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Re: New Zipp 858 NSW and 808 [HTupolev] [ In reply to ]
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I have a drum rig setup (the drum has 1m diameter) with a linear ball bearing to apply the normal force to the wheel through weights, i.e. the weights and the wheel both can move vertically. In addition a damper (a damper usually used in motor cycles to damp handle bar movements) with adjustable damping rate is connected to the linear transducer holding the weights.

Just an observation when an „obstacle“ is mounted on the drum surface or the tire on the wheel is not perfectly round (can happen). At certain combinations of normal force, tire, damping rate … the weights or the wheel respectively may begin to oscillate up and down (obviously a resonance of the oscillating system is attained) at a certain speed. Crr then goes up too, i.e. break point conditions?. Increasing speed further and the oscillation stops. Altering weight or damping rate or tire pressure … and the resonance arrives at a different speed region.
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Slowman wrote:
Tom A. wrote:
Well...combine that with the common opinion (one held by myself as well) that road tubeless for measured tire widths 30mm or smaller doesn't gain advantages over running a tire with a latex tube...and in some cases, disadvantages...then yeah, I think I'd join you in the opinion that hookless is a tough sell for for even 28s. Especially since hookless construction eliminates the possibility of running a non-TLR tire as well.


i've been running conforming 28mm, 30mm and 32mm tubeless tires on just about every wheel made by every brand making hookless road (ENVE, HED, Zipp, CADEX). so far, i'm very happy. no spiking the football, not a flat since 2019 (when i began my hookless odyssey). but that's just so very n=1, and it's not hookless but tubeless that i credit for no flats. but... no rolldown tests. no chung. i'm JRA. i have no data, other than, you know, no flats. and, a pretty comfortable ride, to the limit of how comfortable a tire can make you.

My N=1 is that I suffer the same rate of flats on 25-30mm tires, whether with latex tubes inside, or tubeless setups...perhaps 1-2 per year (over ~3-5K road miles per year). The only difference is that I might be successful plugging the puncture on the tubeless setup, saving a small amount of time vs. changing a tube. BUT, if I can't get a plug to work...then the roadside repair becomes significantly more difficult and messy. At those tire sizes (and my weight) the pressures run are too high, and the air volume too low, for effective sealing of even small punctures IME. Either way, I'm stopping. Best case with tubeless is that my stop is a few minutes shorter. Worst case, it's significantly longer and more messy. That's the calculus I base my opinion on. YMMV.

http://bikeblather.blogspot.com/
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Re: New Zipp 858 NSW and 808 [Tom A.] [ In reply to ]
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Tom A. wrote:
Yes, that's exactly what I said in my reply above. Across a particular model, wider (measured) tire is faster at a given pressure...no matter if the measured width increase is accomplished by a physically wider tire casing (i.e. tire sizes) on a given internal width rim, or by keeping the tire the same and increasing the rim internal width. Basically, "measured width is measured width" in regards to Crr and inflation pressures.

But, compare across the sizes at pressures "equalized" to the measured width, and the Crr differences become nil (for a given model).

This is exactly what I was saying in the beginning of this thread.

If Zipp's rolling road has the 28mm tire rolling faster than 25mm, then either they are not at a comfort equivalent pressure, or they cherry picked a surface roughness and speed that crossed the breakpoint for these tires (or worse, just the 25mm tire)
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Slowman wrote:
Amnesia wrote:
Dan,
Would appreciate your advice if you are happy to share.
These wheels are hideously expensive down under here in Australia.
That being said, I can currently get the 808 NSW Tubeless DB wheelset for about $3500 AUD on sale. I am not sure how many generations of the 808 NSW's there have been, hence how old this technology is.
A tough question I know, but is there likely to be a massive difference in terms of time savings/watts with these wheels over the new ones you have talked about here?
I was an all Zipp person on my previous bikes, but since making the change to DB's have had to start from scratch again.
FYI: late 40's, 2:21 HIM bike split on my P3X running an 80mm Front and Rear disc by Parcours (2nd fastest age group split). Not sure it is worth it to spend anymore money on wheels as these certainly performed OK on the day.


