Are Disc brakes Slower? Rim Vs Disc Aero tested.

Powermeter used (Assioma) - tidd.ly/3Z98OXb
Reference powermeter - tidd.ly/3WJx9Bn
Control tyre (GP5000) - tidd.ly/3GEF512
105 Rim brake holy grail groupset bargain - tidd.ly/3BNlkSb
peaktorque10 discount code ‪@WinspaceBikes‬www.winspace.c...
FS bar, use code peaktorque40 - www.farsports....
FS proprietary wheels, use code peaktorque100 on www.farsports.com
FS wheels, use code peaktorque50 on www.wheelsfar.com
Aero handlebar aero test video:
• Is an Aero Bar Actuall...
Test protocol:
10 x 2km out and back at 35-36kmh on each bike, repeated in ABAB format (40km total)
Same tyre and control pressure (gp5k 28mm @76psi)
Re-zero and torque powermeter pedals after each install.
Riding on hoods, comfortable position.
90rpm cadence (cadence does affect CdA!)
All electronics left to reach ambient temp after exiting car, 1 blank run is done to air-cool electronics before rolling start of 1st lap.

[@PeakTorque]

Update before release: Just realised - in the second chart, the colours have swapped. Values are correct. Update post release: Thanks for all the comments, crazy this one I shall try and keep up. Dont forget to click subscribe, 80% of viewers non-subs, I don't bite! The next videos we have in this series include: Wider Tyres vs control tyre Aero test(at iso-Crr) - self explanatory Wider Tyres vs control tyre Rolling resistance [frictional and vibration attenuation] test (at iso-CdA) - I fix CdA and optimise pressure for a given course. All wheelset data for individual aero tests (which forms the backbone of the Aerolab partnership) can be found in upcoming wheel test videos. The first one to be uploaded here was the Ican35 review which you can find on my channel. Cheers to the patrons, you know who you are!

[@bikedawg]

I think cross wind performance and measurement would be much more beneficial. Most people slow down if they feel the cross winds are jerking their wheels around--that would affect speed more than anything else.

[@Hambini]

PT and his estate car. A man with no shame.

[@PeakTorque]

Low CdA mate. 53mpg+. Remember the Volvo estate in BTCC? Was it banned for being too quick?

[@Hambini]

​@@PeakTorque A load of tosh, that CdA is going to be way worse than my car! It's because you are contributing to lung problems for the masses with your diseasal. for our next video powerpoint reaming I think we should have "Cycling KZbinrs and what they drive". I think the masses would be hooked.

[@Gregory_tottie]

I was disappointed the bikes weren’t in the TR6.

[@Andy-co6pn]

@@Gregory_tottie Thule disappointed ?

[@hisdadjames4876]

The Merc has discs, front and rear. Just sayin’. 🤷‍♂️

[@JamesSmith-qs4hx]

Rim brakes for the win in 2023.

[@SeeYouUpTheRoad]

Thank You for doing the testing. As I’ve mentioned to my fitting clients and coaching clients body positioning is far more important than equipment choices.

[@OmniTierra]

100% guaranteed more people experience rubbing disc brakes than they ever did rubbing rim brakes. Aerodynamics are one thing but when you have a warped disc and you’re on a long ride or in a race it just gonna suck power.

[@theillegalimmigrant9314]

This may seem a very stupid question, but there are many variables with different wheels and handlebars, and one of your bikes has an additional spacer on top of the stem. So your justification of control is not justifiable. Hambini did a similar test and took his front disc and calliper off, which he suggested was the most significant contributor to drag. Could you just do that? In any case an eye-opening video, and thank you for taking the time to do it, as it has taken some effort.

[@PeakTorque]

Practicality. Ive Tested no front rotor and the difference is within the error bar (about 1.5w at 35kmh). A partner has also tunnel tested it up to 55kmh in a tunnel. Am under NDA on that, so say no more.

[@pmcmpc]

@@PeakTorque PTwheels inc?

[@BrentSimon-bl3hw]

That's the main point on a comment I just posted. The 2 bikes are too different to isolate the braking system impact!

[@davidcole6893]

Great content. Fasinating when nearly all new bike reviews talk about ' 25 secs faster over 40 km ' etc as though the bike has an independent engine ! Always good to have the body position emphasised as the most important factor.

[@MarioXcore1]

Do a test with red valve caps vs black vs white 🤔 vs no valve caps 😳. Truly epic and important science done in this channel

[@ProfeTa6]

Disc brakes: heavier Rim brakes: worse when wet Negligible differences when it comes to aero drag

[@durianriders]

Speak for yourself ❤️😆. Some of us ride over 25kph and use race tires. Road disc IS slower and more dangerous.

[@ProfeTa6]

@@durianriders what? I also ride above 25kmh and use race tires. I actually race. For over 10 years. So yeah my opinion but more dangerous? What? Only for the hamfisted and those that lack skill. Get good.

