Features & Functions

Air Cylinder Overview

The air cylinder is mounted on the right side of the single pedal and the primary double pedal. The auxiliary double pedal has the air cylinder mounted on the left side of the pedal. The air cylinder provides the beater return force and replaces the spring mechanism found on most pedals. The cylinder is an assembly that includes a diaphragm, check valve, piston, air pressure gage, pressure relief valve and a pump mechanism. Adjusting the air pressure in the cylinder is equivalent to changing the tension on a spring pedal. The cylinder is pumped up or charged with air pressure introduced into the cylinder’s compression chamber by the pump found at the bottom of the cylinder. Adding more air pressure into the cylinder or pumping up the pressure increases the return force. Letting air out of the cylinder lowers the pressure in the cylinder and decreases the return force. When the pump handle (ball) is moved from the downward most position to the upward most position, ambient air is pushed through the internal check valve and into the the cylinder’s compression chamber. Typically, about 3 to 5 PSI (pounds per square inch) is introduced into the cylinder with each complete pump stroke. The exact amount of pressure in the cylinder can be seen on the air pressure gage.

The recommended playing range is 30 to 120 PSI. When first adjusting the air pressure, it is recommended to start at a low pressure setting and increase the pressure by 1 or 2 pumps at a time, playing the pedal after each pressure adjustment to get the feel of the entire beater stroke. The reading on the gage will increase when the footboard is depressed and the beater travels toward the bass drum head. Starting at a lower pressure will result in about a 20 PSI increase in the return force when the beater makes contact with the bass drum head. Starting at higher pressures will result in up to 40 PSI increase.

A pressure of 120 PSI should not be exceeded when the pedal is in it’s neutral or starting position. Starting the stroke at 120 PSI will result in a maximum return force of 160 PSI. A good rule of thumb is to never charge or pump up the cylinder over 120 PSI. Pressures higher than this will cause the diaphragm located inside the cylinder to fail prematurely. Air pressure can be bled or let out of the cylinder by depressing the little black rubber ball that is enclosed in a brass cylinder, located below the pressure gage. This rubber ball and brass cylinder assembly make up the pressure relief valve. The purpose of the gage is to provide the drummer with the ability to quantify the exact setting of the pedal return force.

The air cylinder is designed to maintain the set air pressure. Adding pressure to the cylinder should be an infrequent adjustment due to the fact that the cylinder is designed to be an air tight system. Room temperature changes can affect the PSI in the cylinder. Elevated temperatures will result in seeing a slight increase in PSI on the gage. Conversely, lower temperatures will result in a slight decrease in PSI on the gage. This is due to expansion and contraction of air based on changes in ambient temperatures. The built in pump and pressure relief valve make it easy to set the exact PSI desired regardless of changes in temperature or elevation.

All air cylinder adjustments can be made with the pedal attached to the bass drum.

Air Cylinder
Air Pressure Gauge

Air Cylinder Adjustments

To increase the return force, add air pressure to the cylinder. This is accomplished by moving the pump ball handle located at the bottom of the air cylinder from the downward most position to the upward most position. When the pump gets near the top of it’s travel, resistance can be felt. As the pump is moved to it’s most upward position, air will be pushed from the pump into the cylinder compression chamber through a check valve. Once the air is pushed through the check valve the pump stroke is complete and should be moved back down to the downward most position. Repeat the pump process until the desired pressure is shown on the pressure gage. Each pump stroke, all the way down to all the way up will introduce 3 to 5 PSI into the cylinder and be reflected on the gage. The higher the pressure in the cylinder the more resistance will be felt when the pump reaches the upward most position. When playing the pedal, the pump handle should be in the downward most position. When pumping up the cylinder starting with zero pressure in the cylinder, it may be necessary to depress the pressure relief valve rubber ball to reseat the ball. If the ball is not seated properly in the relief valve, the pump will not be able to charge the cylinder. If the pump is still not charging the cylinder, press your finger or thumb over the pressure relief valve to seal it from leaking air. Pump up the cylinder 2 or 3 strokes and then quickly remove your finger from over the relief valve. The air pressure inside the cylinder will help seat the relief valve so that the cylinder may be charged with the desired pressure.