there is not enough distance to sweat the time and money for the new wheels if the old wheels are considerably easier/cheaper. and there is one added value to the old wheels: you can use new or old tires; and you can use whatever pressure you want without consideration, which is not much of an issue with 28mm tires but it may well be if you're riding 25mm tires. you can ride 25mm tires with the new wheels, but i wouldn't recommend it because you may want to push that 72.5psi max and you can't safely do that, imo.

me? i would buy the new wheels, all things equal, because i'm done with 25mm tires, i'm all in on tubeless, i have scads of experience on everyone's hookless road wheels, and i have access to conforming tires for those wheels. but you live in a 4th world country down there (where i'm scheduled to visit in december, i'll bring provisions). i don't have confidence you'll have enough available tires. buy the old wheels.

Where are you coming to in December Dan??
If you are over in Western Australia let some of us know and we can help you out with anything you might need.
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Re: New Zipp 858 NSW and 808 [Amnesia] [ In reply to ]
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Amnesia wrote:
Slowman wrote:
Amnesia wrote:
Dan,
Would appreciate your advice if you are happy to share.
These wheels are hideously expensive down under here in Australia.
That being said, I can currently get the 808 NSW Tubeless DB wheelset for about $3500 AUD on sale. I am not sure how many generations of the 808 NSW's there have been, hence how old this technology is.
A tough question I know, but is there likely to be a massive difference in terms of time savings/watts with these wheels over the new ones you have talked about here?
I was an all Zipp person on my previous bikes, but since making the change to DB's have had to start from scratch again.
FYI: late 40's, 2:21 HIM bike split on my P3X running an 80mm Front and Rear disc by Parcours (2nd fastest age group split). Not sure it is worth it to spend anymore money on wheels as these certainly performed OK on the day.


there is not enough distance to sweat the time and money for the new wheels if the old wheels are considerably easier/cheaper. and there is one added value to the old wheels: you can use new or old tires; and you can use whatever pressure you want without consideration, which is not much of an issue with 28mm tires but it may well be if you're riding 25mm tires. you can ride 25mm tires with the new wheels, but i wouldn't recommend it because you may want to push that 72.5psi max and you can't safely do that, imo.

me? i would buy the new wheels, all things equal, because i'm done with 25mm tires, i'm all in on tubeless, i have scads of experience on everyone's hookless road wheels, and i have access to conforming tires for those wheels. but you live in a 4th world country down there (where i'm scheduled to visit in december, i'll bring provisions). i don't have confidence you'll have enough available tires. buy the old wheels.


Where are you coming to in December Dan??
If you are over in Western Australia let some of us know and we can help you out with anything you might need.

thanks. staying east. visiting a friend in sydney. but i must say, the cost to travel to australia has so far kept us booking anything. hoping for prices to come down.

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [BigBoyND] [ In reply to ]
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For their most recent 404/454 release they had their rolling road/real world testing simulating/on unpacked surfaces to get their crazy watt savings…
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Re: New Zipp 858 NSW and 808 [Tom A.] [ In reply to ]
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whats the real life time difference for Joe middle of the pack in a 140.6 vs a used $1,000 set of old firecrest on 23mm

Id have to believe they are the bulk of the buyers, as there are way more MOP then top tier guys
Last edited by: surfNJmatt: Aug 12, 22 12:54
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Re: New Zipp 858 NSW and 808 [surfNJmatt] [ In reply to ]
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I’m racing on my wife’s nearly 10 year old 404’s. With 25mm GP 5000’s they haven’t failed me yet this year.
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Reviving this thread since you posted data on the front page yesterday.

