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Brake Drums
Q: This brake drum has holes that are cast in, not drilled. Will that cause problems with the fit of the hub or wheel?A: Some KIC brake drums utilize cast holes in favor of drilled holes. Cast holes will be slightly larger than drilled holes due to manufacturing tolerances. A drilled hole size of 1.00 inch would be replaced by a 1.2 inch cast hole. This hole size change does not affect form, fit, or function of the drum.
Common misconceptions to understand with regard to hole size in brake drums:
- First misconception is that brake drums align to hubs by the engagement of wheel studs in similar sized bolt holes. Stud-to-hole clearance is typical 10X or more the physical clearance of the hub-drum pilot diameters. All drums have a piloting diameter that locates to a near matching diameter on the hub. Thus, the bolt hole is not designed or involved with locating the drum to the hub.
- Second misconception is that smaller bolt holes will do a better job at preventing wheel and drum rotation due to physical clocking of the stud inside the hole. However in reality, we know that repeated impact of a rotating drum against the bolt will break a bolt in 2 pieces - just like bending a paper clip back and forth repeatedly. The drum can only rotate against the hub when the wheel nuts become loose and no longer clamp the drum tight to the hub. Each wheel stud and nut, when properly tighten, delivers up to 50,000 lbs of clamping force. With 10 wheel studs and nuts, this becomes 500,000 lbs of clamping force. This clamp load produces high surface-to-surface contact friction that essentially glues the hub, drum, and wheel flanges together to prevent rotation. The surface-to-surface contact friction will prevent rotation during even the quickest panic stops. So regardless of brake hole size, the only way to successfully prevent slip and rotation is to keep the wheel nuts tightened correctly.
Q: I bought a balanced drum. Why does it not look balanced?
A: Some KIC balanced brake drums are balanced by eccentrically machining the squealer band of the drum. Each drum is checked with a machine to determine if it needs balancing. In some cases, the drum is within the standard 20 oz. in. and does not need to be machined. If machining is required, the drum is mounted "off center" in a CNC lathe, which then machines off a thin crescent of material from the band around the drum. This means that some balanced drums don't "look" balanced. Other methods of balancing drums include drilled holes and plunge style CNC mill cuts, but these are apparent when examining the drum. (See Technical Bulletin 200908 - Identifying Drums with Eccentric Balance Cut for more details
Q: What is the difference between the 60001-018 and the 53033-018 brake drum?A: KIC's standard drum metallurgy for all brake drums is ASTM Grade 3500b, which results in a more durable drum with the best braking properties available. The 53033 series drums are made with this grade of material. The 60001-018 uses ASTM Grade 3000b, which is the industry standard for brake drums. While both drums are interchangeable with each other as well as all competitive drums, the 60001-018 is a few pounds lighter.
Hubs
Q: What is the difference between "Ball Seat Nut", "Stud Piloted", "Hub Piloted" and "Unimount" hubs and/or wheels? A: Hub Piloted, also known as "Unimount" disc wheels are designed to center on the hub at the center hole or bore of the wheel. The wheel center hole locates the wheel on pilots built into the hub. Hub piloted wheels are used with two piece flange nuts which contact the disc face around the bolt hole. Only one nut on each stud is used to fasten single or dual wheels to a vehicle. All stud and nut threads are right hand. Hub piloted wheels have straight through bolt holes with no ball seat, which provides a visual way of identifying them.Stud piloted, or "Ball Seat Nut" disc wheels are designed to be centered by the nuts on the studs. The seating action of the ball seat nuts in the ball seat bolt holes centers the wheels. Stud piloted dual wheels require inner and outer cap nuts. Fasteners with left-hand threads are used on the left side of the vehicle and those with right hand threads are used on the right side of the vehicle.
Q: How much oil/grease should I use when installing KIC hubs?A:KIC recommends following TMC RP 631 for lubricant fill instructions. Following this recommended practice, there are two different fill volumes to be observed:
- Oil is filled to the maximum fill line on the hubcap sight glass below the axis of rotation (27 mm for 001 axles, 20 mm for 002/005 axles)
- Semi-Fluid grease is filled up to the rotational axes of the hub, but does not the include filling the hubcap.
Q: Can I convert my hub piloted hub to stud piloted and vice versa?
