Has anyone seen a drag comparison between the Firecrest 404 and 808? I’m curious how they compare.
I was looking at the two drag comparison charts on Zipp’s website for both the FC 404 and FC 808. Based on the drag numbers on those charts, it appears the 808 has less drag between 10 - 20 degrees yaw. See below:
While Josh’s video presentation of the 808 Firecrest chart appears to reflect the same drag curve shape and similar numbers to that on Zipp’s website chart, the 404 Firecrest chart seems to differ significantly from the chart on Zipp’s website (both the drag curve shape and numbers are way off). What’s interesting is that if the drag numbers for the 404 Firecrest chart in the video are accurate, the 404’s drag numbers would be very close to the 808 between 0 - 20 degrees, even beating the 808 as you get closer to 20 degrees.
I’m curious to know which is more accurate – the 404 Firecrest numbers in the video or that in the website. If the video is accurate, I would probably be inclined to choose the 404 over the 808 based on overall drag performance between 0 - 20 degrees (not to mention lighter and less affected by cross winds).
Look at the values in the Grams of Drag axis for each of the charts - the 808 goes down significantly lower than the 404. That is why the curves look very different. The 404 goes down to about 80g at 15 degrees while the 808 drops to almost 30g at the same yaw. You can only compare the curves of wheels within a specific chart to other wheels in that chart, but not the curve from one chart to another because the axis are different.
I agree that the 808 is significantly lower than the 404 at 15 degrees when comparing the website charts.
However, the 404 Interbike chart (see video) shows lower drag numbers for the 404. For instance, at 15 degrees the drag is approximately 50g. At other angles, the 404 is very close to the 808 drag numbers (and outperforms the 808 between 17.5 - 20 degrees).
Perhaps that wasn’t the final design? There may have been some other side-force effect from that specific profile that they had to change before the final molds were cut and the new numbers produced.
Listen, I’ve known Josh for years, and I’m pretty sure he just makes those numbers up anyway…
Just kidding. We love working with those guys. There are very few (if any) people in the industry who take this stuff more seriously. I would imagine that the difference between the charts is a matter of production rims vs. prototype or simply more testing data.
If you’re fast enough to really take advantage of the 808, then you will rarely see the yaw angles where the 404 is faster than the 808. Plus both the 404 and 808 with the FC rim design have very neutral steering in the wind - the new 808 probably moves you around less than the non-FC 404 did - so handling shouldn’t be too much of a concern. If you’re TTing or racing a tri hard, I’d go with the 808s.
Funny how these charts are the opposite of what Easton presented last year for the 90TT at Interbike. Kind of make you wonder if you should trust anyone besides what you feel and like yourself. This is a another classic marketing example of ‘let’s just put this number in’, nobody will ever know.
Funny how these charts are the opposite of what Easton presented last year for the 90TT at Interbike. Kind of make you wonder if you should trust anyone besides what you feel and like yourself.
no, you can’t trust what you feel and like yourself either
This is a another classic marketing example of ‘let’s just put this number in’, nobody will ever know.
Feeling that you should not trust a feeling, I guess I will not listen to Tom A. anymore when he says he can feel a couple of watt difference in a component. Also funny that when you ride a light weight wheel set that that you should ignore how much faster it accelerates.
Also where is the data on what tires Zipp put on the wheels for testing?, did they stick a wide 23-25mm tire on the narrow (20-21mm wide) 90TT and H3?, funny how this was not presented.
Funny how these charts are the opposite of what Easton presented last year for the 90TT at Interbike. Kind of make you wonder if you should trust anyone besides what you feel and like yourself.
no, you can’t trust what you feel and like yourself either
This is a another classic marketing example of ‘let’s just put this number in’, nobody will ever know.
Feeling that you should not trust a feeling, I guess I will not listen to Tom A. anymore when he says he can feel a couple of watt difference in a component.
Even tom doesn’t fully trust himself when he says that, or he wouldn’t bother with the power meter. Furthermore, refer to his testing of tire pressures - the higher, slower pressures FELT faster to him.
Also funny that when you ride a light weight wheel set that that you should ignore how much faster it accelerates.
No, you should pay very close attention to how much faster it accelerates, and pay very close attention to how close that number is to zero.
Also where is the data on what tires Zipp put on the wheels for testing?, did they stick a wide 23-25mm tire on the narrow (20-21mm wide) 90TT and H3?, funny how this was not presented.
I’m not suggesting that you can trust zipp’s data either, don’t get on my case about that =)
Perhaps some independent testing will come around soon.
Feeling that you should not trust a feeling, I guess I will not listen to Tom A. anymore when he says he can feel a couple of watt difference in a component.
Well…if you’ve listened closely, you’ll remember that I’m typically one of the first people to point out the fallibility of human perception. What often “feels” fast isn’t necessarily so. Then again, if the “feeling” is backed up by numbers (as in my comments about latex tubes recently), well…then that’s just a case of things being “palpable” (and it’s typically much more than “a couple of watt difference” that leads to those observations).
Any statements I’ve made about “a couple of watt difference in a component” is nearly always backed up by actual measurements.
