Having had experience with bikes in the past it is good to know the availability of tires and inner tubes before you need them. So, how to choose bike tires for folding bikes becomes an important question. First and foremost, check the tire size on your existing bike. Next, determine where you will be riding the bike and how you are going to use it.
You will see that the answers to those and some other questions below will tell you how to choose the right tire for your folding bike.
Since we already have our folding bike, the easiest way to check the tire size is to look at the tires on our bike. Look at the tire sidewall and right down the number markings (## x ##). As an example my bike tire size is 16 inches x 1 1/3 inches or 35 mm x 349 mm. Here is how it was written in raised numbers on the sidewall of the tire: 35×349 (16×1 1/3). This limits the tires available to this size unless we change the size of the tire rim and that goes beyond what we are talking about in this post.
Two tire dimensions must be taken into account. One, the tire width must match the rim width. Two, the inner diameter of the tire must match the diameter of where the bead is seated on the rim. Since Brompton bikes have a non-standard tire size (16 inch) there are not a lot of choices for tires and tire dimensions will not be an issue with this bike.
A tire is made of up to four components; the bead core, carcass, tire tread, and additionally it could have a protection belt.
The diameter of the tire is defined by the diameter of the bead core. The bead core is what secures the tire to the rim. The bead core is usually made up of a wire bundle. However, with touring bikes and folding bikes coming onto the scene bead cores are also being made out of kevlar. A kevlar bead core allows for greater flexibility and hence we have foldable tires. Foldable tires are convenient for touring and travel because they take up much less space than a full sized tire. The folding tire also tends to weigh less than the normal tire.
The innermost layer of the tire is the carcass. The carcass gives the tire stability. The materials used for the carcass and the density of the weave determine the quality.
This is where the rubber meets the road. In tires the rubber content is around 40 to 60 percent, the filler amounts to 15 to 30 percent, and the remaining materials 20 to 35 percent. The finished rubber is comprised of; natural and synthetic rubber, fillers, softeners, anti-aging agents, vulcanizing aids, vulcanization accelerators, along with pigments and dyes.
The protection belt is placed between the carcass and the tread. It helps to prevent punctures from small items that could easily puncture a tire, like a thumbtack or small thorn, by increasing the distance between the tread and the tube. The higher quality tires will use cut-resistant fibers within the protection belt, as well.
There are five different tire types; the normal tire, folding tire, tubeless tire, tubular tire, and the solid tire.
The normal tire (aka clincher) as the name implies is what makes up the majority of tires used by bikers. The clincher includes the tire and an inner tube. The wire core bead is what prevents the tire from popping off the rim when the tire is inflated. The normal tire is the easiest to install and maintain and can be repaired at home or while on the road. Because there is a large volume is this type of tire they are relatively inexpensive and you will normally have several brands from which to choose.
The folding tire also uses an inner tube as part of the tire system. However, the core bead is often made with Kevlar and that allows the tire to be folded into a small space without harming the tire.
The tubeless tire has no need for an inner tube. Having said that, there is a need in most cases for a special rim to go with the tubeless tire. Tubeless tires can be run on a much lower tire pressure than tubed tires, making the ride more comfortable. There is no concern for pinch flats since there is no tube in the tire. There is a huge reduction in possible blowouts with the use of liquids that offer puncture protection by re-sealing the hole almost immediately.
In a tubular tire the inner tube and tire are integrated into one piece. Then, the tire is then glued onto a special rim. The major advantage of a tubular tire is that with a flat the tire stays on the rim. This is much safer with a blowout at high speeds or while touring on the road because you can more easily ride the bike to a stop. The difficulties lie in fixing and replacing the tire as the process takes more time and effort.
Tannus (www.tannus.co.uk) makes a solid tire for 32-349 tire size. It is available from The Solid Tyre Bicycle Store. Since my purpose for riding the folding bike is more for exercise and strolling along I believe that whatever performance is lost on a solid tire would not make a difference for my purposes. I will need to do some more research as my bike tire size is a little wider.
Slick or Smooth Tires
Smooth tires are designed for road and city bikes. Because they are smooth they actually have more surface area in contact with the road than the other tires do. Hydroplaning in the rain is not a concern because the contact pressure is much greater with a two-wheeled bike than a four-wheeled car. In rough terrain or mud these tires will not do well.
Semi-slick or Hybrid Tires
Hybrid tires have a smooth center and knobby or rough treads on the sides. These are used primarily on roads with some limited rough terrain usage.
There are as many different types of knobby treads as there are color combinations on a Brompton folding bike. The different types of knobby tires would fit specific types of trails or outdoor environments where you will be riding.
Inverted Tread Tires
These tires are good for riding on the road and for times when you ride on rougher roads that do not get the maintenance they should be getting on a good road. Perhaps a better idea would be to mix and match tires. Use a hybrid tire in front and a smooth tire in the back.
Let’s look at two wheels on opposite ends of the spectrum. A steel train wheel has little rolling resistance between it and the steel track and therefore requires a long time to stop a train that is in motion. Now, we look at tires on bikes and see that they are flexible and adapt to the shape of the ground where they make contact. Within the tire itself there is going to be friction generated between the different layers of the carcass, protection strip and tire. The rounding of the tire due to the weight it bears when it contacts the ground is also a type of friction. Then you have the friction of where the tire meets the surface when riding.
Other factors to consider are whether the tire is over inflated, under inflated, or inflated optimally to the road conditions. The width of the tire is a factor as well as the makeup of the rubber in the tire.
The protection belt provides some measure of puncture protection. Kevlar is one of the materials that may be used in the protection belt and may help against something like broken glass. The added depth of the belt also offers protection from reaching the inner tube.
The two main types of valves are the Presta and the Schrader. The more expensive higher quality bikes tend to have the Presta valve. The size between the two is different enough that you cannot interchange them on the same rim.
The Schrader valve is similar to one found on car tires. The nice thing about Schrader valves is that you can stop at a gas station and put air in your tires, if needed.
Now that we see that a tire is not just a tire we can better determine how to choose the best tire for our folding bike. We check the tire size currently being used along with where and how we will be riding our bike and we will know what type of tread and tire to put on our bike the next time we change tires.
Why are tires often narrower than the stated tire size?
The tires are narrower than what is stated because there is an allowance for the tire to get wider when they are below optimum pressure and with age. The tires must maintain frame clearance under all conditions to be right for the bike.