Aero Wheels not worth it?

rwoofer

GCN Tech did a great video on cheapest aero gains and one of the worst value for money upgrades were aero wheels
https://youtube.com/watch?v=hd0fXhDkH84

At 35kph (a reasonable speed) the saving from standard to aero wheels was only 5W. This rather suggests that light weight is a much more advantageous attribute that aero, which seems to go against all other advice you read. Did they get it wrong, or indeed are we all falling for the marketing BS.

Personally I've found the sweetspot for wheels to be semi aero (eg. 32mm) lightweight wheels.

thecycleclinic

Man your simply wrong on this. 5w vs what exactly. There are tests that show over double that and I dont mean Micky mouse ones either. You should work out time saved rather power saved.

The sort of gain 50mm aero wheels give you at 30 mph is 1 kph. Not a lot but something.

The deeper the rim the more aero it is. 32mmm deep well that not that aero and you may be adding 0.3 mph maybe 0.5 mph to you speed vs a set of mavic kyrseriums.

timothyw

Haven't watched the video yet, but I built up a set of 60mm rims for myself a couple of months ago and I was absolutely stunned how much improvement they made.

It's obviously hard to perform controlled testing but I always ride with a dual sided power meter and the consistent improvement in times on strava segments (and the power required to record the times) could not be ignored - I pretty much straight away ordered myself another set of rims and hubs so that I could build up some for my disc braked bikes.

Obviously if you find you struggle to handle a bike with deep rims or are always riding in a group then I can see why you would avoid them but I'm an absolute convert.

timothyw

Yeah to be honest I wouldn't read anything into GCNs wheel results (having watched the video).

Clean air at 0 yaw is almost never experienced in the real world, and the benefit of deeper wheels is that they keep the airflow attached to the surface over wider yaw angles.

If the wind is completely straight on (as in this video) then the wheel is basically sheltered by the tyre so has very little scope to offer an improvement even if you're using a full disc.

Hambini has a number of videos etc about all this if you want to go deep.

The thing is, obviously there is lots of speed to be gained from getting low and using tri bars and a big aero helmet, but that doesn't necessarily make it practical for your riding (if you have to ride in traffic, or are doing the saturday chain gang...) whereas deep sections can be used under most circumstances with minimal adaptation.

joe_totale-2

In my personal experience deep rims are the best upgrade you can make if you want to go faster and as stated above they don't impact your ability to ride with others in the real world.

Hambini (who has been on GCN Tech videos) has done tests with lots of different aero wheels and has used the Mavic Kysrium as the shallow wheel to compare with:

https://www.hambini.com/testing-to-find-the-fastest-bicycle-wheels/

He found at 30km/h a 10 watt difference between the Kysrium and 50mm made by Malcolm who posted above and a 37 watt difference at 50km/h which is certainly a speed you're at quite often if you ride things like chaingangs.

Obviously, other brands vary and if you go deeper then the watts saved gets even greater.

rwoofer

I take the point on yaw angle, so it would be interesting to look at that effect.

Given aero wheels tend to cost £1000+ 10 watt difference is still fairly poor cost per watt saved compared helmets, bodysuits etc. which I think was the point of the video. I would be interested how quickly the aero benefit tails off. For example what is the difference between 32mm and 50mm, which is the rim depth of typical carbon climbing and allround wheels vs deep section 60mm+ wheels.

tonysj

I thought it was interesting towards the end of the video where they have done all the tweeks on the road bike and swapped over to the full TT bike. Not a big gain from a decent set up road bike to a full blown TT beast. Surprised me but then again the advertising blurb is there to sell the bikes and don't believe everything you read from manufacturers!!!!!
T.

cookeeemonster

tonysj said:

I thought it was interesting towards the end of the video where they have done all the tweeks on the road bike and swapped over to the full TT bike. Not a big gain from a decent set up road bike to a full blown TT beast. Surprised me but then again the advertising blurb is there to sell the bikes and don't believe everything you read from manufacturers!!!!!
T.

