Aero Bike Wheel Buyers Guide | By an Engineer

This video was requested by lots of viewers and it covers the selection and purchasing of bike wheels. The main topics are covered in detail and more specific info can be found in my other videos if you are interested.

More data and the full guide are located here

An Aerodynamic Masterclass in Bike wheels

Angular Contact vs Deep Groove Ball Bearings

Zipp Wheel Dimples

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Recommended Wheels

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[Hambini]

Any feedback on this type of video is gratefully received!

[ksbbkr]

Being an engineer - applied mathematics - and an avid cyclist I find this video extremely well made and very informative. Thank you.

[tubbista]

I just wanted to say that you influenced both my decision which bike to buy and also my decision to get my bachelor's degree in mechanical engineering. So far both decisions have worked well. I am already looking forward to becoming 5.

[LarsRR]

I enjoy this content much more than the reaming stuff. The latter can be funny from time to time, but gets old quite quickly and feels a little forced.
This flexing of your in depth knowledge is much more interesting for me.

[johnfarrell]

Excellent video really informative and no shit-show commercial advertising BS . It’s great to have factual engineering guidance on such critical & expensive bike parts 👍🏻👍🏻👍🏻

[Mapdec]

Good vid Hambini. I’m halfway through my own video like this, was worried you would cover it all, but there is still lots to add from a mechanics perspective. Durability, spoke tensions, spoke types, nipples, hub (lack of) quality! Agree with you that online reviews are copy and paste waste of space.

[charlesgraham]

ima old man from America, iv watch a few of your videos, love your dry smartass humor. i don't even ride a bike. last time i bought a bike it was in the 80s and it cost me 460 bucks and 8 months of saving working at 7-11 u have a new sub now and it's not only that your funny, i believe you're really trying to help people. plus, u also break down design flaws, homemade frames that the geometry isn't right nor the fit and finish for the cost. your humor is the bonus. again, thank u for your time.

[sparkvideos]

Great vid. I glanced over at my trusty old C50s as I watched. Shallow alpha critical angle, clean transition, bladed spokes, hidden nipples - all check. I’m now basking in the warm glow of a 5 year old's validation. 😊

[acecurry]

Bit of a throwback to some of your earlier videos with less opinions and jokes (which are massively entertaining) but loads of really useful information explained well.
As a sidenote, yourself @Hambini and @Peaktorque inspired me to start studying at age 31 to become a mechatronic engineer and your videos do bring some real life applications to the learning materials I'm studying, and also highlight the challenges of manufacturing / Lazy building techniques and sloppy standards in the bike industry.
So thanks for that, and keep it up. Videos like yours will hopefully one day bring about change in the standards held in an industry with exponentially increasing prices.

[lukaskaciasvili]

Long time subscriber here and I need to say I love this style of video. Great job! Often, I found your traditional style of videos funny, but this style may have far better reach in wider audience. And more ppl understand that reviews on cycling websites and channels are just dishonest ads, the better. Good job!

[richardguggemos]

Hey Hambini! Love your hair, you’ll have to introduce me to your hairdresser.

Let me challenge your presentation, if I might. You start by pointing to the futility of using air tunnels to evaluate wheel (and bike & rider) drag. Something with which I agree. But you then go on to make recommendations based on general aero concepts/rule of thumb and even make some watt estimates of savings (3 watts for hidden nipples, for example). Without some established mathematical basis, these general rules can’t really lead to good recommendations and you’ve offered no alternative basis to replace the wind tunnel estimates.

As far as I know, the general body of aero knowledge has established that small low-speed profiles have different aero characteristics as compared to larger profiles at higher speeds. Most of the research related to this body of knowledge appears to come from work done with small windmills (think personal electricity generation) and model planes. But there is plenty of published work available in this realm.

From spokes to frames, the profiles related to cycling are small and operate in a low-speed environment. So aerodynamics that apply to automobiles and jet planes don’t simply translate to cycling.

And many of the profiles that marketing wankers push have the added complexity of dynamically changing as they are presented to airflow even when that airflow is stable.

There is also the difficulty of keeping profiles properly pointed to the wind (in sailer speak) when the bicycle is traveling in a straight line and the wind direction is steady.

