Road wheel basics
Written by: Greg Kopecky
Added: Thu Nov 21 2013
Yes, those rubber-wrapped donuts on which you propel yourself. Once you’ve been around the sport for a while, it becomes easy to assume that everyone – including beginners – knows what you’re talking about. We assume that they know what ‘aero’ means. We think they know what a ‘racing’ wheel is and a ‘training’ wheel is. We think they know about different wheel sizes, rim materials, construction methods, and nuances of design. I’m guilty of this, and I imagine that many seasoned Slowtwitch readers are, too.
Today, we’d like to take one giant step back and attack the wheel topic from a very basic perspective. What are the truly need-to-know terms? What should I look at when considering a purchase? Should I own two pairs of wheels for one bike, or is one set enough? Let’s get on with this two-wheeled journey…
This is the typical construction of a modern wheel. There are exceptions. Some fancy wheels have spoke nipples that thread in to the hub, with some sort of anchor built in to the rim. For example, some 3T wheels have this reverse-style construction:
Let’s also take a quick look at the most complicated part of your wheels – the rear hub:
All rear hubs must have some sort of clutch or ratcheting mechanism that allows movement in one direction (coasting) and lockout in the other (pedaling). This device is inside of the freehub and/or hub shell, and is typically referred to as a ‘drive mechanism’.
Also note that the freehub in the above photo has more than one name. It is also called a ‘freehub body’, ‘cassette body’, ‘driver body’, ‘driver’, and probably a few other names I’m forgetting. It is the part where your cassette (gears) go. There are different designs of freehubs, which are covered in the article linked at the bottom of this page - Cassette How-To – Part 2. You can also learn how to remove and install a cassette in the first segment of that article, Cassette How-To.
The next thing to understand about road-based cycling (including triathlon bikes) is that there are two different wheel diameters that are primarily used today: 700c and 650c. 700c is larger, and 650c is smaller. For the most part, larger bikes use 700c wheels and smaller bikes use 650’s. For the (very) long version of this discussion, check out Wheel Size Wars, linked at the bottom of this page.
There are other different wheel diameters, as mentioned in the Wheel Size Wars article. We don’t want to get too in-depth and will leave it at this for today.
Tubulars and Clinchers
If you’re new to the sport, you’ve probably heard some people say that their wheels that are, like, totally tubular, dude. Is this sport full of surfer bums? What’s going on?
The word ‘tubular’ is referring to the type of wheel and tire, not how good or bad it is. The old-school name for a tubular is ‘sew up’. This name refers to the construction of the tire – most of them are literally sewn together:
This type of tire gets glued on to the wheel. As such, the rim has a specific shape that must accommodate this:
Here is a look at a clincher wheel, tire, and inner tube:
Clinchers are similar to tubulars in that they have an inner tube that holds air (yes, super-geeks, there are some exceptions out there, such as Tufo’s unique construction). The difference with a clincher tire is that the tube is not sewn in to the tire – it is completely separate and can be replaced.
In addition, most modern test data shows that clincher tires have slightly lower rolling resistance than tubular tires, meaning that they require slightly less effort input from you to roll down the road (tech note: this highly depends on the materials and design of the tire/tube). Clincher wheels are always a little bit heavier than their tubular counterparts, but that in no way assumes that clincher wheels are heavy. It is still possible to build a very light set of wheels; it all comes down to how much money you are willing to part with.
We should also mention that there is a sub category of clincher tires - tubeless clincher tires. These feature special construction and no inner tube at all. For full details, check out our All About Tubeless article linked at the bottom of this page.
Let’s talk about what your wheels are made of. Do you keep hearing about carbon wheels and how great they are? What other materials might a wheel be made from?
The first thing to understand is that it is very rare to have an entire wheel made out of a single material. If someone has ‘aluminum wheels’, it is not as though the rim, hub, spokes, axle, bearings, and every little thing are all made of aluminum. What they’re typically referring to is the material of the rim.
Rim: Aluminum, carbon, magnesium
Hub and hub parts: Aluminum, carbon, steel, titanium
Spokes: Stainless steel, aluminum, carbon, synthetic fiber
Spoke nipples: Brass, aluminum
The tricky part is that the buying process for does not usually get this detailed. Often you see ads for ‘carbon’ wheels, but that could mean a lot of different things. Some ‘carbon’ rims, such as this Easton EC70SL, have a hybrid construction – an aluminum outer rim mated to a carbon inner section:
Racing wheels vs. Training wheels
Do you want a pair of super-fast race wheels? Surely they’re faster than measly ‘training’ wheels. They must automatically gift a free 2mph to your next Olympic distance bike split, right?
Here’s the big secret. Just like tires, there is actually no such thing as a ‘race’ or ‘training’ product. They don’t exist. There are no actual definitions, rules, or governing bodies to regulate those words. Often times people assume that certain attributes are automatic qualifiers in to either category:
“All aluminum wheels are just training wheels.”
