Aftermarket brake friction

Aftermarket brake friction: Know what you need and what you are getting

Air disc vs. drum brakes

meritorSo what about the difference between air disc brake chamber sizes and how does the performance of each differ?

“Air disc brakes are typically more effective than drum brakes, and therefore require smaller service chambers than drum brakes for the same application,” says Haldex’s Dunkleberger. “Chamber size and configuration should be checked when servicing air disc brakes.”

“Air disc brake systems use a brake actuator and wear compensation mechanism,” Stemco’s Geist says, “which is integrated into the caliper and designed based on OEM performance criteria. Drum brake systems utilize an actuator and brake adjuster that is separately serviceable lowering maintenance costs and offers capability for modifying the ‘AL factor’ based on desired braking performance.”

“The friction material utilized in air disc brake pads is engineered specifically to the application to provide the best overall performance for braking and field service life,” says Tony Ryan, SAF-Holland’s technical services and training manager. “The introduction of pads that are not properly specified for that particular application may consist of friction material compositions that could greatly diminish the overall performance characteristics of the ADB system. Air disc pad manufacturers use Jurid539 as a compound for trailer disc brake pads. Performance problems such as accelerated wear, and in some cases cracked rotors, may be encountered when fitting truck disc pads to trailer axle/brake applications. Truck air disc pads are a manufactured with significantly more aggressive compounds to meet RSD legislation.”

“Meritor offers both disc and drum friction materials (pictured left),” says Gopi Krishnan, Meritor’s senior director of brakes for North America. “We determine the customers’ vocation or application need and tailor a specific friction material to their specific vehicle needs.”

“Fleets need to consider that air disc brakes tend to use smaller air chamber sizes compared to drum brakes,” notes Joe Kay, Meritor’s director of engineering and brakes for North America. “Less air consumption results in improved efficiency. The smaller air chambers result in fleets having the option of reducing the number of air tanks used if equipped with air disc brakes. Fleets will have a larger variety of air chamber sizes, which result in multiple air consumption situations. They will also experience the mechanical advantage of air disc brakes over drum brakes in terms of air disc brakes using less mechanical force, resulting in smaller air chamber sizes over drum brakes. Smaller chamber sizes result in less air consumption which in turn results in improved efficiency.”

TMD’s Thompson agrees. “Air disc brake chambers are different than cam brake chambers,” he says. “The mounting studs and push rods are unique and not interchangeable. The standard drum brake air chamber types, 20, 24, 30, etc., tells that there are 20, 24 and 30 sq. in. of diaphragm area inside. This also lets the user know what the expected force output will be. For example, if 100 PSI of air pressure is applied to a type 30 air chamber, the output will be 3,000 lbs. Disc brake air chambers are the same in their ‘type’ designations. There are different sizes beyond the well-known cam brake sizes. When European disc brakes arrived in the U.S., they added sizes of Type 18 and Type 22, to better tailor the input force to the brake to get the output torque desired.“

Click “Next Page” to continue reading.

You May Also Like

Class 8 truck preliminary orders fall in June

While down both m/m and y/y, FTR said order levels are in line with historical averages and seasonal expectations.

FTR-June-24-Prelim-Class-8-orders

FTR reported that Class 8 preliminary net orders in North America for June totaled 13,100 units, down 33% m/m and 6% y/y. Class 8 orders for the past 12 months have now totaled 273,700 units. June’s orders are on the low side of normal market results, but the company said follows a five-month period of sustained strength in orders averaging 25% higher than the prior year.

Scania BEV trucks begin transporting goods for IKEA in Portugal

Scania said beginning an EV rollout in Portugal is challenging, as its EV infrastructure is still developing.

Scania-KLOG-IKEA-Portugal
Accelera, Daimler Truck N.A., PACCAR battery plant breaks ground

Construction is underway for the $2-3B plant, which will employ over 2,000 people. LFP Battery cell production is slated for 2027.

Amplify-Battry-plant-groundbreaking-daimler-paccar-accelera-1
Kenworth offers OOIDA members $1,000 savings on new sleeper trucks

Buyers can use the discount on new or special order Kenworth T680, T880 and W990 trucks with a 52-in. or larger factory-installed sleeper.

Kenworth-T880-mid-roof-sleeper-truck
NACFE: small depots are ready to scale electrification

Dipping your toes into electrification is one thing, leaping into running 15+ BEVs is another. Though NACFE says for many, the time is right.

NACFE-DEPOT-Scaling-Report-Cover-Run-On-Less-BEV-Electrification-fleet-trucks
Other Posts
FinditParts, Diesel Laptops partner to streamline heavy-duty truck repairs

Diesel Laptops’ Diesel Decoder plugs into a diagnostic port and sends data to an app. Customers can then order components from FinditParts.

truck-diagnosis-generic
ACT Research notes significant drop in U.S. trailer orders for May

May net trailer orders fell about 46% y/y, while ytd net order activity is down 25% from the same period in 2023.

ACT-net-trailer-orders-down-may-24
Daimler Truck N.A., Salem, Electrada partner to electrify logistics

The companies say the partnership builds on growing zero-emission vehicle integration, and furthers commitments to sustainable trucking.

Daimler-Salem-Electrada-EV-Partnership-2
Beyond a one-size-fits-all trucking decarbonization strategy

Much of the responsibility now falls on the fleet, but that should be a welcome change.

2024-ACT-After-the-Show-Floor-1400