Casters and wheels are offered in many sizes and types. Although there is no magic formula for choosing the proper caster or wheel, there are some key considerations to take into account when making your selection.
1. Load Weight- the heavier the load, the larger the wheel needed to distribute the weight and roll easier. Divide the total weight by the number of wheels/casters you will be using to get the weight that each must support. It is always a good idea to select a caster or wheel that is rated for a capacity greater than your calculated load/unit to be safe. There may also be other factors that affect the size of the wheel you should select such as floor condition, environmental factors like moisture, oil, corrosion, braking needs, noise concerns, and floor protection. Some general rules of thumb for sizing your wheel are:
- for hand push applications for short travel: 3”-4”dia
- for hand push, longer travel: 5”-6”-8”dia
- for powered-tow at speeds up to 3mph: 6”-8”
- for powered-tow at higher speeds or outdoors: 10”dia min typically
2. Wheel Choices- typically hard tread wheels perform better on soft or smooth surfaces and soft tread wheels roll better on hard or rough or outdoor surfaces. Other factors such as floor protection and noise need consideration as well. Pneumatic wheels are quiet and maximize floor protection but typically have lower capacities. Steel and cast iron wheels carry great capacity but can be loud and sometimes, harmful to floors. Poly wheels are typically a good compromise giving moderate floor protection, low noise concerns, and good load capacity. And phenolic/texite wheels give great load capacity and excellent floor protection at a good price point.
3. Bearings- there are various types to select from based on your application. In simplistic terms, roller bearings are the “standard” for most industrial applications where greater load capacity is needed and moisture isn’t a concern. Then you can go to ball bearings which offer maximum rolling ease and requires less effort to start rolling and keep rolling. There is also a delrin bearing option best suited for wet, wash-down, corrosive conditions. For the most simplistic need, you can go with a plain bore bearing where the wheel bearing bore is in direct contact with the spanner bushing or axle. This is the least costly option but rolling resistance is at its greatest. There are also other options like oilex bearings, and precision ball bearings that have benefits and associated tradeoffs (cost vs rollability, etc) for consideration.
4. Floor Concerns/Environmental Issues- floor obstructions such as expansion joints may need to be considered as well as floor debris, metal shavings, moisture, chemicals, and other environmental factors. Typically, softer, resilient wheels roll over floor obstructions better than hard tread wheels. Larger wheels and stronger carrying capacities may also be required when rolling over debris as opposed to rolling on smooth, clear floors. Metal shavings can get imbedded in softer wheels that can damage wheels or shorten their lifespan so harder tread wheels may be more appropriate. And bonding agents that keep poly and rubber wheels on metal cores can be compromised by exposure to chemicals, impact loading, or overloading applications. There may be no ideal solution, so sometimes, just selecting the most favorable combination of wheels & bearings may be the best solution you can obtain.
5. Cost/Value- too often the purchase of wheels & casters is based on factors other than the ultimate goal of ensuring the load is moving smoothly and easily, and without jeopardizing the health and safety of the workers involved. Price is decidedly one of the key factors but matching the best wheel and bearing and capacity for the application ensures maximum productivity, minimizes long term costs, and provides the greatest return on your investment.
All of this can be confusing and overwhelming when trying to select the best wheels and casters based on application considerations, environmental concerns, and costs. Our staff can provide valuable assistance as you navigate this process. They are knowledgeable, competent, and experienced in matching applications and costs with the proper wheels and casters.