Garage door rollers, often referred to as “wheels” guide your overhead door as it travels up and down the horizontal and vertical track system. Rollers come in a wide variety of materials, sizes and prices. Each type of roller serves a unique purpose in any given setting. Determining the type of roller you need for your door is crucial when purchasing a new set of rollers. This guide will help ensure you select the best rollers for your application.
Roller Diameter – 1″ 2″ 3″
Garage door rollers come in three common sizes; one inch, two inch & three inch. The diameter of rollers is easily determined by measuring the face of the roller with a tape measure. Since rollers are designed to operate through your tracking system actual measurements of rollers are slightly less than your track width. This allows the wheel just enough room to roll inside the track casing. In other words, a 2″ garage door roller diameter is made for a 2″ track, but has an actual diameter of 1 3/4 inches. The 1/4″ less diameter allows it to fit securely, yet allows ample amount of room for movement. Diameter also plays a big role in roller strength. Heavy commercial and industrial doors often use 3″ track and therefore require 3″ rollers. Always install the manufacturer recommended roller size to match your door system.
Shaft Length – 2″ 4″ 7″ 9″
The shaft or “stem” length on rollers can also vary widely based on application. The most common shaft size options are 7/16″ diameter and 4″ length. Shafts lengths come in sizes of two inch, four inch, 7 inch and 9 inch. The shaft diameter is designed to fit securely inside of your hinges roller carrier. Again the diameter of the roller shaft is slightly less than the diameter of the roller carrier. Most rollers have 4″ shaft lengths to allow the shaft to fit the full length of the roller carrier as well. Sometimes roller shafts/stems can be longer in cases where garage doors have double end stiles – that means two hinges side by side at each end of the door. Door manufacturers design doors with double end stiles to support heavy weight. A roller with a 7″ or 9″ shaft is designed to be installed through 2 hinges together at each end.
Materials – Steel vs Nylon
Rollers are for the most part made of steel although the wheel can be made in either steel or nylon. Each material has specific benefits and drawbacks and should be matched to your door based on manufacturer recommendations. Steel rollers can handle heavier loads and are more resistant to general wear. This is especially the case in commercial and industrial buildings where overhead doors face rigorous abuse. Nylon rollers have the advantage of being quieter, but do not stand up to heavy use as well as steel rollers and tend to be more expensive.
Not all garage door rollers have ball bearings inside the wheel casing. Some rollers known as “bearingless” rollers are a simple black nylon design and are used on very lightweight and infrequently used doors. A small door or door used for storage that doesn’t get used often would make sense for this type of roller. Ball bearings influence the quietness and longevity of your garage door roller. The two most common bearing quantities are 11-ball and 13 ball rollers. In general the more ball bearings inside the wheel, the better the quality of the roller. Taking that a step further, rollers called precision bearing rollers are designed for both heavier loads and higher cycles.
Long Stem Rollers
As touched upon under the topic of shafts, rollers called “long stem” were created for situations of double end stiles. Certain doors, especially heavy doors and wide doors have two stiles at each end. Each of these stiles have a fixed roller carrier or hinge. An extra long roller with a 7″ or 9″ stem passes through both of these hinges. Obviously, a 4″ roller stem would not be long enough to pass through two hinges fastened side by side. Again this is where long stem rollers have use.
Truck Door Rollers
Truck door rollers would be considered short stem in most cases. Todco truck door rollers and whiting truck door rollers are the two main types. These rollers are often short due to the limited side room in the back of a box truck or trailer. This means the vertical track system on both sides of the truck sits extremely tight to the side walls. Todco truck door rollers are often made for 1″ track system and have rollers that measure 3/4″ diameter. Whiting truck door rollers are made for 2″ track systems and measure 1 3/4″ in diameter. Both types of rollers are made for high durability due to the likelihood of truck doors being slung open and shut on a daily basis.
Car Wash & Moist Environment Rollers
Some rollers are designed to operate in damp or moist environments, such as a car wash. These rollers are designed to both seal out water and prevent rust and corrosion. This is accomplished by creating a near watertight design in the wheel section of the roller. Unlike regular roller with exposed bearings, sealed rollers have little to no gaps where water can enter. In order to slow the process of corrosion and prevent rust these rollers are often made of metals like stainless steel or plated in zinc. Due to the materials used and precision of a water tight seal, these rollers tend to be the most expensive.
Dust Cap/Shield Rollers
Not to be confused with sealed precision rollers in moist environments, capped rollers are designed to prevent dirt and debris from entering the bearing chamber. Agricultural buildings and workshops are prime examples of places where dust shielded rollers should be used. While these rollers are better at sealing out the elements than regular open bearing rollers, they do not have anywhere near the capability of sealed rollers. Any building with a high amount of dust should be using cap shield rollers. Even residential garage doors would find benefit in installing capped rollers on the bottom section of the door where dust & debris are commonly found.
Roller Cycle Ratings
Garage door rollers are assigned a cycle rating based on manufacturer testing. For example, a common roller on residential doors is the 2″ 13-ball nylon 4′ stem roller. The manufacturer specifications are as follows: 125 lb load,20,000 cycles 12′ Door. In this example one of these rollers is designed to handle a weight of no greater than 125 lbs for 20,000 cycles on a 12′ tall door. This doesn’t sound very good until you remember that a standard residential garage door is 7ft tall and has 10 rollers. 125lbs multiplied times 10 = 1250 lbs. So in this case these rollers can handle a door that is 12ft tall , 1250 lbs for 20,000 cycles. Most residential doors weigh less than 300 pounds. Even doors made of thick wood or larger doors found on a pole barn weigh less than 1000 lbs.
Nylon rollers are much quieter than steel rollers, but tend not to last as long. Any object that hits the nylon wheels will likely dent or chip the nylon coating. Rollers with ball bearings operate smoother, quieter and have higher cycle ratings, but are much more expensive. It is not necessary to have rollers with bearings or high life cycle if the door is lightweight or infrequently used. Rollers designed for moist environments are much more resilient to moisture and its harmful effects due to stainless steel metal and watertight design, but have added cost. Dust shield rollers are designed for environments where rollers come in contact with dirt and debris. They are not sealed from moisture, but are perfectly designed for smaller size doors in agricultural buildings. Long stem rollers are designed to pass through the hinges on double end stile doors. The added material in the length of the stem makes them cost more. Truck door rollers tend to have shorter shafts due to the constrained room of the side walls of the truck. It is okay to compare garage door roller life cycles to that of the mileage rating on tires. If you divide the total cost by the manufacturer cycle information you end up with a cost per cycle. For residential customers this is not necessary, but for warehousing, agricultural and storage facilities with potentially hundreds of doors it becomes important to keep cost per cycle as low as possible. In the end, always use the manufacturer suggested roller to prevent voiding of door warranty.