“Oh, you have carbon race wheels? Cool!” (implying that ‘carbon’ and ‘race’ are intrinsically linked)
“I’m going to put my race wheels on. I have a deep 60mm front wheel and rear disc, so I’m going to smoke the entire field at tomorrow’s race.”
-Their first priority is strength and durability. This should include not only the rim, but also the spokes and hub design.
-Low cost is also a priority. Replacements must be affordable and readily available.
-Given the previous two points, this means that a training wheel will necessarily be heavier than a racing wheel for a given rim depth and overall design. In auto racing, there is a common phrase that is used for buying parts: “Light, strong, inexpensive – pick two”. It’s true. The word ‘strong’ can also be exchanged with ‘reliable’, ‘worry-free’, ‘long-lasting’, etc. You get the point.
-Things like aerodynamics and aesthetics take a back seat.
-Performance is #1. This means light weight, aerodynamics, low rolling resistance, and overall efficiency.
-Price tends to go up compared to training wheels.
-Looking at our light-strong-cheap scenario from above, we might think that a wheel that is both light and expensive is automatically strong, too. I’ll give a qualified ‘maybe’. While a hike in price normally means that durability increases, it gets complicated with bike parts. It is not uncommon to see a super quality rim laced to sub-par spokes and nipples (or vice versa). Companies know that every penny counts. As another example, many race hubs are super light (and expensive), but have a big compromise in longevity. The actual materials of the hubshell might have an outstanding strength-to-weight ratio. However, that hub might have virtually no sealing from moisture and dirt (for low rolling resistance) – meaning that you must replace the bearings every 6 months. ‘Durability’ of the hubshell says absolutely nothing about the design of the bearing seals; they are two separate parts. Got it?
Here are a few features that you can ask for at the bike shop when making that next purchase.
Good training wheels tend to have…
-Brass spoke nipples
-Spoke nipples that are visible through the rim (e.g. ‘external’ – for easy adjustment)
-Large bearings inside the hub
-Substantial bearing seals and grease
-An aluminum rim that is not the lightest on the market
-A steel freehub (light weight aluminum freehubs tend to be much more fragile)
Good racing wheels tend to have…
-High quality aluminum spoke nipples (e.g. DT Pro Lock)
-Smaller and lighter bearings
-Lighter bearing seals
-Deep-section and/or wide aerodynamic rims
-Aluminum or titanium freehub bodies
Do you NEED two sets of wheels (e.g. a pair of training wheels and race wheels)? Absolutely not. They are nice to have, though. Beyond the obvious speed benefit of the race wheels, having two sets leaves you with a backup in case of a mechanical problem (e.g. broken spoke, bearing replacement, etc).
The topic of rim width is a hot one these days, and I’d like to touch on it from a practical perspective. Many wide rims are legitimately more aerodynamic than narrow rims (especially with modern tire sizes), so the average rim width is slowly growing. That’s all fine and dandy with this editor.
The key implication that this has is it complicates your brakes. If you train on a narrow aluminum rim and race on a wide carbon rim, you must completely change your brake setup when you change wheels. The two rim materials require different brake pads, and the width of the brake must change to accommodate the two rim widths.
If your bike has standard caliper brakes (pictured below), the adjustment is relatively easy. If you don’t know how to do it, your mechanic can probably teach you in about five or ten minutes in exchange for a frosty 6-pack of fermented beverages.
That being the case, I highly recommend buying training and racing wheels that are the same width, and ideally the same braking surface material. If you race on a carbon braking surface, you should train on one too. Same goes for aluminum. If you the two rims have an identical width, you don’t have to do any brake adjustments and life is peachy. You may still have to adjust the rear derailleur slightly, unless the two wheels have the same model of rear hub.
What do you think? If you’re a beginner, is all of the wheel talk overwhelming? Are you confident in your next purchase? We’d love to hear your comments.
We review a high tech pair of aluminum wheels from American Classic, the Argent Tubeless. With wide rims, bladed spokes, and feathery weight, they could be just what your tri bike needs. 1.01.14
Everyone should ride 700c wheels. No, everyone should ride 650c. Is there a happy middle ground? What about mountain bikes? We tackle these questions, and propose a solution. 6.11.13
We continue our How-To series on cassettes. This segment covers the nitty-gritty details of cassette spacers, freehub standards, and what to do in the event of a cassette removal problem. 12.02.12
While common on mountain bikes, many triathletes are unaware of the particulars of tubeless tire technology. We offer a complete overview, along with the key take-homes for the average road-based triathlete. 5.28.12
After two decades of heated declarations and ill-informed pronouncements, there remains not one shred of evidence suggesting one of these wheel sizes is inherently superior to the other. And yet... 3.07.07