Resting your foot on the clutch pedal while driving is a common habit for many drivers. However, it can lead to increased wear on the clutch and other drivetrain components. Here’s an in-depth look at what happens when you rest your foot on the clutch.
Increased Wear on the Clutch Disc
The most direct impact of riding the clutch is increased wear on the clutch disc. The clutch disc is sandwiched between the flywheel and pressure plate. When you press the clutch pedal, the pressure plate releases from the clutch disc, allowing you to shift gears.
However, resting your foot on the pedal applies partial pressure on the clutch disc. This causes the disc to slip against the flywheel, generating friction and heat. Over time, this can lead to hot spots, glazing, and excessive wear on the disc’s friction surface.
| Clutch Disc Condition | Effects |
|---|---|
| Hot spots | Reduced friction; slipping |
| Glazing | Hard, glossy areas; reduced grip |
| Wear | Thinned disc; eventual failure |
Severely worn clutch discs have a reduced coefficient of friction. This makes it hard to engage the clutch smoothly, leading to jerkiness when pulling away from a stop. In extreme cases, the clutch may start to slip under high loads.
Premature Wear of the Throwout Bearing
The throwout bearing is what pushes the pressure plate away from the clutch disc when you depress the clutch. Riding the clutch puts continuous pressure on the throwout bearing.
This can cause premature wear, resulting in noise and sloppy clutch engagement. Eventually, it may seize up and prevent the clutch from disengaging fully.
Input Shaft Spline Wear
The clutch disc splines ride on the input shaft splines. Riding the clutch produces friction between these surfaces under load. Over time, this can wear down the input shaft splines.
Excessively worn splines may allow the clutch disc to move back and forth on the input shaft. This can lead to gear grinding when trying to put the transmission into gear.
Damage to the Flywheel Surface
The rear surface of the flywheel mates with the clutch disc. Constant slippage from riding the clutch generates heat that can cause hot spots on the flywheel. This leads to uneven wear and a rough surface.
Flywheels may need to be resurfaced or replaced if the damage is severe. Machining the flywheel reduces available material, and there are limits to how many times it can be resurfaced before needing replacement.
Increased Shifting Effort
Having the clutch partially engaged makes it more difficult to move the shifter. With the clutch disc spinning against the flywheel, components “load up”, placing tension on the transmission and shift linkage.
This tension prevents the transmission from smoothly engaging and disengaging gears. As a result, the shifter may feel stiff and notchy when trying to change gears.
Drivetrain Shock and Vibration
Riding the clutch also places strain on the transmission, driveshaft, differential, and axles. The slight but constant slippage sends impulses through the drivetrain. Over the long run, this can result in increased wear of universal joints, axle shafts, and differential gears.
You may notice increased drivetrain noise and vibration. In severe cases, excessive lash in driveline components may develop.
Fuel Waste
Having the clutch pedal partially pressed keeps the engine partially connected to the drivetrain. This places a small, but constant load on the engine, increasing fuel consumption.
While the effects are minor during highway cruising, fuel usage can increase significantly in stop-and-go traffic. Resting your foot on the clutch pedal while waiting at traffic lights wastes fuel.
Increased Engine RPM
The clutch creates a slight drag on the engine when partially pressed. To compensate, the engine computer (ECU) responds by increasing idle speed to prevent stalling.
The higher idle RPM causes additional engine wear over time. Carbon deposits may also build up on intake valves and combustion chambers.
Difficulty Starting From a Stop
Take your foot off the brake, and the car will immediately start to creep forward with the clutch pedal pressed. This makes for a jerky start when pulling away from a stop.
You’ll need to perform a little foot dance to transition from the brake to accelerator smoothly. It takes practice to avoid stalling or lurching forward.
Increased Stalling
Finally, holding the clutch pedal down increases the chances of stalling. As the clutch wears over time, the engagement point moves higher off the floorboard.
Resting your foot on the clutch pedal causes you to start engaging it too soon. Letting the pedal up becomes more likely to stall the engine.
Tips to Avoid Riding the Clutch
Here are some tips to help avoid riding the clutch pedal and prevent unnecessary wear:
- Keep your foot completely off the clutch pedal when not actively shifting gears.
- Use the brake pedal to hold the car when stopped instead of the clutch.
- Shift gears decisively to limit time spent with the clutch pedal pressed.
- Avoid “covering” the clutch by hovering your foot over the pedal.
- Tune your clutch for proper engagement to avoid slipping.
- Consider a clutch delay valve to prevent premature release.
Signs You Are Riding the Clutch
Watch for these signs that you may be riding the clutch pedal:
- Clutch and brakes wear out faster than expected
- The clutch pedal feels mushy and vague
- Shifting gears requires extra effort
- You hear chirping or squealing noises from the clutch
- The car wants to creep forward immediately when you take your foot off the brake
- You find yourself stalling more than normal
When is Riding the Clutch Acceptable?
There are a few times when riding the clutch pedal is appropriate:
- Very briefly when starting from a stop in tricky conditions (snow, ice, steep hill).
- Momentarily to rev-match when downshifting.
- When rocking the vehicle free if stuck.
- Briefly when performing a hill start.
- During slow-speed maneuvers where precise clutch control is needed.
In these situations, avoid prolonged slipping and only ride the clutch as much as necessary. Return your foot to a neutral position off the pedal afterwards.
Is Engine Braking Bad for Manual Transmissions?
Engine braking involves leaving the car in gear and letting off the accelerator to slow down. This uses engine compression to assist with deceleration instead of just the wheel brakes.
There is a common misconception that engine braking causes premature wear in manual transmissions. However, this is largely unfounded.
The gearbox components are designed to handle the high torques and loads during acceleration. The relatively minor forces from engine braking do not place meaningful strain on the transmission.
Using engine braking can reduce brake system wear and help avoid overheating your brakes when descending long hills. It is perfectly safe for your manual transmission in most normal driving scenarios.
Conclusion
Riding the clutch pedal is a habit many drivers develop without realizing it. But the long-term effects can be detrimental for your clutch and entire drivetrain.
By keeping your foot off the clutch except when actively shifting, you can help add thousands of extra miles to the lifespan of your clutch. Additionally, you’ll reduce the likelihood of costly repairs down the road.
With a little practice and awareness, you can break the habit of riding the clutch. Your wallet and drivetrain components will thank you.