To decrease the return force, depress the rubber ball on the pressure relief valve. The pressure relief valve is located directly below the pressure gage. Depressing the relief valve ball lets air out of the compression chamber. A decrease in pressure should be seen on the gage. It is possible to bleed a small amount of pressure out of the cylinder by pushing lightly and quickly on the pressure relief valve. When the cylinder is charged at higher pressures, it will be more difficult to depress the ball on the pressure relief valve. This is because the pressure inside the cylinder is pushing the ball into the seat with greater force.
When pumping up the cylinder starting with zero pressure in the cylinder, it may be necessary to depress the pressure relief valve rubber ball to reseat the ball. If the ball is not seated properly in the relief valve, the pump will not be able to charge the cylinder. If the pump is still not charging the cylinder, press your finger or thumb over the pressure relief valve to seal it from leaking air. Pump up the cylinder 2 or 3 strokes and then quickly remove your finger from over the relief valve. The air pressure inside the cylinder will help seat the relief valve so that the cylinder may be charged with the desired pressure.

The pressure gage provides the ability to see exactly how much pressure is inside the compression chamber. Unlike a spring pedal, the gage provides the drummer with the ability to set the pedal to the exact PSI desired. As springs age, they lose their original force. Setting a spring pedal to the same position does not result in the same return force calibration due to spring stretch and wear. The pressure gage provides the exact amount of force in a repeatable manner, regardless of temperature or age of the pedal. It is important to not over charge the cylinder. When the pedal is in it’s neutral or starting position, 120 PSI should not be exceeded on the gage. Starting pressures over 120 PSI will result in premature failure of the cylinder diaphragm. The gage will reflect the increase in pressure as the beater moves toward the bass drum. Lower starting pressures will result in about a 20 PSI increase on the gage as the beater travels toward the bass drum. Higher starting pressures will result in about a 40 PSI increase on the gage as the beater travels toward the bass drum. If you look at the gage movement, you will see that the gage increases more slowly in the first half of the beater’s travel and ramps up more quickly just before the beater hits the bass drum. This illustrates the hyperbolic function of the air return verses the straight line function of a traditional spring pedal.

Beater Angle Adjustments

The starting position of the beater can be adjusted without any tools or drum key required. This is accomplished by loosening the T-Screw located at the top of the piston rod above the air cylinder. The T-Screw secures the bearing located at the top of the cylinder to the pedal main axle cam. The wedge shaped cam attached to the end of the main axle contains a slot that houses a lock nut. When the T-Screw is loosened about a 1/2 turn, the attached nut will slide inside the cam slot changing the starting position or angle of the beater. Once the beater is in it’s new position, hand tighten the T-Screw to secure. The beater angle can be adjusted with or without pressure in the cylinder. When the cylinder is charged with a higher pressure, it is a little more difficult to slide the T-Screw and attaching nut due to the cylinder pushing upward. This is accomplished best using two hands. One to loosen and tighten the T-Screw and the other to rotate the main axle and slide the nut inside the cam. Hand tight is sufficient to hold the new beater position. When playing at higher pressures, it may be necessary to add a little extra torque on the T-Screw to hold it in place, using hands only, no tools.

Drive Hub – True Center/Cam/Reverse Cam

The drive hub is attached to the beater holder with 2 T-Screws and provides the path that the chain or strap will follow as the beater travels from it’s neutral position to where it makes contact with the bass drum head. The drive hub has felt inside the channel that the chain or strap rides on. The felt is to eliminate any noise from the chain or belt contacting the aluminum drive hub. The 2 T-Screws can be removed from the side of the drive hub and moved to one of the other bolt patterns. These different bolt patterns provide the ability to secure the hub in any of three different drive settings, true center, cam and reverse cam.

A true center setting provides the most uniform feel as the beater approaches the bass drum because the distance from the main axle to where the chain makes contact with the drive hub remains constant throughout the entire beater stroke. The cam setting provides an accelerator type motion and feel due to the fact that the distance from the main axle to where the chain makes contact with the drive hub decreases as the beater approaches the bass drum. This setting provides the fastest beater return. The third setting is the reverse cam. This setting is the opposite of the cam setting where the distance from the main axle to where the chain contacts the drive hub increases as the beater approaches the bass drum. Although this is not the fastest setting, it provides additional power and force to the stroke.

The side of the drive hub has engraved lettering showing which holes to use to get each of the three different settings. The drive hub was designed so that the setting can be changed without any tools or drum key. Hand torque is sufficient to secure the T-Screws on the drive hub. It is not necessary to detach the chain from the drive hub when changing the drive setting.

Drive Hub Lift Assist

The drive hub includes a feature that provides additional lift assist to the beater as it starts it’s path away from the bass drum head, preparing the pedal for the next stroke. This additional lift assist gives the beater return somewhat of a turbo boost that increases the speed the beater returns after striking the bass drum head.

