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You might not think of them that much, but your motorcycle’s wheels and tires play a crucial role in keeping you on the road and out of the ditch.
Therefore, it’s good that you know a few things about them.
Tune in to learn:
- The important job that the wheels have
- What a “wheelbase” is
- Some common wheel types – from spoked to composite (and their pros and cons)
- How to read tire dimensions and test your tire tread depth – with just a coin
- The differences between bias-ply and radial tires
Transcript
Hello and welcome to 30-minute motorcycling – a podcast for new aspiring and returning riders where you’ll learn something new about motorcycles and other two-wheelers in 30 Minutes or less.
And in this week’s episode, it’s all about wheels, wheels, and more wheels.
More specifically, the job of the wheels, the different kinds of wheels, and the pros and cons of each wheel type. We’re also going to briefly cover what a “wheelbase” is.
Have I said “wheels” enough? That’s because there’s a lot riding on them, and I’m not just talking about your bike.
But since there’s a lot riding on your tires too, we’re talking about those as well.
Specifically about how to choose the best tire type for your motorcycle,
about tire pressure,
tire tread depth and how you can measure it – by using nothing but a coin.
First thing’s first though – let’s begin with..you guessed it… the wheels.
Wheels General
Just like the ones for a car or a van, motorcycle wheels have an important job.
Not only are they responsible for handling braking and acceleration, they also have to support the motorcycle’s weight and provide a mounting point for the tires, brakes, and wheel bearings.
Generally speaking, the heavier the wheel is, the slower the suspension will deal with uneven surfaces, and the more energy you’ll need to accelerate and handle your bike.
Your “wheelbase”, which is the distance between the front and rear wheels also affects the handling of your bike.
The longer the wheelbase is, the more stable your bike will be in a straight line, but it will also be less responsive when cornering. With a long wheelbase, you’re also likely to experience what’s known as “wheelspin” – which happens when the wheels rotate with little to no traction.
This is why many heavy cruisers or touring bikes are built with long wheelbases – they may have poor cornering, but the extra stability makes up for it.
So now that we’ve got a general overview of wheels and wheelbase, let’s talk more about the most common types of wheels, starting with the spoked wheel.
Spoked wheels
Spoked wheels are characterized by tiny metal prongs inside the wheel called “spokes” (hence the term “spoked wheel”), and are common for dirt bikes, cruisers and even bicycles.
The pros of spoked wheels are that they’re very strong and durable – and even when they do go bad, they can be rebuilt.
The cons are they need regular and often frequent maintenance. Over time, these spokes will go dull and will require tightening with a special spoke wrench.
But not too much – tightening the spokes too much might throw the entire wheel out of balance. So if you need to tighten your spokes, check your owner’s manual for the exact spoke tension characteristics.
Let’s move on to cast wheels. stop
Cast wheels
Cast wheels are cast in a big piece, usually from aluminium, and are common on most road bikes, since cast wheels are more capable of supporting bigger tires.
Compared to spoked wheels, cast wheels require less maintenance.
However, if you crash a motorcycle with cast wheels, the entire wheel must be replaced, even if there’s no visible damage.
Cast wheels also have two subcategories – magnesium and composite wheels.
Magnesium wheels
Magnesium wheels are not just extremely light strong – they’re also extremely expensive.
Composite wheels
As for composite wheels, they’re made from pressed steel or aluminium and are a combination between a cast and a spoked wheel.
But even though composite wheels have spokes, they don’t require tensioning as a spoked wheel would. In fact, composite wheels require little to no maintenance.
Sometimes, if the rim or spokes are damaged on a composite wheel, these can be replaced without having to replace the entire wheel – but if it’s made from aluminium, this can be quite expensive.
Tires
So that’s the wheels in a nutshell, but there’s a lot riding on your tires too.
Motorcycle tires have a far more demanding job than car tires – since there are only two of them to support the bike’s weight, they tend to wear out faster.
In fact, the average life span of a motorcycle tire is 8000-9000 kilometers or 5-6000 miles. stop
When choosing tires, pick the most suitable type for the type of riding you normally do.
You ride on the street? Get street tires.
You ride off-road? – get offroad tires.
If you fit off-road tires to your street bike you have 2 problems;
1: The tires won’t grip paved streets as well
2: The offroad tires will be worn out much faster than a pair of street tires
Also, remember that if the wider your tires are, the greater your risk of hydroplaning will be.
