ATVs can be hard to steer at the best of times, especially when stationary. But you know your ATV and if it’s a lot stiffer than normal, you are correct to question it. I’m a mechanic and you are in the right place for ATV steering problem-solving.
Four common causes of hard to steer ATVs include:
- Flat tire
- Power steering fault
- Seized ball joint
- Wrong tires
In this post, you’ll learn why your ATV is hard to steer, you’ll learn how to diagnose the root cause and how to fix it right now.
1 Flat ATV Front Tire
ATVs like all vehicles have a recommended tire pressure setting for optimum performance and user comfort. The higher the tire pressure the smaller the contact patch on the terrain, that’s great for top speed, fuel economy, and maneuverability at low speeds, and likely offers a very bumpy ride that isn’t great for safety.
Conversely then an underinflated tire offers a greater contact patch with the terrain which increases resistance and hurts top speed, and gas mileage, and makes the steering heavy, especially at low speeds. Of course, low tire pressure is a safety hazard not to mention bad for the tire itself.
Diagnose: A soft tire isn’t always easy to spot, you’ll need to check the recommended tire pressure for your manufacturer and take into account the loaded and unloaded specifications.
Fix: Adjust tire pressure.
2 Faulty ATV Power Steering
Bigger more powerful ATVs mean they got heavier with bigger, wider tires which is great but it means we need some help steering these brutes.
The solution is power-assisted steering, some ATVs come with power-assisted steering as standard and on others, it’s an add-on.
If your ATV has power steering it will likely have a dash light symbol (EPS) and also illuminated green to indicate the current state of health.
ATV power-assisted systems aren’t hydraulic like a truck, instead, they are electric. ATV EPS systems are pretty sophisticated, they typically employ sensors, a motor, and a control module. The module collects input data such as speed, torque, records fault codes, and outputs power to the electric motor proportional to rider steering inputs.
The typical EPS system includes the following components:
Speed sensor – a speed sensor fitted to the transmission transmits the current speed to the EPS control unit. The control unit adjusts the amount of assistance proportional to ATV speed.
Electric motor – motor attached to the steering column and is integral to the steering system. When activated by the control unit, the motor assists the rider by turning the steering stem.
Torque sensor – the torque sensor senses rider inputs and signals the control unit.
CDI – CDI sends engine RPM to the control unit.
EPSCU (Electric Power Steering Control Unit) – the control unit receives speed and rider torque inputs and calculates the optimum electric motor assistance.
How to Diagnose?
It should be noted, most ATVs will shut the EPS system down to protect the motor if the EPS gets too hot. Excessive maneuvering could cause the system to overheat, if that’s the case the system will kick back in as the system cools.
We usually begin EPS diagnosis by running a visual check. Check for dash EPS warning lights. Check wiring and block connectors are in good shape too and from the motor, sensors, and control module.
Whenever you have an on-board computer that stores fault data, makes sense to read those fault codes early in the diagnosis process.
Typically disconnecting the control unit diagnostic loom and grounding it on the control unit calls the diagnostic function. The EPS warning light flashes out a two-digit code but that’s said not all ATVs will operate this way. You will need to read your operator’s manual to decipher the codes.
Bear in mind, your control module stores codes until they are removed, be sure you are reading the current fault code and not an old code. If in doubt, clear all codes and ride the bike once again to set the current fault, then go ahead and read the codes.
Typically clearing codes requires the operator to ground the control unit diagnostic pin on the control unit several times within a certain time frame, say 5 seconds.
But if you don’t want to read the fault codes, that’s OK we can still fault find by checking power, grounds, and running component resistance checks.
Power & Ground Checks
The motor and control module will require both power and good ground, these are both easy to check and are among the first items we check when fault finding. The absence of an EPS light on the dash panel is a clue that the power or ground is at fault.
Your EPS system will be fused and that’s first on our list of checks.
A simple test light is great for checking both power and ground on the control unit and motor.
EPS motor power side test
EPS motor ground side test
Control module power side test
Control module ground side test
Test speed sensor voltage – for this test we’ll need a DVOM set to DC and a helper.
Test as follows:
- Ignition on
- Red probe to ref voltage
- Black probe to ground
Reading should be 5v, if not check voltage along the loom back to back to the control unit.
If you still don’t have 5v, go ahead and now check your ground at the speed sensor. A test light works best here. And if that tests good suspect a faulty control unit.
