XMCS - 2026 VRT

[Requiem84]

Oooo, good work!
You need to do another lap on a comparable bike at the same power now

I have about 300 rides here. And never been above 33 km/h in the 4 years I live here, including my 2022 Aeroad with GP5K TT tires and more power (same PM).

I have a Gibli aero sensor to do a proper comparison one day, but that will be quite some work to do it properly.

[patliean1]

Not sure if it was the bike, the tires or the wheels,
Or just going narrow width of the hb (or the ospw 😉), but it certainly wasn’t me.

Anyway 35 km/h+ average with 207 watts is not something I have seen before on any of my other bikes, including my Aeroad.

https://strava.app.link/QXoKf1kbw4b

We need more people riding the VRT to provide real world experience. I didn't spend a lot of time in my latest video discussing ride feel because the video was already long enough with the whole wind tunnel stuff. But I going to do a separate video on the topic. The VRT is indeed fast in the real world.

My 15mm setback seatpost from Peter is currently in transit. Super thrilled. I've also been swapping between my Tavelo Arow, ER One, and Scott Foil basically daily to really validate the fact I need that 15mm seatpost from XMCS. Also I have a series of local crit races at the end of this month that would tempt me to give the VRT its true test. But I don't wanna risk crashing basically a "limited edition" AERYS frame 

[Sakizashi]

I have about 300 rides here. And never been above 33 km/h in the 4 years I live here, including my 2022 Aeroad with GP5K TT tires and more power (same PM).

I have a Gibli aero sensor to do a proper comparison one day, but that will be quite some work to do it properly.

You really should use the Gibli if you have one! This sort of observation is in the grey zone. It’s probably a .01 CDA reduction, so it’s likely not just the bike, though it might partially be. Its also too big not to likely be something.

I would guess a conversion of 0.01 of cda is along the lines of 12-15W at 48km/h.

[Requiem84]

You really should use the Gibli if you have one! This sort of observation is in the grey zone. It’s probably a .01 CDA reduction, so it’s likely not just the bike, though it might partially be. Its also too big not to likely be something.

I would guess a conversion of 0.01 of cda is along the lines of 12-15W at 48km/h.

Position on the bike, 34cm handlebars already do so much. Even if I get a figure out if the Gibli (don’t worry, I will, just out of curiosity), we shouldn’t be too hung up on it given the variables we can’t make the same on my fleet of bikes.

[Sakizashi]

I have about 300 rides here. And never been above 33 km/h in the 4 years I live here, including my 2022 Aeroad with GP5K TT tires and more power (same PM).

I have a Gibli aero sensor to do a proper comparison one day, but that will be quite some work to do it properly.

This kind of statement implies that this bike is something special and is fast. Maybe it it is…

Position on the bike, 34cm handlebars already do so much. Even if I get a figure out if the Gibli (don’t worry, I will, just out of curiosity), we shouldn’t be too hung up on it given the variables we can’t make the same on my fleet of bikes.

But then it might be narrower bars? Or rider position? Narrower bars might have a huge impact. IME, like stack height, it’s a bit of a sweetspot optimization. At a certain point there is a huge gain, and then the gains start to drop off. It wouldn’t surprise me if there is even a point where two narrow affects rider control in a way that makes them less aero.

Overall position is an even bigger wildcard. Maybe this bike frame is really freaking slow with a rider on and it’s just a better position making you faster?

At some point, isolating this to the bike or something else is something you have to try and do if you are going to continue to claim that the bike is noticeably faster IRL—especially given you have a financial interest.

[Swatt]

We need more people riding the VRT to provide real world experience. I didn't spend a lot of time in my latest video discussing ride feel because the video was already long enough with the whole wind tunnel stuff. But I going to do a separate video on the topic. The VRT is indeed fast in the real world.

My 15mm setback seatpost from Peter is currently in transit. Super thrilled. I've also been swapping between my Tavelo Arow, ER One, and Scott Foil basically daily to really validate the fact I need that 15mm seatpost from XMCS. Also I have a series of local crit races at the end of this month that would tempt me to give the VRT its true test. But I don't wanna risk crashing basically a "limited edition" AERYS frame 

a detailed comparison between the VRT and the ER:One would be very very useful. for european customers (I am one of them), those two frames have almost the exact same price.

