Why Ironman are WRONG To Ban Disc Wheels at Kona 

His explanation of center of pressure is super similar to what they do with missiles and aircraft. If you want stable flight you design the thing to have a center of pressure behind the center of gravity if you want super agile steering you design the center of pressure in front of the center of gravity. As a super simple example of this, make a paper airplane and attach a few paper clips on the front of it, and it will fly further and more stable.

Is Dov putting a 3Ax sensor on the frame as well to get a delta between bars and frame - giving the full scale of how big the 'oh shit' moment is relative to the whole bike? Big fan of Dov and very jealous that he gets to do this to improve his product

Super video. Ironman have banned disc wheels at Kona since the 80s. Almost immediately as triathletes started using them in about 83 or 84.

Re Ironman banning the disc wheel, is that why HED brought out that Jet 180mm deep rear wheel I wonder?

Watching your videos daily recently , and it's crazy how if Jota and Sofiane had a baby , he would look like you😂

I’m not worried about pros riding disc wheels. I’m worried about the amateur with a disc wheel about to crash into me

Hellooo

Flat earthers go out testing also... guess what they find... a flat earth...

Roadies (a lot of) lack critical bike handling skills. Check out Gcn for suprising examples!!

When I was a fairly average domestic TT rider I was aware that a rear disc wheel improved stability. It’s fairly common anecdotal knowledge in the TT community. You would run a disc unless the wind was strong enough to physically push the bike sideways. It has happened to lighter riders at Kona but is super rare.

Who has the least progressive and nonsensical rules between Ironman and UCI? Tough call...

You should get Dov to talk about their gravel wheels with built in dynamos for Jimmy :p

Love this! Hope you have an incredible time in Kona. TriathlonCade????

Loved the tech talk from Dov and the dark art of aerodynamics. Full disc is stable? Wow! Impressive Physics! Watched the whole race live here in the Toon, what a race! Congratulations to the podium winners 🏆 and also to Fanella 👏....90 degrees & 80% humidity.....Oh my days! Dovs bike on GTN too!

Yea.... Thanks for explaining that... Still don't understand 😜

Great explanation from Dov. Like a lot of TTers and Du/Triathletes i only put the disc cover on for race days. i train on a lot of the same roads as i race on and (incorrectly) thought i didn't notice the wind as much in a race because i was in a race and had other things to think about. Makes much more sense that the bike is less impacted with the disc cover on.

Electronic stability control would seem like a possibility (electronic shifting seemed crazy a few years ago). I also wonder if anyone is working on a well integrated & efficient dynamo to run all the electronics on a bike, it would eliminate a lot of batteries & charging.

I say obvious thing about Your experiment... Turbulence.

Basically the only explanation you need is that the disc wheel increases upright stability a ton and you can do it when testing a loose disc wheel detached from the bike. Impossible to angle the wheel sideways while spinning Now as for why the rampant anecdotes for friends of friends of disc wheel users falling and dying: it's because they used a deep section front rim. Deep sections on the front have been known to blow pros off course when they are riding to close to the edges. The rear wheel is being held because it's fixed in angle and always points straight. Until the wind is so powerful to push your entire frame and overcome the friction of your rubber tires, you will be safe. If it's too windy for disc wheels as the anecdotes say, then it's too windy for your (front) deep section rims Now as for why the front rim is entirely what causes the blowing off course. It's because the wind doesn't need to push the entire frame like it has to do with the rear. For the front wheel, the wind only needs to be strong enough to pivot your fork sideways, ignoring the strength of your rubber tires. The only thing preventing that front section from pivoting is your own torso downforce weight. And using deep section front rims is what gives the crosswind more leverage to throw your front wheel around. So those anecdotes for friends of friends that you hear? Theyre placebo lies. It's their front deep section rims that's causing them to get blown off course from vehicles and windy bridge crossings.

think they would just cancel them when the weather permits eh?

As if RU-vid's auto-captions can accurately subtitle "ultrasonic anemometer".

i suppose it'll also be bringing the centre of pressure much lower as well, so even if the raw lateral force being exerted is bigger, it's acting closer to the contact points making for a lower tipping force/moment

They Ban Disc wheels because when there's a strong crosswind in Kona it can cause accidents and possible deaths. It's more a safety thing than anything.

You may be right that it can actually prove to be a benefit. But I agree with the decision of the banning based on something you said: "For super lightweight riders it acts as a wall" if it poses a serious safety concern even for a fraction of the participants than it should be banned for all in the name of safety rather than creating many loopholes that would be unjust towards a subset of participants. The tech is still there and should be talked about and explored rather than just saying oops can't do anything since its banned.

that's really very interesting. thanks dov for the explanation

Totally agree. I’m an amateur TTer and I’ve ridden a disc in borderline storms on the A189 which takes you over some really exposed bridges. You get pushed about a bit but you won’t fly away.

