Driving a manual transmission truck is more difficult compared to an automatic transmission, as drivers need to shift gears. This requires using the clutch effectively, requiring more coordination and skill to manage.
Shifting gears on significantly larger trucks can be even more challenging to master, as drivers need to ensure they’re in the right gear according to the road conditions, cargo weight, and vehicle speed.
Apart from shifting gears, truckers also need to learn various techniques to cater to different road conditions. One of these techniques is called floating gears, also known as float or slip shifting.
Float shifting involves changing gears up and down without fully depressing the clutch. Drivers compensate for the partial clutch engagement and disengagement by controlling the throttle to increase or decrease the engine rotation speed.
Although the practice of floating gears sounds straightforward, it requires precise timing and coordination between the throttle, clutch, and the shifting of gears. In this article, we will explain how floating gears work, when this technique is best used, and also share a step-by-step guide on how to perform it.
How Does “Floating Gears” Work?
Trucks with manual transmission consist of a gearbox that allows drivers to choose different gear ratios. Lower gears offer less speed but more torque to the wheels. Conversely, higher gears offer more speed but less torque.
Although the current trend in the trucking industry is shifting towards fully automatic transmissions and automated manual transmissions (AMTs), most trucks still have a manual gearbox.
Both automated manual transmissions and manual transmissions can improve torque and speed control when transporting heavy loads, climbing steep hills, or starting from a complete stop.
Float shifting is based on throttle manipulation and controlling the engine’s speed and power output during gear shifts. This technique involves slightly reducing the throttle before the gear shift to reduce the engine load.
The transmission’s synchronizers then match the gear and engine rotational speeds. To execute float shifting successfully, the gearshift must be timed precisely to ensure the engine RPM and transmission speed match. Once both are synchronized, the new gear can be engaged without interruption.
Floating gears can also be executed without engaging or disengaging the clutch at all during gear changes. However, this advanced technique requires more precision, coordination, and driving experience.
Mastering this driving technique enables smoother gear changes, improves fuel efficiency, and even reduces clutch wear.
Why & When Should You Float Gears?
Slip shifting requires truckers to engage gears without using the clutch pedal. Instead, they try to match the engine and transmission speeds to smoothly engage the next gear. Below, we explore when and why truckers use this technique.
Floating gears or slip shifting can only be performed on semi-trucks with manual transmissions. However, not all manual trucks are the same. Some are equipped with synchronizers to protect against component damage and simplify gearshift, which makes float shifting easier.
If done correctly, float shifting can simulate the feel of operating an automatic truck and allow drivers to enable quicker and smoother gear shifts without breaking their vehicle’s momentum. Moreover, it’s known to lower fuel consumption by ensuring drivers don’t lose speed. This driving technique can also make driving easier and less tiring in urban or high-traffic areas.
Skill & Experience
Float shifting is not for everyone. It requires a certain level of knowledge and skills. Unskilled drivers can do more harm than good by grinding the gears and damaging their truck’s transmission system. The jerky movement, as a consequence, can also cause potential accidents.
Wear & Tear
Floating gears can help prolong the clutch’s lifespan by limiting its use, especially when hauling heavy loads. Moreover, they can help drivers decide the optimum time for gear shifts based on their engine’s revolutions per minute (RPM) and load weight.
How to Perform Float Shifting
Before you attempt float shifting, be sure that you are fairly comfortable with shifting gears normally and that you have memorized your gear shift positionings. Below is a simple step-by-step guide on how to float shift a truck:
- First, regardless of your driving skills and experience, ensure you practice in a safe environment, such as an empty parking lot or on private property, to avoid potential accidents.
- Put the truck in first gear and start accelerating.
- Increase the engine speed gradually until it reaches the optimal RPM for a gearshift.
- Partially disengage the clutch. You can forego this step if you want to apply clutchless shifting.
- Next, ease off the throttle and put the gear in neutral temporarily.
- If you’re down-shifting, reduce the engine RPM further to match the engine speed before slipping the lever into a lower gear.
- Similarly, when up-shifting, you must accelerate in your current gear to synchronize the next gear with the higher engine RPM. Once you do that, you can slip the lever into neutral and immediately into higher gear.
Double Clutch Versus Floating Gears
Double-clutch gear shifting is another popular driving technique truckers use. Most manufacturers recommend it, as it facilitates smoother gear changes. Double clutching works by engaging the clutch and shifting to neutral, and then re-engaging the clutch before shifting into gear.
Doing this allows you to match the rotational speed of the engine and the gearbox. In contrast, float shifting requires you to shift gears without engaging the clutch at all. This technique is typically more difficult to master as it relies heavily on precision and engine speed synchronization.
Drivers must adjust the throttle and match the engine and transmission speeds before shifting. As a result, float shifting offers a quicker transition between gear ratios since double clutching requires two clutch engagements and disengagements.
In terms of ease of application, double clutching is more straightforward. Meanwhile, floating gears is regarded to be more advanced, requiring more skill, experience, and understanding of engine and transmission components.
6 Best Practices for Truckers
If you’re looking to master float shifting, you’ll find six best practices that you can use. Remember, practice makes perfect!
- Master Your Gear Shifting: One key aspect of executing this gear-shifting technique is to be completely comfortable with your lever positions. Knowing exactly where the higher or lower gears are without looking at your shifter or transmission lever is essential. As such, practice normal gear shifting until you’ve mastered it before moving to float shifting or any other technique.
- Perfect Your Throttle Control: Another prerequisite to becoming good at slip shifting is mastering throttle control, as this technique heavily depends on throttle control. This means the better you match the engine speed with the desired gear, the more successfully you will be able to execute gearshifts.
- Practice First: Failure to properly execute this can damage the engine and transmission. Damaging either of these components can force you to lose control of the truck. Therefore, before you try this on the road, practice in a safe environment, preferably on a closed road or parking lot. Secondly, you should start practicing on flat terrain before trying the technique on hills and bumpy roads.
- Time It Right: To master float shifting, you must learn to feel and listen to the engine, as this will give you an idea of when you’ll need to shift. This will allow you to time your shifts perfectly.
- Be Patient: Floating gears is not something you can learn overnight. This technique takes time to develop and master, so it’s best to be patient and keep practicing until it becomes a habit.
- Get Training: One of the best ways to learn how to float shift is by getting lessons and valuable tips from experienced drivers who have mastered this technique. The last thing you want to do is to slip shift without any practical knowledge, as this can result in engine and transmission damage.
Co-Founder & Writer
About the Author
Andrew is a multi-business owner with over 10 years of experience in the fields of logistics, manufacturing, operations, training, and education.
Being the co-founder of freightcourse has given him the ability to pursue his desire of educating others on manufacturing and supply chain topics.