Wesley36

Sort of. Rim design is also important. The old v-style rims are most aero from a direct headwind, but much less aero when wind comes from other directions (almost always), in addition to handling problems. Newer toroidal and semi-toroidal shapes are designed to be much better in crosswinds (like Zipp and Flo), both from an aero and handling point of view.

merlinextraligh

Personally, I think 58mm deep Zipp 404 Firecrests hit the sweetspot. Pretty aero, and handle well except in extreme crosswinds.

we've got 80mm deep 808's on our tandem. The weight of a tandem team, and the long wheel base of a tandem reduce the impact of crosswinds. Even on the tandem though, the 808's can be a handful in stiff winds.

I would not go with 808's for everyday wheels on a single bike due to crosswinds.

noglider 

... for some value of "generally!" I generally ride at a speed of less than 15 mph. Aero components won't do much for me.

moppeddler

It may be more marketing hype than real effect, but many companies are now going to a toroidal shape to their rims which more closely resembles the shape of the wheel, and therefore supposedly reduces the turbulence from crosswinds. In other words, deeper rims that are more manageable in windy conditions. Flo, Zipp, and Boyd have wheels like that. I'm sure there are others.
For me, I'm not serious enough to want to spend big bucks on wheels, and don't want the hassle of carbon. A good compromise for me is the Flo 30 or Boyd Altamont. Both Al with 30mm depth and wider rims with the toroidal shape. The Flos are about 100gm heavier at 1625 and about $150 cheaper, but very similar wheels. The Boyds have cool laser engraving, so no stickers, which I like. These wheels give you a lot of the benefit of carbon at half or less the cost, without having to change brake pads, worry about stopping performance, etc.

dmcdam

I just got a set of the Flo 30's. We're still encased in snow up here so haven't had a chance to try them out but my thinking was along the same lines as yours. I get some aero benefit in a mid-weight wheel set for under $500. Realistically it's probably as much wheel as I'll ever need.

kgoings

subscribed

moppeddler

I got them too. Bought a set for my wife as well. I've only ridden once due to weather and health, but I like them. I'm sure I'll be very happy, especially with the money I spent, but those Boyds are very sexy! I'm still having second thoughts about not getting them.

hillcrawler

https://www.chainreactioncycles.com/t...t/rp-prod76252

These are my entry level not-so-deep rims. If you are really short on budget they are a good set of wheel.

KantoBoy

Those beasts @ Omega Pharma insist on using 50mm's.

Every.
Damn.
Race.

I think the only guys who won't use 50s there is Uran and maybe Bakelants.

I'm surprised with Nibali loving deep sections though. For a skinny climber he uses them a lot. Quintana use regular depth rims especially when he's at the mountains.

I personally owned 50s and had to downgrade to 38s. 50s were too much in the crosswinds for me.

TheSame

You have good taste in beer, Plinay is sooo good.

I <3 Robots

My 404's are my only set of wheels. Its not really windy where I live.

bbattle

They had full disk FRONT wheels back in the 80's. I have some videos of the old Red Zinger races in Colorado and the riders used them. But it was okay; Colorado isn't known for high winds.



Spokes act like fan blades and create a lot of turbulence/resistance. The fewer and the shorter they are, the better. I believe that was the thinking that led to the 650c wheels on tri bikes.

The aerodynamic benefits of deep rims only comes into play at higher speeds and when the rim is at least 40 mm deep. At least, that was the consensus argument on the last 20 or so threads on this subject.

But you can get 40mm deep carbon rims that weigh the same or less than the old 26mm aluminum rims. Have your cake and eat it, too.

Then there's the whole problem of the unaerodynamic shape of the rider.

StanSeven

Sports car wheels are just like bicycle wheels - there's a wide variance in pricing. I just destroyed a car wheel on a pothole. It was $1900 for a new one.

