It’s that time of year when you’re looking at your bike, thinking about what you can do to upgrade your rig. Well, nothing impacts the performance of your bike more than a fresh set of solid hoops! Yes sir, you will be amazed how much your present set has lost its snappy response. In fact, after two seasons your wheels are more tired than you think.
Wheels endure unrelenting compression and tension cycles as they roll. Add in the lateral force placed on them, and you can imagine the beating your wheels take. Unlike a frame, the wheels feel everything: every little root, rock, boulder, huck to flat, or crash into a tree.
The wheel market is currently booming: everyone and their brother is producing at least a couple of sets. Some wheels are good… and some are not so good. Over the course of this article I will go over the main factors to consider when upgrading your wheels.
I will not define the difference between 26″, 650b, and 29″. Other than an increase in rim diameter, everything else remains pretty constant (except for an increase in spoke count for 29″ wheels).
Tubeless and Tubeless-Ready
Lately we have seen a few innovations becoming much more commonplace, especially tubeless / tubeless-ready wheel sets. Currently, nearly all the big names have a set or two of tubeless wheels. Mavic started it all, followed by Easton, DT-Swiss, Fulcrum, Crank Brothers, Shimano, and others. Other reputable brands like Stan’s, Sun Ringle, Easton (EC70, EA70), Chris King, Industry 9, Syncros, and many others also produce tubeless-ready sets.
A true tubeless wheel does not use a conventional spoke drilling pattern. The common drilling through both the inner bead of the rim and the spoke hole is replaced with a continuous inner bead and some form of spoke fastening. A special valve stem is also needed to finish the wheel at the rim joint. To further prevent air leaks, these rims are welded and not pinned.
Tubeless-ready wheels feature rims that are conventionally drilled but use an inner sealing tape to prevent leaks. Along with that, a sealant is used to further stop leaking air.
Both tubeless and tubeless-ready wheels feature a locking bead which has slight raises where the tire’s bead snaps over and secures in place, preventing it from slipping out.
Tubeless-ready wheels can be run with or without tubes, but some tubeless wheels must be run tubeless.
More and more we are seeing wheels produced with straight pull spokes. The advantage of straight pull over the conventional J-bend spokes is that we can now have a true straight path for the spoke to follow rather than bending around an overlapping spoke. This tends to help spokes keep their tension longer and reduces the chance of tension spikes, which snap spokes. The downside of straight pull spokes is that presently they are harder to find at the shop level. Most shops stock J-bends, but tend to order in the straight pull.
A couple of thoughts on rim selection:
- Typical mid- to high-end wheels use 6000- or 7000-series alloy for rim construction.
- Stay away from single wall rims that are sometimes found on lower-end bikes. If you’re upgrading, double wall is the way to go.
- Spoke holes can be drilled with seats so no eyelets are needed, or drilled with inserted eyelets. I personally think a properly aligned spoke hole drilled and and seated does not require an eyelet.
- Rim width dictates maximum tire size. For example, a 19mm (inside measurement from bead to bead) rim would work with tires up to 2.2 inches. Rims that are 21mm in width work well with tires from 2.2″ to 2.4″, and 23mm+ work well with tires greater than 2.3″. There are some massive rims that get up to a 31mm inside width. Do you need them? Unless you can honestly say “I ride the Rampage,” you’re not in that league of rim.
Hubs can be forged then machined, or machined-only from billet alloy. If you can find forged go with them, as they tend to be stronger.
Bearings are either loose (Shimano) or cartridge, and honestly there are benefits to either one. The big factor impacting bearings and bearing life is sealing. Do your research on hubs and find out how well they stay sealed. A poorly-sealed hub will allow contaminants to enter and destroy the bearings, flush out the grease, and generally mess things up.
When buying hubs the most important is the rear. Look for cassette body materials and points of engagement: this can make or break a wheel set. Some cassette bodies have very fine engagement, which is great if you’re a rider who likes to keep his feet parallel to the ground. With little foot movement you’re on gear again. Fine engagement is great as long as there are enough teeth in contact. Look for at least three cam pawls or more.
When purchasing wheels, keep your braking system in mind. If your bike is not one with disk brakes, then you will need a rim that is made to run V-brakes. Otherwise, be mindful of your rotors. You’re either running centerlock rotors or the well-accepted 6-bolt ISO standard.
The industry has broken wheels down into different classes. In general, today we have Cross Country/Trail, All Mountian/Enduro, and Freeride/Downhill.
XC/Trail wheels typically weigh south of 1800 grams, with the lightest wheels hovering around 1200 grams. These wheels have spoke counts of less that 32. Rim widths are narrow and usually have some trick work done to the rim to reduce weight. High end models feature either a lightweight milled rim or carbon. Hubs are either QR (quick release) 9 or 15mm up front with QR 135 or TA (through axle) 142 in back. Cassette bodies are mostly alloy for further weight reduction. Some brands go to the extent of using alloy spokes. On the top end of things spoke counts drop to 20.
For a trail rider with a bike that has 4-5 inches of suspension travel, go for a wheel with at least 28 spokes and a cross section of at least 21mm. Longer travel bikes encourage a rider to hit bigger logs and drops, so I recommend a wheel with a bit more strength.
AM/Enduro wheels are designed with a balance of weight and strength in mind. Strong rim profiles that take impact better, higher spoke counts, and larger axles are commonplace here. Look for wheels that start at about 1600 grams a pair. There are a few carbon wheels like the Easton Haven that are an astonishing 1450 grams that also fall in this category. Nearly all of these wheels are 15mm or 20mm TA setups up front and range (depending on frame design) from QR 135, 12×135 TA or 12×142 TA rear wheels.
FR/DH wheels are your heavy-weight slope tamers. These wheels feature larger internal rim widths of 21mm or more for DH race and 23mm or more for FR wheels. Typically these wheels range from race weights of 1900 grams to well over 2500 grams for those FR huckers. Wheels with 32 to 36 heavy-gauge spokes are normal, with a few race sets at an alarmingly-small 28 spoke count. Today, nearly all FR or DH bikes are 20mm TA fronts, with 12×135 to 12×150 TA rear wheels.
You also have the option of building your own set or having them custom made. That way, you can choose the rim, spokes, nipples, and hubs you want. For a true match to your bike, a wheel builder will ask common questions like your weight, what kind of riding you generally do, your ability, and your budget.
Our very own dgaddis just opened up shop as a custom wheel builder. Be sure to check out his wheel building company, Southern Wheelworks.
You’re probably wondering, “Now what do I do? Which pair should I buy?” Below is my personal short list (in no particular order). If I was looking for a set of wheels, I’d save up my money for one of these:
Armed with this information you are now equipped to make an intelligent mountain bike wheel purchase. Start working on your wishlist now!