asgelle

All fine and good, but a far cry from saying weight isn’t a factor below 6%.

chaadster

Correct, and specifically to your point, the SwissSide modeling that is (insofar as I can tell, although Flo did some good modeling, too) the source for these numbers being tossed around so imprecisely, does in one of their model scenarios nail the break-even slope at 3%, meaning anything steeper than that for a 70kg rider at 200w would be faster with 10% lower weight than a 10% reduction in aero drag.




In any case, it certainly seems like there’s very little need to parse use cases or choose sides, as wheels which are both reasonably light and decidely aero can be had new at pretty accessible pricepoints, like around $500 or so.

PeteHski

Obviously there are plenty of variables at play, but the above study is looking at an arbitrary percentage reduction in total bike weight vs total aero. The numbers I've seen from comparing actual wheelsets (Again I think it was from SwissSide) show a break-even slope much steeper than 3%. Probably because the aero gain for aero wheels is relatively high compared to their weight penalty.

nomadmax 

The answer I have is:

Campagnolo Zondas

As to the airchair/internet "engineer" argument, I'll pass.

PeteHski

Here is a nice, easy to read study of the effects of wheel weight, rotational inertia and aero:-

https://www.swissside.com/blogs/news/aero-vs-weight

The conclusions speak for themselves, but the big take-home is if you want to ride fast then aero is far more important than lightweight wheels and wheel rotational inertia is negligible in all scenarios.

delbiker1 

IMO, for high dollars, its Hed Ardennes and Belgium. For lower cost, Zonda. IME, Zonda wheels are hard to beat for the value.

chaadster

That chart is from SwissSide (see https://velo.outsideonline.com/gear/...r-aero-wheels/).

And yes, that there are plenty of variables at play is exactly the point and why asgelle ’s reply to the comment, “weight only becomes a factor when the gradient is 6/7%+” was both appropriate and poignant. Doomrider74 ‘s introduction of the aero vs. weight slope percentage breakpoint concept was sloppy and certainly not fact in the way it was stated. In fact, depending on how the terms are set and what’s being evaluated, let’s say by speed, the impact of weight is of *diminishing significance* at slopes above 6%:



https://www.wheelscience.com/pages/aero-v-weight

Without conflating concepts, that “aero is king” when it comes to performance road wheels is indisputable. I’ll take just as much weight savings as aero advantage myself, if only because a lighter bike is easier to hoist onto a roof rack!

chaadster

The thing I disliked about the Zondas— which I think have been disco’d, BTW— is that even with the C17 update they were too narrow internally at 17mm. I think it was like ‘16 or ‘17 when they made the move, by which time I’d been on 19.4mm IW rims for years, so I was definitely unimpressed. I think the newest Shamal are 21mm IW, but I don’t know about Scirocco, which are a nice alum rim at 35mm deep.

Also, there is no armchair engineering argument, it’s about correctly representing data and factual statements, that’s all. But we have it covered and it has been sorted, so thanks anyway.

Chandne

Ally wheels are very comfortable and can be light (but a bit fragile). The old American Classic race wheels were tubeless and light and rolled so darn well. I am not sure of anyone still builds them like that. Too bad they went kaput and not sure who is making their tires. Many have narrow internal width, if that matters. If you're running 25s, it is fine. For steeper climbs and all we have seem to be longer (4 miles to 12 miles) climbs that go from 5%-10%, I find that lighter is faster.

Broctoon

[/capitalization and spelling corrections]

HTupolev

Yes, although that's a pretty strange way to frame it. The raw speed difference caused by every source of resistance "diminishes" at extreme gradients simply because bites are being taken out of a smaller pie. It's far more useful to look at proportional effect, i.e. what percentage does it slow you down by.

chaadster

Maybe, but as you say, since the pie is smaller, is 1/10th of a KpH any more or less strange or insignificant than, say, 50% of 1/60th of minute?! It’s all kind of vanishingly small, no matter how it’s sliced and diced, and personally, I don’t worry about it at the micro level, and instead just do my best to be reasonably light, reasonably aero, reasonably fit, and extremely hopeful it all works out in the end!