[@username8644]

Disc brakes: extremely dangerous

[@albr4]

@@ProfeTa6 I heard and saw pro riders claiming that they've been injured by discs, but in a race I did last week some guy had his finger sliced down to the bone in a crash, I can't see how that could've happened other than landing on a disc rotor, I guess it could've been a chainring but it was a very clean cut.

[@stevec6232]

Honestly I'm amazed the disc isnt slower but 2cm bar width feels huge going 40 vs 42 in terms of air resistance. It's true body position far more important than anything else.

[@overbikedrandonneuring]

Just wanted to add to the comments thanking you for your work. It is quite valuable to the community surely took way more time than the compensation you will get. I hope viewers can appreciate how much more rigorous your methodology has been compared to what is commonly reported. Chapeau!

[@davidgeorge9233]

PT I thought this was a fantastic video, finally putting some real world data to the huge argument that is rim vs disc. Kudos to you for taking so much time to put this and your other content together. First time I’ve ever considered patreon simply because I respect the work involved. As an enthusiast rider with both disc and rim brake bikes this test mirrors my own findings that in the real world the differences are not worth worrying about, when you’re having a good leg day even the winter bike on 28s with mudguards is a 20+ bike.

[@henrikerdland578]

Conclusion is that the riders position are much more important than any thing. That’s supports my theory that the most aero bike most be the bike with the lowest bottom bracket hight. A low bottom bracket will put the rider more “in the bike” and therefore covering the rider. I have been looking in to this, an on of the bikes with the lowest BB height is a Focus Izalco Max. It could be really interesting to test this Focus against a “real” aero bike.

[@global_nomad.]

interesting to confirm the idea that body position is the big issue, followed by wheel choice....thanks for your explanations of the process and keeping your shorts on!

[@svenbruning9124]

The Hambini sound in the intro EPIC!!!

[@shaneryan2418]

Heloooo 😂

[@PeakTorque]

Credit to the Dark Install. Rest his soul.

[@trepidati0n533]

Every time you do one of these tests....the more I'm convinced that cycling is so far down the marginal gains hole that they are actively hurting themselves by pricing people out.

[@ronitdebnath]

+++

[@nellyx1x493]

There has been a noticeable historic tendency for roadies to aim to emulate the look and equipment of the pro's, this has got to the point now with tech advancements where many riders end up with equipment barely suited to their real usages - or more specifically a higher degree of wasted 'needless' performance. I'd like to see a definitive split between ProTour level race bikes and a more realistic alternative marketed towards keen enthusiasts...without it having to tend towards the old-man comfort bike - a sort of 'classic' Tour bike with an emphasis on ride feel and enjoyment.

[@PeakTorque]

Isn't that why we're here? We love all this minute detail.

[@trepidati0n533]

@@PeakTorque Oh don't get me wrong. Your videos have probably saved me $1000's by not buying shit that really won't help me. This probably isn't helpful if you are looking for sponsors though. :P

[@veganpotterthevegan]

They can only get marginal gains now. That's just the reality of engineering within UCI rules. As for pricing, it's hard to say they care that they're pricing people out if people are still buying their bikes in mass. *Also, PT noted that his fit between the two bikes may be enough to throw off the data anyway

[@robinrai4973]

Given we're exploring these tiny marginal gains and losses, one thing I want to see bearings vs bushings in jockey wheels - I imagine a few watts on a particularly tightly tensioned drive train, and bigger differences when grit and dirt is introduced, but it's certainly not me who knows anything about efficiency, I ride a full suspension everywhere lol Great vids, and great dedication for the testing

[@szurketaltos2693]

I doubt this setup would be able to measure a difference there, that's an effect another order of magnitude or so down from this.

[@ChrisMillerCycling]

Great test PT! On a side note, potentially KZbins finest (and deepest) voice over 😍

[@PeakTorque]

Glad you liked it!

[@HendrikNieweg]

Thanks for this no BS test, highly appreciated!

[@chrislevick7837]

Superb video - Best real world empirical testing I've seen on the rim vs disc aero debate. Thank you.

[@cipo36an203]

But everything else is different! Wheels, frame, bars… can’t drive any conclusion

[@durianriders]

Watch mine then. 2 riders then swap bikes each lap so wind and air pressure is IDENTICAL.

[@sepg5084]

I don't really care what's faster, i just prefer hydrau discs for the actuation feel. Just feels so smooth. This vid was good entertainment though.

[@durianriders]

Retest so the wind and air pressure are the same. Retest with 2 riders who swap bikes each lap then you have the truth. Ride apart so no draft. I did this and road disc on SL7 Sworks mega slower vs rim brake tarmac for $650 off Gumtree.

