileage, not just for a smoother ride for your goodies on the truck.

Also take a look at the car manufacturers that have air bag suspensions, most all use rolling sleeve. I can't think of any with double convoluted bags.

Lastly what comes to mind are Baja race trucks with those enormous travel suspension systems. Those trucks can soak up the most gigantic bumps and the drivers are hardly affected. It seems to me that the smoothest ride is achieved with the most travel possible. Factory coils springs for the front allow for the most travel utilizing the factory control arms and suspension design. If you could design and build a long lever type front suspension and place a double convoluted bag somewhere in the middle of that lever you could get the best of both worlds, smooth ride because of long travel and air bag adjust-ability. Ford's old twin I beam comes to mind.

As is stands now, the smoothest ride for my truck will be long, soft factory coil springs in the front with a soft shock. I will lower it some with a dropped spindle if I need to which will not affect my ride at all. In the rear I may keep my rolling sleeve bags or I may look into long coils. Either way, I will need much more travel than the 3 inches I now have which means frame and bed floor modifications. I want this thing to ride so well that people comment on the smooth ride. To get there though I may also need to have a taller tire sidewall.

[Beetle]

Such an awesome truck. Like I said, when I win the lottery I am gonna buy me a POS truck and send it to you and let you have at it

I want the quad steer, 6.3L, and 4L85, not being picky...

[drewskiren]

Originally Posted by Beetle

Such an awesome truck. Like I said, when I win the lottery I am gonna buy me a POS truck and send it to you and let you have at it

I want the quad steer, 6.3L, and 4L85, not being picky...

I hope for my sake you don't win the lottery!

[drewskiren]

So here's what I did Thursday afternoon and night. My front bag is completely deflated here just for kicks.

Thursday morning I went to the junkyard and walked the lot to find a 2wd, V8, 2002-2006 Crew Cab Silverado and a Standard Cab truck with a V6. I got both sets of springs and shocks from both trucks. Clearly the V6 trucks springs are lighter duty - less coils and thinner wire. Thursday night I pulled it all apart and put it back together with the lightweight springs. I was worried it would drop too much, so that's why I had backup springs of the correct truck.

And for the moment of truth: Ahhhhhhh, so smooth now and a 3/4 inch drop from factory 2002 height. It is a night and day difference, now I can actually tell that the rear rolling sleeve bags are pretty smooth.

The bottoms of the fender lips are at 33 inches now which gives me 4 inches of down travel. Full extension on the up side measures at 37 which is 4 inches for up travel. Total of 8 inches of travel in the front, just like Chevy had engineered it. See what happens when you stray from factory????

[drewskiren]

Originally Posted by VA72C10

that's such an awesome stance for the truck....guessing though that it's the last we'll see it that low...

Thanks, and I love it, but neither the front or rear will make a turn at this height. So what's the point - I found that I didn't really want to bother lowering it for a car show, and if it won't drive like this, I'll never see it like this.

[VA72C10]

Originally Posted by drewskiren

, or people just want to make themselves believe, or maybe a bagged truck would ride better than a worn out 40 year old suspension.

I have talked to several on here who have run stock, lowered, and bagged 67-72 trucks and by far the best riding is a Properly set up bagged suspension.

Your truck is unique in many ways (weight distribution, modern frame, engine, quadrasteer, etc) so that it doesn't have much to do with how stock frame 67-72 trucks run on a bagged frame...

just don't want the many who subscribe to your thread to read your comments and think air ride on 67-72's is a bad idea....

and I still think if you worked on the bag setup up front it could be better than the coil setup....although it might take a complete re-work and re-engineering so it likely isn't worth it at this point since you seem pleased with the ride...and on your truck the rear being able to be adjustable is more important than the front.

[Gokart Mozart]

Originally Posted by drewskiren

See what happens when you stray from factory????

You get one awesome truck! Just making it more to your liking.

[drewskiren]

Originally Posted by VA72C10

I have talked to several on here who have run stock, lowered, and bagged 67-72 trucks and by far the best riding is a Properly set up bagged suspension.