The lift assist feature is in addition to the lift provided by the 3 different drive hub settings. The drive hub has 3 drilled and tapped holes at the front of the hub under the chain, closest to the bass drum head. A set screw is secured into one of the 3 tapped holes which creates a cam lobe effect. As the chain or strap rides over this cam lobe created by the set screw, the beater return is accelerated, creating an instantaneous lift, returning the beater faster for the next stroke. The top set screw position pulls the beater off the head the earliest. The other 2 settings pull the beater away from the head a little latter in the stroke. The set screw can be completely removed from the drive hub if this feature is not desired.

Changing the lift assist set screw is usually an infrequent adjustment. A hex key or Allen wrench is provided for removing and installing the set screw. This is one of the few adjustments that require a tool or hex wrench. The set screw should be installed under the felt in the chain/belt track so that the felt and chain are on top of the set screw.

Footboard Angle Adjustment

The pedal footboard angle can be adjusted into any of 3 positions without tools or a drum key. The chain rides in the track of the drive hub. One end of the chain attaches to the footboard while the other end of the chain attaches to the drive hub by means of a pin that goes through the last chain link and threads into the drive hub.

The pin has a round knurled knob attached to one end. This pin can be inserted into any of the 3 holes on the drive hub to set the starting footboard angle. The pin can be disconnected from the chain and drive hub by unscrewing the black knurled knob and pulling the pin out of the last chain link. When the pin and chain are installed into the first hole on the drive hub, closest to the drummer, the highest footboard setting or starting position is achieved. The other 2 holes move the footboard downward, decreasing the starting footboard angle.

To secure the chain and pin to the hub, align the last link of the chain inside the hub track and with one of the holes on the track hub, then insert the pin from the right-side of the pedal (from drummers playing position) through the right-side of the hub, through the last chain link and then into the other side of the hub. Once the pin is all the way through the chain, the pin can be screwed into the hub using fingers only to secure the chain to the hub. It does not require a lot of torque to retain the chain in the drive hub, hand tight is adequate.

Footboard Slip/Grip Adjustment

The pedal footboard has a smooth finish to provide the drummer with the ability to incorporate different slide type techniques, however, it also offers the ability to add some grip between the drummers foot and the footboard if desired. This is accomplished by giving the drummer the ability to add 1, 2, 3, 4 or 5 nylon set screws that attach to the footboard to provide a slightly raised surface texture to the footboard, adding footboard grip.

Each Airlogic pedal comes with 5 nylon set screws that can be installed into the drilled and tapped holes on the footboard. They are installed using a straight blade screwdriver. The nylon set screws are installed from the bottom side of the footboard. It is best to hand start the nylon set screws into the holes where more grip or less slip is desired. Once hand started, the set screws can be fully seated into the footboard with a screwdriver. When fully seated, the dog nose end of the set screw should be slightly above the footboard playing surface.

It is recommended that the chain pin be removed from the drive hub to disconnect the footboard from the drive hub, allowing easier access to the backside of the footboard. It is acceptable to install 0,1 2, 3, 4 or all 5 set screws based on the amount and location grip is desired. Once the set screws have been installed from the underside of the footboard, reattach the chain and chain pin to the drive hub.

Hoop Clamp Attachment and Hoop Clamp Adjustment

The pedal has been designed so that the process of attaching the pedal to the bass drum can be done with the drummer sitting on the drum throne, no tools or drum key required. All attachments can be done from topside of the pedal. To attach the pedal to a bass drum, loosen the 5 lobe knob located on the pedal right side upright. When this knob is turned counterclockwise, the hoop clamp will open wider. Turn the knob until the hoop clamp is fully open. Lift the batter side of the bass drum up slightly and slide the pedal base under the hoop. Push the pedal forward until it is fully seated against the bass drum hoop. Turn the 5 lobe knob clockwise until the clamp head just makes contact with the inside surface of the bass drum hoop. The clamp head that makes contact with the bass drum hoop can now be adjusted fore and aft (towards the bass drum head or away from the bass drum head).

