Are Disc Wheels Worth It? | Triathlon Bike Tech Explored In GTN Does Science

When it comes to triathlon bike upgrades, wheels are often regarded as one of the biggest. Surely that means that the disc wheel is the ultimate. It’s the deepest profile. Meaning the smoothest airflow, and the fastest option! But with more material & heavier weight, is it really worth it for any time-saving? Well, that is the million-dollar question isn’t it & with the help of our friends at DT Swiss we’re going to be tackling that very question!
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[@gtn]

Do you ride with a disc wheel and what are your experiences with them? Share them with us 👇

[@tomcodling5465]

You should contact EZDisc and compare the disc to a solid disc cover (which costs much much less) I think the results will surprise

[@graemepaterson1983]

faaaaaast

[@gengar678]

I ride with a super 9. Looks great, sounds great and no issues at all with wind. A disc just has something supercool about it . Like a coach behind you that keeps telling you to push hard 💪🏼

[@a.k.1351]

God, that sound is just absolutely amazing. I love hearing it when I pass all those dentists at races.

[@mulsannestraight]

You must be fun at parties

[@Alex-kr7zr]

It's even more awesome if you pass them with a folding bike.

[@dew_reg1574]

A table with the results would add a great value to the video. Otherwise great content and science with the CDA measurement

[@wilfdarr]

Ya, for the ADD among us tracking random numbers like this isn't easy.

[@a.l.s.718]

the genuine happiness in the face of Mark when talking about the sound of the disc wheel is priceless!!!

[@dnulty10]

We needed less music so we could hear the sound of the disk wheel. Especially on the last hill climb

[@markthrelfall3577]

I’m not sure you would have heard much over my pained breathing! Man that was a tough one

[@crawfordbrooks5151]

I disagree. I think the play between the sounds and the track was well done! Keep on gtn videographers

[@martygriff2001]

Haven’t raced in 15 years. I still miss the sound of riding on a disk wheel in back and tri-spoke in front.

[@CenaSitnica]

Lol

[@Vishnjaaa]

tri spoke is not longer cool :)

[@Alex-kr7zr]

So we are talking about 300€or more per Watt saved, definitely for dentists. Btw. what would happen if you put a disc wheel in the front as well?

[@nicolasdomise]

Great video! And actually there was the infamous Embrunman that James has done several times and it is known for its deadly 188km bike course with over 5000m of positive ascent. The winner, Leon Chevalier, who went onto break the course record in 9h28 decided to ride a full TT set up, disc wheel and all and that was even when there are proper HC climbs and everything... Just some food for thought

[@theredracer]

Thanks for the info, would appreciate a visible table or something though, I'm completely lost with the information given.

[@mmarcheto1]

As anything in triathlon, it depends on how much money you are able to spend ... I would love having this Beautiful Canyon with this brand new DT disc wheels, but in Brazil this setup costs about 40.000 USD, the same as a BMW 320 for example, but here the minium salary wage is 250 USD per month. Even if you have the money, stills sounds absurd to spend this amount here in cycling gear . On the other hand there are guys here who make 9h Ironmans with Trek Concept 7.0 2015 + 2015 Zipp 404/808 ( Less than 4.000USD in total here )

[@kenhiew2900]

Those prices . .. well , capitalism is what it is

[@robertlee3002]

40,000 USD, that doesn’t sound right. That set up would cost around 12,000 GBP

[@IanLoughead]

Canyons website has the Speedmax CF SLX 9.0 TT with disc and Di2 in Brazil for $9000 on sale now, normally $10,000

[@mlustosakm]

@@IanLoughead Brazilian taxes take it to the next level, so 10,000 outside becomes 40.0000 easily, i am now living in Europe, and i feel the diference, same vaule i was paying for continental ultra sport 3 in brazil, i can buy a gp5000 tubeless here

[@automotive474]

​@@robertlee3002 taxes.