I am not sure I 100% understand

What we know
There is a tradeoff between wider/lower pressure/aero
We know that ideal pressure is very surface dependant.
We know that CRR is pressure dependant

In the article, I see nothing about the aero benefit/penalty for different widths. Am I missing something ?
While the show rolling resistance benefits, is there any indication of what type of surface this was on ?

How can I tell if this wheel is any faster than a 25mm tire on a reasonable road ?
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Re: New Zipp 858 NSW and 808 [Tom A.] [ In reply to ]
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the data, or the compilation and results from the data, from zipp on their new wheels is up on our front page.
tom, you wrote in a FB comment below that article, "Can you ask Zipp for the plots in raw power? These delta plots are a regular "dogs breakfast" in trying to understand what they're trying to say, and how things agree, or don't agree, with other data...and seems a bit "obfuscation-y". Some details on the rolling road setup would be nice. If you're wanting to call this "science", then details of the test methods should be revealed. No way to put the results in context without that."

i assume you're talking about the Crr data. i'll ask zipp about that. there is some additional color i can give you, tho it's not specifically what you're asking. there was 1 rider on the rolling road for all the runs. the weight was 85 kilos total, with the bike. i believe the entire suite of runs was 96. there were 4 pressures x 3 tire sizes for each wheel. the 808 firecrest and 858 NSW were tested. so, that's 24 total discrete plot points. that's how i can up with (in the article) 4 runs per discrete instance. what i don't know is what was done with those 4 points. average the 4? throw out the 2 on either side and average the other 2?

i disagree with you that the way zipp presented this increases obfuscation. the way they presented the data was designed to do exactly the opposite and i think they achieved that. the data they provided is designed to help their audience understand what these new wheels give you over the old wheels.

if i can spitball here a little: they aren't claiming science in this sense: they're not claiming that their charts, as presented, are ready for publication and will withstand all reasonable scrutiny. they're claiming science in this sense: science is what guided them, internally, on the choices they made. they're sharing their internal results with their readers; they're not presenting a paper to nature magazine.

but i agree with you that we can't just stop here and call it good. i have some of the same questions you do. i think we all know there is value to drum testing, and there are limitations to drum testing. but up 'til now drum testing has been the easiest, cheapest way to test tires, and so drum testing has been gospel. rider-aboard testing seems a step forward, but it's so infrequently used that i don't know that we all know what its limitations might be.

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [marcag] [ In reply to ]
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marcag wrote:
Reviving this thread since you posted data on the front page yesterday.

I am not sure I 100% understand

What we know
There is a tradeoff between wider/lower pressure/aero
We know that ideal pressure is very surface dependant.
We know that CRR is pressure dependant

In the article, I see nothing about the aero benefit/penalty for different widths. Am I missing something ?
While the show rolling resistance benefits, is there any indication of what type of surface this was on ?

How can I tell if this wheel is any faster than a 25mm tire on a reasonable road ?


i'll tell you what i glean from the results:

1. there's about a 4w or 5w benefit in rolling resistance in the new wheels. per pair. you achieve that with a wider tire (28mm is best). in other words, the new wheels, with 28mm tires, run way better than the old versions of the same wheels with 25mm tires. the reason 25mm tires were tested on the old wheels is that the old wheels were optimized for that tire.

2. the new wheels are *provisionally* faster than the old wheels aerodynamically. but we don't know for 100 percent sure, because there was one big protocol difference in aero testing versus Crr testing: in the aero testing all their testing previously, and all their testing of all the wheels in this new series of testing, is done on the same tire: a zipp tangente 25mm. they chose this in order to retain continuity, test to test. the problem is this: these new wheels were designed around 28mm tires. so that's what we'll ride on these wheels. we don't know what the 28mm penalty is, aerodynamically, when it replaces the 25mm tire used in the aero tests.

but what i will tell you is this: when i slap a set of calipers on all these new hookless tires and rims, they all obey the rule of 105 with 28mm tires on. i know of almost no hookless road wheels with inner bead widths of less than 22.5mm. these wide inner beads push the width of the wheel, and i haven't measured any hookless rims that are less than 30mm in width on the outside. the 28mm tire is routinely 29mm inflated. so, you aren't riding a lollipop.

i've really pored over these charts. ask anything you want, i'll answer it as well as i can, and i'll inquire of zipp if you and tom and i or anyone else feels there's a question that should reasonably be asked.

