Weight is one of the things that we don’t like to talk about, but when it comes to determining the capacity of a caster, it’s a must-have discussion. At first, calculating the required capacity of a caster would seem simple. Start with the weight of the equipment to which the casters are being fastened. Divide by four, and Bob’s your uncle.
But not so fast. There are lots of other considerations.
Load Weight. It’s not just the weight of the equipment that you have to think about. You must also include the weight of whatever is going in or on the equipment. And this isn’t a time to be modest about weight. Be sure to calculate the absolute maximum load that the equipment will carry.
Floor Surface. An uneven surface means that all four casters will not touch the floor at the same time, which means that a smaller number of casters will bear the load. Your capacity calculation must be based on the minimum number of casters that will be in contact with the floor at any time.
Wheel Selection. To reduce noise, avoid marking or provide a smoother ride, customers often choose soft tread wheels, like rubber and polyurethane. But here’s the thing. Those wheels generate more surface friction making a piece of equipment harder to move. The solution is to select casters with higher capacity.
Movement. A caster’s specified capacity usually assumes movement at a walking speed – up to 3 miles or 4.8 kilometres per hour. However, if your equipment is moving faster than that, let’s say as part of a towline, the caster’s capacity will be reduced. That’s because increased speed leads to increased wheel temperature and greater friction. Also, many starts and stops also increase surface friction and require casters with greater capacity.
Caster Components. Many components impact capacity. The choice of bearings, for example, can offset capacity requirements by increasing a caster’s rollability. In addition, using a stem will increase the capacity requirement by 25%. Be sure to discuss the effect of components when specifying a caster.
Practical Wisdom – Divide by Three. After almost 60 years in the caster business, we have lots of practical wisdom – particularly regarding capacity. So, here’s a gem that you should keep in mind. When calculating capacity, divide the load weight by three, not four. That creates a 33% safety allowance to account for uneven surfaces or unforeseen stops and starts. It may cost a little more but it will keep your employees safe, protect your investment in what is being transported, reduce maintenance costs, spare you a ton of aggravation and may even save a bundle of money in the long run.
For much more information about capacity, contact your local Algood representative or a member of our customer service team. Just remember that when you’re talking about capacity, it’s not a time to be shy about weight.
For help choosing the caster that best meets your needs, contact your Algood Sales Rep or reach out to our customer service team by email service@algood.com or by phone at +1 (800) 254-6633.