[@MrAnders1000]

I love my discwheel. Done all my fastest time trail and triathlons with my discwheel and trispoke front wheel. I have an older mavic disc and it is fairly heavy but in flatter races that is something good. Harder to get it going but once it is rolling I always feel like it is helping to keep it rolling If this is true or only in my head it doesn't matter really. It feels faster It sounds amazing And it makes me feel awesome while riding so I am all for it. Found it second hand for 400 pounds. Would never buy any aero wheels new. Crazy money but the second hand market is awesome for stuff like this

[@iivv_nn]

I made a disc wheel with foam filling. My friend then laid a thin layer of carbon on top. It actually makes that noise but very lightly.

[@velodavid1287]

You filmed this on lots of my old training roads in Wiltshire! The course of one of the Outlaw tris’ if I’m right? I can’t work out where the third hill climb was though?

[@LarsRR]

There is a huge misconception with disc wheels and stability. Disc wheels are *more* stable than a rear deep section wheel. The added area shifts more pressure to the rear of the bike, away from the front. Since only the front can steer, only here you’ll experience steering moment, which is the “instability” You experience in cross winds. For me, the rear disc has been the best upgrade to my TT riding, as it has given me a lot more confidence in strong winds.

[@user-rl3ef4ju9k]

So they should allow disc wheels also in Ironman Kona?

[@DanielGoupil]

Completely agree with you on the stability. I lot of people are asking me about the wind and I had a 1080 in the rear before and all the wind going thru it was causing a lot of turbulence. And yes the front wheel is way more problematic! As for Kona there's a limit at wind you can take with a disc sideways as +70kmh wind in the lava field is not 25-30kmh wind that you can deal with it.

[@gudrune]

@@DanielGoupil kona gets windy like that? That's got to suck!

[@kenhiew2900]

100 agree ,Up to a point.. I think for Kona's iron man world champion ships it'd be too much

[@LarsRR]

Why would Kona be too windy for a disc wheel, I don’t get it? Kona is not the windiest place on earth, many places, including the mountains or coasts get as windy or windier. The problem with crosswind is not that you experience force from the side (an aero bike frame and rider will present larger side area than the a disc wheel), but that the wind turns your front wheel. This steering moment makes you feel unstable on the bike, and might potentially be dangerous. Having a rear disc is dangerous when the wind is so strong, that you‘d get blown off your bike. Probably in such conditions, you shouldn’t ride deep section wheels either… or a bike at all. Probably should be sheltered somewhere from the 50+ knot winds.

[@gabedellar588]

Interesting video guys, I thought it was mark I saw attacking milk hill the other day😛

[@k04s4]

Need a light shallow wheels and also a tri spoke front wheel.

[@joeborowy5794]

Much better then the one I hade on board.

[@aldude9511]

Discs are worth it for the sound alone! No question. Thank you for the ASMR intro. Poor James though. He seemed so awkward at the start trying to hold the character.

[@bobbybostic7947]

Thanks for the DT Swiss infomercial…..

[@Mike0]

No problem, now you just need to justify the $3000 for a 1-3w saving

[@klaw7705]

Sound matters :D

[@1z4nagi67]

Im wondering if i can put it in an mtb since i only use it in pavement roads

[@markkulinnoskivi9350]

Why did you not keep the front wheel constant if the point was to study rear disc wheel effect? The comparisson between shallow set and deep set is completely besides the point. One could argue that it’s reasonable to update entry level wheel set with a disc rear only - if it’s worth it.

[@gudrune]

Most of aero gains from wheels come from the front wheel, and I don't see who would buy a top end disc and keep a crappy alu front wheel.

[@markkulinnoskivi9350]

@@gudrune sure but the topic is specifically about disc wheels. Let’s say you have the shallow wheel set that came with entry level tri bike and you have the budget to get a deeper wheel set or just the rear disc. Actually you should just get the deepest front wheel you can get but people usually would not accept that. Any way it would’ve been only one test more to do to run with the alu front + disc rear. And for that matter run the 80mm front with alu rear.

[@markkulinnoskivi9350]

Also the 3w benefit from the disc wheel is well inside the error margin of this rest protocol. For instance power meters have 1% accuracy. So with a sample of one the disc did nothing.

