rear truck suspension replacement with air bags for improved
handling, braking and load carrying. Self levels adjusting to
your load. I'm sure you've noticed semi trucks and trailers have
air bag suspensions.
The semi-tractors have had air bag
axles, air ride cabs and air seat for decades. Our pickup trucks
are rated for larger trailers and payloads each model year. Why
aren't we copying how semi trucks are made? Larger trailers and
payloads also means more rear axle squat and more axle travel
between empty and loaded. That difference between a loaded and
empty truck, changes the pinion angle effecting the drive shaft
alignment with the end of the transmission. When the angle from
transmission to rear differential isn't at the proper angle,
your truck will buck, shake and pitch. If too straight, you'll
This is a growing problem in the last 10
years with truck manufactures trying to split the difference in
pinion angle from loaded to empty by shimming the differential
angle with blocks between the springs and axle. This is not a
good fix for the problem, but a band aid. The right way to solve
the pinion angle problem is a total air bag suspension that self
levels to keep pinion angle the same all the time automatically.
Whether you are hauling 1 horse or 4 horses, the truck will be
keep our trucks longer, Auto Flex air suspension can make it
handle better than new. Fixing up your truck instead spending
$60,000 on a new truck makes sense now more than ever. Gas
engines can last 200,000 miles and diesels 300,000. We've been
talked into trading trucks often. Save money keep your truck
Auto Flex can dramatically improve your trucks ride and
handling. Keeping your truck level automatically, with better
braking, and handling curves flatter. Headlights won't be star
searching and oncoming traffic won't be flashing you. Have you
ever had your truck full of feed or a slide in camper and the
truck squatted and wandered, making driving work? The suspension
your truck came with is a compromise.
I tow trailers across the country, mostly on Interstates.
While we seem to be always driving in road construction during
the summer, even the normal asphalt is rough with potholes,
washboards and patches. I've broke battery cases, headlights and
blown tires on Interstates. You'd think you were on forgotten
county roads instead of federally funded super highways. Auto
Flex on my F250 is the cats meow. I might even take some
shortcuts cross country on the next trip. We also added Auto
Flex to my
Safety Hitch giving me air ride on my auxiliary
axle. This summer we'll add Trailer Flex to my gooseneck. Then
I'll be floating on air on these off-road Interstates.
Everything should last longer including me. I'll miss seeing my
belly bounce. Why do you think semi-trucks went air ride on
trucks, trailers, seats and cab? Truckers knew the Interstates
were getting worse each year with less road tax being used to
keep the roads maintained. If we can't elect officials that will
invest in infrastructure, we better get air ride.
We installed two Auto Flex Systems and tested on different
trucks, both diesels both 3/4 ton's that tow trailers as
part of their job description, both had aftermarket air
assist. One was a 2006 Ford F250 diesel, 129,000 miles new
front brakes. Second was a 2006 GMC 2500 diesel, 104,000
miles new front brakes.
|Tires and the leaf springs
||Factory leafs with 104k
miles squatted with a load
||Our test trucks had
aftermarket air assist
||These leafs with 129k miles
have flat spots each side of center
install as bow replaces the factory leaf springs, eye to eye
replacement. No welding or drilling, just chain the axle each
side to the frame, put a jack stand under the pinion and take
the leaf springs off. You'll reuse the rear hanger on the new
bow arm to fit where the spring was. Then you attach the lower
swing arm to the axle and the front of the bow, add the air
bags, compressor and tank. The tracking bar goes from the
drivers side bow to the passenger side lower swing arm. All
that's left is the leveling valve from cross member to the
differential, air lines and juice. AutoFlex comes with a dump
valve to lower the truck to ease hooking to a trailer. Each air
bag comes with a valve to lock air in or out. This allows you to
level a slide in camper on uneven ground or hold air in the bags
if you have a line leak.
with all brass fittings, no 45 or 90 degree fittings in line
from tank to air bags. This makes the air flow faster for the
automatic leveling system. Steel braided line from compressor to
tank for faster flow and pressure using a high performance air
compressor with a check valve. The compressor has 20 amp fuse,
fills a 3 gallon air tank. I went with the optional 5 gallon air
tank. With the performance compressor putting out 120 psi, I can
run an impact wrench to change tires. The system comes with a
female coupler for attaching air hoses for airing up truck and
Also comes with new hydraulic shock absorbers. The factory
gas shocks come off, air bags only push up, need hydraulic
shocks to dampen the suspension.
|Swivel that allows it to
flex with axle...
||..Has a brass bushing..
||...for the superior harden
||...with a grease zerk
Locking nuts on the bows, 3/4 in grade 8 bolts. The air
lines are 3/8" just like the semi-trucks. That keeps them
from freezing as well as the compressor tank and brass drain
petcock. My old system aftermarket air bag helper springs
would freeze the 1/4 air line each winter. Then they stopped
working until they thawed out, and you couldn't do anything
to speed that up. AutoFlex was developed in the cold part of
Canada, if they don't freeze there, I should be in good
shape in Colorado.
|Rear hanger is reused from
the leaf springs
||Air bags have bumpers
inside if they loose air
||Kit comes with hydraulic
||...to dampen the air bags
Auto Flex and Trailer Flex are manufactured by LBC Trailers.
