SON hub Flo 45 rim

I value the reliability, aerodynamics, and braking performance of wheels far more than their weight. Complete wheelsets dominate the market, and there are some good ones available, but I don’t discuss which stock wheels I would recommend partly because the models change so quickly and partly because I prefer to build my own wheels so that I can choose the hubs, the number of spokes, and the rims separately. I therefore explain what I look for in each wheel component and why. The most complete and independent comparisons of current wheelsets is at In The Know Cycling, and BikeRadar gave a detailed overview of the topic.

Front Hubs & Dynamos

Many people have successfully done self-supported, ultra distance bikepacking races without a dynamo hub, instead using battery-powered lights, backup batteries, and wall chargers (see the page on Lights & Chargers). However, the majority of racers prefer to have a dynamo front hub to power their lights so that they have no concerns about charge levels.

There are a few budget dynamo hubs available that tend to be heavier and cause more drag (especially when the lights are off) than the higher-quality options described below. Budget dynamo hubs are fine for urban / utility cycling, but I wouldn’t recommend them to anyone interested in long-distance cycling. Compared to using a standard hub, the slight extra drag caused by a good-quality dynamo hub decreases predicted average speeds by about 0.1 kph when no lights are on and no devices are charging, and by about 0.4 kph when something is connected (see the Hub Resistance page).

Shimano make a variety of good-quality dynamo hubs that tend to get model number in the 70’s and above (their budget versions tend to have model numbers in the 30’s and below). Even the best Shimano hubs tend to be cheaper than the other options listed below, but are a bit heavier and have been measured to create slightly more drag for the same power output; in addition, they only come in 32 and 36 hole versions.

The German-made SON dynamo hubs are extremely high-quality, have high efficiency and are available in many hole drillings. The only downsides are that they are the most expensive option and they use slightly different wire connectors than the other options, which can be more fiddly to attach and detach.

Shutter Precision (or SP) dynamo hubs are a high-quality, Asian-produced alternative (they are also sold under other brand names including Exposure). Their hubs are similar to SON in most respects but are significantly cheaper. Being a younger company, the reliability of SP hubs is not as well established as SON or Shimano, but the only problems that I’ve heard about their hubs all involved the thru-axle disc brake version, which they claim to have eliminated in an updated design for 2017 that uses larger bearings. I’ve been pleased with the two quick-release SP hubs (rim and disc) that I’ve used extensively.

There are three ways to obtain a front wheel with a dynamo hub:

  1. Select and purchase the parts (hub, rim and spokes) individually and build the wheel yourself, which requires knowledge and skill to be done well (I recommend starting by reading this book).
  2. Pay a custom wheel-builder to do it for you, based on your specifications and some guidance from the wheel-builder. You could visit your local bike shop or do an internet search to find an expert who is reasonably local. I’m based in Switzerland and offer a wheel-building service myself, see the page on Ride Far Wheels.
  3. Buy a stock wheel that has a dynamo hub. No major brands offer such wheels, but some online retailers offer options, see below. These are also hand-built, but use a stock specification. Most are built as solid wheels with 32 or 36 spokes and touring rims; higher performance options are noted when available. The list was last updated in June 2017.
    • SJS Cycles (UK) offer dynamo wheels with SON hubs.
    • Alpkit (UK) offer an option targeted at gravel bikes using a re-branded SP hub.
    • Hunt (UK) offers a disc-brake option with a SON hub.
    • Bike-Discount (Germany) offer dynamo wheels with Shimano hubs.
    • Bike Components (Germany) offer many rim– and disc-brake options with Shimano, SON and SP hubs.
    • Bike 24 (Germany) offer dynamo wheels with Shimano and SON hubs, including some Citec wheels with a proprietary version of a SON hub with 16 or 24 spokes.
    • Intelligent Design Cycles (USA) offer two dynamo wheelsets with SP hubs, including one option with 24 spokes front and rear.
    • Veloplus (Switzerland) offer dynamo wheels with Shimano and SP hubs.

You may choose to change just your front wheel or both front and rear wheels so that you have matching rims and have the wheels built with the same goals in mind with appropriate spoke counts.

All dynamo hubs are front hubs, no rear dynamo hubs exist. Dynamos that are not in the hub do exist. Some urban bikes have budget dynamos that rub on the tire sidewall, but those are not recommended due to having low efficiency and being unreliable, especially in the wet. Velogical make a high-quality dynamo that runs on the wheel rim; reports of this are good (e.g., Chris Bennett) but I have no direct experience.