There are 2 L shaped screw heads on the side of the clamp arm, the clamp head is attached to the clamp arm and the clamp arm is attached by 2 L head shaped screws to the clamp body. Loosen each of the 2 L screws 1/2 turn. Slide the clamp arm so that the clamp is in the center of the width of the bass drum hoop. Hand tighten the 2 L shaped screw heads by hand to lock the fore/aft position of the clamp in the center of the hoop. Turn the 5 lobe clamp knob by hand clockwise until the clamp is tight to the hoop. Do not over tighten. The fore/aft adjustment does not have to be made again unless the pedal is attached to a different bass drum. The purpose of this adjustment is the have the clamp head centered on the width of the bass drum hoop for best clamping force.

Bass drum hoops are not all the same width so this adjustment insures a better fit to each bass drum. To remove the pedal from the bass drum, loosen the 5 lobe knob to open the clamp mechanism.

Chain Drive and Strap Drive (Conversion)

All Airlogic pedals are shipped with the chain drive configuration installed. Included is a strap that can be installed in place of the chain. The strap offers a different feel than the chain drive configuration. To convert from chain to belt or from belt to chain, a hex wrench/Allen wrench is required and is included with every pedal. Both the chain and the belt attach to the footboard in the same manner using 2 4-40 screws, washers and nuts. The chain requires longer screws than the belt to attach to the footboard. The belt is provided with the correct screws loose assembled to the belt.

To remove the chain from the footboard, use the hex wrench to loosen the 2 4-40 screws from the footboard. It may be necessary to hold the nuts with pliers to remove the screws. The nut is a locking nut followed by a lock washer and a flat washer. The flat washer makes contact with the chain. The belt is installed to the bottom side of the footboard with the smooth textured side of the belt against the footboard bottom surface. The screws are assembled in the proper orientation in the belt when shipped. The 2 4-40 screws go through the footboard from the top side of the footboard, the strap should be against the bottom surface of the footboard followed by a flat washer, a lock washer and then the lock nut. Secure both screws to the strap and footboard with the supplied hex wrench. Do not tighten excessively. The strap should be squeezed somewhat but not flattened. Remove the chain pin and chain from the drive hub. The strap should ride in the chain track on top of the felt. Attach the free end of the strap to the drive hub with the supplied 4-40 screw. There are 3 holes punched in the strap, any of these 3 holes can be used to attach the strap to the drive hub. The hole closest to the end of the strap will set the footboard angle at it’s lowest starting position. The other 2 holes will raise the starting position of the footboard.

There is a drilled and tapped hole on the end of the drive hub, closest to the drummer to attach the strap. The strap should be against the hub followed by a flat washer, a lock washer and then the screw head. Secure the screw and strap to the drive hub with the hex wrench. Do not over tighten. Replace the chain pin into 1 of the 3 holes in the drive hub. The pin will fit over the strap and is not required for the strap drive configuration. The chain pin will be needed when converting back to chain drive. When the strap is installed properly the textured side of the strap should be visible.

Double Pedal Spreader Bar (Installation)

The double pedal spreader bar that connects the primary pedal to the auxiliary pedal requires a drum key to attach. The spreader bar should be orientated so that the “Airlogic Percussion” logo is right side up, facing the drummer when seated on the drum throne. At each end of the spreader bar are universal joints. Each universal joint has a drum key tension rod screw that is used to connect the universal joint to each pedal axle. The end of the axle on each pedal slides into the universal joint. The universal joint will bottom out against a snap ring that is installed on the axle. This insures that the universal joint will never make contact with the pedal upright.

The axle is round and has a flat section milled into it. Rotate the beater until the flat portion on the axle is lined-up with the drum key tension rod screw. Tighten the screw with a drum key making certain that the screw is only contacting the flat on the axle. Repeat the same process to connect the opposite end of the spreader bar to the other pedal. Make certain that the beater is rotated so that the drum key screw only contacts the flat surface milled on the axle. When the spreader bar is connected properly, each beater should be at the same angle when the 2 pedals are set-up the same, beater angle adjustment and footboard angle (same setting on both pedals). The pedals can be moved closer together or further apart by loosening the T head screws on the spreader bar. There are 2 T screws on each end of the spreader bar, 90 degrees apart. It is important that the T screws on the spreader bar only make contact with the flat surfaces milled onto the spreader bar axles. The axles that go into the spreader bar have 2 flat sides. Hand tight is all that is required to secure the axles inside the spreader bar, no tools required.

When disassembling the double pedal for transportation, it is best to only loosen the 2 drum key tension rod screws, one on each universal joint. Do not remove the drum key tension screws from the universal joints, loosen only. With the spreader bar removed, the primary and the auxiliary pedals can be used as 2 single pedals. Remove the left beater from the primary pedal and install it in the auxiliary pedal.