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A buyer's guide to road bike wheels

Stu Bowers BikesEtc
1 Mar 2017

Upgrading your existing road bike wheels can be a daunting process, but we've put together some options to make things a little clearer

Page 1 of 2A buyer's guide to road bike wheels

When it comes to adding speed, stability and sexiness to your bike, the best place to spend your money is on a new pair of wheels.

But buying wheels has become a complicated business recently. If you walk into a bike shop and enquire after a set of high-end road wheels, you’re likely to be met with something akin to an interrogation. 

Would sir or madam like disc or rim brake? Carbon or alloy? Thru-axle or quick release? What rim depth? 30mm, 50mm, 80mm? What sort of riding are you mainly doing? Racing, sportives, gravel, time-trial?

What about internal rim width? Tyre preferences? And, of course, how much would you like to spend? The best of the best can set you back up to £4,000. That’s correct: £4k. 

When Cyclist asked a few major UK retailers (both online and high street) what the most popular wheel upgrades were, it seems that their customers are happy to spend four figures (and not always beginning with a 1), with the preferred style being carbon rims with a depth
of about 40mm.

So is that the best type of wheel to go for? We put the question to some of the world’s leading wheel manufacturers.

Brave new world

‘We’re at a really interesting point for wheels, particularly as disc brakes become more popular globally,’ says Jason Fowler, wheel product manager at Zipp.

‘Disc brakes speak to a lot of people and as that wave comes we will look at advancing wheel technology in line with that. It means we can explore new designs, but there are still a lot of rim brake bikes out there and we can’t just stop thinking about those customers, so we’ll keep pushing in that sector too. 

‘On the rim brake side in terms of performance, for Zipp it’s currently about focusing more on side-force reduction in conjunction with aero benefits, as we have done with the [recently launched] 454 NSW,’ he adds.

‘So the progression might be to see if we are able to apply this to even deeper wheels.’ 

Fowler’s implication is that soon we could all be looking to ride deeper wheels more of the time, because technological advances will mean they become less susceptible to crosswinds, and riding fast on a blustery day will no longer be such a white-knuckle struggle. 

This sounds like an appealing notion, and perhaps we’ll all soon be blasting around on 80mm rims day in and day out, but this is just one perspective on the perpetual problem that deep section wheels face in crosswinds. 

‘Stability solutions vary,’ says Jordan Roessingh, product manager at Bontrager Wheels. ‘For sure we value stability as very important, but we primarily optimise our rim shapes around pure drag.

‘That allows us to use a lower rim section for a given speed and we can achieve a 50mm rim that is as fast, or faster, than our competitors’ 58mm rims. A shallower rim is lighter and also has lower side force, so you can use it in more varied conditions.’

Stability is plainly a hot topic, but as yet it doesn’t dictate the best rim depth for your perfect pair of upgrade wheels. In which case, let’s turn our attention to rim widths, which seem to be increasing all the time.

The wider issues

Where once aerodynamic rims were deep and thin, like blades, increasingly external rim shapes have become wider and blunter. Despite going against logic, these more rounded rims have proven to produce less drag as well as less side force in a crosswind. 

Hed and American Classic were early exponents of wider rim dimensions, and now the majority of high-end wheel rims are getting wider, both externally, with some ballooning out to a bulbous 27mm, and internally, widening from a once standard 13-15mm to over 20mm
in some cases.

The knock-on effect of these wider internal dimensions is that it encourages the use of wider tyres, which in itself is having a significant impact on wheel performance.

A wider tyre in a wider rim has more of a ‘U’ shape and less of a lightbulb shape, which is less disruptive to the airflow across the tyre/rim. That means wider 25mm or 28mm tyres can be more aerodynamic than traditional 23mm tyres, as well as having the benefits of improved grip and greater comfort.

So is it just a case of opting for the widest rim with the widest tyre that will fit in your bike?

‘We tested various internal rim widths for the effect on tyre shape and frankly 17mm and even 19mm did not produce the same kind of benefits as 21mm could,’ says Zipp’s Fowler.

‘But that’s not to say 21mm will work best for all rim depths. From what we’ve seen you need to evaluate internal rim width on a case-by-case scenario.

‘The kind of rider that uses an 80mm deep rim will probably be using a different tyre width than someone riding a 40mm deep rim, so you have to ask what tyre width speaks to the rider and look at what internal rim width works best for that scenario. You can’t just replicate the same thinking across the range. It doesn’t scale the same way.’

No guarantees

Maxime Brunand, road concept manager at Mavic, is also quick to point out that going wider isn’t necessarily the golden ticket to improving overall performance: ‘More than 80% of our 2017 range integrates wider rims, but this design evolution has to take into consideration every aspect.

‘Meaning: wider to what extent? Wider rims could lead to heavier rims, resulting in higher inertia. Winning only on the aero side can’t compensate for the additional power consumption if the rim is wide and heavy.

‘There’s a balance to find the sweet spot. Another factor to take into account is safety: some combinations of too wide rims with “too narrow” tyres have proven to be unsafe [with tyres blowing off rims]. Developing wheel/tyre systems is a guarantee for our consumers to always
buy the best combination.’