Wesley36

FWIW, the math disagrees:
https://www.cervelo.com/en/engineerin...st-riders.html

UnfilteredDregs

1:26 gain for a 30 minute effort is greater than 1:47 gain for a 40 minute effort. A bit of snake oil there...

merlinextraligh

Go to Velonews, and search Pro Tour bicycles and I think you'll find, many if not most pro's are typically riding carbon fiber rims in the 50-60mm range, i.e. Zipp 404's or similar.

On mountain stages, you'll see a mix of riders using 50-60mm rims, and some using shallower, lighter wheels.

The data would tend to suggest that the riders using the deeper sectioned rims, even on the mountain stages are smarter, particularly when UCI weight limits are considered.

But the idea that light wheels are fastest for climbing persists, and sometimes the pro peleton is slow to change dogma.

Also, pro's for the most ride the equipment their sponsors want them to. So if you use 404's for most stages, and 303's for mountain stages, and 202's for a hillclimb TT, it helps sell more wheels for Zipp, or Reynolds, or Mavic as the case may be.

merlinextraligh

And despite your admonition, 30 posters following this, still call them deep dish.

They are deep sectioned rims, not deep dish.

And in this case, it's not just a pedantic rant.

Dish, in the case of a bicycle wheel, refers to the centering of the rim over the axle, and is required by the fact you've got a cassette on one side of the hub, and not the other.

Wesley36

The comparison is standardized to a 20 min TT, as indicated by the vertical dotted red line in the chart. This is also stated explicitly in the text, immediately before the chart.

Wesley36

Unfortunately, this bears repeating. "Dish" has a specific meaning in regard to bicycle wheels, and it has nothing to do with the depth of the rim.

wphamilton

And the percentage of power needed for a percent speed increase is about the same regardless of speed. I think that the main thrust of it is that the small gains are more important to people who ride fast to begin with.

I was more concerned about the other part, the depths of the rims about which I'm inclined agree with bbattle although some very accomplished cyclists have opined otherwise. I've seen somewhere a table comparing performance against the depths of the rim and if I recall correctly the deeper rims won (around 40 mm) and the shallower "deep rims" didn't have much affect. I wasn't going to mention it because I strongly suspect that with the variables of rim width and mounted tire shape either opinion may be valid in the right context.

One aspect that I haven't seen in this thread is that crosswinds at some angle might obliterate the aero advantage of deep rims. If so, under those conditions you suffer the extra weight and control issues for no gain or perhaps even greater drag. And that brings up something else that had slipped my mind: at higher cycling speeds the drag arising from the crosswind is less apparent than at lower speeds. So the people saying that aerodynamic wheels are only useful at high speeds may be more right than not in the real world sense.

UnfilteredDregs

I know...but relative to the time of effort 1:26 gain out of 30 minutes is greater than 1:47 out of 40 minutes. To say the slower rider gained more time than the faster rider is not accurate relative to the effort.

The faster rider still reaped a greater aerodynamic reward unless I'm missing something.

noglider 

Wesley, what are the weight costs of adding the aero advantages that the authors of the article used? They don't say. Unless I'm missing something, it looks like a hugely flawed analysis.

wphamilton

You're picking over a difference of .001 between the two ratios. Essentially the same.

UnfilteredDregs

It's a 1.6~% gain for the fast rider versus a .93~% gain for the slow rider...

So, yeah, close (?) but this statement is indeed inaccurate: "The slower rider saves more time!"

If you're going to quantify the results in terms of time it should be the ruler for the whole exercise.

They start with distance and do a switcharoo...

daven

It is accurate either way you look at it. The slower rider finishes faster over a fixed distance with aero than without than similarly equipped faster riders. It is just a statement of mathematical fact as calculated. When you translate that to a percentage of improvement, then you have to take into account that the faster riders are finishing 10 minutes faster than the slower riders. The time gain from aero, taken over the overall finishing time still grants the faster riders a larger 'gain' from the aero equipment.

'The slower rider gains more time' is not inaccurate. It very accurately states one part of a story.

And to stay a bit on topic, this thread has been immensely useful for me. I've identified a number of high-quality 50-60mm carbon rims that will not break my bank account (as much). Hopefully I'll have a set of aero wheels by June when my fitness justifies the purchase!