Focus On: Crown PTH50 Hand Pallet Jack
May 16, 2024
Welcome to our Focus On! series of blog posts. I know that last time I said we'd likely be talking about another Crown forklift, but instead we're going to be talking about the humble tire, that simple piece of hardware that keeps us all moving; because we saw something we just needed to talk about.
Tires, on your car or forklift, are one of those things most people don't think about too much until they need to. A flat tire on your forklift can mean a lift truck sitting idle or carving lines in your floor if an operator keeps driving on it. Luckily for many forklifts they have solid tires (usually called either a "cushion" or "resilient" type of tire, more on these below). If you do have a solid type tire there are other problems you need to think about like flat spotting, chunking, or compound de-bonding, but you never need to worry about flats.
Every once in a while though we here at Industrial Truck Service (whether it be our Winnipeg, Regina, or Saskatoon branches) see a tire that just gets to us. The tires that got to us recently are detailed below. In this customer's defense there was a problem with email that meant they weren't receiving our quotes to replace their tires; once that was fixed they got them replaced immediately.
As always we're here to help with your material handling, so if you think your tires need replacing or even just some tips on what to watch for, give us a call and we'll have a Technician or one of our CSS people out to see you.
Worn and new cushion tires
Spot the difference: Easy Mode
So the tire on the left rolled (mostly) into our shop a while ago. The tire on the right is what it looks like new. A pretty huge difference right? This is what happens when a tire is kept in use well past any safe level.
As you can see on the worn tire the rubber compound has been worn all the way down, right to the metal band where the tire meets the wheel hub. In some places it has even started to wear the metal band too, which means this forklift was probably REALLY loud to drive. Lots of thunking and grinding noises, especially on concrete. This picture is also a testament to the quality of the tire however, as even with parts of the rubber completely missing the rest has stayed bonded to the metal band.
Camso, who makes this kind of tire, recommends replacing these tires once 2/3rds of the original rubber has been worn away. They're even got some blog posts about it. This is handy information because many forklift dataplates will give you the intended dimensions of the tires on the truck; even if your dataplate doesn't do this you can contact us to find out what it should be. We'll either have it in our records or will usually be able to find out what tire should be on your forklift. A measuring tape and knowing how to read the tire size is all you need.
In the picture above, these are 21 x 7 x 15 Magnum PON 555 tires. This means that the outer diameter is 21", the width is 7", and the inner diameter is 15" (the 533/178-381 you can see on the side of the tire is the same size in millimeters). By Camso's standard this tire should have been replaced when the rubber was about 1" (25mm) thick.
Obviously that didn't happen and when our Road Technician reached the customer's site to replace these tires the truck was being used. After tagging out the forklift, jacking and blocking it up and removing the tires to get them pressed here at our shop, we knew the moment we saw these that we needed to talk about tires.
Part of this is about training: your operators need to know what to look for. They should be doing their pre-shift inspections before getting on the lift truck for the day, and tire wear is one of those things that should be checked. Some tires (newer models from Camso mostly) have a wear line or mark right on the tire to take the guesswork out, but these tires in particular don't. Some re-training would let these operators know that if a tire is looking this small, its probably past time to check with your service provider if they need it.
There was another give away for this particular case that could serve as a warning sign that your tires really need replacing. Because forklifts have a mast mounted to them there's a certain minimum amount of floor clearance they need to maintain or the bottom of the mast will start scraping the floor as you travel. Especially around ramps and the like is where that sudden scrape can be noticed, but if you're seeing new metal-on-concrete marks on your floor you need to start looking at the tires on your forklifts. The tires in this case were worn down so far that the mast and carriage of the forklift had started to drag on the floor and wear down; the sideshift hooks actually had to be replaced they'd been dragged so much.
Over-worn forklift tire 1
Over-worn forklift tire 2
Tire wear is a safety item
Something we'd like you to look at is the two pictures above. For the tire on the left you can see how randomly it is worn; metal showing through in some spots and even an uneven wear on the metal band where the rubber is gone. For the tire on the right it shows a far more even wear pattern, having a roughly even amount of rubber left all around.
This is most likely caused by how the forklift is typically driven. Lots of turning or cornering in one direction will put more stress in one direction than the other, as will acceleration or braking through turns. It could even be caused by the design of the forklift: if only one drive tire gets power and the other side is slaved to it, uneven torque forces could be wearing one tire more.
The big reason this is a problem is because it can impact how stable your forklift is. The "triangle of stability" that keeps forklifts right way up depends on a stable and predictable base to bear the weight of the forklift and load, and every forklift's dataplate is written assuming that this stability is in place. If your tires are worn unevenly it means that your forklift is leaning over a few degrees even before you take into account things like how a load is positioned, whether or not it is stacked evenly, turning, speed, height, etc.
