There are a couple of odd things about the data Trek has published. As you noted they compare a tubular tire on the old wheels and a tubless tire on the new wheel both with nominal widths of 25c inflated to 81 psi. I wouldn't be surprised if these are optimal conditions for the new wheels and less optimal for the older tubs. The 'Stability' values are also odd given what they measured isn't so easy to correlate with real world stability. The stability of a wheel has much more to due with how the force changes around the stall angle and how sharp the stall angle rather than the maximum side force you can generate on the wheel. A wheel with a gradual stall profile will be much more stable in terms of handling than a which stalls sharply even if the first wheel has a higher maximum side force.

anecdotally... a friend and often ride partner of mine got a pair to test (for a local guy "in the know cycling" gets )... we rode on a fairly windy day as well with moderate climbing (rollers) .. 73 miles and 4k, ave about 21-22mph

His feedback was: wow. super light and quite quick

**please note I heard this feedback as I was on the front pulling at max HR and i rolled my eyes bc this kid is quite quick and making him quicker makes my life (on the bike) that much harder.

ha

daved

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http://www.theundergroundcoach.com

I like training on the wheels I race on. I don’t train on tubs. So I am a big fan of the development of super fast non-tubular wheels. By all accounts the new tubeless wheels are every bit as good as their previous best tubular race wheels and that’s good news. I’m suspicious of the exact speed claims relative to the XXX wheels but I have no doubt they are top notch wheels.

I was looking at used bikes a few days ago and came across a beautiful P5 with 808s and gator skin tubs. I am sure as soon as Conti comes out with a tubeless Gatorskin people will still roll with it but it shows the problem with tubs. The hassle of flats is such a PIA people make crazy sacrifices to avoid the flats.

 
but isn't tubeless also a crazy sacrifice to avoid flats?

I’m the wrong person to ask here as I still run clinchers on my road and TT bike. I am tubeless on my gravel/CX bike and I do see value but tubeless makes a lot more sense on 45mm tires at 30psi.

what makes you think that? I love tubeless road tires, a little faff to set up but once that's done they're pretty chill, hold pressure well after a couple of rides and with the quality of roads I ride on 95% of the time (even in races) are likely quicker by me being less beaten up from high pressures to avoid pinch flats, meaning I can put power out better and more smoothly. Only big shame is that there's limited tan wall options

What's the crazy sacrifice?

While I don’t think their stability metric is appropriate, stall is probably not a concern since wheel/tire aerodynamics can not be said to ever be “attached.”

A genuine measure of stability describes a restoring force or moment when a disturbance is applied. For a wheel, it should mean that if a sudden gust appears, the wheel should naturally point into the gust, and cause the bike to roll into the gust as well, because if the opposite happened the effective side gust would strengthen and the cycle would repeat until the rider falls or is heading downwind.

In general, for the above reason, I think a good design for stability is opposite of the common Zipp/oval trend. To induce a stabilizing rolling moment, more sideforce has to be created at the front than the rear of a wheel, then gyroscopic precession will phase shift the yawing force couple into a rolling moment 90deg later.

That aside, I haven’t seen anyone else publish side force vs (aero drag force + rolling resistance) which is something I’ve harped about. It definitely costs something measurable to “sail”.



edit: I don’t think one can deduce much about rolling resistance vs side force from these graphs, and it may even be the case that they merely superimposed one value of rolling resistance to their data. To truly measure this, the bike would have to tilt and the sideforce load should be reacted on solely by the contact patch.

 
to me .. the sacrifice is not being able to fix a flat. i have a set of clinchers for my gravel bike for when i want to go exploring, which sort of helps. the times i've flatted my tubeless its been totally game over.

but this is a dead horse i shouldn't have tried to flog back to life with my dumb quip. this is the aeolus thread :)

Opposite for me. Not only has it greatly reduced the number of stops for flats, but the stops are also much shorter when it happens. (because ~3/4 of the flats can be quickly plugged without breaking the bead). I think once in the past 4 years or so I've had to install a tube. And even that wasn't that hard.

I'm fine beating the horse!

The new Air-liner inserts from Vittoria have really made transitioning to tubeless intriguing for me, particularly for some notion of safety for punctures at high speeds and corners. If not for that, clinchers with latex inner tubes seemed to be good enough.

I'm sorry to call slowtwitch/Dan out on this, but I'm finding more and more of the front page articles like the Dan posted yesterday on the new Bontrager wheels, now really appearing to be an advert by stealth or shameless promotion and not a review. I found it uncomfortable reading because Slowtwitch always used to be above this kind of stuff (that we read so often on the magazine websites). Loads of talk about fast, stall and aero that is then walked back with a stated lack of data and not actually a lot of testing substance when you really dig into the article. I've been on this site a long time now but my confidence in the integrity of the product reviews is really being eroded.

 
I don't remember ST ever do any kind of aero testing themselves, so I don't expect that. I am sure that's a hole Dan does not want to go down.

What is your expectation of data ?

But as I said in the Ventum thread (which they plan to review without aero data), I would like to see ST require data from the manufacturer and publish it with some type of comment on the way the test were conducted. ST can question the data, us the readers probably can't get answers.