Rear Hubs

Most modern bike hubs contain cartridge bearings that can be replaced when they wear out, and so they are preferable for people who don’t want to or don’t know how to occasionally service the more traditional style of hubs that have loose-ball bearings. All Shimano hubs have loose-ball bearings, so I prefer their hubs because I can easily service the bearings when needed.

Unfortunately, there are a couple of problems with Shimano hubs: First, the only models that are available as a hub only and have fewer than 32 holes are the expensive Dura Ace models. Second, all Shimano hubs that are available separately use “J-bend” spokes, which makes it difficult to replace a rear, drive-side spoke; they may therefore be a poor choice for bikepackers who want maximum serviceability.

Spokes can break at any time for a variety of reasons. I therefore advise people to always carry spare spokes and nipples that are the correct length and style for each side of their front and rear wheels, which may mean bringing up to four different spokes and two different nipples. Spokes on the drive-side of the rear wheel are the ones that break most often because they are under the most tension and they can be damaged by the derailleur if it gets knocked out of line or by the chain if it falls to the inside of the largest cassette cog. Unfortunately, these spokes are the hardest to replace on most hubs because the cassette must first be removed, which normally requires special tools.

If you have wheels with 32 or 36 spokes or you have disc brakes then you may be able to keep riding for some distance with a broken spoke, but with rim brakes and fewer spokes then you’ll probably need to fix a broken spoke quite soon, if not immediately. If you intend to find a bike shop when a spoke breaks then which hub you have is not so important because the shop will have the tools to easily remove the cassette; however, you should still carry the appropriate spokes and nipples because shops cannot stock all possible versions. If you want to be self-sufficient in spoke replacement, then consider the design of your rear hub.

To avoid needing to remove the cassette to change a spoke, you can choose a rear hub that uses straight-pull (instead of J-bend) spokes. Another option is that on some hubs the entire cassette body and cassette can be removed from the hub together, either without any tools or with only two 5 mm hex/allen keys. One more option is to use a FiberFix emergency spoke, which is a Kevlar cord that can be attached to the hub without removing the cassette, although it is obviously not a permanent fix. Another option is to carry a special portable cassette removal tool like the NBT2, as shown here; however, tools like that should not be used with carbon frames.

Although Shimano don’t sell any hubs separately that use straight-pull spokes, DT Swiss offer good quality rear hubs that do. The DT Swiss 350 (rim brake: Wiggle, Amazon or disc brake: Wiggle) is not too expensive and made for a decent number of spokes. The DT Swiss 240 (rim brake: Wiggle, Amazon or disc brake: Amazon) is significantly more expensive, slightly lighter than the 350, and some models take fewer spokes than the 350.

I like my rear hubs to be reasonably quiet when freewheeling (i.e., not pedaling), which Shimano hubs always are, and although the DT Swiss hubs start out that way, they soon develop a freewheel noise that can only be silenced temporarily by putting fresh grease into them. I therefore haven’t yet found a hub that fits all of my preferred criteria (sold separately in multiple spoke drillings, uses straight-pull spokes or has a freehub body that can be removed with basic tools, is reasonably quiet when freewheeling, and preferably has loose-ball bearings).

Spokes & Nipples

Wheels with more spokes are less likely to go out of true than wheels with fewer spokes and are easier to re-align when they do. Modern rims tend to be a lot stiffer than those that were made 20+ years ago, so it’s no longer necessary to have 32 or 36 spokes except when using very light rims, on heavily loaded bikes, or on bikes ridden frequently on rough terrain (e.g., mountain bikes). For rim brake road bikes, I therefore prefer to have 24 to 28 spokes on the rear wheel and 20 to 24 spokes on the front. For disc brake road bikes, I would advise four more spokes front and rear because the spokes have to transmit all of the braking forces from the hub to the road. The amount of spokes on most complete wheels that are sold today tend to be at the bottom end of these ranges or below because so many people focus on weight and looks when buying wheels rather than durability.

The difference between a 24-spoke and an equivalent 28-spoke wheel was measured in the wind tunnel by Flo Cycling. The conclusion was that the weight difference of 30 grams would have basically zero effect and the aero effect would result in 2 seconds per 40 km, which could mean 3 minutes over a 4000-km route. Normally, the extra rigidity and security of having more spokes is more than worth this minimal cost.