Tire dimensions
To pick the right size for your tires, you must know what the tire dimensions are. Luckily, these are written on the sidewall, in a sequence that might look like this:
180/60R-16
The first number displays the tire’s width in millimeters.
The second number, which is usually preceded by a forward slash, is the tire’s aspect ratio – i.e. the height of the sidewall
The letter “R” or “B” indicates whether the tire is a radial or a bias-ply tire – something which we’ll cover later on in this episode.
And finally, the last number shows the tire’s rim size in inches.
So if a tire has tire dimensions of 180/60R-16, it has:
- A 180 mm width
- An aspect ratio of 60 – roughly 60% of the total width
- Radial-ply tire characteristics
- And a rim size of 16”
If you’d like to know more, I’ve included a link in the show notes to a video from Chaparral Motorsports that talks more about tire dimensions: [https://www.youtube.com/watch?v=CidSR5AM9Tg]
Tire Pressure
Just as it’s important to get the proper kind of tires, you must also inflate them properly.
An overinflated tire can cause:
- Stiff suspension
While an underinflated tires can cause everything from:
- Increased stopping distance
- Reduced stability
- Increased risk of the dreaded “death wobble”
So, therefore, check your tire pressure regularly and verify that it matches the recommended pressure as stated in your owner’s manual.
Let’s move on to the tread depth.
Tread depth
You might have heard the term “tread depth” mentioned a lot – but what is it?
Well, simply put, every tire has a groove cut into it called the “tread” which allows water to escape and keep its grip.
If this tread didn’t exist or if it’s too shallow, you’d lose traction and hydroplane as soon as the road gets a little wet.
And that’s why you need to make sure that you have enough tread depth.
Laws regarding minimum tread depth might vary depending on the country you’re in. but generally, speaking at least 3 mm or 0.12 inches of tread depth is recommended.
The best way to test your tread depth is by using a tread depth gauge. But if you don’t have one, you can use a coin.
Yes – you heard that right; a coin.
The type of coin you need to use varies depending on the country you’re in.
If you’re in the UK, you can use a 20p coin.
In Sweden, an old 5 kronor coin can be used.
And in the United States, you can test your tread depth with the “Penny test”. You probably have a couple of pennies here and there that you thought you’d never use, right?
Well – now it’s time to use one of them.
Whatever type of coin you’ve got, all you have to do is stick it into the tire grooves. If the lower bottom part of the coin is hidden by the groove, you have enough tread depth
If the whole coin shows though, it’s time to replace your tire.
Speaking of which, when the time finally comes for a tire change, make a habit of changing both tires.
Even if the other tire looks fine when compared to the other one, the truth is that it has most likely gone through the same stresses.
When you got to buy new tires, check your owner’s manual for the correct tire dimensions – get a tire with the wrong dimensions and your bike’s handling capabilities will suffer.
So how long does a tire last? Depends on the type of tire
Cruiser tires can last up to 5 years, while sportbike tires only last for up to 3 years before they need to be replaced.
Either way, the tire’s manufacturing date is always stamped somewhere on the sidewall – represented by four digits.
For example, if you see a number like “3521”
That means the tire was made on Week 35 of 2021 – that would be this week, actually.
Anyway, It’s also important to note that most new tires have a tiny silicone layer on them – if you’ve just put on a new tire you should write slowly for a while until the layer has dissolved.
I should also mention that if you replace a tire, the new one must be balanced before you put it on.
Finally, let’s talk briefly about tire ply. Every motorcycle tire has a layering of synthetic fiber cords coated in rubber that gives the tire its strength.
This layering is called the “carcass.” In the past, tires were made with the so-called “crossply” or the “bias-ply” carcass.
On these tires, the plies were laid out in a pattern so that the layers overlap. But while this gives the tire a strong sidewall, it also means that it’s prone to overheating.
On a radial-ply tire, on the other hand, the carcass runs straight across the tire. Because of this, these tires are lighter, deform less and above all, they’re less likely to overheat.
If you’d like to know more about bias-ply and radial tires, I’ve included a link in the show notes to a great video from the Motorcyclist Magazine YouTube channel, which explains it in greater detail.
So in short, that’s motorcycle wheels and tires.
I hope that you enjoyed listening, and above all that you learned something new.
Until next time, keep your helmet on and your eyes on the road. Bye!