A: Some KIC hubs can be converted from Hub Piloted (HP) wheel mounting systems to Stud Piloted (SP) and vice versa. Hubs using 1-5/8" diameter studs are not convertible. In the cases where this is possible, the wheel studs will need to be replaced. Items to consider:
- Stud Pilot studs are 3/4" or 1.125" in diameter. Hub Pilot studs are 22 mm (.866"), typically described as M22.
- You will have to switch the wheel rims from Stud Pilot to Hub Pilot, or vice versa.
- SP wheel rims have a spherical recess that the "ball seat" nut engages to align the wheel. The HP wheels have no recess. HP flange nuts don't work well with SP wheel rim flanges as a result of the spherical recess.
- The wheel rim pilot diameters are different for SP (larger) and HP (smaller).
Q: What is the recommended method of installing a KIC hub?
A: For wheel hub bearing adjustment, KIC recommends the use of TMC RP618 (Truck Maintenance Council's Recommended Maintenance Practices). TMC members represent manufacturers and fleets, and have well written Recommended Practices for a host of truck issues and technical matters.
RP618 calls for the bearing cones to be adjusted to have endplay (ie no spindle nut torque creating bearing cone force against the bearing cups.) The process requires initially torquing the spindle nut to 200 ft*lbf while rotating the hub to help seat/align the rollers. The nut is then loosen 1 turn and the hub rotated. The nut is retorqued to 50 ft*lbf and backed off a partial turn (see full procedure and back off table in RP618). By doing this, ~.003" of endplay is created, when .001" to .005" endplay is required. RP618 recommends locking nut to maintain the adjustment as well as verifying the endplay with a dial indicator. KIC does not generally support SAE J2535, which describes setting wheel hub bearings in preload. SAE J2535 places the bearing cones into preload (ie no endplay), and provides no direct procedure to achieve the recommend preload forces. To implement SAE J2535 successfully, there must be significant study and testing done to ensure the bearing adjustment is done correctly. It is not meant for general wheel hub installation. SAE J2535 requires high degree of knowledge and precision and is not readily measurable. RP618 is highly repeatable by its nature and is measurable. Additionally, SAE J2535 warns that hub failure can occur, if its information is not used correctly. Thus, KIC recommends RP618 as a general wheel hub bearing adjustment procedure. Some wheel end products with bearing spacers or other special bearing devices made by other manufacturers require special installation procedures. KIC always recommends consulting the manufacturer's recommendations, before adjusting or re-installing a wheel end.
Q: Does hub or wheel material affect the nut torque recommendations for wheel mounting?
A: The type of material does not affect the nut torque recommendations. Hubs are typically made out of aluminum, ductile iron, and austempered ductile iron. Wheels are also made out of aluminum and steel. The wheel studs and nuts are designed to accommodate these different materials for hubs and wheels. Torque recommendations are based on the threaded diameter of wheel studs in the hub. Most KIC hubs utilize either 22 mm or 3/4 in. wheel studs, so the torque recommendation for tightening nuts should be 450 to 500 ft*lb. KIC publishes wheel installation instructions along with torque recommendations in the service section of our catalog (pdf), which provides more detailed information.
Q: What is load rating (dynamic capacity) of KIC hubs?
A: KIC hubs are designed to meet different load ratings for different axles. KIC does fatigue testing to assure that the hub and bearings will meet the life expectancy of the axle/tractor/trailer/etc. The hub ratings assume typical wheel(s) are used - e.g. dual wheel for rear and trailer hubs, and single tires for front hubs. If the hub is used in an unusual way, contact KIC for specific load ratings for the hub with different wheel/load offsets. For all standard applications, see the hub rating chart on page 3 of the KIC Product Catalog (pdf).
Warranty and Ordering
Q: What is your warranty policy?
A: KIC warrants its products with a lifetime limited warranty, meaning if there is anything wrong with the workmanship of the product, we'll replace it. You can download our warranty here (PDF) file
Q: Can I return product?A: KIC accepts returns of unused product with a 15% restocking fee. KIC does not accept returns without a Return Goods Authorization (RGA). Please call KIC customer service at 800-488-5422 to obtain an RGA
Q: Who do I call to track my container-load shipment?
A:Please call KIC customer service at 800-488-5422 and ask for the logistics department. We can give you the most up-to-date information on your delivery
