Rims

Mountain Bike Rims Buyer's Guide

The tumultuous nature of mountain bike trails constantly abuses bicycles and their components. Because they are so close to the point of impact, rims are one of the most battered parts on any bike. Rocks, roots, stumps, ruts and everything in between smash into rims head on with only a tire separating the aluminum hoops from the ground. Depending on their intended riding style, rims can either be burly loops of double wall aluminum made to take whatever you can throw at them, or they can be lightweight hoops built for speed. There are also many models that find a balance of strength and weight to provide good all-around performance.

Types

There are four types of mountain bike rim designs: those compatible with rim brakes, disc only rims, tubeless. and non-tubeless. In order to accommodate v-brakes, rims must have a flat braking surface for the pad to make contact with. These rims are not exclusive to rim brakes and are compatible with discs, too. Disc only rims, on the other hand, have a contoured shape to increase strength, provide a sleeker look, and are not compatible with rim brakes. On tubeless rims, the interior wall is not perforated like traditional dual wall rims. This creates an airtight seal between tire and rim. Because of this they require special nipples that thread into the outer wall.

Sizes

Rim sizes vary depending on the total diameter of the wheel and the effective rim diameter. There are three sizes of rim that coincide with the three mountain bike tire standards: 26-inch, 650b, and 29-inch. The effective rim diameter (E.R.D) of a rim is specific to each model. Rims with higher profiles will have a smaller E.R.D and vice versa. This number is important only when choosing the appropriate spoke length.

Materials

Rims are almost all made from aluminum because it is both stiff and light. There are also high-end rims made from carbon fiber, which provides greater strength and lower weight, but at a much higher price.

Things To Look For

When shopping around for a new rim, there are four main things to consider: the type of riding it will be used for, whether or not it will be a tubeless model, the number of spokes the hub accepts, and the E.R.D. Rim manufacturers help simplify choosing a rim by classifying their models according to intended use. There are rims purpose-built for downhill, freeride, all-mountain and cross-country applications. Tubeless tires are quite popular on mountain bikes across all disciplines and there are many tubeless-specific rims to choose from. Next, be sure to know how many spokes the hub requires and choose a rim accordingly (most rims are 32 or 36 holes). Finally, if you are performing a rim swap and wish to keep your old spokes, choose a rim with the same E.R.D.

How Much To Spend

Aluminum dual wall mountain bike rims start at around $35 each and go as high as $750 per carbon fiber hoop.

Rims in the $35-$70 range are available in both rim and disc brake specific styles and are made of aluminum. This range has both lightweight cross-country and heavy-duty downhill/freeride rims, as well as some all-mountain choices in between.

Moving up to the $75-$150 range, tubeless specific rims become available, as well as super lightweight racing rims, strong all-mountain rims, and downhill specific models. These offerings incorporate the best in aluminum rim technology and are the perfect choice for any enthusiast seeking superior performance over a basic rim.

Carbon fiber rims, because of their extremely high price, fall into a category all their own. They cost over $500 per rim and are available from a limited number of companies. Their strength to weight ratio is above and beyond any of the aluminum options and they'll likely last much longer than their aluminum counterparts.

Product Reviews

Before buying, be sure to do your research and read product reviews. Reviews are a great way to find out specifics about a particular model, user impressions, and things to watch out for. After you've purchased a product and had enough time to thoroughly test it, we encourage you to leave a review for other people to see when they are researching bikes and parts on the web.

We hope you've found this information to be helpful. If you have a question that isn't answered in this guide, our mountain bike forums are a great place to get advice from knowledgeable riders. Your local bike shop is also a great resource.