If you do have 5 volts, go ahead now and move the red probe to the signal wire (center usually) and have the helper push the ATV forward.
Voltage should alternate from 0 to 6 volts. If not suspect a faulty speed sensor.
DVOM Resistance Checks
We also have the option of checking the resistance of the various components on the system. To do that we’ll need a DVOM set to measure resistance (Ω).
Check motor resistance – Check resistance between both motor terminals and also motor terminals and motor body (Ground). If outside spec, replace the motor.
Check EPS torque sensor resistance – somewhere between .875Ω and 1.625Ω is typical, but check your model’s specs.
Fix: Repair wiring, replace sensors, electric motor, or control module.
3 Seized ATV Ball Joint
ATV suspension and steering pivots on ball joints, they are critical components and make steering and suspension possible. A ball joint is exactly what it sounds like it’s a metal ball with an attached arm that pivots inside a cup. The ball and joint and press-fitted together at the factory and are not repairable.
Ball joints are under tremendous stress and wear out a lot. Some heavy-duty ball joints employ a greasing point but most are grease for life, meaning they wear out and become loose, which causes symptoms like vague steering, wandering, uneven tire wear, and rattles.
But not all ball joints fail by wearing out, some just seize solid, especially common on ATVs that hit the drink and lay idle for periods.
Diagnose: Your ATV front end likely has eight ball joints, that’s four on each side.
They are as follows:
Suspension
1 Upper A-arm ball joint
2 Lower A-arm ball joint
Steering
3 Inner tie rod ball joint
4 Outer tie rod ball joint
With so many ball joints makes sense to isolate the left side from the right side before further testing. To isolate the left side from the right side we’ll remove one outer tie rod.
The process is as follows:
Jack up the front of the ATV and remove either the left or right wheel. Locate the outer tie rod ball joint and remove the nut.
Use a ball hammer to strike the knuckle to loosen the joint.
With the tie rod removed from the knuckle, (check it pivots freely on the inner ball joint if it doesn’t replace it) the hub is free to turn independently from the opposite side.
Steer the hub (wheel) by hand, is it stiff? If not, check the opposite side.
Assuming you found one side to be stiff, which is common, jump on down to ball joint checks here.
If however, neither side is stiff, check the tie rod ball joint you just removed, is it stiff? If so replace.
Otherwise, investigate your steering column bearing positioned at the base of the steering stem.
The most likely cause is lower suspension A-arm ball joint seizure.
To test release the knuckle from the ball joint and check if seized, I’ve covered that previously in the following post How to check ATV ball joints? (covers the upper A-arm but the process is similar)
Fix: Replace the ball joint (How to check ATV ball joints?)
4 Wrong ATV Tires
Bigger tires offer greater ability when the terrain gets soft, but there is such thing as too much tire. Bigger boots as you know offer a bigger contact patch, but you also know that a bigger contact patch has a downside too – greater resistance.
Some typical complaints I hear when riders fit bigger tires, include :
- Steering feel heavy
- Down on power
- Lower top speed
- Harder on gas
ATV owner’s manual will likely not recommend you increase tire size and that’s because the steering, suspension, engine output, and transmission gearing have been designed to work with the OEM tires. Increasing the tire width means your ATV no longer operates within the manufacturer’s tested component tolerances.
You’ll find fitting bigger tires will not only have the aforementioned negative effects but in addition, will wear out components prematurely, components like ball joints and bushings, they may also cause frame welds to fracture.
Diagnose: Check your owner’s manual recommended tire size.
Fix: Fit original (OEM) tires and wheels.
Other Possible Causes Of Stiff ATV Steering
- Binding cables – ATV cables and brake lines are cumbersome and as you know they are routed from the handlebar controls down alongside the steering column. Common reasons for steering binds include incorrectly routed cables and foliage caught in the steering column.
- Steering column bearing – A bearing at the base of the steering stem and a bushing at the top of the column are responsible for maintaining the steering column securely and allowing for free column movement. Check the bearing and the bushing are in good condition.
- Driveshaft CV joint – The driveshafts are as you know responsible for getting power to the wheels. CV (Constant Velocity) joints allow the drive to flex both with the suspension but also with the steering. A failing CV joint may cause steering binding. Check the CV joints.
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John Cunningham is a technical writer here at ATVfixed.com. He’s a Red Seal Qualified Service Technician with over twenty-five years experience. He’s worked on all types of mechanical equipment, from cars and trucks to ATVs and Dirt bikes.