Because of all those factors, that couple of degrees at the floor can be magnified many times at the top of the mast, pulling your forklift further and further outside the triangle of stability until it falls over entirely. This can cause damage to racking, the forklift, the warehouse itself, and risks injury or death to the operator and anyone else in the building when that forklift tilts over.
Add to the risk of tip-overs things like damage to dockplates or trailers when worn down tires let the mast slam into something near the floor and you have a perfect storm of danger that is just waiting to happen in your business. All because of tires.
So what can you do?
Thankfully there are some simple things you can do to make sure that tire wear doesn't reach a dangerous state for you business.
- Operator training and aids: training your operators to make sure they're doing pre-shift inspections (as required by legislation) is a huge help to avoid tires getting over-worn. They're an inspection point that needs to be covered and a visual inspection is all it takes. If you want to take an extra step something you could do is get your tire specs and figure out what 1/3 of the tire remaining measures to. Then you can get a strip of durable plastic (or something like it) and cut or clearly mark it to show what 1/3 remaining looks like. Keeping this on the forklift takes out the guesswork and keeps the inspection process quick and easy.
- Regularly scheduled Planned Maintenance (PM) visits: Having one of our experienced Technicians stop by regularly means you'll stay up to date on the condition of your machine(s). Every PM we do includes checking the tires on your equipment and when we spot something that could become an issue we'll note it on our inspection forms. Copies of these are sent to you with every invoice (for your records) and our Technicians will be happy to discuss the results with you if you'd like.
- Buying the right kind of tire: just like for your car there are actually different grades of tire for your material handling needs. Everything from an "economy" grade for light or occasional use and up to the "extreme" environment tires (for foundries, mining, rough floors, 24/7 operations, etc...) are available and ready to go on your lift trucks. Different compounds, hardness, tread patterns, and overall design can all feed into the life of your tires and we can help you assess which might best fit your needs.
So there are options?
Earlier we mentioned that there are a few different types of tire, and below you can see a small selection of material handling tire types. All of these tires have somewhat different properties and specs to really let you dial in what you need for your forklifts.
- The first four of these tires are actually air tires. Otherwise known as "Pneumatic" or "Air Pneumatic" these are used on a fair number of forklifts, especially for trucks that are outside in a yard. The big thing about air tires is they do provide a more comfortable ride for your operators because the air filling them helps take some of the shock out of hitting potholes and bumps. The downside? Flats. Especially in places like wreckers or machining work where there's going to be metal shards or sharps around this can be a big problem.
- The next tire looks like it has holes in the side because it does. Camso calls these tires "SolidAir" because they're a solid type tire, but with the holes through them they provide more cushioning against shocks kind of like a pneumatic tire does. Other manufacturers may have a spider web or honey comb structure instead of the holes. This means they're more comfortable out in the yard, but it does mean the tire doesn't have as much life to it because it can't wear as far. Their design also means they can't be applied in the field unless there's a mobile hydraulic press available.
- The next eight tires are "Cushion" tires. They're kind of misnamed because they definitely don't cushion much at all. Typically they're harder compounds bonded to a steel band, and they're usually seen on trucks with higher lift capacities. Because they're so solid you usually only see them in paved areas because they really don't have any give in them to navigate uneven surfaces. The over-worn tires we talked about above are cushion tires. This type of tire also needs a tire press to be mounted because that metal band needs to be forced down over a heavy-duty metal wheel hub.
- The last four tires have been called a couple of things in the past. "Solid Pneumatic" was a little confusing to a lot of people and "solid" sort of made people think about cushion tires, the the industry has been moving toward calling them "Resilient" tires for a while now. In a lot of ways they're a halfway point between pneumatic tires and cushion tires; they're much tougher than pneumatic tires because they are a solid compound all the way through, and they're a more comfortable ride than cushion tires because they're usually a softer compound and don't have that solid steel core. This type of tire also needs a hydraulic press to get it fitted to the wheel hub.
There are more options of course. Above you'll see black and grey tires; the grey means that they're "non-marking" tires that won't leave black scuffs everywhere. Some non-marking tires come in white or a kind of orange colour as well which just means they're a different compound. Different manufacturers often put their own spin on things, with Camso putting their "Quick Heel" system on some tires (so you don't need lock rings or the like but are more difficult to press) and Continental having their "EasyWay" tires (which don't need pressing, but require you to use their proprietary mounting system).
So that's a quick little blurb about tires. Like most things there are a lot of details we could go into, but for Focus On we try to keep things pretty simple.
If you have any questions or comments you can Get In Contact with us for more details.
Keep your eyes on this space though, because the next Focus On could be waiting to answer questions you didn't know you had about forklifts. Until next time folks!