The cheapest spokes are plain gauge, meaning that their diameter is constant throughout their length (typically 2.0 mm). Butted spokes that are thinner in the middle section than at the ends are only slightly more expensive, are lighter, and should be more durable because the narrower central section gives them some elasticity and the butting process actually adds strength (see this article). Butted spokes with extremely narrow central sections (e.g., 2.0 mm at the ends and 1.5 mm wide) tend to be a lot less rigid and are more difficult to build with and maintain because the spokes easily twist instead of the nipple tightening. I therefore prefer more moderately butted spokes (1.8 mm in the center) like the DT Swiss Competition (Amazon).

If you want the ultimate in lightweight spokes that are strong, are easy to build with, and are more aerodynamic than standard spokes, then bladed/aero’ spokes are an excellent option. A tool can be used to stop bladed spokes from twisting while building or truing the wheel, which is a massive advantage, and the extra forming process again adds strength (again, see this article). Unfortunately, bladed spokes cost much more than round spokes. I tend to use the DT Swiss Aerolite spokes (Amazon), but Spaim CX-Ray spokes are also very good.

Using aluminum spoke nipples is popular because they are slightly lighter than brass nipples and come in a variety of colors. Unfortunately, most aluminum nipples are easily damaged when trying to true the wheel, the only ones that this is not true for is the oversized aluminum nipples used on some specifically-designed rims by Shimano, Mavic and others. For all rims that take standard-sized nipples, brass nipples are far more reliable, they are available in silver or black, and the weight penalty is only about 1 gram per nipple (e.g., these DT Swiss black brass nipples at Amazon). Aluminum nipples may also corrode if the wheel is used extensively in wet conditions and using tubeless tire sealant can cause aluminum nipples to corrode.

Rims

Characteristics

The front rim and tire are the most important parts of the bike for aerodynamics (see the Air Resistance of the Bike page). Rims that are less than 30 mm deep are considered shallow and within these the differences in aerodynamic performance are small. Mid-depth rims in the 30-50 mm range can make a significant improvement in aerodynamics over shallow rims. Modern rims in this range perform reasonably well in all but the strongest crosswinds without greatly affecting bike handling. Deep rims (over 50 mm) are not so suitable for unsupported ultracycling because they can cause problems with bike handling in severe crosswinds, and so may be a problem on some sections of the route.

Deeper, more aerodynamic rims traditionally had a simple V-shape (e.g., Mavic CXP rims), but modern testing has shown that rounder, U-shaped, rims are far better aerodynamically, particularly in cross-winds. There is no objective aerodynamic data available for most rims, so often the best that can be done is to estimate the aero’ properties based on how deep the rim is and whether it is U-shaped or V-shaped.

It is far easier to make a carbon rim deeper, wider, and more aerodynamic without causing a significant increase in weight than it is to make an aluminum rim with the same properties. Unfortunately, using full-carbon rims on rim-brake bikes can cause problems because the braking on carbon is never as good as it is with rims that have an aluminum braking surface, and this difference becomes quite extreme in wet weather (regardless of the brake pads used). Full-carbon rims are also far more susceptible to problems of overheating the brakes, possibly blowing out the tire and/or damaging the rim. One solution is rims that have an aluminum braking surface but a carbon structure or fairing for aerodynamics. With disc brakes, full-carbon rims cause no problems but do cost more than aluminum rims.

Rim width may be as important as rim depth in terms of aerodynamics. This was discussed on the Air Resistance of the Bike page, with the general finding being that the front rim should be wider than the tire to optimize aerodynamics, but this is far less important on the rear. Tire width has a significant effect on comfort, so that is discussed on the Saddle, Shorts & Tires page. Having a front rim that is as wide as possible can therefore allow more comfort without compromising aerodynamics. If using tires wider than about 28 mm, any differences in aerodynamics between different rims will probably be negligible because of the turbulence created by the tire.

The final important characteristic of road rims is whether they are designed for tubeless tires or not, meaning that they have an appropriately-shaped hook to safely hold a road tubeless tire on under high pressure (check this with the rim manufacturer). There are advantages and disadvantages of using tubeless tires, as discussed on the Tire Rolling Resistance page, so this is a matter of personal preference.