[@TheMerckxProject]

I won a 3km pursuit event once by 0.11 seconds. I never looked across the track to see where my opponent was. Like you state at ~7:30, I fully believe had I even tried to look it would've cost me the race.

[@robinhawes8843]

Really interesting thanks for making this stuff understandable. Good to see the differing frame years of the TCR not showing significant differences as they made all the usual aero claims with the new one😆 It would be cool to see the narrow 320mm Fouriers bars get tested, perhaps against the carbon aero bars, just to further contextualise the priority of body position over components :)

[@veganpotterthevegan]

Despite the advertising fluff, the fact that you don't lose watts, but get better breaking gives the win to disc brakes. At least with comparing these two bikes. I'd also like to see a similar test done with two bikes without so much cable housing. Even the disc bike in this scenario has plenty of cable housing showing.

[@cipo36an203]

You have so much apple and bananas differences between those two bikes that you can’t drive any conclusions. The rim brakes has an aero bar… but it’s wider (probably the biggest I pact since rider will generate a lot more drag), rim brake has a different rim height, and has exposed cables, cranks are different… we have no idea how this add up.

[@IronHorsey3]

How many rim brake riders you at the side of the road with a brake problem? Rim brakes on road bikes FTW! 😱🫠🐸😎

[@AnvilAirsoftTV]

Thanks for doing this. Super interesting

[@mpvsystems9302]

Was your rim brake bike using a radial spoked wheel with 6 or 8 fewer spokes? If not, I suspect this would have more than offset the extra cable drag. I guess another factor is that since the switch to disc brakes by the industry, there has been no further aero development of rim brakes. Back in the day, some brands were putting the brakes under the chain stays, behind the fork, and even inside the fork crown. It is worth observing that highly aero rim brakes, perhaps those inside the fork crown, for example, would have less drag than discs.

[@EthansTerrarium]

I agree. And the aero data from your magazine can support this-for example, the rim brake madone was a few watts faster than disk madone (in a wind tunnel, that is). There are a couple more examples. R&D on rim brakes is almost non existent it seems. Those integrated rim brakes were also a pain to work on though, and as PT says, disk brakes can be faster due to late braking, confidence, and relaxed upper body on descending. They also permit more complex wheel designs and contours. Though I would love to continue seeing TT bikes with aero rim brakes with development there, and I think this will continue… just not on road bikes.

[@eoinkenny3188]

I'm loving this comment section. So many people drawing incorrect conclusions. My take away is that the same old rules apply, if you want to reduce your system aerodynamic drag don't worry about the brakes or running gear for miniscule gains. Focus on body position, fitness, kit and rims.

[@PeakTorque]

basically

[@Ninja_Revenge]

Always rim brake road bike for me! Nothing beats my Zipp 202 tubulars with DA9100 brakes in terms of both acceleration uphill and braking on nasty descents!

[@TrickyTree84]

Somewhere on the other side of the world some guy called DurainRider just exploded.

[@aerobrain2001]

Pretty much summed up my hunch, any aero difference in the real world rim v disc is essentially negligible for us mere mortals.

[@mbee6606]

A great real world comparison test. Conclusion for us mere mortals …ride whatever you want to ride. I have both and enjoy riding both.

[@TracKnGravelDeWd]

Wouldn't a better test be done on an indoor velodrome? There are so many variables you really can't control outside in changing conditions.

[@mariovr8416]

Thank you for the test. I will stick to my rim brake bike.

[@ifitrollsrideit530]

This is properly interesting, thank you. My own experiences have been that I don't get much better braking with discs vs aluminium rims but I do enjoy the much lighter feel of hydro disc brakes. That's especially so on either very long or multi-day rides when your hands/arms can cramp a bit on long techy descents. It's good to know that aero losses are not too big a penalty to pay for that.

[@glennoc8585]

My rim brake bike with tubular carbon wheels brakes as good as my disc bike in dry weather and I get consistency with my rim bike as I have days of terrible front end disc braking due to contamination until I clean off the rotor. Where my disc bike ultimately wins is the all weather braking and long life of the rims

[@Nico-jt8ll]

How are these 28x spokes 3x cross wheels with exposed nipples not significantly slower than a wheel with 20x radial hidden nipples without disc?? Can`t believe it, what`s going on. Explanation?

[@Mapdec]

Kudos to you for so much effort into a fairly obvious conclusion in the end. Doing yoga is possibly the best aero solution?…

[@PeakTorque]

Cheers. Obvious but theres always that niggle of doubt when it comes to air... that has now been eliminated.

