It can often be confusing when attempting to pair the right tires with your bike rims. A bike rim width tire size chart can make your life much easier!
Cycling has changed a lot in the past few decades. With the arrival of new disciplines, we are seeing new technology and new sizing. Sizing and compatibility can often be quite difficult to understand when it comes to bike tech, particularly rim width.
For many, bike rim width can be challenging to wrap their head around, not just exactly what it is, but how to measure rim width and what effect it might have on the rider.
Don’t worry! Here, we’ll explain everything you need to know about bike rim width and give you some example rim width tire size charts to help you a lot the way. In this article, we’ll cover:
- What Is Bike Rim Width?
- How To Measure Rim Width
- Why Does Bike Rim Width Matter?
- Bike Wheel Rim Width For Different Cycling Disciplines
- Rim Width Tire Size Charts By Discipline
- Universal Bike Rim Width Tire Size Chart
Let’s dive in!
What Is Bike Rim Width?
The rim of a bicycle is the circular section of the wheel, where the tire is seated. The rim and the tire combined house the inner tube or the sealant.
Internal rim width is usually the measurement referred to when discussing bike rim width, as it has more of an influence on the handling and tire compatibility than external rim width.
Internal rim width refers to the internal section of the rim where the tire bead sits. The gap isn’t very wide, so it’s measured in millimeters.
This isn’t a measurement you’ll typically pay much attention to unless you are building your own bike and need to choose the wheels and tires. We generally put faith in the manufacturers to select the correct pairing for us.
Over the years, there’s been a trend for rim widths to increase in size. This is largely due to cyclists using wider tires, but there’s also evidence to show that a wider rim can improve handling in certain situations.
How To Measure Rim Width
Rim width is very easy to measure and can be done quickly with the right toolkit.
You can either use a vernier caliper or a tape measure. The vernier caliper is the more precise tool of the two, as we will be working with very small measurements, and the margin of error on a tape measure is far greater.
Take the tire off the rim, and remove the inner tube or clean out the sealant if you’re running tubeless. Remember to reset the vernier caliper to the closed position before measuring.
There are two different sets of jaws on the vernier caliper: one is used to measure internal widths, and the other is used to measure external widths. Next, take the internal measurement jaws of the vernier caliper and rest it where the rim tape is.
Once there, push the jaws out to the sides, ensuring that it remains square with the rim. You’re all done! Just read the measurement given; this is the internal rim width.
Why Does Bike Rim Width Matter?
Although it may seem insignificant, bike rim width plays a surprisingly large role in the handling and performance of the bike. Generally, the most important thing is to ensure that you use the correct tire width for your rims.
Here are three reasons why it makes such a big difference:
#1. The Rim width Defines the choice of Tire
When a manufacturer designs a wheel, it is designed to be used with certain tire widths. You can usually find this information on the manufacturer’s website. They test the rims with tires of various sizes to determine which pairings work properly.
If you don’t use the correct tires on your rims, then you could push the tolerance limit of the wheels, which could cause the tire to slip or the wheel to break.
Essentially, if you use the wrong tire size, you run the risk of the wheel-tire system not working as it should.
So, the compatible tire widths depend on the width of your rims. Typically, the smaller the rim width, the narrower the tires you can use.
#2. The Rim Width affects the shape of the Tire
The rim width on a wheel is designed to be a certain size for a reason.
When paired with the correct tire size, it shapes the tire properly. A properly shaped tire, inflated to the correct pressure, makes for a great combination and will maximize handling performance.
If you have the wrong size tires on your rims, then you’ll know about it. Too big, and they’ll feel like they’re going to roll over the edge of the rims on corners. Too small, and you’ll be risking damage to your wheels.
#3. different Rim Widths can alter the tire width
Interestingly, although a given tire states a certain width on the box, it is also dependent on the width of your rim. The stated width of a tire is exclusively applicable when paired with the correct rim width.
If you have a rim width of 19 mm and fit a 28 mm (28c) tire, then when properly inflated, it will probably measure 28 mm in width, as you’d expect.
However, if you put that 28c tire on a rim width of 25 mm, it could measure 31 mm wide, as it adopts a “light-bulb” shape. Not only has the narrower rim pushed the tire out wider, but there is also an increased volume of air inside that tire.