From what I've read a well set up and fitted TT bike will gain around 2-3mph over a road bike? Seems about right from some of the TT rides I've seen locally on strava (compared to their normal road bike rides). Will check out the video later. I like GCN but they can be a bit 'Top Gear' in some of their tests - entertaining but not always entirely trustworthy

naavt

Deeper section wheels can give an advantage over flat terrain and that’s why the pro peloton rides them in the chrono stages where every second - and watt - counts.

Nonetheless, in the majority of the grand tours (Tour, Giro, Vuelta), you clearly see the pros changing to lower rims when things go steep.

Buying a set of wheels have to have those things into account: the terrain you ride the most or, if your budget allows, at lest 2 pairs of wheels for the same bike.

On a ride with 100 kms and, let’s say, 1500 elevation gain, you won’t gain nothing riding a 50 or 60 deep section wheel. The seconds you gain in the flats or descends will be much less important than the ones you loose on ascents because of the higher rotational and overall weight.

On top of that, saying that a wheel with a 50 mm depth will be more aero than a 33 or a 38 is just plain wrong. If you want a proof of that just look at the wind tunnel comparison of the A-Force AL33 and the Zipp 303. Basically 33 VS 45 mm and see the results, now at various yaw angles (so no excuses there).

Strava segments say nothing! You can put the exact same effort on a segment (which I really doubt), and have significant time differences related to a zillion of factors (your own weight, a bottle filled vs an empty bottle), humidity, asphalt conditions, your position on the bike, drag, wind and so on).

Summing up, I’m always saying to the friends I ride with that wheels are the most paradoxal item in cycling. Someone once told that they were the “best secret” in the business, and the guy who said that probably told it so many times that everyone started to believe it.

Wheels are just that. Deep section really looks cool on your bike and you spend a lot of money for that. They really give you a - small - advantage over flat terrain and descends, but learn to tuck the right way behind your cockpit and you’ll blow away any advantage that a 2000€ wheel set will give you.

You can reply that tucking and adding a deep section wheel set will contribute even further to added gains, but a simple helmet will do a much better job and it will cost you 1/10 of the money!

cycleclinic

Naavt, sorry but you post means you dont get aerodynamics. Alot of those "test" done by Zipp et al mislead. Deeper is a a rule of thumb more aero. You really have to mess up the profile to make it less aero.

I can ride my 50mm deep wheels on flatish terrain and hilly terrain in yorkshire and they feel great in both landscapes. Im not a pro so saving a three hundred grams over a "climbing wheelset" wont get me up any quicker.

No one has to buy a set of deep section wheels but to say they dont make a difference that is noticable is simply bollox. They make a difference but you can still enoy riding on high spoke wheels. threads like this always get the anti aero crowd out to spout there rational. These threads achieve nothing. Aerodynamics is not a field you can discern from a couple of graphs posted by Zipp and others. The best treatment of it is done by Hambini. Air flow in the real world is not static so static flow testing of wheels in a wind tunnel does not tell you much about they will perform in the real world it will tel you how they perform in that wind tunnel though. I am not sure how many windtunnels you ride in...

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timothyw

Naavt, guessing you've never ridden on deep section wheels? It isn't a million miles from my thinking before I decided to bite the bullet and give them a go.

Thing is, I have an aero helmet, it's great for early spring and autumn but in summer I cook. But yeah, it was practically free from planet X so definitely worth getting one.

Similarly, getting low in the drops and slamming the stem, of course that helps, but it also can make it harder to get the power out, and fatigue you faster - it's a balance in short.

What works for riders in a huge peloton with a lead car is very different from what works for us in the real world.

If I can save a few seconds on the commute, or just plain have an easier time of it, then that's worth it to me.

angry_bird

thecycleclinic said:

The sort of gain 50mm aero wheels give you at 30 mph is 1 kph. Not a lot but something.

