Everything You Need to Know to Buy Mountain Bike Wheels

Wheels are one of the first components a rider typically changes when upgrading their mountain bike. It is a frequent investment that is usually made between 1 and 2 years after the purchase of the bike, when enough time has passed to have a budget to improve the bike, and our evolution as a cyclist invites us to want to improve our performance.

If this is it and you’re considering buying wheels for your mountain bike, there are many things you need to know before settling on one or the other.

Everything You Need to Know to Buy Mountain Bike Wheels [Guide and Suggestions]

Weight distribution

One of the main reasons for changing wheels is weight. In general, there is an obsession with cycling and mountain biking with the lightest possible components.

Indeed, the wheels are of paramount importance when it comes to lightening the weight of a bicycle, but it should be known that all the elements of a wheel do not have the same influence on the distribution of the weight. It is a matter of physical law.

We all know that to move a specific body, we have to apply the energy or work necessary to move it. It is kinetic energy.

Thus, our entire bicycle will be affected by the kinetic energy of translation (work required to move an object in space). The wheels will also be affected by the kinetic energy of rotation (work associated with a movement of rotation with angular velocity), which can make the weight of the wheels twice as effective as for the rest of the components of our bike.

But this last statement is very relative because depending on where we gain weight at our wheels, it will be more or less noticeable, and the closer we are to the centre of rotation, the less it affects the kinetic energy of the rotation. Therefore, the weight of a thru-axle or hub has much less influence than the weight of the rim or tire.

It is essential to remember this because sometimes we mistake spending a few euros more for wheels with a lighter hub, thinking that we will be lighter with them. However, the effect will not be as beneficial if the rim is heavier.

Which Material is the Best?

You can find wheels made of different materials or combinations in the market. For example, some wheels have an aluminium frame (spokes and rim) and a carbon brake track. The characteristics that either material brings to the wheels are as follows:

Steel

Yes, although it seems that everything is dominated by aluminium and carbon, steel wheels are still made. These are cumbersome wheels that are usually used for lower-range bikes. So if you want to upgrade your bike, you should not consider buying these.

Aluminium

Aluminium is currently the most used material for mountain bike wheels, although this trend is slowly changing as professional and high-end amateur bikes now use carbon wheels.

The main advantages of aluminium are reflected in the price (cheaper than carbon wheels) and weight (lighter than carbon wheels).

Carbon

The benefits of carbon are already implemented in almost every cycling component, but in MTB wheels, it costs more due to the feeling of fragility it causes. We tend to think they are more fragile than aluminium wheels.

The main advantages of carbon wheels for mountain biking are notable. The weight, without a doubt, is the first thing that catches our attention, and we can speak of half a kilogram of difference between aluminium and carbon wheels (with all that this implies, as we have seen previously).

On the other hand, they offer greater rigidity and better acceleration capacity, allowing a smoother ride.

But there is one significant downside: the price, as good quality carbon wheels can start at around £1000, while their aluminium equivalents will be around half the price at around £500.

How to protect carbon wheels

With the advent of carbon in mountain bike wheels and the growing trend to use tubeless tires, we all have our first fear: what if I break the tire or get a puncture that doesn’t seal? Not the tubeless liquid? What if I hit a rock?

In my experience, carbon wheels are more rigid than they look and don’t break at the slightest rim crack, as many enthusiasts fear. However, many brands have started to market a foam component to reassure us.

Cylindrical foam (usually made of low-density polymers) is placed inside the tire to prevent rim blowout during pressure loss.

It is used with tubeless liquid. The downside is the price, which is around €40-50 per unit, depending on the brand. Many people also complain that when the surface layer cracks, the foam can absorb all the liquid from the tubeless. Therefore, it is necessary to check the tire’s condition periodically.

Rim width

Currently, the market trend is to have broader and wider rims, which give us more stability, and comfort, and, thanks to them, we can ride with lower pressures. However, they disadvantageously that a wider rim implies a higher weight.

If you’re looking to make your bike as light as possible and rule out buying a wider rim, for this reason, you have to keep in mind that you’ll be sacrificing a more comfortable ride and better traction.

Ray Types

The wheel spokes are an element that often goes unnoticed, and we do not consider them in our purchase decision.

The spokes carry all the tension between the wheel’s rim and the hub. Depending on the material and treatment they are made of, they may offer certain riding benefits.

How many spokes should a good mountain bike wheel have? It usually is recommended to have 28 spokes, but this number is not a fixed rule. There may be fewer spokes but more muscular wheels because they will receive more tension. You can also find wheels on the market with a higher number of spokes to absorb less pressure on each spoke, but they may be lower quality.

Depending on their geometry, spokes can be round or flat. Generally, this shouldn’t affect their performance; it’s just a matter of aesthetics.

Depending on the hub anchoring system, the spokes can be bent or straight (also called “straight pull”). Bent spokes are more economical and make an angle to anchor to the hub. It is this angle that is subject to the most stress. Straight-pull spokes go straight into the hub and are more reliable because they spread the pressure across the entire spoke, not just one point.

Types of hubs

The hub is the centre of the rim, where the wheel’s axle is connected to the bicycle. It is more important than it seems because many cyclists do not know what kind of hubs and axles they need when buying mountain bike wheels. Here are the different types of hubs:

QR

This system was used in the past on most bikes, with a width of 100 millimetres for the front rim, 135 millimetres for the rear rim, and a quick release of 5 millimetres.

Thru-axle

With a thru-axles appearance, the same hub widths have been kept at the front and 142 mm at the rear, gaining rigidity with this new type of closure.

Boost system

The Boost system is a new hub standard implemented in 2017 (15 x 110 millimetres for the front wheel and 12 x 148 millimetres for the rear wheel).

This change in width made it possible to increase the stiffness of the wheels by varying the angle of attack of the spokes and obtaining more significant wheel travel, which made it possible to fit wider tires.

Additionally, for bike manufacturers, implementing the Boost system makes it easier to design flatter chainstays that better absorb vibration.

You must take into account the bike’s frame you have because the wheels that use the Boost system cannot be mounted on frames prepared for 100 and 142 mm.

We achieve widths of 20 x 110mm and 12 x 150mm for enduro and downhill.

Findings

If what matters most to you is to improve your mountain bike, you want to see a significant performance improvement, and you have a specific budget aside, the carbon wheels with a boost system compatible with your frame are the best option.

If your budget is tighter, but you still want to improve your bike, you will find 400 to 500 euros aluminium wheels that increase the performance of the standard wheels on your bike.