Mavic is a believer that the way forward involves developing wheels and tyres in conjunction, and indeed it has been doing just that since 2010.

Its CX01 concept directly addressed the airflow across the rim and tyre surface to create what it claims is the lowest wheel/tyre drag ever measured (although the system didn’t achieve UCI approval).

It seems like a sensible move, so why aren’t we seeing more of the big brands creating specific wheel and tyre combinations? Zipp’s Fowler has the answer.

‘We do a lot of our testing with our own tyres and yes, we can optimise our rim designs to work best with certain tyre widths, but we also realise that consumers are unpredictable and want a choice,’ he says.

‘Long-term I could see more system integration of tyres and wheels as a package, but the voice of the customer has always been unanimous – they want choices, and we can’t ignore that.’

Weighing up

Amid all the discussion of rim depth, widths and tyre compatibility, there’s one subject that has yet to raise its head: weight. It’s often the area that cyclists obsess over most, so is it equally important in the choice of wheelsets?

‘There has been a shift in market perception,’ says Fowler. ‘As bikes have got much lighter there is less of a focus on wheel weight. Braking performance and going faster are more important for the consumer now.

‘You will always have weight weenies but it has been proven that aerodynamics matter more, even when climbing. About 10-12 years ago when we were trying to sell aerodynamic performance, the push back we always got from consumers was, “Well, what does it weigh?” But that’s usually one of the last questions that comes up now.’

Roessingh at Bontrager agrees, saying, ‘Weight in terms of the overall ride experience is much less important than it once was. Aero and comfort are significantly more important parameters assuming you’re comparing within a reasonably narrow window of weight.

‘Obviously if we’re talking pounds that’s a different story, but a small amount of weight is less of an issue.’ 

‘It’s kind of “easy” to create the lightest wheels,’ adds Brunand at Mavic. ‘But as of right now it’s about price, production cost, reliability, rigidity… weight is not the only consideration.’

Make your mind up time

Where does this leave us in our search for the perfect wheel upgrade?

‘I would argue there is no such thing as one wheel to do everything,’ says Roessingh. ‘People really need to question how they are actually using products. We often find that consumers buy based on being aspirational.

‘By that I mean they think they are going to be riding around everywhere at 40kmh. But the reality is they’re not. Just as they aspire to ride gravel or dirt on their road bikes because it’s a new trend, when in reality they spend the vast majority of their time on paved roads.

‘These are two very different scenarios but in both cases you see there are significant compromises in trying to find a single solution.’

Fowler remains a little more open-minded. ‘The ideal world scenario would be to have the [low] aerodynamic drag of the Zipp 808 with the [low] side force of the 202. But unfortunately that doesn’t exist today,’ he says.

‘That said, it’s still written on the board at Zipp because of course that notion is what really led us to the 454 and we will continue to chip away at that. Today, though, that wheel doesn’t exist.’

‘There’s no one single answer,’ adds Brunand. ‘There are too many variables. Race or tour? Heavy rider or light rider? Nice tarmac or poor pavement? Need for speed or quest for comfort?

‘Plus a 25mm rim [depth] will always be easier to steer than a deeper one, whatever some brands would like you to think! It’s just basic physics.’ 

The message seems to be to match your products to your requirements, which means you may have to endure an interrogation from the bike shop salesperson after all.

Key questions

Don't part with your cash before you've assessed your needs. ‘The biggest problem with the current wheel crop is a lack of education,’ says Jonathan Day, director of Strada handbuilt wheels.

‘People don’t understand what they need. We get a lot of customers who don’t know what a thru-axle is.’ 

So, here are the points to consider:

Rim depth – how much importance do you place on aerodynamic speed versus stability in crosswinds? 40mm is probably the limit for total confidence in all conditions.

Rim width (external)– wider can be faster aerodynamically but it depends a lot on the width of tyre. Be realistic about your bodyweight and riding expectations (eg, do you want to go off road?), as wider may also provide added stiffness/strength.

Rim width (internal) – important as it determines the overall shape of your tyre. An inverted ‘U’ profile has proven aerodynamic and contact patch benefits over a ‘lightbulb’ shape, and wider internal rim dimensions help achieve this. But it depends on the width of tyre you use.

Tyre width – wider tyres deliver more grip and comfort (and off-road capability), but are heavier and increase frontal area, so it’s about matching your requirements and expectations for the best outcome, relative to the rim dimensions.

Tyre compatibility – tubeless, clincher or tubular are the options, but tubular is practically extinct now save for devout racers and pros. Tubeless requires more faff initially but has many pluses – low rolling resistance, comfort, puncture protection – once you’re set up.

Hub type – if you’re using disc brakes, make sure your hubs are compatible with your bike’s spec. Is it quick release or
thru-axle, and which of the varying axle standards do you use? Many hubs simply use different end caps to adapt, but check.

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Page 1 of 2A buyer's guide to road bike wheels