[@chasbikeravda3933]

My buddy and I have tested this out on several occasions. I ride rim, he's got discs. We have a local hill, at the top we stop pedalling at exactly the same time at the same speed, side by side and freewheel to the bottom. Our feet are placed in the quarter to 3 position, our hands on the hoods and therefore in the upright ride position. And yes, we are of very similar build and weight. First up was me on my alloy Boardman Team with Mavic R-sys wheels, he on a carbon aero Giant TCR with 55 and 65 aero SLR wheels. After 20 metres I was rolling clear, at the bottom of the 200 metre descent I was 40 metres clear. We repeated a few weeks later, but this time I was on my carbon Cannondale Synapse (2007) with a Prime carbon 50mm wheelset, again, not an aero bike, but rim brakes once more. Very similar results. My mate later acquired a very new version of the Cervelo (some letter, P or R) 5 which was not only an aero bike, but also fitted with the new super cool looking aero bars with a wind reducing bridge 🤔 across the top. Once more on my Cannondale, the same results occurred, I can't even say that the super aero Cervelo was any closer than the Giant, but it was certainly left trailing in my wake. Was it rim brakes making that much difference? I don't know, but it's certainly a factor.

[@LFMC1]

Aren't the wheels and the calipers a giant disc braking system already??!!

[@czeckson74]

Conclusion, no need to go to disc !!!

[@gokaygs]

Differences of body position and bike setups aside, all the Cda and watts results are within 1% of each other which is likely smaller than the margin of error of the Aero Lab device, even Assioma power pedals have +/-1 % margin of error, so can we realistically claim any solid conclusions from this test? Even if we were to accept that disc is a few watts more aerodynamic, rim brake is still the undisputed winner in weight, price and maintenance.

[@PeakTorque]

You're not wrong, but fortunately 'accuracy' is not the same as repeatability. That's why we do repeated runs! And there does seem to be some bias in terms in favour of the disc bike, albeit very slim.

[@gokaygs]

@@PeakTorque Great research vid by the way, it is quite interesting to see some independent real world riding data. However, statistically speaking, I'm not sure if 10 laps is enough data to favor even a small bias when the results are within 1% of each other and the measurement devices' margin of error is at best +/-1%. If you were to do a bigger sample size there is a good chance that small bias could flip. Not trying to torture you man, I just find the discussion interesting. Cheers!

[@slowcyclist4324]

Price and maintenance are moot points in reality. The majority of cyclists entering the market, and thus will eventually dominate the population, are covid era cyclists. These folks have 1) cash to burn and 2)self-maintenance offers a low return of investment for time spent. As such, money ain’t an issue, and if there are any issues, it’s the mechanics problem to deal with, not theirs. So they have every incentive to use whatever is cutting edge in cycling, regardless of the time or servicing technicality.

[@gokaygs]

@@slowcyclist4324 Ahh gee! How could I miss the fact that cycling isn't about seasoned riders who are passionate about the sport and log in thousands of miles each year but actually cycling is about the covid era cyclist who just picked up the sport and hardly rode a few Ks of miles during the pandemic because he/she found cycling fashionable during their "new normal". I probably walked into more bikeshops and dealt with more mechanics then you have seen browsing online. Without being a moot schmuck like yourself, I most likely spent way more $ than you have in cycling. A real cyclist who actually rides will benefit from maintaining own bike, knowing that every bolt is specced to torque and the bike is safe to ride hard. Dropping off expensive equipment to get serviced by random bike shop mechanics is a recipe for disaster, I know from first hand experience and not blabbering assumptions like you. Finally, only a confused pandemic era cyclist would think they have every incentive to use the "latest cutting edge" on their twice a week 30 mile rides with 15 mph average speed. These also happen to be the same group of people who claim that rim brakes don't stop but they think they can descend "oh soooo good" with disc brakes. Now go on and wear your $400 pink Rapha jersey which you put on every week and go on a ride. Stop by the LBS on the way back and buy a new bike since $ is no issue for you and you get to show how you dominate cycling with the latest and greatest tech under you. Good job Fred!

[@assaultedpeanut9]

The most impressive part of this test is how smoothly PT moved the mouse at 2:54

[@PeakTorque]

I used to be an Airbrush/tattoo artist. That was a lie

[@KleineJoop]

It's all a lot of money for trivial aero gains as the type of bike is the limiting factor really, an recumbent or velomobile is the next step. I don't have space for a velomobile sadly, also a nice one is expensive.

[@ml1186]

I guess the main takeaway is when you get above 40km/h ability to maintain an aero position has a much higher significance compared to having a disc or rim brake bike.

[@PeakTorque]

No, i would say that's the most important above about 20kmh!

[@durianriders]

Was the wind and air pressure the same each lap? Impossible. I did this test using 2 riders then swap bikes and average the data. Road disc IS slower.