Seriously, wtf? Can you not stick to one unit?

bobmcstuff

They also make a cool whoosh-whoosh noise so there is that too.

step83

I have two sets of wheels for my summer bike, 25mm deep alloy rims, or 66mm deep carbons, carbons are a bit heavier but. definitely faster.
I cant say I have done back to back testing but on two consecutive calm days I rode both wheels. The carbons were faster, quite noticeable at times just how much faster as well.

Of course they are much more aero, but also better tyres latex tubes all add a bit, but they are genuinely quicker, your never going to suddenly become a pro slapping some deep wheels on but it will give you some extra speed, I wont say for free as you have to buy the wheels.

Also I think we should all be measuring speed in knots currently. general road conditions it would seem more appropriate.

naavt

First things first. As I told the moderators of the site, this is now the 4th time that I’m writing this and I don’t know how and why my post keeps being deleted. Wrting this in a Word page now, just for the sake of keeping it saved and copy/paste it in case of being deleted… for the 4th time!

cycleclinic said:

Naavt, sorry but you post means you dont get aerodynamics.

No need to apologize. Forums are just that, a great way to share and discuss different points of view, hopefully with the right amount of common sense.

cycleclinic said:

Deeper is a a rule of thumb more aero.blockquote>

No, it isn’t! Everything being equal… Ok. But look at the newer trend for toroidal profiles for instance. You will find lower toroidal profile wheels that are more aero than deeper V shaped ones from a couple of years back, and that’s not all! You’ll find lower profiles with internal nipples more aero than deeper ones with external nipples, and so on and so on…

cycleclinic said:

I can ride my 50mm deep wheels on flatish terrain and hilly terrain in yorkshire and they feel great in both landscapes. Im not a pro so saving a three hundred grams over a "climbing wheelset" wont get me up any quicker.

You acknowledge that your 50mm depth wheels feel great on both terrains (I’m assuming flat and hilly), but you also state that you’re not a pro to get the adbantage from a lighter wheelset.

Let me say to you, that “feeling” is the worst evaluator on such scenarios. Much worse than the worst wind tunnel I’m afraid. On top of that, saying that your wheels “feel great” on both terrains (so I assume… once in motion), and not being capable of discerning the great advantage that a 300gr lighter wheelset gives you on momentum and acceleration tells me that your “feelings” are off (and now it’s me asking for sorry when I’m telling you that).

cycleclinic said:

No one has to buy a set of deep section wheels but to say they dont make a difference that is noticable is simply bollox.

Nowhere in my previous post you’ve read such a comment from me. If you read my post carefully, you can see that I’ve written (and I’ll quote myself): “They really give you a - small - advantage over flat terrain and descends(…)” and sorry – once again – I don’t believe that someone who can’t tell a difference from a 300gr lighter wheelset will be capable of telling a difference from a 33 to a 50 depth profile once in motion.

timothyw said:

Naavt, guessing you've never ridden on deep section wheels?

Not only do I have ridden several but I’ve assembled some as well, so my experience with wheels go beyond the experience of the majority of users who only use wheels as end users. I’m posting some images here, one of them is me building my Fulcrums Racing Quattro from the ground up after a crash.

I’m posting an image of my everyday commute bike as well with Deda carbon wheels on it and I have a pair of Zipps 303 collecting dust in the garage. Why? Bevause I’ve chosen to ride what you see in my race bike picture. Alu toroidals A-Force with a 33mm profile.

And you may ask: How the hell a guy has – at least – 3 sets of carbon mid depth wheels and rides his race bike with the lowest profile from them all, and aluminum on top of that?

Well… For starters, once in motion you don’t notice any difference from this to my Zipps (wind tunnel confirms it, and I confirm it).

Second, they accelerate better than any carbon clincher that I have. And that’s the weight of the rear wheel:

Third, they brake MUCH better than any carbon clincher that I have, and I preserve my integrity.

timothyw said:

Thing is, I have an aero helmet, it's great for early spring and autumn but in summer I cook. .