[@markthrelfall3577]

There are obviously so many other options and variables for this. We went with the common choice. If you’re getting yourself a disc wheel, you will more than likely be upgrading from a set of deep section wheels. It’s this difference that most are interested in. I understand your point though. With regards to power meter accuracy - it’s the same pm for all runs, so that will not affect the results

[@flosa1995]

2 DIY disc covers on a cheap ass Decathlon 500€ road bike, shaky af but try to beat that aero per dollar ratio

[@JimHaysom]

Freehub and Disc wheel sound check please.

[@onilovni1234]

Free speed for much $$$, I love cycling.

[@maxmurray8284]

Would you recommend for a 60kg rider?

[@jm_sc]

wha th- Is this a brother company of GCN? Found the name quite hilarious

[@chrissarkkinen7422]

Find it weird that every time I see a deep section vs training wheel comparison the only thing considered it aerodynamic drag and weight. No-one seems to talk about the inertia of these wheels. It does not matter if the disk wheel would be double the weight if it would be closer to the center than training wheelset.

[@levbobrov1398]

The moment of inertia (or weight distribution) does not really matter.

[@Mike0]

There are countless videos on GCN saying rotational weight doesn't matter, but it seems GTN don't watch GCN

[@Nonixification]

I only can hold 400 watts when I lift my computer power supply.

[@98GuitarTECH]

Sponsor may not be a huge fan but Arc 1100 vs homemade disc?

[@karimbahri784]

Did you have to adjust derailer or gears with the disc wheel swap? Or straight swap and ride ?

[@Jon-lf2dj]

Just ride. The position of the cassette is the same as a spoked wheel (i.e. it doesn't snug up close to the flat disc surface). I ride a 90mm rear for training and a disc for races (triathlon), and never have issues swapping.

[@karimbahri784]

@@Jon-lf2dj thanks heaps for the reply Jon. I just returned a disc as it sat very differently to my other wheel and would have had to adjust gears each time and not be able to use lowest gear. New bike might be in order to ride the Arc Disc

[@Jon-lf2dj]

@@karimbahri784 Might have been a missing spacer issue. Assuming the cassettes are the same speed (and both Shimano/Sram compatible) they should be plug and play.

[@karimbahri784]

@@Jon-lf2dj thanks Jon. Yes same cassette but different brand wheel. With the spacer the smallest /fastest cog doesn’t fit on at all and still needs gear tuning. Good lesson for next disc I buy

[@markthrelfall3577]

Straight swap for all. Not spacers on cassettes or adjustment of callipers needed :)

[@MrTigerlilly68]

Yes, absolutly, there is nothing like ridning a discwheel on a flat course... 😁 🌞

[@ericappiah5235]

I get my Amazon Dollar$ worth every time.

[@jamiefuhrman403]

$3000 for disc wheels?! Seems crazy... so with all the aero upgrades the pros' bikes cost upwards of $15k?! Seems like there are much more cost effective aero upgrade options for amateurs.

[@davidcallan7844]

Those weird fibreglass trispokes were popular when I was heavy into cycling 25yrs ago, now my bike has saddle bags for going to the grocery store.😂 “Do some more sciencing”😳😂🤦‍♂️

[@blinzi69]

ive got a CdA of 0.215 on a standard Canyon Ultimate with Aerobars attached and no deep section wheels, is that good? Wonder what i could get on a TT Bike with Disc.

[@crnkspinnr5863]

Short answer, Yes! I was 5:30 faster on a Zipp 808/Disc over a 40K TT. Compared to aluminum rim spoke wheels.

[@Mike0]

Not surprised, I've been 3 mins faster depending on wind directions with the same wheels I've also gone 1min slower over 20km with disk vs 808 depending due to slightly different wind conditions

[@mulsannestraight]

I've ridden different wheels from manufactuers and I can safely say its good to experiment because each wheel to their own have different advantages with regards to straight line speed and cancelling cross wind. This why I love cycling the bike is literally a moving laboratory.

[@derkong7114]

None of us will be able to hold 400 watts...