Finally, there is the whole cumulative impact of small gains concept which argues from the assumption that there really are many small gains to be had, and that each can be built in independently of each other so they truly add up like 1 + 1 = 2. Instead let me suggest that each of these gains is sensitive to a variety of different factors (assuming that they can be realized at all). So each factor need to be adjusted by this and that sub-factor and probability of same. This leads to the assumed additive model being fragile in practice. Statistics is a relentless bitch.

Given these considerations, general aerodynamic rules of thumb (apart from frontal area) can’t easily be applied to cycling.

Let me offer a few examples related to wheels:
1) I believe that effective drag reduction with small low-speed airfoils require a profile with an aspect ratio of at least 10:1, not 4:1.
2) The top of the wheel (which is moving into the wind faster, due to rotation, than any other portion of the wheel) produces the majority of wheel drag. The profile the top presents to the wind is quite unlike any pictured cross-section profile used to describe a wheel/rim combo. All the discussion/analysis of bike wheel profiles ignore that only a brief band of the frontal area conforms to the conventional cross section diagram. Hence discussions of shape, aspect ratio, trips and stalling affect based on this limited area of the wheel are not a good proxy for what occurs over the rest of the wheel.
3) Wheels (especially the front) are rarely pointed into the wind. First, cyclists move around on he road and both the movement and the turning & leaning related to same alter the wind direction. Second the wind can and does at various times come from all points of the compass. While there are prevailing weather and geographic factors that can make prevailing winds less than random in direction, the addition of route choices should make sure that, overall, wind direction is random. Depending on wind strength, this can dramatically impact apparent wind direction and speed on bicycle components, and thereby further dynamically alter the profile presented to the air.
4) The leading edge of a profile is by far the most aerodynamically important. For our wheels, that means he tires, not the rim. Some years ago, Reynolds offered aero down-tubes to frame builders. An American builder, preparing to build a frame to attack some track TT records had contacts in the Sandia National Labs for wind tunnel testing and computed flow analysis (Sandia being a place with powerful compute capabilities). It turned out that the tube didn’t reduce drag unless it was turned around backwards. The front edge was round leading to flow separation which the rear tapered edge couldn’t recapture. Because the down tube slopes, it actually presented a modestly parabolic shape to the airflow. While parabolic leading edge are generally preferred for drag reduction, this tube, even at its angle, didn’t have enough parabolic taper to reduce drag. Our tires don’t present parabolicly either. And I suspect riders wouldn’t really like their handling characteristics if they did. Perhaps one day a tire manufacturer will build a parabolic tire and we can find out. But with the limited control we have over tire shape, it’s not clear to me that rim design is the answer to our aero-prayers.

I could go on, but I not trying to dump on you or troll. But I am curious about whether you’ve done much study into small low-speed aero profiles? I’m no engineer, so you know many things that I don’t. And if they relate to my analysis above, I’d love to learn from you.

Best regards,

[sdsdsd]

Superb video, for us no techies a list of specs that you'd recommend would be useful ie: this internal rim width, with this rim depth/profile, this bearing size, these manufacturers

[Dubadai]

Great video! The only thing I have trouble with is actually applying all the information into picking a wheelset. I understand that it might be difficult to give recommendations, but if you could give a few options based on everything in this video, I think that would be super helpful.

This could of course also apply to frame sets and whatever else.

[torstencx]

I'm mostly interested in wheels that look cool because considering my abilities to pedal this is the only factor that really matters! Interesting vid nonetheless!

[gregbyrne]

21 minutes and 0 grams of BS. Great video, exceptionally useful and well put together. Thanks Mr H.

[Tommy]

Absolutely brilliant video, thank you so much 👍 this educational format to kill the marketing bs of cycling companies is definitely a winner 👏👏👏

[mikeadb]

I’m sure I’m going to have to watch this a few times. I’m a physics geek but this had extremely high technical information density even for me. It was very helpful and matter of fact too.
The Hambini in my head completed your sign off catchphrase for you btw 😜

[johnbiggs]

Excellent video. The only comment I would add is that with Shimano hubs, you will get water ingress and the bearing surfaces will rust, ruining the hub. I now use hubs with cartridge bearings after 4 Shimano hubs were all ruined from water ingress. And no, I do not jet wash my bike.

[tylerkronebusch]

Commenting to boost the numbers. I’m a fat f**k so it’s still cheaper for me to skip the Big Mac but I do appreciate helping me see through the marketing crap. Thank you.

[aeonsnarfus]

useful information and learning opportunities per minute of video = Hambini FTW, absolute legend, full stop.