Everybody’s different. Yes, I sweat a lot too, but my mention to GCN’s findings was just that. A helmet makes much more of a difference than a wheelset. Nowhere near a wheelset will make a 100 watt difference, no matter what yaw angle you’re talking about.

timothyw said:

Similarly, getting low in the drops and slamming the stem, of course that helps, but it also can make it harder to get the power out, and fatigue you faster - it's a balance in short.

If there’s one thing that Ollie’s Bridgewood experiment from trying to beat Merckx hour record teaches us, is that you can teach your body to produce power in a TT position. If you’re not following his progression on Strava, I’ll recommend you to do just that and verify for yourself.

timothyw said:

What works for riders in a huge peloton with a lead car is very different from what works for us in the real world. .

Thank you for pointing that! Since the majority that’s riding “in the real world” buys mid depth profile wheels BECAUSE the pro peloton is using them. But then, they are the ones who can gain or loose a race for a tenth of a second, and in that world it makes a lot of sense if you can gain 0,00001 seconds on whatever metric you can think of.

timothyw said:

If I can save a few seconds on the commute, or just plain have an easier time of it, then that's worth it to me.

You will loose not only a few seconds but a few minutes if you encounter adverse climate has humidity or saturation in the air, not to point the obvious and say headwinds.
You can also loose minutes by being sensible about how you descend with a 50mm profile in heavy crosswinds, difficulty that you won’t encounter in lower profile wheels, so every case is a case.

I can tell you that I’ve beaten probably all my Strava segments on my 33mm alu wheels. You know why? Because I’m fitter, not because a a single pair of wheels gives me an advantage of 3 or 4 watts

naavt

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cruff

LOL - attempting to equate GCN's five minute videos with years of aerodynamic research

What do you mean by 'faster'? For whom? Doing what? Over what terrain? At what speeds?

'Aero' is incontrovertibly faster than 'not aero'. Would you make more gain from wearing a skinsuit? Yes, usually - but doing that on the commute would make you look a bit of a prat, whilst doing it on a TT would be appropriate

Am I 'faster' on my race wheels (60mm Rovals) than I am on my training wheels (regular Ksyriums)? Yes - appreciably. If I do a flat 40km training loop (no drafting, solo) on my regular wheels I average about 34k/k, whereas on the race wheels, I'm 2k/h faster. Is that a massive difference? Again - it depends what you're doing on them. If I was commuting to work, it might get me there three minutes quicker... but if I'm in a race and working in the break, it might mean I win as I'm doing less work than other people in the break (although they're likely to be riding deeps as well, of course)

Your post doesn't make a lot of sense, and there's no pointy getting hissy about it. People are pulling you up on it because you're making an assertion based on one small part of one GCN video and extrapolating it to fit some view that's counter to decades of aerodynamic science

There's a few excellent articles about 'bang for your buck' around the internet that suggest you should invest in things in the following order (for a time trial - obviously some of the stuff on this list doesn't apply to regular racing, and less still to 'normal' riding:

1 - Position (tri-bars, followed by a good tuck, followed by expensive analysis)
2 - Skinsuit
3 - Shoe covers
4 - Aero helmet
5 - Trispoke front (a deep section rim if you can't afford one)
6 - Aero frame
7 - Rear Disc

Even those are flawed, since they're largely based around 'value' eg: a set of shoe covers might save you 30 secs on a 25 mile TT, whilst an aero lid might save you a minute, but cost 200 quid. Also, the Skinsuit will save a huge amount of time, but only really over loose fitting 'regular' jersey and bibs - if you already ride in tight 'race fit' clothing, you won't get the same amount of benefit.

naavt

Again... apparently you seem not to be reading my posts right (or I’m not expressing myself right), but in a few words... you’ve made my case (and GCN’s), in your post!

shortfall

Great taste in bikes with the Gold Tifosi. Sh1te taste in wallpaper.

naavt

shortfall said:

Great taste in bikes with the Gold Tifosi. Sh1te taste in wallpaper.

well... no one’s perfect! One out of two isn’t that bad

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