[@Mike0]

at 200w you'll still save watts, just less than 3watts, depending course & conditions

[@ljadf]

After hearing the scientific experiment explained, I heard something other than "fine".

[@scotts6067]

A full disc is always faster. Speed gain vs the price value........well that's up to the buyer.

[@leslie7922]

Cool

[@JackofNothingess]

My opinion... It's worth it if and only if you can mount it on the FRONT wheel, where ram-air dynamics causes more turbulence. Only problem is, it can become unstable in high crosswinds, so it is a bit of a coin toss on when you should use one.

[@george83815]

Have you done a 1:1 comparison with a rear disc Vs no rear disc? For me using 50mm front and back Vs a 50mm front and disc rear saved me an average 28 seconds on a 10mile TT (did 3 runs of each and took the average saving)

[@basildaoust2821]

"That one felt faster." Please explain how riding the whole distance at a fixed pace of 40km/hr you can be faster or slower, you going exactly the same speed, it seems you should have been equipped with equipment to track you.

[@EatMyPropwash]

Mark, what RPM do you ride at typically?

[@markthrelfall3577]

For TT and Tri stuff, around 85rpm typically

[@OFFSHOREDOUG]

400watts isn’t your average rider though really. If we all had the money we would have the deep wheels or disc even if it saved .5 watt. A saving is a saving. Should have did a test with shallow front disc rear.

[@wrxzboost]

never worth it...but a nice to have. i'd rather spend the money on a high end deep set of wheels and chuck a cheap disc for flat courses - little difference in high end/low end disc rears.

[@standandeliver8376]

Good idea for a video, but there are too many variables at work here. Aside from the aero differences, you have an alloy rim with standard bearings, a carbon rim with ceramic bearings and a carbon wheel with standard bearings. We don't know quantitatively what difference the material choice and bearing type makes.

[@anerdwitdacamera204]

You gotta be one of the fastest in a race to equip a disc wheel. Imagine riding a disc wheel and being dropped by a 5 year old random road bike....

[@andrecoelho4992]

please try to add a graph next time, lazy work

[@robfetty6497]

Your channel seems focused on age groupers, not pros - right? Like your segment on breaking 6 hours for the Ironman bike. But then you have Mark ride at 40K per hour and at 400 watts. How many age groupers are doing that? How bout you do 30K per hour and 200 watts? That would make way more sense for the majority of your viewers.

[@Alex-kr7zr]

At my local age group triathlons plenty of people go close to the 40km/h mark. With the right gear you don't need 400W for that, more like 250-300. I bet that a lot of the GTN viewers are more in the faster section as they are actually informing themselves about things like disc wheels and aero savings.

[@Datboyvideo]

I'm quite an average rider, with great gear. BMC TM TT with Zipp808s and a skin suit. My last olympic distance I did 40kph at 258 watt average. I think that speed is more obtainable than people think. I wasn't even close to taking first. Lots of guys faster than me.

[@Alex-kr7zr]

@@Datboyvideo Yes, I just did a 40kph average on Half-Iron distance yesterday with a BMC TM and stock carbon wheels, 251W average. The best rider did a 44kph average! Completely flat course, almost no wind. So yes, it's more doable than most think.

[@deanb61]

I'm not going to win anything, but equally I'm not usually last. So only for the sound, the performance for me would be irrelevant I think. I'm still not going to win anything, even in my age group (60-65)

[@markthrelfall3577]

I thought you were going to sign that off with “and that is why I own a disc wheel” 😂

[@deanb61]

@@markthrelfall3577 there's a balancing act. I want gear that allows me to perform to my capabilities, but there would be an embarrassment in turning up with pure bling costing £££ to shave an insignificant amount off...Still for the sound, yes, that's why I got a disc wheel :)

[@karstenmeinders4844]

