Thai
Elite Member
How to tell if you need new shock absorbers
by Jim Kerr
I was driving to work the other day on my normal route over the freeway when I crossed over some expansion joints on an overpass. My truck gave a slight jump as I crossed the angled joint and I suddenly realised that my truck was soon due for new shock absorbers. It wasn't bad yet but the telltale signs were there.
Most people don't realise their vehicle needs new shocks until they get much worse. The wear is usually so gradual that we become accustomed to how our vehicle drives and take it for normal. Every now and then I see another vehicle on my travels that is slowly floating up and down as it travels down the smooth highway. The driver seems totally unaware of the vehicle's motion but this vehicle has badly worn shocks.
Struts (MacPherson Struts), used on many cars are a larger version of a shock absorber. Struts have a shaft in them about the diameter of a large thumb because the strut has the job of holding the suspension upright. Shock absorbers have a shaft about the size of your little finger and are only used to control suspension movement. Struts can wear the same as shocks but usually last longer because of their larger surface areas on the shaft and internal parts to accommodate the wear.
So how do you know when it is time to replace your shocks or struts? Let the handling of the vehicle tell you. The typical test is to push down with all your body weight on one corner of your vehicle at a time and quickly jump off. The vehicle should rise, go down slightly and then return to its normal height. If the vehicle bounces more than this, then the shock or strut is worn. The trouble with this test is it only checks for severely worn units.
Most of our driving is done on relatively smooth road surfaces. The suspension is moving up and down only a small amount so all the wear in a shock or strut is concentrated in that small area. Hit a bigger bump and the shock moves to an unworn part of its travel and seems to work fairly well. It is the smaller bumps that need improved control. To check for wear in this small range of travel, you have to become aware of your vehicle's handling.
Because I test drive many new vehicles, I am used to the feeling of good shock control. Worn shocks become much more obvious. If you are driving the same vehicle every day, then you need to take a critical assessment of your vehicle's ride and handling over small bumps to determine how good your shocks are working. If your vehicle skitters a little bit or gives an extra little bounce when hitting a small bump, then you are soon ready for new shocks.
Shocks (and struts) control suspension movement by regulating the flow of oil through small orifices in pistons inside the body of the shock. When you open a door with an automatic closer, you are using the same type of control. The door opens easily but closes slowly. For suspensions, the shock allows the wheel to move upwards quickly as it hits a bump but lets it return to the normal ride position slowly so the vehicle doesn't bounce.
Heavy duty shocks and struts use larger internal parts for better control, while gas-filled shocks and struts use gas pressure inside the shock to prevent the oil from foaming. Foamed oil passes through the orifices inside the shock without any damping effect, so it acts like a badly worn out shock. I always recommend heavy duty shocks as a minimum. If you drive a performance vehicle or drive on washboard roads or rough off road surfaces, you could benefit from the extra control that gas-filled shocks provide.
Some vehicles have variable ride control. There may be normal, touring and sport modes. These vehicles use shocks or struts with adjustable valving inside the shocks. Many use a small motor on the top of the shock or strut that turns a rod down the centre of the shock shaft to vary the size of the internal orifices. Other vehicles use a solenoid to change the size of the orifice, while a few GM vehicles now have MagnaRide shocks that use magnetic fluid and electro-magnets to control the viscosity of the oil. All these systems provide greater ride comfort and control but replacement shocks can be very expensive!
Shocks do much more than give us a smooth ride. They are a critical part of the suspension control. A vehicle with poor shocks can be dangerous to drive. It may seem fine until you need to panic brake and hit a bump or need to make a sudden swerve to avoid something. Then the vehicle may go out of control. Next to better tires, new shocks will make the most significant difference in your vehicle's ride and handling. If you find it is time to replace them, buy the heavy duty or gas-filled units. This is one area when the extra cost is worth it.
by Jim Kerr
I was driving to work the other day on my normal route over the freeway when I crossed over some expansion joints on an overpass. My truck gave a slight jump as I crossed the angled joint and I suddenly realised that my truck was soon due for new shock absorbers. It wasn't bad yet but the telltale signs were there.
Most people don't realise their vehicle needs new shocks until they get much worse. The wear is usually so gradual that we become accustomed to how our vehicle drives and take it for normal. Every now and then I see another vehicle on my travels that is slowly floating up and down as it travels down the smooth highway. The driver seems totally unaware of the vehicle's motion but this vehicle has badly worn shocks.
Struts (MacPherson Struts), used on many cars are a larger version of a shock absorber. Struts have a shaft in them about the diameter of a large thumb because the strut has the job of holding the suspension upright. Shock absorbers have a shaft about the size of your little finger and are only used to control suspension movement. Struts can wear the same as shocks but usually last longer because of their larger surface areas on the shaft and internal parts to accommodate the wear.
So how do you know when it is time to replace your shocks or struts? Let the handling of the vehicle tell you. The typical test is to push down with all your body weight on one corner of your vehicle at a time and quickly jump off. The vehicle should rise, go down slightly and then return to its normal height. If the vehicle bounces more than this, then the shock or strut is worn. The trouble with this test is it only checks for severely worn units.
Most of our driving is done on relatively smooth road surfaces. The suspension is moving up and down only a small amount so all the wear in a shock or strut is concentrated in that small area. Hit a bigger bump and the shock moves to an unworn part of its travel and seems to work fairly well. It is the smaller bumps that need improved control. To check for wear in this small range of travel, you have to become aware of your vehicle's handling.
Because I test drive many new vehicles, I am used to the feeling of good shock control. Worn shocks become much more obvious. If you are driving the same vehicle every day, then you need to take a critical assessment of your vehicle's ride and handling over small bumps to determine how good your shocks are working. If your vehicle skitters a little bit or gives an extra little bounce when hitting a small bump, then you are soon ready for new shocks.
Shocks (and struts) control suspension movement by regulating the flow of oil through small orifices in pistons inside the body of the shock. When you open a door with an automatic closer, you are using the same type of control. The door opens easily but closes slowly. For suspensions, the shock allows the wheel to move upwards quickly as it hits a bump but lets it return to the normal ride position slowly so the vehicle doesn't bounce.
Heavy duty shocks and struts use larger internal parts for better control, while gas-filled shocks and struts use gas pressure inside the shock to prevent the oil from foaming. Foamed oil passes through the orifices inside the shock without any damping effect, so it acts like a badly worn out shock. I always recommend heavy duty shocks as a minimum. If you drive a performance vehicle or drive on washboard roads or rough off road surfaces, you could benefit from the extra control that gas-filled shocks provide.
Some vehicles have variable ride control. There may be normal, touring and sport modes. These vehicles use shocks or struts with adjustable valving inside the shocks. Many use a small motor on the top of the shock or strut that turns a rod down the centre of the shock shaft to vary the size of the internal orifices. Other vehicles use a solenoid to change the size of the orifice, while a few GM vehicles now have MagnaRide shocks that use magnetic fluid and electro-magnets to control the viscosity of the oil. All these systems provide greater ride comfort and control but replacement shocks can be very expensive!
Shocks do much more than give us a smooth ride. They are a critical part of the suspension control. A vehicle with poor shocks can be dangerous to drive. It may seem fine until you need to panic brake and hit a bump or need to make a sudden swerve to avoid something. Then the vehicle may go out of control. Next to better tires, new shocks will make the most significant difference in your vehicle's ride and handling. If you find it is time to replace them, buy the heavy duty or gas-filled units. This is one area when the extra cost is worth it.