Rim Options for Rim Brakes

Rims for rim brakes are listed in the table below, including most of the options that are readily-available as rims only, are at least 21mm wide, and have an aluminum braking surface.

Brand & Model Material External
Width
Height Shape Wind TunnelData Tubeless
Compatible
Weight (g) Hole Drillings
Available
Price
(USD)
Astral Radiant Alu 23.5 32 U No Yes 495 20-32 $135
Astral Solstice Alu 22 22 U No Yes 425 24-32 $135
CBK CA50C-25 *1 Alu/Carbon 25 50 U No No 590 16-32 $200
DT Swiss R460 Alu’ 23 23 U No Yes 460 24-32 $40
DT Swiss RR511 Alu’ 21.5 32 U No Yes 530 20-32 $85
Flo 30 Alu’ 26 30 U Yes Yes 570 20-32 $80
H Plus Son Archeype Alu’ 23 25 V No No 470 20-36 $70
Halo Carbaura A Alu/Carbon 23 38 U No Yes 535 20-24 $250
HED Belgium Plus Alu’ 25 24 V No Yes 465 20-32 $150
Kinlin XR-22 Alu’ 24 22 V No Yes 440 20-32 $68
Kinlin XR-31T /
BHS C31w /
Halo Devaura
Alu’ 24 31 V No Yes 485 16-36 $75
Mavic CXP Pro *2 Alu’ 19 24 V No No 470 32 $55
(Amazon)
Pacenti Forza Alu’ 25 26 U No Yes 460 20-32 $109
Velocity A23 Alu’ 23 20 V No Yes 450 18-36 $88
(Amazon)
Velocity Quill Alu’ 25 25 U No Yes ? 20-36 $127

*1 Several similar rims by CBK with other depths and widths are also available. Prices are not listed on their site, contact them for a quote.
*2 The Mavic CXP Pro is a very old design that is only included for reference as a classic option; it is poor on almost all characteristics except price.

Everyone has their own criteria, but personally I would choose a rim that is at least 24 mm wide and 30 mm deep to optimize tire shape and aerodynamics. This leaves only 3 options from Kinlin, CBK, and Flo. The Kinlin XR-31 comes in a regular version and in an asymmetrical version that is good for building a rear wheel with more even spoke tension (as does the Velocity A23); however, although it is officially tubeless compatible, the offset holes on the asymmetrical version of the rim cause a lot of problems when getting tubeless tires to inflate without replacing the rim tape every time, but it is fine if using inner tubes. However, the shape of the BHS/Kinlin is a simple V-shape, so it’s unlikely to be any better aerodynamically than several of the shallower options.

The Flo 30 is the only rim with wind tunnel data to validate the aerodynamic claims. The only drawback of the Flo 30 is that it is slightly heavier than the other options around the same depth, but that also makes it more solid and so fewer spokes are needed, plus small weight differences aren’t actually very important (see the page on Weight).

The aluminum/carbon rims sold by the Chinese company Carbon Bike Kits (CBK) look very interesting because they should be quite aerodynamic and still offer reliable braking. I haven’t been able to try one myself yet, but I’ve been pleased with the performance of similar ‘hybrid’ rims that I’ve used on complete wheelsets from other brands. Halo (a UK-based brand) appear to be offering the 23mm-wide, 38mm-deep version of this rim under the model name Carbaura, but with only one spoke drilling offered (20-hole front, 24-hole rear for 16 drive-side and 8 non-drive-side spokes). Halo are also using the 50mm-deep version as part of a complete wheelset that BikeRadar gave a positive review of.

Rim Options for Disc Brakes, Aluminum

Aluminum rims for disc brakes are shown below. Some of these rims can be used with either rim brakes or disc brakes, but only the drilling options with at least 24 holes are included in this table and the next because that is the minimum amount on disc brake hubs.