The tests no 2 and 3 are pointless IMHO because the rider (Mark) gets standing up which destroys any aero benefits provided by the wheels. The main benefit is not wind from 0° angle, but with some yaw angle to provide lift. Some questions on the featured product remain open: Is the DT Swiss disc wheel flat or does it have a belly kind of shape? Does it come with valve cover? Is there enough space around the valve to use a variety of pumps to inflate the wheel? Can tyres be easily mounted? As a medium-gifted triathle of medium age, I ride a Roval 321 since 2019 in training and races with 25 mm tyres without any issues (although I own some DT Swiss wheel sets, too). I have never noticed any "comfort issues". As a side effect, due to the "whap-whap" sound, pedestrians and other riders give space intuitively when I am approaching. Spares the bell ;-)

[@markthrelfall3577]

Try cycling up a 20% gradient without getting out of the saddle 😂 That’s the point of the test. It’s putting it through real life situations, and displaying that tipping point

[@makemebadfan95]

Not worth it unless you can sustain high speeds in my opinion.

[@Jon-lf2dj]

While slower riders will see a lower wattage savings, paradoxically they get a greater time savings from improved aerodynamics (since they spend longer on course). There isn't a minimum speed needed to justify a disc (well technically there is due to the added weight adding rolling resistance, but it's down in the single-digit kph).

[@makemebadfan95]

While I agree there is a benefit to having one, I just find that the price doesn't outweigh the typical $1K+ USD price tag for the average athlete is what I meant

[@Jon-lf2dj]

@@makemebadfan95 That's why I got mine used (a Renn 575 for

[@makemebadfan95]

@@Jon-lf2dj where'd you find it lol? I can never find a cheap used one. I always see them almost at retail prices

[@Jon-lf2dj]

@@makemebadfan95 Mine was slowtwitch classifieds. Now with folks getting disc brake bikes the rim brake wheels start to come available. It also helps that Renn is a lower end disc (vs. a Zipp9, etc.). A wheelbuilder cover ($100) is always an option. Not as blingy (and no rumble), but the wind doesn't care.

[@therealmontiecarlo]

That guy has a South African accent I don’t know if I’m tripping or what

[@DublinDapper]

Not even close to being worth it

[@jigglypuff4227]

Just 3 Watts saving at 40 kph?

[@Jon-lf2dj]

That's over 1% (based on the 250ish watts in the test), which at the pointy end of the field is significant....and that's vs an already hi-end 80mm rear wheel. That's why most pros will lug a disc to any race that allows them.

[@tylerwirch8259]

please never put the shallow wheels on your bike again.

[@markthrelfall3577]

😂

[@jonathanzappala]

I enjoy racing against the commenters who think it’s not worth it. Ironically many of them would shave off more time than I do because they are slower. They don’t understand that.

[@wilfdarr]

Good point: because I'm slower, if I'm saving 0.1%, I'm still saving twice the time a professional would be saving on a run have l half my time. Still, I'm doing this as a hobby, not professionally, so I'm still not convinced it's worth it.

[@jonathanzappala]

@@wilfdarr it can be a hobby, so you don’t have to buy one, but you shouldn’t be ignorant. It’s not a tenth of a percent. If your on a 8 hour end of an Ironman it could be 5 minutes. If your a pro, more like only 1 minute, but translating for more watts saved in their car than yours. Maybe 5 minutes isn’t worth it to you for the money, that’s fair. But like I said I’m glad to race and beat people who believe it’s not worth it.

[@yogipool]

🚴‍♀️🧘‍♀️

[@vinniedisa]

New has e a personality that doesn't suit well the role of a presenter. Where is Fraser?

[@robertlee3002]

Not sure how robust the ‘science’ is in this video. More like back of an envelope calculations. GTN, you need to up your game, love the idea of the channel but the content is often so poor and rushed

[@jameswestgate4896]

Kiev wheels bru

[@RoomNo.20]

19 min later... No it is not. Note: get a lab coat.

[@mjs1231]

You all failed Shallow carbon wheels, rim brake is still far better to today's over priced boat anchors. Climbing matter most, thats where you win or loose.

[@caloferrero78]

YOU TALK TOO MUCH WAY TOO MUCH I'M NOT ONLY PUT I DON'T LIKE THIS VIDEO BUT ALSO BLOCKED YOU !