PeteHski

The way to frame it is by the effect weight has on elapsed climbing time for a given power, not speed - which gives this strange and potentially misleading result. In reality the detrimental effects of weight increase with gradient as you would expect.

PeteHski

Yet there are plenty of cyclists out there who still think wheel weight and rotational inertia is “massively” important. They don’t care about any of the physics, simulations or real world testing.

The OP should just bear this reality check in mind when considering “fast” wheels.

Doomrider74

...and deliberately so as I am not an expert in the matter. I was just passing on one viewpoint stated in an interview I saw with someone who has spent his entire career in the field.

chaadster

Well now…weight has no direct effect on time, but weight does have a direct effect on speed up a climb. It seems to me it makes more sense to talk about weight and speed; 10kg sitting on the road is 10kg sitting on the road regardless of how long you look it. It’s only once the speed component— i.e. time over distance— that 10kg translates into anything.

chaadster

I would be surprised if was Poertner’s viewpoint that weight doesn’t matter until +6% inclines. Perhaps you can link the interview so we can get it from the horses mouth? I suspect there’s a lot more context there which needs understood.

aliasfox

Personally, I buy into the argument that weight doesn't matter for performance relative to the clock. That said, it's hard to get over the difference in 'feel,' especially in real-world riding conditions that most of us get to play with. Most of us have to deal with traffic and stop lights, and heavier, deeper dish wheels often just feel like a bit of a bear to get going, or to flick around in slower, tighter turns like parking lots. I think this translates into the mindset that heavier wheels are slower and take more effort. My 1900g Visions just feel like boat anchors from a stoplight compared to my old Ksyrium Equipes and Zondas that are 2-300g less.

That said, my 45mm carbon wheels have a very pronounced sail effect relative to all of the other wheels in my stable, so I can definitely feel the aero bit.

I don't have any experience, but if I were looking at high end alloy, HED Ardennes and the high end DT Swiss options would be on my list, though I have a soft spot for Campy's cool lacing patterns, too.

georges1

Older Mavic Cosmic Pro and Mavic Cosmic Expert , very durable and reliable wheels.

asgelle

I knew there were people who believed the Earth was flat. I didn't know there were some who didn't believe in gravity.

aliasfox

Obviously a simplification, but if you don't think sacrificing weight for aero is the right idea in most instances at this point, then I don't know what to tell you.

asgelle

If you were paying attention, you'd have seen I never ventured an opinion on aero vs. weight. I only responded to people who said weight doesn't matter in an absolute sense. For example,

aliasfox

Sigh. And I thought I could write something short Obviously, the pedant police are out today.

In the context of the conversation of this thread, within the realm of performance road bicycle wheel weights, aerodynamic properties, and their intended uses, I have bought into the fact that trading weight for more aerodynamics makes sense for the majority of road riding, for most people.

Does that work better for you? Now, I'm going to go for a bike ride.

asgelle

Yes it does because it means something totally different from what you wrote earlier. And if you think it's pedantic to say no the Sun doesn't rise in the West, it rises in the East, so be it.

harrier6

I think the best testing on the aero qualities of aluminum rims that I've seen comes from November Bicycles

https://novemberbicycles.com/blogs/b...d-other-alloys

It suggests that some wide aluminum rims paired with the right width tire can compete with carbon rims, at least in most of the yaw angles that matter, and there is a significant difference in drag between the best and worst aluminum rims.

Assuming a rim brake bike, you'll have to replace the rims eventually anyways, why not try to find the aluminum rim that will give you 80% of the benefits with none of the drawbacks of carbon rims? Maybe not possible, but it's a tempting idea. I'd look into the HED Belgium + or the Kinlin XR31T myself.