His explanation of how cross winds interact with a disc wheel was interesting…

Tick, tick, tick, tick, tick, tick, tick. Fix that BB.

Fenella had the day of her life

The catch of a disc wheel is that amateurs buy or rent a disc wheel and do their race in it without much experience or practice. If you are not prepared then yes you can thrown off a bit or nervous with a hard crosswind. For the pros, they shouldn’t be banned at all, as this is their lively hood and they will have 100s of hours of practice to do it.

Random question for Dov - Does he know someone called Ben Westlake? He looks and sounds so much like a guy I know called Ben its freaky

Watching this just made me clever-er

Really disappointed Jimmy didn't manage to sneek along:/

Science!

It does sound very counterintuitive. 🤔

Has parcours website been hacked? Can’t get on certificate not valid?

very hard agree, with hard R

Oh cool disk wheels

You could have picked me up a Kona Bike Works cycling cap...mine has just given up the ghost :-)

SCIENCE THE SHIT OUT OF IT!

he definitely had explained that very well and he correct. that just how the air works around the wheels during moving thew air.

Dov should’ve done the So Hot in a Scottish accent for full effect

Cheers, and thanks for the video.

Are you cycling up Mauna Kea?

Это полная чушь. Влияние ветра крайне маленькое на заднее колесо! Люди в пелотоне ЗАДЕВАЮТ заднее колесо других людей всем свои телом и гонщик впереди НЕ падает! А все потому что заднее колесо лишено возможности поворачиваться и загружено всем весом гонщика. Так что айронмен тупо выдумает правила) Now in English Thats a a total bullshit! Impact a wind force to a handling is fraction of noting! People in a peloton having a crashes, when person behind one smashing in a rear wheel of other and man on the front NOT fall! That because rear wheel have no any possibility to turn and change direction of rinding person on bike. Hope non triathlete never believe in that)))

I've also experienced that a disk makes me more stable. I rationalized it as: the ratio of surface that catches wind that is able to steer vs. the area that is not is decreased. So this leads to less movement in your steering column due to wind.

Disc wheels for the win. Plus they look cool

People that sell disks want them to be legal so they gain an advertising venue. Really simple math.

Would the added spinning weight in the solid wheel also add to the gyroscopic stabilizing effect?

As a guy from a coastal town that has done a huge number of crosswind TTs, disc wheels (on the rear) are not a problem. A disc on the front is a different story 😮. It amazes me how many triathletes don’t take advantage of a disc wheel when it is legal. It’s money see monkey do.

See what happened in sub7 sub8, when crosswinds created "ow shit" moment

It must be hard being the smartest person in the room all the time. You wear that hat well Dov. 🤓👍

Question: if disc wheels are more stable, does that mean we should be using them in road and crit races too?

Would a preferated disk wheel be legal in Kona as it's not a solid disk? Or why not run a wheel so deep that it has a hole about the size of the cassette (still not a disc) Is there a maximum wheel depth allowed in Kona?

Lets ban disc wheel but allow disc brakes and also allow a bike position when your head is between the handlebars and you are just looking at the ground for 80% of the ride…….

But the question is - is a back disc wheel faster in heavy cross winds? Probably not. Francis should ask Dan Bigham. Dan setup Filippo Ganna 1-hour record attempt bike to be the fastest bike humanly possible within the UCI rules. Two extremely simple and obvious things Dan did that none of the Pros in Kona are doing - 1) Ganna does not have brake rotors on his wheels because a wheel without brake rotors is faster than with brake rotors - this statement is too obvious to write down. So the Pros should be riding their old TT rim brake bikes or demand their bike sponsors to build them a rim brake TT bike. This will save them several minutes on a 112 mile individual TT. One day a bike company will figure this out and take the Tri market. I am surprised no one has figured this out yet. 2) Ganna is likely running 150 psi tubular tires and not 73 psi tubeless tires because the track is smooth. The Kona roads are deadly smooth. They probably paved them recently. Plus the Pros ride on closed roads, so they can choose their line (i.e. the smoothest part of the road). They are definitely not riding on the shoulder where there are gravel patches. So the Pros should be riding on high pressure clinchers with latex tubes because this setup is faster than a 73 psi tubeless setup on smooth roads. GC Performance tested this out and came up with a 1 kph increase in speed when riding high pressure clinchers over 73 psi tubeless setup on a smooth road. This is huge!! How can the Pros in Kona be so oblivious to these simple gains?

Last 🌊

The stupidity of wearing a mask to stop a virus has trickled down to Kona banning a solid disk rear wheel lolol