Dan Empfield
aka Slowman
Last edited by: Slowman: Aug 21, 22 7:28
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Slowman wrote:
the data, or the compilation and results from the data, from zipp on their new wheels is up on our front page.
tom, you wrote in a FB comment below that article, "Can you ask Zipp for the plots in raw power? These delta plots are a regular "dogs breakfast" in trying to understand what they're trying to say, and how things agree, or don't agree, with other data...and seems a bit "obfuscation-y". Some details on the rolling road setup would be nice. If you're wanting to call this "science", then details of the test methods should be revealed. No way to put the results in context without that."

i assume you're talking about the Crr data. i'll ask zipp about that. there is some additional color i can give you, tho it's not specifically what you're asking. there was 1 rider on the rolling road for all the runs. the weight was 85 kilos total, with the bike. i believe the entire suite of runs was 96. there were 4 pressures x 3 tire sizes for each wheel. the 808 firecrest and 858 NSW were tested. so, that's 24 total discrete plot points. that's how i can up with (in the article) 4 runs per discrete instance. what i don't know is what was done with those 4 points. average the 4? throw out the 2 on either side and average the other 2?

i disagree with you that the way zipp presented this increases obfuscation. the way they presented the data was designed to do exactly the opposite and i think they achieved that. the data they provided is designed to help their audience understand what these new wheels give you over the old wheels.

if i can spitball here a little: they aren't claiming science in this sense: they're not claiming that their charts, as presented, are ready for publication and will withstand all reasonable scrutiny. they're claiming science in this sense: science is what guided them, internally, on the choices they made. they're sharing their internal results with their readers; they're not presenting a paper to nature magazine.

but i agree with you that we can't just stop here and call it good. i have some of the same questions you do. i think we all know there is value to drum testing, and there are limitations to drum testing. but up 'til now drum testing has been the easiest, cheapest way to test tires, and so drum testing has been gospel. rider-aboard testing seems a step forward, but it's so infrequently used that i don't know that we all know what its limitations might be.


Thanks for posting the write up however. It still leaves allot of questions unanswered regarding the rolling road itself. There is no information on either what surface they are trying to simulate with the rolling road: rough/smooth asphalt?, dirt/gravel? (for the 303 relaunch and their TSE numbers they were doing dirt roads to get the large efficiency gains). I am very curious what the surfaces look like and especially what the interface between the segments look like. Do they create smooth transitions or is there some sort of bump every time?

To clarify this, I would really like to see a PSD plot of the rolling road vs the road surfaces they are trying to simulate and pictures of the roads they are trying to simulate themselves. Additionally with a PSD we would be able to quantify the comfort increases, and reduction in rolling vibrational losses that we see to further provide color to their TSE story.

I have access to some high quality accelerometers. I might actually do that experiment myself, setting my current tires at varying pressures and looking at the change in the PSDs, but controlling the speed and which part of pavement Im riding over exactly will introduce some noise the measurements as I would want to ride over the same segment 10s of times to get better data.
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Re: New Zipp 858 NSW and 808 [Cajer] [ In reply to ]
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Cajer wrote:
Slowman wrote:
the data, or the compilation and results from the data, from zipp on their new wheels is up on our front page.
tom, you wrote in a FB comment below that article, "Can you ask Zipp for the plots in raw power? These delta plots are a regular "dogs breakfast" in trying to understand what they're trying to say, and how things agree, or don't agree, with other data...and seems a bit "obfuscation-y". Some details on the rolling road setup would be nice. If you're wanting to call this "science", then details of the test methods should be revealed. No way to put the results in context without that."