[@quarkonium3795]

@@durianriders Keep telling yourself that Durian and maybe it'll come true

[@basedgodstrugglin]

@@durianriders You should test riding down a steep descent with no skewers in the quick release and see what happens

[@torma99]

​@@durianriders you also said, that the Trifox X8 is a good frame for the value. But I chewed through 2 seatposts, the wrap on the fork was unwrapping itself from the getgo,, had to drill the front brake hole, at the rear the painting started to melt away around that hole, the seat tube and the post were so out of their intended dimension I had to use 2 and 3 layers of sports tape for the posts, yet the second one went down still and got stuck, ofc many tiny painting imperfections (I cpuld live with them actually), but no warranty, very bad customer support. So I am glad you had good experience with that shitbox Trifox, but I would seriously reconsider recommending it without mentioning all the problems which that brand has.

[@thedronescene7474]

Nice video. If the rim bike had Di2 then the results would have been the same since you can hide the Di2 cables the same way as the disc one.

[@apair4002]

Front rim brake still got cable exposed.

[@pierrex3226]

Very interesting. I remember a gcn wind tunnel video where they admitted that discs were a good 5W (or was it 8?) Slower, I think on a pinarello. I don't remember the front end. We do know that every exposed cable slows you down, so there's a good chance disc + no exposed cables= rims with exposed cables. Also, vanity. Integrated cable bikes just look cool 😎

[@onepunchbud1472]

Yeah, that's why all new high end bikes have fully integrated cockpits and an aero monobar. That's the sector where they had the largest gains left. I mean the result is - discs are only a bit worse. Probably not too surprising considering their position on the bike and the relatively small size of the disc. Also they try to hide the breaking mechanism behind the fork which helps. But since all they do nowadays are marginal gains it's funny that they force everyone on discs. I mean with discs they can make the bikes more expensive, the maintenance is more costly, fewer people do it on their own and most important point - they had an argument to sell new bikes to people who already had great ones and there was no real performance gain anymore.

[@jaredfontaine2002]

RIM BRAKE!!! NO DISC!!!

[@jaredfontaine2002]

I can't wait for the industry to make a U train on Disc brake bikes like they did with threaded BBs...

[@appa609]

"until you do the test it's all speculation" Naive empiricism is not it. Sometimes analysis is genuinely better. A guy on a bike produces less drag than the same man on a bike plus a tiny far field parachute. I can be completely confident in that with no test. And if you did the test and you couldn't discern the difference then there's very strong reason to believe that the test is not precise enough.

[@jonasbielskis1033]

I tried emonda disc and rim version. And rim feels much more faster and nimble, and feeling it what I go for

[@BrentSimon-bl3hw]

long time viewer, first time commenting. As Engineer (mechanical eng. building bridges and towers and putting them in wind-tunnels) I love your videos and like the more data you bring-in, but this one bother me. You seem to have removed the variability in the test by alternating bikes and by making multiple repetition to stack possible errors, good point here. But what you test is not making sense and reading people's comment it appears many got a missleading takeover and miss the limits of your set-up. You are comparing two very different bicycles, you haven't quantified at all the impact of each changes, different frame, different wheels, different bar width (this seems to be the biggest one). I understand that's yet difficult to have 2 identical set-ups but without this you just can't make any finding (well you could say, and seems to be your underlying conclusion, your two bikes are relatively similar aerowhise but that is not what you were looking for) and claiming "differences are minimal"). If I may suggest changes: - at least re-run the test swapping bars - you seem to have laced your own wheels on the past, get the same rim and use it on a rim and disc set-up To some extend an older GCN video had a way better bike set-up but quite a questionable way to measure things. Brent S

[@velobey7832]

Always loved to see these comparison videos, that I have also done in past. Giant also claimed aero efficieny increase on their new TCR frame which should not be trown out of the window. To be certain, and to have more controlled environment, it is crucial to take up 100% identical frames (rim vs. disc), wheelset, handlebars, same cableing, same tyres etc to compare x to y if we try to learn or observe an idea that rim brakes are faster or otherwise.

[@ErichVonCartmann]

The Rim Braked Bike had the slower tires, wheelset, handlebars, and cabling, and the rim brake bike still won. If you don't believe me, then you are welcome to do the test yourself.

[@markj.a351]

I've never understood how non elite riders could possibly think discs are going to significantly slow them down. It's nice to have some numbers to point to. Thanks for your effort. I still have rim brakes. Only thing i have against discs is the asking price for bikes.

[@MTBScotland]

Its a nice video but from a science point of view it is flawed given the differences between the bikes.

[@MTBScotland]

@Teakhead Al that isn't how science works.

[@KushPizzaSleep]

Disc brakes are heavier and harder to service , maintain, noisy ect and ugly I don’t understand the appeal

[@MTBScotland]

@@KushPizzaSleep piss easy to maintain, work significantly better (even more in the rain), don't wear out your wheel. I'll take the wee bit of weight over better braking. only thing I hate about road discs is the price.

