In some situations, a difference of one and a half inches is inconsequential. When it comes to tire sizes for bikers, the small difference between 26 inch wheels and 27.5 inch ones can make a big difference. In this 26 vs 27.5 comparison we look at some differences you can expect to encounter and why one may be a better option for you.
Hi, my name is Crystal. Like all other professional cyclists, I am always looking for ways to optimize my performance. I know there has been a long standing debate amongst us in the cycling world around the best wheel size. I have never really got involved in it because I am taller than average and have therefore always stuck to the larger 29ers.
Now I am looking to explore other wheel size options to find out if the advantages they come with are worth a shot for me.
Here is a 26 vs 27.5 comparison detailing various aspects which tend to be different with the two sizes.
26 Vs 27.5 – A Comparison Table
26 |
27.5 |
|
Top Speed |
High |
Higher |
Maneuverability |
Better |
Good |
Suspension requirement |
High |
Lower |
Acceleration rate |
Faster |
Fast |
Traction |
Good |
Better |
26 vs. 27.5 bikes – How do they differ?
Attack Angle
Rolling resistance, also known as rolling friction refers to the resistance to movement against which the wheel moves. It is caused by friction between it and the surface it is moving on.
The size of your bike’s tire determines the amount of rolling resistance you get as you are riding along trails. With a larger wheel base, you can overcome larger obstacles than with smaller tires.
The science behind rolling resistance and obstacles in tires is called attack angle. This is the angle formed between the tire and the obstacle. The larger the angle, the harder it is for the wheel to roll over the obstacle. When a small angle is formed, the tire easily rolls over.
If you are riding a 26 inch bike and come across a thick root on the ground, the root meets the tire at a higher point and at a larger angle than it would if you were riding using a slightly larger 27.5 inch wheeled bike. The result is more force reverberated back against the wheel which makes it harder to control the wheel, reduces stability and forward momentum.
When you are riding at high speed, the difference in tire size, albeit small makes a significant difference.
The smaller the tire, the more force reverberated back against it when you encounter an obstacle. If you are riding on a trail with many obstacles, the 27.5 inch wheel is a better choice.
Tire Pressure
Correct tire pressure gives you a comfortable ride because it allows the bike to roll smoothly over obstacles and avoids flat tires.
The most important thing to remember when it comes to bike tire pressures is that there are no rules or formulas which you can use to calculate exactly how much pressure you should have in your tires. It depends on several aspects such as the kinds of trails you will be riding, how hard you ride and your weight as the rider.
Rougher trails require higher pressure and if you like to ride through trails at high speed without maneuvering to avoid obstacles, a little extra pressure will do. The heavier you are, the more pressure you need to support you when you are seated on the saddle.
Again there are no rules regarding the exact amount of pressure you should use for specific weight but a common measure used is addition of 1% of tire pressure for every 1kg. Here is a guiding table from one of the world’s most renowned tire manufacturers.
That said, smaller tires generally require more air pressure than larger ones. Smaller tires have a smaller contact patch compared to a larger wheel. If the same person were to ride the two bikes, a smaller patch is required to support the same weight in the smaller wheel. Larger tires spread the weight over a larger area thus the need for lower pressure.
Many riders also advise using slightly higher pressure (by about 2 psi) in the rear tire compared to the front tire because this is the tire which bears the weight of the rider.
On the overall, finding the ideal tire pressure for your bike comes down to trial and error and settling for what the individual rider finds most comfortable.
26 inch wheels require more pressure than 27.5 inch wheels. You will also need to check your tire pressure more frequently. If this is not your cup of tea, opt for the 27.5 inch wheel.
Suspension
Suspension on your bike is what allows the wheels to move up and down to absorb the force from bumps while maintaining contact on the ground. Although suspension is a consideration in all types of bikes, it is especially essential in mountain bikes.
26 inch bikes generally require more suspension than 27.5 inch bikes because of the size of the wheel. Smaller wheels are more likely to be strained in order to bear the pressure of the rider’s weight and force from landings.
If you have decided to buy a 26 inch bike, opt for one with suspension rather than one without. This is not to say that 27.5 inch bikes do not require suspension. They do if you are going to be riding hard on rough trails but you will have a more uncomfortable ride on smaller wheels in the absence of a suspension system. Suspension also helps to even out braking and improve traction when cornering.
Smaller wheel require more suspension. If your bike has no suspension, you may be better off with the larger 27.5 inch wheel.
Acceleration and speed
How fast can you move from a stationary position to relatively high speed on your bike? This is what acceleration is about. Acceleration is faster and easier on smaller wheels compared to larger ones. This means when comparing 26 inch wheels and 27.5 inch wheels, acceleration performance is better on the 26 inch wheels. This is thanks to lower weight which creates a lower moment of inertia. The result is faster acceleration.
How important is acceleration? Well if you ride along busy streets often, a good acceleration rate is important for comfortable and safe riding amongst vehicles.