i assume you're talking about the Crr data. i'll ask zipp about that. there is some additional color i can give you, tho it's not specifically what you're asking. there was 1 rider on the rolling road for all the runs. the weight was 85 kilos total, with the bike. i believe the entire suite of runs was 96. there were 4 pressures x 3 tire sizes for each wheel. the 808 firecrest and 858 NSW were tested. so, that's 24 total discrete plot points. that's how i can up with (in the article) 4 runs per discrete instance. what i don't know is what was done with those 4 points. average the 4? throw out the 2 on either side and average the other 2?

i disagree with you that the way zipp presented this increases obfuscation. the way they presented the data was designed to do exactly the opposite and i think they achieved that. the data they provided is designed to help their audience understand what these new wheels give you over the old wheels.

if i can spitball here a little: they aren't claiming science in this sense: they're not claiming that their charts, as presented, are ready for publication and will withstand all reasonable scrutiny. they're claiming science in this sense: science is what guided them, internally, on the choices they made. they're sharing their internal results with their readers; they're not presenting a paper to nature magazine.

but i agree with you that we can't just stop here and call it good. i have some of the same questions you do. i think we all know there is value to drum testing, and there are limitations to drum testing. but up 'til now drum testing has been the easiest, cheapest way to test tires, and so drum testing has been gospel. rider-aboard testing seems a step forward, but it's so infrequently used that i don't know that we all know what its limitations might be.



Thanks for posting the write up however. It still leaves allot of questions unanswered regarding the rolling road itself. There is no information on either what surface they are trying to simulate with the rolling road: rough/smooth asphalt?, dirt/gravel? (for the 303 relaunch and their TSE numbers they were doing dirt roads to get the large efficiency gains). I am very curious what the surfaces look like and especially what the interface between the segments look like. Do they create smooth transitions or is there some sort of bump every time?

To clarify this, I would really like to see a PSD plot of the rolling road vs the road surfaces they are trying to simulate and pictures of the roads they are trying to simulate themselves. Additionally with a PSD we would be able to quantify the comfort increases, and reduction in rolling vibrational losses that we see to further provide color to their TSE story.

I have access to some high quality accelerometers. I might actually do that experiment myself, setting my current tires at varying pressures and looking at the change in the PSDs, but controlling the speed and which part of pavement Im riding over exactly will introduce some noise the measurements as I would want to ride over the same segment 10s of times to get better data.

feel fry to hypergeek but please remember and respect your audience (and offer succinct background when appropriate). i assume you refer to power spectral density and i can see how this might be measured either with an accelerometer or a photometer. if zipp didn't do this at the point of testing they don't have that data for you.

perhaps if you find yourself in the proximity of indianapolis i might try to make a match between zipp and you for the purpose of seeing what their rolling road surface really is.

what they say that surface is is "standard" road, analogous to the eagle creek field loop they use. i could imagine, tho, that the entire contraption might have some give to it. imagine a treadmill that has x amount of bounce built in, but y amount of bounce simply due to the vibration of the entire unit. any additional bounce or vibration that unweights the rider might make the rolling road's results mimic a slightly rougher road than the belt surface itself. i'm wildly speculating here. i don't know.

i'm *provisionally convinced* by zipp's data, tho that phrase is kind of an oxymoron. i find the data compelling. just, my wild speculation would help answer the one question i have, which is, why is the ideal tire pressure so low in the 858 NSW graph? i'm provisionally convinced that the new wheel is fast, and faster than the old, and with the 28mm tire. i'm not yet convinced i'd run it at 50psi or lower.