Your truck is unique in many ways (weight distribution, modern frame, engine, quadrasteer, etc) so that it doesn't have much to do with how stock frame 67-72 trucks run on a bagged frame...

just don't want the many who subscribe to your thread to read your comments and thing air ride on 67-72's is a bad idea....

and I still think if you worked on the bag setup up front it could be better than the coil setup....although it might take a complete re-work and re-engineering so it likely isn't worth it at this point since you seem pleased with the ride...and on your truck the rear being able to be adjustable is more important than the front.

My point here IS that I want to help guys understand and have an honest assessment of before and after. I searched high and low and asked many and never could really get a straight answer. Now that I have finally found engineers and other smart people in the industry willing to explain the dynamics of suspensions systems, I want to share that knowledge with others.

Also I have read Firestone's own technical sheets on applications of their bags and design strengths and limitations. There are several tech sheets available on the web at Firestone.com available for download.

What it all boils down to is that the double convoluted bags that are small enough to work for our applications have a very small effective range of low pressure/soft enough ride. In Firestone's own application manuals they detail this and show multiple applications using the bag mounted on a lever arm to maximize their throw -or in our case - wheel travel. The rear suspension system on our 67-72 trucks is exactly how this bag is intended to be used. Our front suspension double A arm is not a long enough lever to keep this bag in it's sweet spot. Picture a blow up rubber kickball, push your thumb down on it 1 inch. Easy (soft) how about the next inch down? Harder! How about the next inch?- so hard that it hurts your thumb and it can't be done. This is what is happening inside the double convoluted air bag. As the bag is compressed, the air pressure goes up exponentially (multiple times). When you design the air bag system you are always searching for the lowest air pressure that will keep the truck at the correct height to give the smoothest ride. When you hit a medium to large bump the air bag absorbs the first little part but then the pressure rises so high in the bag it is all of a sudden very hard, like you were cruising around with 30 psi more. Try adding 30 psi to your bag and see how hard it rides. These double convoluted bags are very soft and smooth in the bags first inch or so of travel. Depending on your suspension set-up this could equate to 1 to 3 inches of travel depending on how long your lever/control arm is and where the bag is placed on it. The closer to the wheel or axle, the less travel and the less sweet spot of smooth travel you will have. Beyond that these bags get very stiff very fast

The next part comes from suspension engineers:
Longer travel equates to a better chance for a smooth ride, but it must be engineered with a soft, long traveling spring and shock. Long travel with a stiff shock will be stiff, don't bother. Again, look at a Baja race truck video and watch a proper long travel suspension soak up huge bumps with very little truck body movement. Fortunately we don't have to design for this extreme, just potholes and speed bumps.
Truck rear suspensions by nature are designed with longer travel in mind and respond well to soft springs and shocks be it air spring or leaf or coil. The problem in the rear though becomes how to have a soft rate with no load and a firm rate when you have a load. Some leaf springs on trucks have a upper helper leaf that comes into play when the truck is weighed down, some coils springs use a progressive rate design with tighter and wider spaced coils. Using an air spring (airbag) can be the best of both worlds with soft and firm at the touch of a button.
Truck front suspensions, and most all vehicles for that matter, have severe space limitations when it comes to the front suspensions. Long travel suspension arms are hard to make room for and most front suspensions make do with less travel, shorter arm setups. For that type of suspension it is impossible to get a double convoluted bag far enough away from the tire to have much lever action which would give the front more travel at the low pressure sweet spot of this type bag. So in the front, you end up with the first inch or so of travel really smooth, the next inch of travel a bit firmer, the next inch of travel really hard and not much any travel after that.

In summary, double convoluted bags in the front suspension will not be as smooth a ride as a factory coil at normal factory height.