[@Tarmaccyclocross]

@@MTBScotland disc brake bikes are quite a bit heavier and hydraulic disc brakes are a pain in the arse ask Chris froome. Total over kill on skinny tyre road bikes but it’s a world full of all the gear no idea morons

[@Jacob99174]

Excellent work, mate

[@iberiksoderblom]

I do only rim brakes. My rim brakes are tugged at the back of the front fork and down by the crank case. So mutc, much supprior to any discs. And looks so much cleaner.

[@peterers3]

luv the blue color on the TCR 2021

[@maustar6746]

Probably, the main result of this test is that Winspace wheels are (little) faster. This and some other secondary factors compensate disk drag effect. This does not mean that disk drag effect does not exist.

[@RadCJ33]

I remember Swiss Side did a comparison test in the wind tunnel, with the rim brake having significantly lower drag.

[@joeshmoe7967]

.....wind tunnel a good reference, but often real world results are different. Unless a pro racer, I have serious doubt anyone is beating all comers who ride disc vs rim......

[@danielsemyonov]

Ah dismantling purists’ white castle one brick at a time, love to see it

[@PeakTorque]

Its white until it rains, then it goes grey and sludgy and ruins everything!

[@quarkonium3795]

@@PeakTorque Perfectly said-turns out cycling is made up of more gray areas than marketing shills or old-school purists would have you believe

[@ml1186]

You should have done 10 laps with an aero helmet just for comparison, that would have put things into perspective :) Should I buy a new bike or a new helmet to save 5 seconds over a course of 20km :D

[@SeeYouUpTheRoad]

Interesting test - new wheels, new bike or just a new aero helmet?

[@nellyx1x493]

Aero enough helmet, tall lycra overshoes and 45mins in the shower with the Bic.

[@SeeYouUpTheRoad]

@@nellyx1x493 love it! Yes Nelly!

[@quarkonium3795]

New helmet for sure. Clothing and body position are the most important factors in aerodynamics by far

[@Mr71paul71]

Go home have a cup of tea and work up a sweat with the wife, as your never going to win the tour de France. It's not aero gear that wins races it's pharmaceutical products that wins races these days 😅

[@albr4]

wouldn't the discs get worse and worse as the speed increases since they're spinning faster, whereas the rim would stay pretty much the same at all speeds? (if anything they would get faster due to being in increasingly more turbulent air from the wheels) I think at race speeds (26-32mph) the disc would be much slower than the rim brake.

[@openwheelracing88]

The disc TCR has updated aero tubing right? That makes all the difference.

[@PeakTorque]

Speculation. Its still almost square shape.

[@dylanl9532]

What about the water bottle myth? some say with or without water bottle there’s a 5w difference

[@luismanrique5373]

Lol hambini is going to sue you for that “Hello” intro 🤣

[@jameshoward9700]

Good practical protocol and totally plausible results. My speculation from owning/racing both was that there was little difference - what the rim gained from the wheel/lack of disc, it lost in crown junction bulk and cables. But what ain't in doubt is that the rim bike is definitely quicker uphill and in acceleration, simpler to maintain, cheaper and causes less frame compromise. The disc bike is better at braking in the wet, has less compromise to rim composites and for training allows a wider tyre. But all academic as everything is disc now...

[@durianriders]

Tell us how road disc increases traction in the wet? Why so many more crashes now in wet races with road disc? Tony Martin retired because it's 'just ridiculous out there now'.

[@tubbytoast2]

Thanks for giving this a go , clearly what you are trying to say is in a near perfect world there is probably very little difference between disc and rim aerodynamically ( especially if the disc bike is made to ' compensate ' for the rotor etc aerodynamically) I can't understand why some get so worked up about it , so there were some variables which means it wasn't 100 , but in the end it's a f*#"&g bicycle travelling alone a road not an Jet aircraft or a Rocket into space!! I am more concerned about the cycle industry getting the fork and steering tube interface correct with some kind of redundancy fail safe built-in 😬

[@10ktube]

I love these videos showing miniscule differences. I do think aerodynamics are a "thing", but a lot of it is like the moment of inertia. I think there's a moment of aerodynamics, where the aero gains exist for a fraction of a second, until they don't, due to swirling winds and changing "stuff" relating to the system (pedaling, breathing, rocking the bike, etc). Think like an aero cockpit setup. Looks pretty, cleaner, but once the wind is through that area, game over and back to messy. The gains never have a chance to exist outside of that moment.

[@PeakTorque]

That's why i don't really trust tunnel data at these lower speeds. There's too much swirl in the real world, and the results are less flattering.

[@wsnx_]

Interesting but also contradicting to your and Hambini's old videos, which stated that disc bikes are way slower and you were bashing the cycling industry for their move to disc brakes. Both of you also explained why the disc is way worse (with scientifically explanations regarding aerodynamics) but your results don't show any of that?

[@cipo36an203]

the 2 bikes set-up are fairly different, so we can only say "the new Disc TCR tested here is faster than previous gen rim brake TCR tested here", that's quite less attractive, but that is the real conclusion.