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Hi,
I have been following this thread in the past few days. I currently ride the 858 NSW from 2021. They came with the bike back then. I do like the feeling and of course the looks of the wheels, though I would like to ride 28 mm, at least in the rear.
My bike shop made me an offer to swap the 2 year old ones out for the new ones for 650$. I am thinking about pulling the trigger. How do you guys see the value here? I might be considering riding the new 858 NSW as they are, without a disc wheel in the rear in races?
Cheers.
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Re: New Zipp 858 NSW and 808 [Voodoo90] [ In reply to ]
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Voodoo90 wrote:
Hi,
I have been following this thread in the past few days. I currently ride the 858 NSW from 2021. They came with the bike back then. I do like the feeling and of course the looks of the wheels, though I would like to ride 28 mm, at least in the rear.
My bike shop made me an offer to swap the 2 year old ones out for the new ones for 650$. I am thinking about pulling the trigger. How do you guys see the value here? I might be considering riding the new 858 NSW as they are, without a disc wheel in the rear in races?
Cheers.

first, i would make sure that your current bike easily accepts a 28mm tire. second, i would make an internal calculation on tires. is the tire you want to ride hookless compatible? we maintain a list of tires and while this would've been a real concern a year or two ago i don't think it's a concern anymore. but you should bear this in mind.

third, i'm done with 25mm tires. most of us are done with 23mm tires, just as we were done with 20mm tires before that, but i've gone this additional step. you need to make sure you're done with 25mm tires, at least on this bike. while you can ride these new wheels with 25mm tires i think you'd be throwing good money after bad to buy these new wheels only to continue to ride 25mm tires.

if all that is answered to your satisfaction, i think that's a pretty compelling deal. that's a $4,400 wheelset. to get a trade-in for faster, more comfortable, better handling wheels, yeah. if that wheelset came OE on your bike you spent north of $12,000 on your bike, which means you're not afraid to spend. i would do that deal, assuming that all the other conditions i mention above are met. this is really the case if you're over, say, 170 pounds, or 50 years of age, or both.

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Here is why I get confused

if I take this chart



Just focusing on the "old wheel" (red line).

Would you agree the fact that there is no CRR difference between 60 and 100 PSI is strange ?

Do you not believe there are road surfaces where 110 PSI will be substantially better than 60 PSI with a 25mm tire ?

I would expect this (from this ST article)




And if so, if there is a .001 difference, that is close to 8watts better at 36km/h, bigger than the savings in the top chart.

Where does my logic break down ?
Last edited by: marcag: Aug 21, 22 9:33
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Re: New Zipp 858 NSW and 808 [marcag] [ In reply to ]
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marcag wrote:
Here is why I get confused

if I take this chart



Would you agree the fact that there is no CRR difference between 60 and 100 PSI is strange ?

Do you not believe there are road surfaces where 110 PSI will be substantially better than 60 PSI with a 25mm tire ?

I would expect this (from this ST article)




And if so, if there is a .001 difference, that is close to 8watts better at 36km/h, bigger than the savings in the top chart.

Where does my logic break down ?

as to your first question, here is what i wrote in the front page article: "The 808 Firecrest chart has its own strange phenomenon. Both the 25mm tire on the old wheel and the 28mm tire on the new seem impervious to pressure changes. While the 858 NSW is very sensitive to tire pressures, not so this wheel, until you consider the new wheel with a 28mm tire mounted." so, yes. that's a point that needs investigation. the one thing i will credit zipp for is this: i asked them about that. i asked them a lot of questions. their decision was just to present the data, and they know full well that this question of yours (and mine) was going to come up. but rather than bend the line or throw out the data they just presented what they found.

yes, i for sure believe that road surface smoothness and tire pressure increases track. obviously. i could easily see, if you take all cases where a bike could be ridden in a timed race, that the best pressure for a given course would be 50psi and 150psi.

as to your logic, and whether it breaks down, i'm not sure i know what your thesis is.

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Slowman wrote:
as to your logic, and whether it breaks down, i'm not sure i know what your thesis is.

I guess my logic is that if you are showing an improvement relative to something that is probably wrong do you believe there is an improvement ?
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Slowman wrote:

first, i would make sure that your current bike easily accepts a 28mm tire. second, i would make an internal calculation on tires. is the tire you want to ride hookless compatible? we maintain a list of tires and while this would've been a real concern a year or two ago i don't think it's a concern anymore. but you should bear this in mind.

