Thursday, 2/5/09 at 1:16 PM
by Tara Llanes
by Tara Llanes
Let's Talk About Rubber
Okay ladies now when I say rubber I am not being dirty, however the rubber I am talking about will get dirty. Tires are what I’m talking about and there are a wide variety of them. There didn’t used to be nearly the amount of choices when I first started compared to today. Not that I am ancient, but I think rubber companies were just in the beginning stages of figuring out how different sizes, different knobbies, and even casing would change the way the tires would feel. And these days there are a ton of different manufacturers making tires. Michelin, Kenda, Maxxis, Schwalbe, WTB, Continental, Tioga, Nokian, Hutchinson, Panaracer, and Geax and I might even be leaving out a couple. Let’s see if I can shed a little light on some of the reasons why tires are different and what you would use which tires for.
So to begin with there are many different sizes of tires. The size of the tire is measured by both the diameter and the width. So for instance I would normally run a 26x2.1 inch tire on my everyday cross-country bike. The 26 stands for the diameter of a mountain bike wheel and the 2.1 is the width in inches of the tire. There are many different widths of tires these days for just about any occasion. For cross-country riding a lot of times riders would use a 1.75, which would be considered a “skinny” tire. The point to using a skinny tire is that it is generally very light weight and as we all know in cross-country you want your bike to be as light as possible for climbing. The only other reason you would possibly want to use a 1.75-inch tire would be if you were riding around on the road and didn’t want a lot of drag. What I mean by that is that more surface area of the tire that is touching the ground the more resistance you have. So less is faster in that instance.
If I were doing say some trail riding and I was on my 5-inch Giant Cypher then I wouldn’t care so much about weight and I would want a tire that was a little wider and more stable. So maybe I would choose a 2.1-2.2 inch tire with some good knobbies that would grab into the dirt.
And then let’s say the next day I wanted to go out downhilling on my Team Giant Glory DH well then I would more than likely want a tire with a lot of width to cover more ground. I wouldn’t be concerned so much with weight since I’m going downhill and not worrying about climbing. So in that case I would probably use a 2.5-2.8 inch width of tire. A 2.8 tire is a pretty big tire, but when you’re flying down rocks and wet roots you want as much grip as you can get so the more of the rubber that is actually touching the ground the more traction you should be getting.
Alright, so I’ve given you some examples of widths of tires and when you would use them so now let me try and explain a little about knobbies. Knobbies are those knob-looking things on your tires and those are what help grip the ground. There are many different knobby patterns for different reasons. Most knobs are in some sort of square or rectangular pattern and are usually angled. The reason for them being angled is for less rolling resistance. If you had a knob that was just square and sat just like that on a tire, as the tire would roll it would actually want to slow you down. You see you want the most grip with the least rolling resistance. So now that I’ve stressed low rolling resistance another important thing to notice is how high the knobbies sit on the tire. The taller the knob the more resistance you will have and the lower the knob the less resistance. Voila! I hope I’m making sense. I know I am in my head. Hehe! Not only do you have the knobbies down the center of the tire, but you also have knobbies on the side of the tire. Those are put there so that when you go around a turn and lean your bike over you’ve got more 'grab' into the dirt. Boy those tire guys and girls thought of everything didn’t they!
Another important thing to talk about are which tires are better in wet and which are better in dry. If you take a look at the spacing between the knobbies you will notice those channels. An easy way to figure out which tires more than likely work best in dry conditions would be to make sure the knobs are spaced closer together. And if the knobs are spaced further apart that means they are better for wet and muddy conditions. If you were riding in a mud you would want the tire to be able to clear better. If the knobs are closer together the mud just packs up into the tire, but if you give it some space it has less of a chance of doing that.
I want to talk to you briefly about compounds. I don’t want to get too crazy on you, but it’s good to know these things. Traditionally you would want to run a softer compound tire on the front and a harder on the rear. The reason for that is that front tires are usually set up more for cornering traction and you want some give in the tire. The rear tire is more for climbing and braking so it’s better to have with some bite. You can always ask someone at your local bike shop which tires are harder compounds and how to tell. And also a lot of times it will say on the side of the tire if it should be used as a front or a rear tire as well as which direction they should be put on. A lot of tires are directional and are made specifically for braking or climbing.
