Wheels are among the most confusing components you can buy for your mountain bike; there’s a seemingly endless array of choices, all with their own set of claimed benefits.
Factors to consider –
2) Tubeless or not?
3) Rim Width
When it comes to mountain bikes, one can choose from 26 inch, 29 inch or 27.5 inch (650b) wheel diameters. Here is a short jist of the pros and cons of each of these –
26er – Smaller wheel base makes the bike more maneuverable and easier to accelerate or decelerate since inertia is lower. Over rough terrain the ride quality will be slightly rough compared to the 29er and 27.5 size wheels
29er – Bigger wheel size means the wheels will carry more momentum and the ride will be smoother over rough terrain. However, due to the size, manouverability is not as nimble as a 26er
27.5 (a.k.a. 650b) – Just like its size, this ends up being the jack of all trades. Has the advantages and disadvantages of the 26er and 29er to a lowered extent.
So what wheel size should you choose? Well, if you already own a bike and are just looking to change the wheelsets, then you will be restricted in choice to your original size of wheelset due to suspension and brake clearance/lengths on your existing bike. As for someone who is looking at picking up a new mountain bike, I would say there’s no better way than to test ride a few bikes before seeing what suits you best.
Tubeless or not?
There’s a lot of talk now a days about going tubeless on mountain bikes. Tubeless set-up’s might take longer to get started with, but when one looks at the advantages that they offer a rider, especially if riding on terrain where the chances of getting a puncture are high, they do make good sense. Also, these tires can be run at lower pressures than non-tubeless wheels, hence giving a more comfortable ride over rough terrain, if required.
Moreover, some tubeless rim designs are also inherently stronger and more durable than traditional ones so there’s little reason to pass over that feature.
So if you are looking at going tubeless, make sure the rims chosen to build your wheelsets are tubeless ready rims.
Rims these days are trending wider (and keep in mind that the critical dimension here is internal rim width, not external). While 19mm used to be the standard for mountain bike wheels, the typical dimension is more like 21 to 23mm with some models going up to 30mm or more.
With wider rims, tire stability, contact patch size and air volume increase, which aids in providing better traction. Though generally this is accompanied with a slight weight penalty. So it would be wise to keep your intended use in mind. For cross country riders where grip is not going to be as much of an issue, narrower rims make better sense.
Also, some tires are less rounded than others. And on wider rims, if one installs tires of that kind, the contact surface ends up getting quite squarish. Not that it’s a bad thing, but just something to keep in mind for performance riders since it does impact rolling resistance of the tire.
Lighter wheels are generally preferred over heavier ones, all else being equal. The reduced mass not only equates to easier climbing but also quicker handling as there will be less of a gyroscopic effect to battle when changing directions. Even braking performance is improved as there’s less rotational inertia.
Lower weight should never be pursued at the expense of your particular durability requirements, however, and of course, less is more when it comes to cost. Those lighter wheels are fun to ride but you’ll also spend a pretty penny in the process.