They've been making logging trailers with lift-able axles since
1998. Fourteen years building semi trailers with air suspension,
I'd call that well tested.
Bow framework on top fits F250-550 and 2500-5500, just
different air bags, lower trailing arm attaches to truck axle.
Lower arm pivots at axle. Bushings in trailing arm are greasable.
Rubber bushing in tracking bar for quiet and rubber bushing with
steel sleeve for trailing arm keep the suspension tight. The
lower arm oscillates for uneven roads.
Auto Flex single stage air bags self center, are a rolling
bag to give on corners. Double bellows used in after market air
assist products, just support weight, aren't a real suspension.
Auto Flex is not an add on, but leaf spring replacement. No
drilling, welding or cutting your truck means is doesn't' affect
you warranty. On-board air compressor adjust the pressure inside
the air bags to match a truck’s load.
If compressor or air line failure, each bag has a valve for
filling or shutting off bags. Rubber stops inside air bags
are incase of air loss you can still drive to get repaired.
Automatic leveling valve You don't have to think about it.
Just enjoy it.
|Each bag has a shut-off
||Tracking bar options,
deeper one for aftermarket differential cover
||Tracking bar centers the
axle and stiffens side to side movement
||The tracking bar is
adjustable to keep the axle centered
|Tracking bar attaches to
the driver side bow...
||...goes across to the
trailing arm on the passenger side
||Semi-trucks use a tracking
||Semi's have used them for decades, why
not heavy duty pickups
trucks nosed dived braking from 60-0 mph with stock leaf
springs. With Auto Flex there was less body roll, most trucks
don't have anti-sway bars anymore. Handling improved, ride
improved with more wheel travel. In our brake test stopping from
60mph, factory leaf springs stopped 133.9 ft verses 120.7 ft
with Auto Flex, 13.2 ft. shorter with the Ford F250. More
controllable handling under braking.
During acceleration, the air bag pushes up on the truck body
pushing down on the axle for more traction and better fuel
If your trucks loaded and squatting, your drive shaft angle
to transmission and differential is in a bind and will cause
vibration, bucking and wear. Wheel hop and pinion angle
deflection are hard on U-joints. Imagine always being level
in your truck, no sagging, being level with different
trailers and heavy loads. you don't always haul the same
load with your trailer, so sometimes, the trailer is level
and sometimes it goes down hill. Brakes on your trailer work
best when equal load is on both axles. The dump valve will
lower your truck 5 inches to get under your gooseneck
without as much cranking on the trailer jack.
|No drilling, including the air tank and
||They tuck up out of the way along the
||Air tank along frame above
the exhaust pipe height
||Air compressor behind the tank in a safe
The steering problems are not just from the front, with a
loose rear suspension, the truck can wander. Auto Flex takes the
slack out of the rear suspension. The two test trucks we used
had over 100,000 miles on them and dramatically improved
handling and steering after Auto Flex was installed.
If you race your truck or just accelerate when
passing or the on ramp to the freeway, you've experienced axle
rap from flexing both sides of the axle on leaf springs. This
air suspension eliminates axle rap. when the rear of the truck
squats, this changes the frame angle which changes the drive
shaft angle to the pinion.
Adjustable tracking bar makes for tighter suspension. Your
rear end won't be doing the Elvis pelvis action. Auto Flex air
bag is behind the axle for leveraging the trailing arm and is as
wide side to side as leafs for stability and less teeter toter
action than you get with after market air assist bags that are
inside the leaf springs. Aftermarket air assist bags puts
pressure on one spot on the axle and frame. With Auto Flex, the
air bag pushes on the replacement bow not the frame.
We used an accelerometer to test movement. Auto Flex had a
rounding impact smaller range verses a sharper spike with
leaf springs. This could be a big improvement in the RV
market especially Class C motor homes.
|Powerful air compressor
with steel braided hose
||Tank drain is brass as are
||You can use the air gauge
as a way to judge the payload
||I had my outlet at the rear
to run impact and air chuck
See it work, SEMA Video
below; with the extra wheel travel you can see when the
truck accelerates shifting gears, the air bags push down
on the axle for more traction. During braking you can
see how level the trucks stays. Big improvement in
handling and braking while automatically load sensing to
self level your truck. Sport camera left, stayed steady
with the Auto Flex Suspension.
Ram 1500 with rear coils 2009 + have a big problem with
squatting at their max capacity rated by the factory.
Auto Flex replaces the coil with an air bag to
dramatically level the Ram and improve handling.
GMC Test Truck
|Dump valve for easing
||They come standard black
||The bows are different...
||...between truck brands
|Black frame blends in....
||... you have to look
||...to see the suspension is special
||A lift is nice for installs
|Tracking bar for factory
||Automatic leveling valve
||...tucked behind running
And the truck will stay level loaded or empty
We're going to test Auto Flex on a new truck
next, to see the difference.