So you see mountain bike tires have come along way and when you find the right combo for you it’s amazing how well your bike will respond to acceleration and braking. I know there are a million more things about tires that I didn’t even touch on but once you read this blog why don’t you write in and ask me some questions and I’ll so my best to answer them. It’s always a bonus when you do because then other readers learn as well.
Cheers!
Tara
So to begin with there are many different sizes of tires. The size of the tire is measured by both the diameter and the width. So for instance I would normally run a 26x2.1 inch tire on my everyday cross-country bike. The 26 stands for the diameter of a mountain bike wheel and the 2.1 is the width in inches of the tire. There are many different widths of tires these days for just about any occasion. For cross-country riding a lot of times riders would use a 1.75, which would be considered a “skinny” tire. The point to using a skinny tire is that it is generally very light weight and as we all know in cross-country you want your bike to be as light as possible for climbing. The only other reason you would possibly want to use a 1.75-inch tire would be if you were riding around on the road and didn’t want a lot of drag. What I mean by that is that more surface area of the tire that is touching the ground the more resistance you have. So less is faster in that instance.
If I were doing say some trail riding and I was on my 5-inch Giant Cypher then I wouldn’t care so much about weight and I would want a tire that was a little wider and more stable. So maybe I would choose a 2.1-2.2 inch tire with some good knobbies that would grab into the dirt.
And then let’s say the next day I wanted to go out downhilling on my Team Giant Glory DH well then I would more than likely want a tire with a lot of width to cover more ground. I wouldn’t be concerned so much with weight since I’m going downhill and not worrying about climbing. So in that case I would probably use a 2.5-2.8 inch width of tire. A 2.8 tire is a pretty big tire, but when you’re flying down rocks and wet roots you want as much grip as you can get so the more of the rubber that is actually touching the ground the more traction you should be getting.
Alright, so I’ve given you some examples of widths of tires and when you would use them so now let me try and explain a little about knobbies. Knobbies are those knob-looking things on your tires and those are what help grip the ground. There are many different knobby patterns for different reasons. Most knobs are in some sort of square or rectangular pattern and are usually angled. The reason for them being angled is for less rolling resistance. If you had a knob that was just square and sat just like that on a tire, as the tire would roll it would actually want to slow you down. You see you want the most grip with the least rolling resistance. So now that I’ve stressed low rolling resistance another important thing to notice is how high the knobbies sit on the tire. The taller the knob the more resistance you will have and the lower the knob the less resistance. Voila! I hope I’m making sense. I know I am in my head. Hehe! Not only do you have the knobbies down the center of the tire, but you also have knobbies on the side of the tire. Those are put there so that when you go around a turn and lean your bike over you’ve got more 'grab' into the dirt. Boy those tire guys and girls thought of everything didn’t they!
Another important thing to talk about are which tires are better in wet and which are better in dry. If you take a look at the spacing between the knobbies you will notice those channels. An easy way to figure out which tires more than likely work best in dry conditions would be to make sure the knobs are spaced closer together. And if the knobs are spaced further apart that means they are better for wet and muddy conditions. If you were riding in a mud you would want the tire to be able to clear better. If the knobs are closer together the mud just packs up into the tire, but if you give it some space it has less of a chance of doing that.
I want to talk to you briefly about compounds. I don’t want to get too crazy on you, but it’s good to know these things. Traditionally you would want to run a softer compound tire on the front and a harder on the rear. The reason for that is that front tires are usually set up more for cornering traction and you want some give in the tire. The rear tire is more for climbing and braking so it’s better to have with some bite. You can always ask someone at your local bike shop which tires are harder compounds and how to tell. And also a lot of times it will say on the side of the tire if it should be used as a front or a rear tire as well as which direction they should be put on. A lot of tires are directional and are made specifically for braking or climbing.
So you see mountain bike tires have come along way and when you find the right combo for you it’s amazing how well your bike will respond to acceleration and braking. I know there are a million more things about tires that I didn’t even touch on but once you read this blog why don’t you write in and ask me some questions and I’ll so my best to answer them. It’s always a bonus when you do because then other readers learn as well.
Cheers!
Tara
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