I'll give an example : a manufacturer published their bike was 17watts faster, 10 coming from a set of wheels that didn't fit on the previous bike, 5 from a position not achievable on the previous bike and 2 from "real" improvements. I would like ST to see that, question and comment on it.

I am sure ST could turn to a handful of behind the scenes advisors, publish as their opinion and better educate the masses. The argument that "all bikes and wheels are about the same" doesn't make sense for these types of product reviews.

1) My expectation is really that I feel a site, with its typical readership has slowly moved past reviewers saying something merely feels fast and then not adding a lot of other value in the review. Dan's reviews on this site on new bikes in particular (in terms of their geometry and specs) are really good and give extremely high value (I actively seek them out) but many of the reviews on products like wheels and other high performance equipment are coming across to me as increasingly disingenuous and merely adverts or subtle retreads of the brochure.

2) You're talking about providing a proper critical appraisal. I agree completely.

 

<pink>Dan needs to hire Hambini </pink>

Let's just not go there..... LOL.

I tend to think the "blacked out with Sharpie" products appearing in the TdF or "worlds" is the stuff to look into. It's good enough to cause you to paint over the logo and go against your sponsor. Or photos of what the British TT guys and gals are doing.

I may see "cool" on articles, but wait for someone else to buy it first and try it out. If it gains some traction, I'll try it.

man, i'm with you all the way brother. it stinks. only problem is... bontrager is not one of our wheel partners. send me your address and i'll remit to you every penny i got paid to write my "shameless promotion."

i just liked the wheel. i found it interesting on several levels: the fact that it's a hooked bead wheel with the widest inner bead width of any road wheel i've ever ridden; the easy-snap liner; the closet-toroidal shape; 105-obedience with a 28mm tire and the fact that a house brand can produce such quality tech.

maybe my true sin was verbosity. i just wrote the whole review above in 2 sentences.

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Dan Empfield
aka Slowman

But isn't that maybe the point Dan ? Is an emotive and subjective piece now enough with this kind of product ? Where is the data and why are the brands not sharing it with you because the design of wheels is seemingly so complex now (as are market expectations in my view), to me, that review in particular felt it lacked depth and sincerity. Just saying someone liked it surely isn't enough these days. And yet, if I read any of your articles when a new bike launch happens, we all get so heavily schooled by the detail put into it. It's a fascinating exploration and exchange of knowledge.

Maybe it's just me though. I get that. So much these days is shoved behind paywalls or is advertising driven I'm getting more cynical about what I read.

i don't think the piece i wrote was "emotive and subjective." it rides smooth, like cognac, with a hint of orange peel. that's subjective and i hate that, which is why you've never read anything like that from me about a bike. that wheel has objective features, which are what i wrote about. i made no speed claims about that wheel, unless you can point something out to me that i'm missing.

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Dan Empfield
aka Slowman

1) That's fair - my apologies. I guess we're differing in opinion about what people may expect these days when a new and interesting wheel comes to market.

2) I do think the very need for speed claims and data is needed these days for such items. Since aerodynamics is one of the cornerstones of a contemporary race wheel (if not the foundation), I think its an incomplete to not mention it in terms of the numbers. Or to put it the same way you did, you gave me the cognac but no orange peel..... and this drink needs orange peel.

i absolutely agree with you that speed claims absent data = ignorance or propaganda. but not just wheels. also bikes, chains, lube, tires, helmets, pulleys. how much product have you seen launched in the last 3 years features published competitive testing against industry leading product? the data you want, and the data the manufacturers make available will satisfy you a fraction of the time, i fear.

beyond that i do want to say, however: i don't want to appear reactive to criticism. one of the real and true values to this forum, for 20 years, has been that i get instant feedback on the content i write, and when i screw the pooch i get valuable lessons on what and how to write. so, keep that up. don't muzzle yourselves on my account. give it to me straight!

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Dan Empfield
aka Slowman

You're not wrong, My eyes were sucked in to several cycling websites today that announced the new bicycle design from BMC and Red Bull Racing billed as the 'worlds first F1 bike' - declaring it as the fastest ever with all kinds of name dropping going on but no information was given to its performance. Not a sausage. When we were arguably just prior to 'peak aero' 10 years ago, there was a trend of white papers coming out from various brands to at least try and give themselves some scientific or engineering credibility. Those days seem to be gone and if anything, it feels that some brands are going backwards in how they communicate to their markets. Anyway, I'm off on a tangent at this point so I'll park this one right here.

Yeah, I’m even sceptical of the wheel and position data. I think if we look at the old SC with a reasonable set of zipp/other clinchers with correct tire size and same rider position/clothing/helmet at best we are looking at 0-3 watts for the new SC…to say it’s 17 watts faster is bonkers. Especially without even a reasonable effort at a white paper.

Having said that, I honestly think they did a pretty good job. To throw discs on a bike, add storage, have perhaps better positional change options and keep the weight in line while being ***hopefully*** aerodynamically neutral is no small feet.

Let’s just not claim 0-3 watts is somehow 17.

Maurice