That being said, if you lower your truck with short stiff springs in the front which many people do, going from that set up to bags WOULD end up riding better than it had with the short aftermarket springs. This is usually how it goes- lower your vehicle on a budget at first with lowering springs, love the look, but hate the ride. Then someone says to bag it and it will ride like a dream (compared to how it is now). This statement ends up being true and furthers the myth that double conv bags ride soft in the front. They don't when compared to a standard factory coil suspension, but that's usually not what people are talking about.

If you needed your truck to be low AND ride well then a dropped spindle on the front is the way to go. It leaves your factory engineered coil spring geometry and the longer travel alone, but just makes the wheel/tire higher in the wheel well - thus lowering the truck. For the rear with long control arms a double conv. bag works well and is capable of delivering enough travel smoothly if it is set up right, and you can raise the pressure to handle a heavier load. Short aftermarket springs in the rear will most likely be much stiffer than factory and result in a poor ride. Lowering blocks (coil rear) or long shackles (newer truck leaf rear) would ride the exact same as stock just like a dropped spindle in the front.

I hope all this helps!

[NewType72]

show going with the lowered stance is an amazing look it really tucks the tires very well but of course it is completely not functional being like that so Im sure you like displaying it as how you would drive it. and yes I agree straying from factory can be very bad I'm extrememly jealous that my great grandpa's stock truck rides as comfy as a spaceship compared to my modified and slightly lowered truck.

[NewType72]

I've haven't had the chance to do bags yet (many other projects and low cash as always) but so far my experience with being lowered has been crap I tried 3" drop springs with 2 1/2" drop spindles and got rid of them immediately since I went straight to fender lip went with 2" and I rubbed still using spring helpers got 1" drop springs and well under normal driving same result finally back to stock coils (cept they are from a 66 v-6 truck) and viola no rub unless harsh bouncing (crappy CA, roads) but I'm still using a minimum of 3 springs helpers so maybe this winter I will save a bit and swap to Air bags in front and keep my drop spindles where they are at hoping to solve all issues it seems that when we got these spindles it just would never come back up to ridable height. but I must say that factory height coils have me at a smoother ride once again and the sway bar helps a ton

[gringoloco]

Some hard to swallow, but good info here, Drew. As with all modifications, there is always some give and take. Glad you found what works best for your setup. Now, time for some drop spindles!

[Mike Bradbury]

I have been of the opinion that bags are great for looks but not so good for handeling. The reason I think this way is because I rarely see any auto crossers running bags. The tech is getting better and some guys have tried but still industry standard suspension is steel springs. I bought my 2.5 lowered springs off of a board member that couldn't stand the way his truck rode and was converting to bags. Since I put them on in addition to very nice mono tube Bilstein shocks it handles great. It rides a little rough, but it is all a matter of what you are expecting of your suspension. With a lowered truck you get about 3" of travel out of the suspension, and you have to arrest the inertia of a 5000 pound vehicle in that short amount of time. Sports cars are about half the weight and have an easier time absorbing the bumps. I would much rather have a slightly rough ride but know that my truck handles great, than a truck that has a soft suspension and gets loose when I need it most.

I have found that one of the most important and often marginalized components of the suspension system is the shocks. If the shock cannot effectively control the rebound of the spring (weather steel or air) then the ride is going to be subpar. Invest in a good set of mono tube shocks and it will make a world of difference. Think of the spring like Drews rubber ball metaphor, the harder you bounce it the harder it wants to rebound. With ineffective shocks the suspension is acting like a kids paddle ball game, it will bounce up and down and the tire will not have adequet friction on the road surface throughout the travel of the suspension. That is just the handling aspect, the ride is effected as well. When you hit a pot hole or speed bump the shock has to control the energy contained in the spring, if it doesn't then you will get that jarring feel as the wheel rebounds from the compression.

I think the best thing for New Type's suspension set up would be a new set of wheels so that the truck can get a full range of motion. I know we have discussed this before on your build thread but I really think that until you get the right wheel tire combo, you are just going to be throwing good money after bad. Either that or you need to remove your inner fenders and get a custom made set so the wheel can travel up into the well further.
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