[@alastairstedman7840]

I won't ask you to do it again because damn those laps would be torture for me. But I WOULD like to still see the bikes using the same equipment. So same handlebars between the bikes and exposed cable etc. But I don't expect peak torque to do that.

[@PeakTorque]

😎. Practicality of doing these tests in winter without being paid. Is the answer from me 😎

[@alastairstedman7840]

@@PeakTorque @Peak Torque yeah no obviously not practical at all. Although my impression that I am getting from the result of this test is... Alll things being equal between the two bikes equipment wise, the Disk brake equipped model should be a hair faster.

[@waynosfotos]

Is that a German shaggy wagon I see there????? Well looks like body position in the back of the shaggy wagon and on the bike makes the biggest difference. Cough Cough, equipment “size” has little affect. 😂

[@joeshmoe7967]

As a non nutbar rider....I would think the way to get faster is to get fitter. Tour riders are not faster because their rim brakes are a zillionth more aero, they are fast because they are in better shape, stronger, can pedal harder longer. I would find more satisfaction improving my times on the same bike because I got fitter, vs dropping cash for tiny real world improvements. Get a nice comfortable bike, that maybe has some modern technical improvements, then ride the hell out of it. Gear envy is expensive. If $7K isn't 'fast' enough, $10K isn't going to make a serious difference. I am happy on any bike that is comfortable enough to ride for hours.

[@MrHuddy]

Could've put aerobars on to mitigate the width of handlebars and to help stabilise the position?

[@ben4373]

Good video - I still think the last of the rim brake Trek Madone’s must be the most aerodynamic of all. Bit it doesn’t really matter because that bike can’t stop 😂

[@michaelmechex]

Frankly, that's pretty much exactly what I expected

[@jearwood85]

It’s crazy how fast gravel bikes are these days

[@darringrey4329]

PT could you glue a rim brake on the disc bike ? Then take it off .

[@supertampon5]

is the rim brake giant the 2019 version with the square downtube?

[@julmeissonnier]

Sorry, but it seems to me that different width bars are probably dominating... All the rest is noise... Narrowing your entire upper body by 1.5 cm is a very big change in frontal area and has a huge impact...

[@olekmehera7256]

Very objective and analytical video, this one video right here has more science and data than all of the Global Cunts Network videos combined EVER. Good shit PT, how easy are discs to live with for you? Do you get a lot of rub and warping or do you have a combo or rotor/pads/ calipers that minimise the potential for rub? Interested to hear your thoughts

[@endianAphones]

Not much global in it. There's an Irish guy... 😅

[@basedgodstrugglin]

Brilliant reframing of the GCN name

[@anaxa4883]

If the difference is so small that this question is so often asked, why deal with the added cost, complication, and weight of disk?

[@hail_sagan2830]

Because of superior performance in varying conditions, better wheel compatibility, and improved tire clearance.

[@anaxa4883]

@@hail_sagan2830 I'd wager that if consumers were aware of the pros and cons you and I both listed, most would go with rim brake. But markets don't actually work how people are taught. In reality consumers have very little power and have to buy whatever is given to them which explains the popularity of disk.

[@hail_sagan2830]

​@@anaxa4883 I don't know that I agree with that. Hearing, "disc brakes will stop you much more reliably in the wet," is a pretty big motivator for a lot of people. Adding onto that, "they also suffer virtually no aero penalty, which is shown to be more relevant to average speed than weight" will seal the deal for those that are concerned about performance even if they can barely hold 150W.

[@rosomak8244]

@@hail_sagan2830 This is not true. Disc brakes fail in a dangerous way and generally don't perform any better than good clinchers. In esp. they are not better in wet conditions at all.

[@hail_sagan2830]

@@rosomak8244 gonna need you to go ahead and cite some sources on that one. disc brakes have repeatedly been shown to perform better in the wet.

[@spikev5842]

Perhaps to complete the value proposition of this data, some additional math ... - R vs D brake bike retail cost (cyclist) ÷ the wattage delta - R vs D brake bike % cost of sales (supplier) - enthusiast Vs pro % probability of related cash rewards = > R vs D brake bike retail ∆ - joy factor (rated 1 - 10) of owning the latest 'bike tech' vs actualised personal performance gain . . . with graph where x-axis is weekly average outings (measured from "0") 👍

[@RustyRacer]

What are the error bars with the yaw measurement? My assumption is that yaw worsens disc more, maybe?

[@PeakTorque]

The yaw is fully dependent on the wind direction, not the equipment. I'll get in touch with the engineer at Aerolab to ask about yaw error but i imagine it about a tenth of a degree.

