Bike tires play a major role in how comfortable you feel when riding through any terrain. They can give a smooth ride on a bumpy trail or a rough ride on a relatively smooth track.
So, what should you consider in your tire purchase? If you are shopping for wider bike tires, both the 25c and 28c fit the bill, unlike their 18 0r 20 counterparts. But between 25c and 28c, which one should you go for, in terms of price, comfort, and weight?
Here is a detailed guide on these tires. The article will also give a final verdict on which one ranks higher. Let’s take a look.
Comfort is one of the main aspects of riding your bike. You want tires that can enhance this and help you propel more easily. Although comfort is a product of several factors, tires play a role and should not be ignored.
When changing from 25c to 28c, you might not notice a significant difference compared with jumping from 23 to 28 or 18/20 to 25. However, technically speaking, 28mm tires will typically be more comfortable on rough roads like cobbles or gravel.
The difference in weight between a 25c and 28c tire is approximately 10–15 grams, which isn’t much at all. However, every gram counts if you’re trying to get a lighter bike or are especially conscious about weight. As with most things in cycling, lighter is better. Lighter wheels are faster and accelerate faster. They provide more responsive handling, and they’re easier to climb with. They are also more comfortable since they absorb less vibration and can be easier to maneuver.
Often, manufacturers will offer two versions of the same wheelset model. One version built up with 23s or 25s, and another with 28s. The version with the wider tires will weigh considerably more even though the rims are identical because the extra weight is entirely coming from the larger tires.
If subjected to similar conditions, such as riding surface, load, and braking, a 28c tire would last longer than a 25c. A wider tire has shorter contact patches and leaves behind more rubber, while a narrower one wears less but on a thinner section.
This has an overall effect of the wider tire lasting longer.
Aerodynamics and Speed
When most people hear the term “aero,” they think of the pointy helmets and long-tail skinsuits that triathletes wear for their bike legs. But aero is about more than just aerodynamic gear. Aero is also about your tires, which can be one of your bike’s most significant influences on drag.
A 28c tire rolls better than a 25c tire because of its lower rolling resistance, good grip, and comfort. Likewise, a tire with a relatively smaller diameter has a higher rolling resistance than a wider one if the two have the same inflation pressure. This has the effect of a flatter and less round one.
Therefore, a wider tire is more aero, especially on rugged trails. But if on a smooth track, a 25c tire would serve you better. So, if you’re not racing and on rides where you’re covering super-long distances at slower speeds, tire width isn’t as important as tire pressure. So, keep an eye on how hard your rubber is; make it by ensuring it’s firm enough to feel fast but soft enough, so it doesn’t bounce around too much.
Similarly, many individuals believe wider tires are slower due to wind resistance. However, technically speaking, the effect of wind resistance between a 28c and a 25c is negligible. And even where there is some difference, the effect gets swallowed up in other factors influencing a bike’s speed.
25c tires typically cost less than 28c tires, but the price difference can vary quite a bit depending on the brand, durability, and other factors. Your location will most likely also play a part in determining prices, as can the time of year when you’re buying them.
On the other hand, you’ll probably have more trouble finding 25c tires for sale for closer to $15, whereas that’s about average for 28c tires though they can range widely in price, anywhere from $15 to several hundred dollars. Neither tire type has a dramatic edge over the other here.
Final Verdict: 28c has more comfort, but 25c wheels are more aero
There are two main differences between 25c and 28c tires other than their width: air volume and air chamber, the latter being one of the former’s factors.
The larger contact patch with the ground that 28c tires have means more comfort for your rides. With all else held equal, you can run lower tire pressure with no loss in rolling efficiency or other performance aspects. The larger air chamber translates to more give, which will help absorb vibrations from the road surface, translating to increased rider comfort.
That is why most people opt for wider tires like 28c when riding on rough surfaces or cobblestones because the larger tire absorbs these vibrations better than a smaller one would.
Aero-wise, 25c wheels are advantageous because they have less frontal area exposed to the wind compared with 28c wheels. However, depending on how much racing you plan on doing and if you plan on doing it professionally, you may find that it’s not worth sacrificing comfort for a few seconds off your race time per kilometer. This is true, especially if your wheel/tire setup is mainly used for training and casually riding around town.
Finally, your decision will depend on your needs, although the 28c has the upper hand in all the considered aspects.