Also funny that when you ride a light weight wheel set that that you should ignore how much faster it accelerates.
What’s funny *to me *is that I’m currently in the process of putting together a little article that addresses that very topic. As a relatively “extreme” example of an acceleration, I’m using an actual “event” from a recent race where I attacked to create a gap to the field on a flat portion of a course and had a peak 1s power output of 1080W and an average of just under 766W for 5 seconds. My speed increased from 24.9 mph to 30.4mph in that 5 seconds.
Care to guess what the peak 1s acceleration was, both linearly for the entire “system”, and also rotationally for the wheels? I’ll give you a hint…it’s pretty freakin’ small
I’m thinking of calling the article something like “The Myth of Wheel Weight and Inertia ‘Mattering’ More Than Other Factors”…or something like that
Please write this paper soon, Tom. The last time I started a thread about weight not mattering, no one listened to me until you came along. Usually, I just link to the Josh from Zipp article where he talks about how insignificant it is compared to aero, but since he’s a businessman, no one wants to believe him. Unless you own Zipps, of course.
Chad
Please write this paper soon, Tom. The last time I started a thread about weight not mattering, no one listened to me until you came along. Usually, I just link to the Josh from Zipp article where he talks about how insignificant it is compared to aero, but since he’s a businessman, no one wants to believe him. Unless you own Zipps, of course.
Chad
To save me the search time, can you send me the link to that article? I’d like to look it over…Thanks!
Feeling that you should not trust a feeling, I guess I will not listen to Tom A. anymore when he says he can feel a couple of watt difference in a component.
Well…if you’ve listened closely, you’ll remember that I’m typically one of the first people to point out the fallibility of human perception. What often “feels” fast isn’t necessarily so. Then again, if the “feeling” is backed up by numbers (as in my comments about latex tubes recently), well…then that’s just a case of things being “palpable” (and it’s typically much more than “a couple of watt difference” that leads to those observations).
Any statements I’ve made about “a couple of watt difference in a component” is nearly always backed up by actual measurements.
Also funny that when you ride a light weight wheel set that that you should ignore how much faster it accelerates.
What’s funny *to me *is that I’m currently in the process of putting together a little article that addresses that very topic. As a relatively “extreme” example of an acceleration, I’m using an actual “event” from a recent race where I attacked to create a gap to the field on a flat portion of a course and had a peak 1s power output of 1080W and an average of just under 766W for 5 seconds. My speed increased from 24.9 mph to 30.4mph in that 5 seconds.
Care to guess what the peak 1s acceleration was, both linearly for the entire “system”, and also rotationally for the wheels? I’ll give you a hint…it’s pretty freakin’ small
I’m thinking of calling the article something like “The Myth of Wheel Weight and Inertia ‘Mattering’ More Than Other Factors”…or something like that
Does that mean you are going back to Tubulars to save on some weight?
Also where is the data on what tires Zipp put on the wheels for testing?, did they stick a wide 23-25mm tire on the narrow (20-21mm wide) 90TT and H3?, funny how this was not presented.
Think Zipp always test all the wheels with Corsa CX 700x21 unless otherwide noted. So 90TT and H3 are also tested with this tubular. It is not writted on the graph but clearly written in the “aero edge flyer” http://zipp.com/technologies/aerodynamics/aeroedge.php
Tom,
I found the original post and the link does not work anymore. Or maybe it never did, someone commented on that.
Here is the paragraph I quoted.
Aero is THE primary factor of wheel speed. It’s not weight, it’s not inertia, it’s aero. Everything else is obviously huge in terms of nuance, but weight will save you a watt or two. Inertia will save you a fraction of a watt to a watt. Aero will save you 40 watts at certain speeds. It’s huge to go from a wheel like an R-Sys to a wheel like an 808 clincher which is a pound heavier, but it’s about 50 watts more efficient at 30 mph. But of course the problem is in the consumer’s mind, 1350 grams vs 1680 grams, that has real tangible meaning to people. Arguing about inertia seems tangible to people because they’ve always heard that weight is important in wheels because it hits you twice. There’s just nothing tangible about aero."
Tom,
I found the original post and the link does not work anymore. Or maybe it never did, someone commented on that.
Here is the paragraph I quoted.
Aero is THE primary factor of wheel speed. It’s not weight, it’s not inertia, it’s aero. Everything else is obviously huge in terms of nuance, but weight will save you a watt or two. Inertia will save you a fraction of a watt to a watt. Aero will save you 40 watts at certain speeds. It’s huge to go from a wheel like an R-Sys to a wheel like an 808 clincher which is a pound heavier, but it’s about 50 watts more efficient at 30 mph. But of course the problem is in the consumer’s mind, 1350 grams vs 1680 grams, that has real tangible meaning to people. Arguing about inertia seems tangible to people because they’ve always heard that weight is important in wheels because it hits you twice. There’s just nothing tangible about aero."
Thanks! Yes, I’d seen that interview before…and I’m glad you pointed it to me again since it’s probably where I first saw the “808s are the new 404 for me!” quote from Cancellara…I’d planned on using a take-off on that quote from him in a review of the 404 CC wheels I’ve got coming up soon as well. Now I know where I saw that quote