Brand & Model Material External
Width
Height Shape Wind TunnelData Tubeless
Compatible
Weight (g) Hole Drillings
Available
Price
(USD)
Astral Radiant Disc Alu 23.5 32 U No Yes 495 24-28 $135
Astral Solstice Disc Alu 22 22 U No Yes 425 24-32 $135
Astral Leviathan Alu 23.5 32 U No Yes 515 32-40 $135
Astral Wanderlust Alu 25 23 U No Yes 450 24-32 $135
DT Swiss R460db Alu’ 23 23 U No Yes 450 24-32 $40
DT Swiss RR511db Alu’ 21.5 32 U No Yes 490 24-32 $85
Flo 30 Alu’ 26 30 U Yes Yes 570 24-32 $80
HED Belgium Plus Disc Alu’ 25 24 V No Yes 465 28-32 $150
Kinlin XR-22RTS Alu’ 24 22 V No Yes 440 20-32 $68
Kinlin/BHS XR31TS/
Halo Devaura Disc
Alu’ 24 31 V No Yes 500 24-32 $75
Pacenti SL25 Alu’ 25 26 U No Yes 450 24-32 $109
Stan’s NoTubes ZTR Grail Alu’ 24 25 U No Yes 460 24-32 $105
(Wiggle,
Amazon)
Velocity Aileron Alu’ 25 28 U No Yes 460 24-40 $127
(Amazon)

The Flo 30 rims are delivered with a black braking surface that gets worn off quickly if using rim brakes, but would remain black if used on a disc brake bike. All other rims are disc-brake specific with no braking surface. The Flo 30 rims are again the only option with proven aerodynamics, and all of the others are narrower and/or shallower.

Rim Options for Disc Brakes, Carbon

Full-carbon rims for disc brakes are shown below. Full-carbon rims pose no issues when using disc brakes except for being more expensive. Carbon rims can be made wider and deeper for improved aerodynamics without increasing weight significantly.

Brand & Model Material External
Width
Height Shape Wind TunnelData Tubeless
Compatible
Weight (g) Hole Drillings
Available
Price
(USD)
Astral Hollywood Carbon 29 22 U No Yes 390 28-32 $650
BDop DTO-40 Carbon 26 40 U No Yes 420 24-32 $299
CBK WR45C *1 Carbon 25 45 U No No 460 24-32 $150
Curve G4 25 *2 Carbon 25 25 U No No 390 24-32 $500
ENVE M50 *3 Carbon 27 28 U No Yes 370 28 $975
ENVE SES 3.4 Carbon 26 35/45 U Yes Yes 410 24 $975
Flo 45 Carbon Carbon 24 45 U Yes Yes 480 24-32 $399
Light Bicycle U-45 *4 Carbon 25 45 U No Yes 475 24-36 $170

*1 Several other depth options are available.
*2 Deeper rim options are available as complete wheels, contact Curve to inquire whether they can supply deeper rims separately.
*3 ENVE M50 rims are designed as 29er MTB rims, but they officially say that road tires down to 25 mm can be mounted on them, which makes them an alternative to their road rims if more than 24 spokes are needed (see here).
*4 Light Bicycle also have 25, 35, and 55mm deep versions available, and a narrower V-shaped rim option.

There is a very large variation in prices between the carbon rims, which is partly explained by the manufacturing location and distribution model. Light Bicycle, CBK, and BDop are all based in Asia and sell direct to consumers, so their prices are the lowest but their quality and service is less certain (I’ve used some of the BDops myself and had no problems, and people have reported being satisfied with the other brands). Curve and Flo are small Australian and American brands that sell Asian-produced rims direct to consumers; they should be easier to deal with than the Asian brands if any after-sales service is needed. ENVE sells American-made rims through distributors and then retailers, so the production costs and profit margins in each link of the supply chain increase the price considerably without necessarily increasing the value.

All of these options except for possibly the Curve 25 and Enve M50 should be reasonably aerodynamic, but the Flo 45 and Enve SES are the only ones with actual wind-tunnel data to support these claims. Personally, if I was looking for something in this category then I would choose the Flo 45 due to it having proven aerodynamics, a reasonable price, and decent after-sales service.

Conclusion

Hopefully this information has helped you to decide what wheel components are best for you, your preferences and your type of riding, and you may also realize that stock wheelsets can’t satisfy all of your requirements. You could therefore try to use one of various step-by-step guides that show you how to build a wheel yourself. Wheelbuilding can be a very satisfying process, but it takes some skill to do it well.

If you’d like to get a pair of custom wheels built for you then ask at your local bike shop, search for one of the web-based businesses that offer the service, or you can contact me to build you some Ride Far Wheels. I’ve built several hundred wheels including many that have been or will be used in the Transcontinetal Race and Trans Am Bike Race.

prevnextThe next two pages cover gearing, starting with Gear Shifting.