Clearance is fine, so there is no concern on compatibility.

Slowman wrote:
third, i'm done with 25mm tires. most of us are done with 23mm tires, just as we were done with 20mm tires before that, but i've gone this additional step. you need to make sure you're done with 25mm tires, at least on this bike. while you can ride these new wheels with 25mm tires i think you'd be throwing good money after bad to buy these new wheels only to continue to ride 25mm tires.

As I said before, I would like to go 28mm.

Slowman wrote:
if all that is answered to your satisfaction, i think that's a pretty compelling deal. that's a $4,400 wheelset. to get a trade-in for faster, more comfortable, better handling wheels, yeah. if that wheelset came OE on your bike you spent north of $12,000 on your bike, which means you're not afraid to spend. i would do that deal, assuming that all the other conditions i mention above are met. this is really the case if you're over, say, 170 pounds, or 50 years of age, or both.
Well, I am 32 years of age and 179 lb.

Sounds like I shouldn’t worry too much about throwing away money in this particular deal.
Just the Super-9 Disc doesn’t fit into the setup anymore then. Maybe I should think about selling that as well?
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Re: New Zipp 858 NSW and 808 [marcag] [ In reply to ]
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marcag wrote:
Slowman wrote:

as to your logic, and whether it breaks down, i'm not sure i know what your thesis is.


I guess my logic is that if you are showing an improvement relative to something that is probably wrong do you believe there is an improvement ?

again, not following. what do you mean by "improvement relative to something probably wrong. "improvement" over something "wrong" means zipp previously did or made or reported something wrong, and the demonstrated improvement is unreliable because the previous data was unreliable. all this data was recently generated. perhaps you mean that zipp's methodology is probably wrong - because the tire Crr flatlines as pressure changes - ergo the improvement the data reports is unreliable. is that what you're saying?

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [Voodoo90] [ In reply to ]
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Voodoo90 wrote:
Slowman wrote:


first, i would make sure that your current bike easily accepts a 28mm tire. second, i would make an internal calculation on tires. is the tire you want to ride hookless compatible? we maintain a list of tires and while this would've been a real concern a year or two ago i don't think it's a concern anymore. but you should bear this in mind.


Clearance is fine, so there is no concern on compatibility.

Slowman wrote:
third, i'm done with 25mm tires. most of us are done with 23mm tires, just as we were done with 20mm tires before that, but i've gone this additional step. you need to make sure you're done with 25mm tires, at least on this bike. while you can ride these new wheels with 25mm tires i think you'd be throwing good money after bad to buy these new wheels only to continue to ride 25mm tires.

As I said before, I would like to go 28mm.

Slowman wrote:
if all that is answered to your satisfaction, i think that's a pretty compelling deal. that's a $4,400 wheelset. to get a trade-in for faster, more comfortable, better handling wheels, yeah. if that wheelset came OE on your bike you spent north of $12,000 on your bike, which means you're not afraid to spend. i would do that deal, assuming that all the other conditions i mention above are met. this is really the case if you're over, say, 170 pounds, or 50 years of age, or both.

Well, I am 32 years of age and 179 lb.

Sounds like I shouldn’t worry too much about throwing away money in this particular deal.
Just the Super-9 Disc doesn’t fit into the setup anymore then. Maybe I should think about selling that as well?

yeah. sell the disc. ride the double 858s with 28s or even 30s. i know a guy at zipp who's riding this very set with a 28mm in the front and a 30mm in the back. your 179lb body will thank you, and the money you get from your disc will more than cover the trade-in cost. and you'll have more room in your garage, which your sig other will appreciate. quadruple win.

Dan Empfield
aka Slowman
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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The TC858-25 data looks like the red line here,
TC808-25 data data looks like the Yellow line.
This leads me to believe they did all their tests rough/course surfaces.

