Hey everyone, Im Lee. Im on the order desk here, but more importantly,
I'm also one the many employee investors at Gregg Distributors!
Welcome back to another edition of Gear up with Greggs.
Today were going to be talking about our line of Heavy Duty Shock Absorbers from Gabriel.
Did you know that Gabriels Heavy Truck Shock Absorbers are the shocks the fleet here at Greggs uses?
Thats because here at Greggs, we only use the best.
*DING*
So, lets start with the basics. What are shock absorbers and how are they used?
Shock absorbers are part of a trucks suspension system which are made up of its axles,
leaf spring,
and the shocks, obviously.
The shocks purpose within the system is to soften the bumps on the road,
reducing the excessive feedback the driver receives.
If we want to get real technical and make our Physics teachers proud,
they're designed to capture the kinetic energy received from the bumps on the road
and then release it as thermal energy.
As the first law of thermodynamics states, Energy Cannot Be Created Or Destroyed.
So, the shock absorber converts energy into heat, leading to a smoother ride.
It does this by using a piston and some oil. If we look at this example here, we see the piston
moving from the impact of the road, forcing oil through valves within the piston.
The speed the oil flows through the valves controls the amount of resistance needed.
There are other features of a shock absorber like the size of the bore,
the type of fluid used,
and the fact that some shocks even use gas;
which all affect a shocks absorbing characteristics!
But Ill get more into that a bit later.
First things first, how do you know when to replace your current shock absorbers?
Well, Gabriel recommends to replace them every 80,000 km. But, when it comes to large fleets that
are constantly on the road racking up kilometers, they may need to be serviced sooner than what
is recommended. So, to be safe, incorporate a routine visual inspection of the shocks
for any leaks or damages.
But what causes reduction in a shocks absorbency-characteristics? Well, a lot of it has to do with heat & cavitation.
The constant heating and cooling from everyday use will eventually wear the oil out causing
it to lose its viscosity over time decreasing the shocks dampening ability.
Cavitation occurs when the shock absorbs a large amount of impact
which causes the piston to extend too quickly for the oil to move into the pressure chamber.
This creates a pocket of air, or a vacuum, of low pressure which is where the problem occurs.
The vacuum is filled with air that was previously dissolved in the oil.
On the return stroke this air is crushed quickly,
creating a shockwave that damages the shock internals like its seals and gaskets.
This is why driving over excessively bumpy roads reduces the life of the shocks,
in addition to general wear and tear. When this happens, youll start to notice signs that the shocks
need to be replaced.
An obvious tell that your shocks need to be looked at is if you receive excessive feedback
from the road. Normally, if the shocks are doing their job properly, they will absorb
the impact and the feedback that the driver receives from the road will be far less noticeable.
For larger trucks and trailers that arent as aerodynamic, you might also notice excessive
swaying while driving and leaning when making sharp turns. This is because the shocks have
lost their shock absorbing ability over time, compromising their ability to respond to weight transfer,
which puts a hamper on the drivers ability to control the vehicle.
Another important sign to look for is uneven or premature tread wear.
This is caused by the shocks inability to control the suspension
which causes excessive bouncing leading to tread wear.
The next sign to look for is especially important during the winter season. Ice, snow, grit,
and debris can cause damage within the piston seal.
When the seal is broken, fluid may leak and compromise the shocks ability to control the
vehicle because it doesnt have the proper amount of oil to disperse the heat properly.
When this happens, youll notice a thick coat of grime mixed with the leaked oil,
compared to one in good condition with minor dirt and debris.
If you observe this, you'll want to take it in to be inspected immediately
because a damaged seal can cause further damage
to the shock absorber, and in some cases, damage to the trucks suspension.
There are numerous other signs but these are the most common when it comes to shock absorbers that need to be replaced.
It is important not to ignore these warnings,
as broken shocks can have some dangerous consequences.
Now that we know some of the most common signs of worn out shocks, how do you go about deciding
on what shocks to buy? Well to start off, shocks are organized by the weight of the
truck they're intended to be used on, the type of suspension the truck has and the trucks
intended use. We carry four lines of Gabriel shock absorbers here at Greggs designed specifically
for trucks, trailers, and buses. For light weight trucks with heavy front suspensions
that are going to be primarily used for delivery, the 83000 series with a 1 3/8 inch bore, would
be the proper choice. The size of the bore, which I mentioned earlier, is important to
a shock absorbers functionality because it is the shell that protects the piston which
effects the strength and durability of the shock. The series features the thinnest bore,
but is still capable of withstanding large amounts of impact making the shocks perfect
for lighter trucks. So, whether youre driving through a busy downtown or bumping along a
gravel road in the country, you can trust in the durability of this small compact series.
For trucks and trailers with low friction suspensions weighing between 19,500 lbs and
33,000 lbs, the 85000 Series is going to be your best choice. With a thicker 1 5/8 inch
bore and a larger design, the series has more durability and fluid capacity to keep up with
heavier payloads and harsh road conditions.
The next series is the 85700 series which is designed for heavy trucks and buses.
This series features a patented triple lip, nitrile rod seal as seen here, which provides extra
protection and fluid retention compared to others in the industry that only use nylon
braided seals. Since the shocks are going to be used for trucks and buses, you'll want
the strongest seal possible. The fluids used in this series are custom blended with a high
temperature resistance to withstand the extreme pressures that would normally break down standard
shock absorber oils. All this translates to more time on the road, and less time in the shop!
Last is the 89000 GasLx Series. These shock absorbers are designed for long life commercial
trucks weighing 26,000 lbs to 33,000 lbs. The thing that makes this series different
is that this series uses gas contained in separate chambers.
The gas aids the oil to withstand large amounts of impact by providing an extra cushion.
As we see here, when the piston forces oil through the valves,
it is slowed by the gas, providing extra shock absorbing capabilities,
which is why they are meant for heavy commercial trucks.
The addition of gas takes pressure off of the oil to absorb the majority of the impact,
thus reduces the effects of cavitation,
leading to a longer lifespan of the shock.
It is important to note, even though cavitation isnt as much of an issue with gas shocks,
an effect known as aeration can still occur. Aeration, causes the fluid to foam when the oil and gas mix
in the gas reservoir causing the oil to lose its viscous nature.
This happens over a longer period of time,
and is part of the standard wear and tear for gas shocks. No shock can be perfect,
but the GasLx from Gabriel will keep your truck shocks maintenance free for longer periods.
There are also three adjustable settings of how firm the shocks can be set.
Regular, Firm, and Extra Firm; depending on the intended use of the truck,
you will want to choose the setting accordingly.
That about does it for shock absorbers. Hopefully you were able to Absorb all that information
so you can Shock all your friends with what you learned. If you have any questions, please
feel free to come in to any of our locations or give us a call and one of our friendly
customer service staff will be happy to help you out. If you liked this video, then hit
that thumbs up, and if you want to keep learning with us, hit that subscribe button!
From all of us here at Greggs, have a wonderfully Canadian day.