This is why the same tire can look bigger on some wheels than others.
Note that certain manufacturers have a reputation for coming up slightly wider or narrower too!
Bike Wheel Rim Width For Different Cycling Disciplines
Rim width varies significantly across different cycling disciplines.
Off-road disciplines tend to use larger tires to enable them to easily traverse uneven terrain. You generally get wider rims for disciplines that require larger tires. So, mountain bikes will have a wider rim than road bikes.
Here are some typical rim widths for each cycling discipline:
Road bikes, in general, require the narrowest tires. The most common road bike tires range from 23c to 30c, meaning you’ll need fairly skinny rims.
The most common corresponding modern rim widths are between 17 mm and 23 mm.
This was much smaller on older road bikes, and you could see rim widths as small as 13 mm. Since then, the steadily increasing tire widths used in the pro peloton have necessitated an equivalent increase in the rim width.
Running a rim width of 17 mm to 23 mm seats most road tires perfectly, shaping them correctly.
Although similar to road bikes, gravel bikes use different tire sizes since they need to be able to roll smoothly over rougher terrain.
The most common tire sizes you’ll find on gravel bikes are from 35c to 50c.
You can expect a gravel bike to have an internal rim width somewhere between 21 mm and 25 mm.
Gravel bikes generally need a rim width that works with multiple sizes, as riders often swap between both narrower and wider tires according to the terrain they plan to ride, which can also affect gravel bike tire pressure.
Gravel bikes are used as “do-it-all bikes” for many riders, and it’s not uncommon for people to swap out their tires depending on the ride they are doing that day, which is why most gravel bike rims are built to accommodate a range of tire widths.
When it comes to mountain bikes, the internal rim width gets much larger as tire sizes across mountain bikes change significantly.
On a mountain bike, the typical range of tires is from 2.1” to 2.7” (53-69 mm). The rim width generally ranges from 21 mm to 31 mm on modern mountain bikes.
Yes, this is a huge range, but companies produce a variety of sizes to change the way the bike feels to ride. You will also see that budget mountain bikes tend to have quite small tires compared to high-end mountain bikes, which usually have more width.
These are the widest tires you will see on bikes, which require huge internal rim widths.
Tires can range from 2.8” to 5”, while the rim width ranges from 35 mm to a massive 85 mm.
Again, like mountain biking, the range is massive for these tires. With 4”+ fat bike tires having so much width and volume, the rim needs to be super wide to avoid the tire feeling like it’s going to roll over the rim on each corner.
Rim Width Tire Size Charts By Discipline
Now, you’re probably wondering which size tires are compatible with which internal rim widths.
Here we have rim width tire size charts comparing rim width vs tire width for each cycling discipline.
Wheels are all made differently, and so are the tires, so tolerances vary between brands and models. In this guide, we are giving you the optimal tire size for the rim width. These are estimations and generally not hard and fast rules.
Road Bikes: Rim Width Tire Size Chart
Firstly, we have road bikes. This chart shows that the smaller the rim width, the smaller the tire works best. As the internal rim width gets larger, it suits bigger tires.
It doesn’t mean that the pairings that aren’t shaded green won’t work; it just means they won’t necessarily provide optimum handling performance.
Gravel Bikes: Rim Width Tire Size Chart
Secondly, we have gravel bikes. There are many more tire choices for different rim sizes. When manufacturers sell gravel bikes, they typically choose rim sizes that work well with a variety of tires.
The larger the internal rim width, the more choices of tire width are compatible.
Mountain Bikes: Rim Width Tire Size Chart
Next, we have mountain bikes. Although with wider rims, there are more tire width options, now the tires are wider too, and it gets more challenging.
Remember that the pressure in your tires is crucial, as these tires have much more volume than gravel and road tires.
Fat Bikes: Rim Width Tire Size Chart
These are very wide, and you generally have a lot more room to play with.
You don’t have a huge amount of choice in this range regarding tire sizes, and you might have to do a bit of searching to find the best possible performance.
Universal Bike Rim Width Tire Size Chart
Bear in mind that pairings that aren’t shaded in green may still work without major issues (though safety can be compromised if you veer far from the recommended range), but you’re unlikely to get optimal performance from your rim and tire combination.