So the question : "is this wheel faster on a smooth surface, at 110PSI" is not clear. (green line)

The test "looks like" they presented data for a very specific road condition.


Last edited by: marcag: Aug 21, 22 10:00
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Re: New Zipp 858 NSW and 808 [marcag] [ In reply to ]
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i don't want to appear abstruse or argumentative. i'm just going to tell you how i approach this. the chart you present is from a slowtwitch article from about 3 years ago and, as well as i remember (from memory) relies on drum testing. what we know - what i think i know - is that drum testing has a problem, but that this problem is generally overlooked because while drum testing is not reliable at telling you a tire's optimal pressure on a given (or any) course, the relative values are reliable. meaning, it can't tell you what pressure your conti 5000 should run at, but it's reliable at telling how that tire stacks up against a schwalbe pro one tt. is that fair? are we agreed on that?

this testing on the rolling road caused me to ask two questions of the data: first, on the 808, why don't pressure increases require greater or less power expended by the rider? second, are the optimal pressures for the 858 unreasonably low?

but sauce for the goose is sauce for the gander. if relative values are acceptable for drum testing, why aren't relative values acceptable for rider-on rolling road testing?

we lost my favorite theologian this week. frederick buechner died at the age of 96. i remember reading many decades ago from a book of his and he tackled the inconsistencies in the synoptic gospels. how can irreconcilable data presented as fact occur in the inerrant word of god? buechner's answer? "somebody [matthew, mark, and/or luke] made a mistake."

this closely aligns with slowman's 7th law of epistodynamics: shit happens. but shit happens against the landscape of what we have that is valid. you believe that with drum testing. so do i. you don't believe that with rolling road testing. why do you accept the known problem with drum testing but reject rolling road testing? don't they both offer value in the *relative* even as we know there are issues in the *absolute*? if we can't stipulate to the reliably good while acknowledging the imperfect, then rolling resistance data and christianity both have a big problem.

Dan Empfield
aka Slowman
Last edited by: Slowman: Aug 21, 22 10:47
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Re: New Zipp 858 NSW and 808 [Slowman] [ In reply to ]
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Slowman wrote:
i don't want to appear abstruse or argumentative. i'm just going to tell you how i approach this. the chart you present is from a slowtwitch article from about 3 years ago and, as well as i remember (from memory) relies on drum testing. what we know - what i think i know - is that drum testing has a problem, but that this problem is generally overlooked because while drum testing is not reliable at telling you a tire's optimal pressure on a given (or any) course, the relative values are reliable. meaning, it can't tell you what pressure your conti 5000 should run at, but it's reliable at telling how that tire stacks up against a schwalbe pro one tt. is that fair? are we agreed on that?


actually the article was quoting a Silca article that was showing data on the road in real world conditions. BTW, this data lines up perfectly with my experience of testing on the road, hence why I believed it to be correct.

It showed trends in rolling resistance on different surfaces at different tire pressures.

It showed that on rough surfaces CRR trended up or flat like the trends Zipp shows with it's red lines

It showed that on good surfaces CRR dropped. We don't see this on the Zipp charts

It showed that on good surfaces at higher pressures, the CRR saving is as substantial as the improvements Zipp shows in it's charts .

Maybe, the data on the zipps are simulations of rough roads only. I don't know.

The real question for me is "are these wheels faster on a given course (say Kona)" ? I have never been to Kona, but if the roads are good, it's really not obvious from this data that these wheels are faster for that course.
Last edited by: marcag: Aug 21, 22 11:26
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Re: New Zipp 858 NSW and 808 [marcag] [ In reply to ]
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marcag wrote:
The TC858-25 data looks like the red line here,
TC808-25 data data looks like the Yellow line.
This leads me to believe they did all their tests rough/course surfaces.

So the question : "is this wheel faster on a smooth surface, at 110PSI" is not clear. (green line)

The test "looks like" they presented data for a very specific road condition.


When will this graph be corrected?
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