Speed.Although smaller wheels perform better when accelerating, when high or top speed is achieved, larger wheel become more efficient. It take less effort to maintain high speed in larger tires. This is most important for professional riders for whom speed is essential.
If speed maintenance is more important to you than acceleration rate, then the 27.5 inch wheels will serve you better.
It is important to note that if you have installed on your bike larger tires than it came with, the speedometer is likely to give you inaccurate speed readings. Many riders report getting slower speed readings on the speedometer than actual speed after replacing original tires with larger ones. This happens because the larger tire has a larger circumference which causes it to travel more distance per revolution compared to the original tires.
If you frequently ride on city roads where quick acceleration is crucial, opt for the smaller 26 inch wheels. If speed is your primary need, opt for the larger 27.5 inch wheel.
Size and weight
The correlation between size and weight is quite direct. The smaller the frame and wheel, the lighter the bike. The 26 inch bike is therefore smaller and lighter than the 27.5 inch bike.
If storage space is an issue for you as it is for many people living in apartments, a smaller bike is easier to deal with. If you travel with your bike a lot and have to fit it into the car, the smaller it is the better.
Where weight is concerned, you may be thinking about it if you live in an apartment where you have to carry your bike up and down the stairs every time you need to use it. The lighter it is the better. Some people also opt to store their bikes suspended on the wall. If this is the case a smaller, lighter bike would be preferred.
If you are looking for a small, light bike opt for the smaller 26 inch wheels. If you don’t mind extra storage space and weight, opt for the larger 27.5 inch wheels.
Traction
The tire is the only surface which comes into contact withthe road or ground you are riding on. In order to achieve comfortable and safe traction or grip, the tires must be in good condition. That said, experts agree that the larger the contact patch (section of the tire which comes into contact with the ground at any one time), the better the traction.
It also follows that the larger the tire is the larger the contact patch is. If traction is a primary concern for you, the larger of the two tires under comparison that is the 27.5 inch is best.
When you are riding on the road under wet conditions, such as during or immediately after a rain storm, traction is reduced. To deal with this, some riders recommend reducing tire pressure to slightly below manufacturer’s recommendation (1.5 to 2 psi and not more). This does increase the tire’s grip on the road and reduce chances of slipping, but it comes at the expense of lower tire life and the need for more pedaling effort.
Although this pressure reduction technique can be of great help in sticky situations, don’t forget that if your tires are underinflated and experience significant jolts, you run higher risk of pinch flats. Pinch flats happen when the inner tube gets caught between the tire and the rim.
For maximum traction, opt for the larger 27.5 inch wheels.
Conclusion
At the end of the day, there is no perfect wheel size for everyone. Each size comes with its unique advantages and disadvantages to deal with. Smaller wheels let you enjoy better maneuverability and quick acceleration. Larger wheels give you better top speed but at the expense of maneuverability.
The best way to decide what works best for you is to try a few bikes with different wheel sizes to see what feels most comfortable.
Of course there is the option to swap out one pair of wheels for another on your current bike, even though it takes a fair level of caution and expertise to do it right.
FAQs
Can I put 27.5 wheels on a 26 bike?
You have a bike which came with 26 inch wheels but want to enjoy the benefits of 27.5. You can swap them out but check to see if the frame is compatible for conversion. If it is not, the wheel could rub on the stays or bottom bracket.
These are some issues to think about before converting your bike. Firstly, will the rear wheel fit the frame? Secondly, will the front wheel fit the fork, and lastly how does the whole conversion affect the geometry of the bike?
Is a 26 inch wheel bike too big for my child?
To determine the ideal wheel size for your child, all you need to do is measure his/her height. Have him stand against a wall, preferably barefoot and get an exact measurement of his height. Then use a measurement chart like this one to figure out what wheel size is best.
If for instance your child is 100cm tall, a 12 inch wheel is best. If he is 140cm tall a 26 inch bike is fine. Anything smaller than 26 inches is considered a children’s bike while 26 inch ones and larger are considered adult bikes.
Generally, 26 inch bikes can be used by teenagers from the age of about 15 years or slightly younger for taller kids.
Are 26 inch wheels dead?
It is true that 26 inch wheels which were once a standard feature in mountain bikes are now almost impossible to find. At least not on adult bikes. They are still quite common on children’s bikes but 27.5 and 29ers have become standard for adults’ mountain bikes.
Even then, they are not completely gone. A few manufacturers are still making 26 inch wheels and some old school riders still swear by the smaller wheel size for better maneuverability and handling.
When they are used for adult’s bikes, there must be consideration for extra suspension to help absorb bumps especially since it is an adult’s weight being supported by the small wheel.
26 or 27.5. Which are better for climbing?
It depends on the kind of terrain you are riding in. if you are on smooth tarmac, lower rotating mass on the 26 gives you an advantage. If you are on a more technical climb 27.5 wheels let you roll over obstacles which you would otherwise have had to avoid or remove from your path.