Condensed Answer: The nominal difference between a 700×25 and a 700×23 tire is small. Consequently, in most cases, one can successfully replace one with the other.
To ensure complete compatibility, one should take into consideration, the inner rim width.
Tire Sizes Aren’t Accurate
Very often the tire width on the label does not match the actual width of the tire upon installation. For example, a 23mm tire might end up 23.9mm when you pump up it to the needed air pressure and measure it with a caliper.
Rims Influence Tire Width
A wider rim results in a wider tire. A narrower rim makes the tire “pointy” and thus slimmer. Consequently, the same tire might end up measuring differently on a new rim.
Inner Rim Width
The inner width of a rim directly influences the minimum and maximum tire size that the rim can safely operate with.
If a slim tire is installed on a very wide rim, the tire won’t be secure. If a wide tire is installed on a slim rim, there won’t be enough space for the inner tube and the tire bead. As a result, the tire might pop off either during inflation or when riding.
The table below can serve as a general guide for rim and tire compatibility:
|INNER RIM WIDTH||COMPATIBLE TIRE SIZES (MM)||COMPATIBLE TIRE SIZES (IN)|
Conclusion: If the inner rim width is between 13 and 16.9mm, then the rim is compatible with 23mm tires. That said, the numbers above are not set in stone and slight deviations will not necessarily make the combination incompatible.
The Inner Tube Shouldn’t Be Too Wide
Most inner tubes designed for 25mm tires will operate just fine with a 23mm tire.
However, if the 25mm tires in question are equipped with inner tubes designed for larger tires (28mm+), the tubes may be too wide for a 23mm tire.
An unnecessarily large inner tube can create the following issues:
- Difficult installation. A wider inner tube is more inconvenient to install.
- Pinch flats. A wider inner tube is easier to get pinched between the tire bead and the rim wall during installation.
- Non-secure Tire Bead. The inner tube and the tire bead are fighting for space within the inner rim. Normally, this isn’t a problem because the inner tube is very flexible and allows the tire bead to grab the rim with a little effort. The valve area, however, is problematic because it cannot compress as much as the rest of the tube due to the valve stem and its base. Thus, a wider inner tube can make it difficult or even impossible for the tire bead around the valve area to sit properly.
This problem is more likely to manifest when a wider than needed inner tube is combined with an ultra-slim tire.
The Advantages of Replacing a 25mm Tire With a 23mm One
1. Extra Clearance
A 23mm tire is slimmer and offers greater fork and frame clearance. This could be beneficial if the user is riding a road or track bike with minimal clearance making the usage of 25mm tires dangerous.
Also, the extra clearance makes it easier to install accessories such as full fenders.
2. Less Weight
Narrower tires require less material and can therefore be lighter.
3. Less Drag
The narrower profile of slimmer tires makes them more aerodynamic.
FAQ: Are 23mm tires faster than 25mm models?
People used to believe so because 23mm models are more aero and can operate at a higher air pressure which is naturally associated with reduced rolling resistance.
Over the years, tire manufacturing and testing improved enough to question the idea that a slimmer tire is a faster tire. In fact, tests have shown that wider tires have less rolling resistance when running similar air pressures. This is also backed by the fact that some professional cyclists are running 25 and even 26mm tires.
Ultimately, 23mm tires have the potential to be faster only in a very specific racing situation. The speed benefits that they offer are negligible in the world of recreational cycling.
One can also argue that 23mm tires are slower because they offer a harsher more tiring ride.
It’s also worth mentioning that less comfortable tires encourage the user to look for the smoothest roads. This tendency hurts one’s time too.
The Disadvantages of Replacing a 25mm Tire With a 23mm One
- Firm Ride
The skinnier the tire, the greater air pressure it needs to avoid pinch flats (a type of puncture that happens when the wheel hits a firm object like a curb.)
Thinner tires have a smaller contact patch with the ground resulting in reduced traction. This makes slimmer tires suboptimal for commuting in wet conditions.
- Pinch Flats
23mm tires are more likely to get a pinch flat when the air pressure drops.
- Narrow Profile
The narrow profile of 23mm tires increases the chance of “trapped wheels”. Or in other words, a crack on the road or a water drain would have an easier time grabbing the tire. When that happens, the rider is very likely to fall, usually over the handlebars.
25mm tires are not much wider and do not provide as much protection against this scenario as 28mm+ tires but reduce the chance nonetheless.
FAQ: Is the switch from 25mm to 23mm tires worth it?
If the bike is used for recreational purposes or amateur riding, the transition is unlikely to provide tangible benefits. A rider who isn’t competing on the highest level won’t benefit from the reduced weight and the improved aerodynamics that come with 23mm tires.
As far as commuting is concerned, the main pro of 23mm tires is the extra clearance. However, if the bike is used primarily for commuting and yet doesn’t have proper clearance for 25mm tires, then the model is designed for racing and is non-commuting friendly, to begin with. In that case, the user is advised to search for a more “relaxed” bicycle that can serve commuting duties better.
In short, the transition has little to no benefits for the vast majority of riders.
Summary: What You Need To Know
- In most cases, a 700×25 tire can be replaced with a 700×23 model without much trouble.
- When the inner rim width is 13-16.9mm, the chances of success are higher. Nonetheless, some deviation is allowed.
- The main advantages of switching to 23mm tires are greater clearance + less weight + less drag.
- The main downsides of switching to 23mm tires are harsher ride + reduced traction + narrow wheels that can get “trapped”.
- 23mm tires can be faster in certain racing situations, but the extra speed isn’t worth much to recreational riders.