[@marekchmiel2741]

PT, I think I might need some help 😀. The last two years I've been building bikes from used frames and selling them for profit - I've now reached a point where I want to upgrade to a good carbon wheelset, but I can't decide whether to go rim or disc. The basic principle is to keep the wheels long term while trading the rest of the bike for profit. I live in an area with steep hills and I'm not the lightest - 75 kg, so I'm thinking it's better to go disc for the longevity of the rims? The only thing I'm afraid of is the maintenance cost. Also, what would you pick as the best VALUE wheelset? 2023 Hypers?

[@michaelkennedy9064]

I think testing aero rim vs disc is best tested on time trial bikes where aero is everything

[@geonwilliams]

How is CdA affected by yaw angle?

[@kanenasithaki4669]

are the aero wheels faster than normal wheels?

[@zebounce]

My biggest question is: what on earth is this knockoff Curb Your Enthusiasm tune playing in the background 2:53 ?? Did you ask an AI to "recreate a song in the style of Frolic by Lyciano Michelini, but faster and without copyrights" or something?

[@stuartbennett4476]

My take aways: - biggest impact riding position - Then good fitting clothing and a good helmet on your noggin - Then wheels and rudder + component choices - New frame will bring less bang for buck in aero gains (regardless of which braking system you choose) Thanks for the insights and energy invested 👍

[@anotheryoutuber_]

the rider is always going to be the heaviest and dragiest part of the equation, and component differences are always going to be small, but folks keep spending money on the things underneath them hoping itll make em faster, at least placebo is measurable.

[@slowcyclist4324]

Yes, but the bike as a system doesn’t change in aero performance because of fatigue etc. you, as a rider, are way more inconsistent. Your weight fluctuates, your posture changes as you ride, and your clothes also changes depending on what’s in the wash. So, if I have a constant variable that will never change (aka the bike) doesn’t it make more sense to fully optimise that consistent factor, over a variable like posture and weight which changes consistently? In short, money spent on an aero bike/equipment is actually the best investment you can make. Your body comes next, as that comes over time and changes constantly.

[@PeakTorque]

The best bang for your buck is tyres. Way more savings there than the difference between wheelsets/frames.

[@slowcyclist4324]

@@PeakTorque that is true. That said, inevitably when you’ve gotten your wheel/tyre down( because in all seriousness how long can that take?), the next area for investment should be your bike frame.

[@bidigi]

@@PeakTorque only interms of rolling resistance, or do you think that width (25mm vs 28mm same tire model) is also important for aero gains?

[@smfr123]

Was that first snippet of audio Mr Hambini?

[@paulschulman8131]

From what I gather from this is no matter the bike an aero position will do more than most components. Cool. Still want my rim brakes grrrr 🤣

[@Veloscape]

Very interesting analysis (as always) my take is that there is not a lot of difference in CdA. I think more relevant would be the impact of the extra weight of a disc bike vs. a rim brake bike (I reckon you need to spend £2000 extra on a disc brake bike to match the weight of a comparable rim brakes bike). How much extra wattage does an extra 500g on the bike weight requires to push the same speed on a 10% slope...maybe another video.

[@bradbarbour23]

Bit of a shame the handlebar widths were different, I think it may have helped the disc out more than anything

[@PeakTorque]

Same width but just 15mm narrower at the middle of the hoods

[@SPLSE]

FACTS. 💿💿💿💿 I read the comments first and knew the outcome of the video as the conversation is shifting to clothing😂.

[@duketran6093]

Hello, what’s your advice on rim vs disc for a race bike, re brake performance can rim be equal to disc? Many thanks

[@PopEmUpChem]

Gods work is happening on this channel...

[@PeakTorque]

He isn't even a patron. What a douche

[@gamingaccount4935]

Comparing newest gen adv SL (top end) vs previous gen adv (low end)??? Come on man, It's just like comparing tarmac sl6 comp vs sworks sl7 🤣

[@PeakTorque]

Adv pro, still top end boi ;)

[@appa609]

I would expect a difference of something like 10-20 cm^2 of CdA between the two.

[@peterscuba]

i thought it was more about the weight difference on a climb

[@phoenixaroui8712]

What do you think about a slight rub does it makes slow ?

[@rosomak8244]

People should now realise that the top riders just ride what they are told to. Performance at the top level comes mainly from the medical department.

[@pmcmpc]

You mentioned very cold and dry as being slow. Cold, granted. Why is low humidity slower? Surely the air is thinner.

[@sammyrides5536]

More humidity makes air less dense. H20 (water) weighs less than N2 (nitrogen) and O2 (oxygen) per molecule. Combine that with Avogadro's law, and you'll see that high humidity air is less dense and therefore easier for objects to move through.

[@pmcmpc]

@@sammyrides5536 didn't think about it displacing heavier gases.

[@peterers3]

The handlebartape isnt the same colour obviously the testing methodology is fluked. Let ur twin do the testing next time.

[@cipo36an203]

What about bar width, different frames, different wheels, different housings?