[Requiem84]

This kind of statement implies that this bike is something special and is fast. Maybe it it is…

But then it might be narrower bars? Or rider position? Narrower bars might have a huge impact. IME, like stack height, it’s a bit of a sweetspot optimization. At a certain point there is a huge gain, and then the gains start to drop off. It wouldn’t surprise me if there is even a point where two narrow affects rider control in a way that makes them less aero.

Overall position is an even bigger wildcard. Maybe this bike frame is really freaking slow with a rider on and it’s just a better position making you faster?

At some point, isolating this to the bike or something else is something you have to try and do if you are going to continue to claim that the bike is noticeably faster IRL—especially given you have a financial interest.

You may recall my post just a few posts above;

Not sure if it was the bike, the tires or the wheels,
Or just going narrow width of the hb (or the ospw 😉), but it certainly wasn’t me.

Anyway 35 km/h+ average with 207 watts is not something I have seen before on any of my other bikes, including my Aeroad.

Is it possibly freaking slow with a rider on it? Possibly, if the SSE hub completed messed up the bike+rider wind tunnel runs.

Meanwhile the standard Cervelo are applying for their Aspero 5.

Cervélo has long been synonymous with aerodynamic performance, and we’ve brought that 30 years of expertise to gravel racing. The new bike is a stunning 37 Watts faster than the outgoing model, and 34 Watts faster than its nearest competitor.

[Sakizashi]

You may recall my post just a few posts above;

Is it possibly freaking slow with a rider on it? Possibly, if the SSE hub completed messed up the bike+rider wind tunnel runs.

Meanwhile the standard Cervelo are applying for their Aspero 5.

If u want to rely on windtunnel data from SSE. Do that.

Don’t make a claim about real world riding experience with so many potential confounding factors. Don’t imply that the new bike you sell is faster than your Canyon Aeroad if you arent going to measure it. Or maybe it isnt? 

Cervelo and others are really careful to not do that or play games like this. Sure they markup headlines, but they always caveat it with the appropriate details. Its marketing, sure, but its honest in the details. Edit: well honest enough not to get them sued…

[Requiem84]

If u want to rely on windtunnel data from SSE. Do that.

Don’t make a claim about real world riding experience with so many potential confounding factors. Don’t imply that the new bike you sell is faster than your Canyon Aeroad if you arent going to measure it. Or maybe it isnt? 

Cervelo and others are really careful to not do that or play games like this. Sure they markup headlines, but they always caveat it with the appropriate details. Its marketing, sure, but its honest in the details. Edit: well honest enough not to get them sued…

Interesting, can you share the appropriate details for the Cervelo claims?

Perhaps I can learn something from how they do it. Always open for feedback.

Cervelo Aspero 5: https://www.cervelo.com/nl-NL/bikes/aspero-5

[hubba]

I'm not saying the bike is not fast it's clearly as fast as the competitors. But 2km/h is a huge difference that can't be just the bike or the wheels. Maybe you were more motivated to hold a better aero position on the VRT vs the others.

[tjebakka]

Everyone knows a new bike will make you faster. It's basic science. 

[k0M_hUnter]

System weight limit: 115kg (VRT)

Is this true?
https://xmcarbonspeed.cc/products/xmcs-vrt-vortex-aero-road-racing-frameset

[Requiem84]

I'm not saying the bike is not fast it's clearly as fast as the competitors. But 2km/h is a huge difference that can't be just the bike or the wheels. Maybe you were more motivated to hold a better aero position on the VRT vs the others.

I certainly did not want to imply any exact numbers, hence I did not make any numerical comparison when I shared my ride. 2 km/h frame only is impossible. That would be 30-40 watt at these speeds for just the frame. My point merely was that I feel it is a good platform to build a fast bike.

I have said exactly the same on the wind tunnel test in this topic: I don’t want to get hung up on X watt faster than a S5 with rider, but the takeaway for me is that it simply is a fast platform.

Lesson for me is to not share numbers as people are keen to think I imply certain things. Lesson learned….

I am not very keen on sharing my Gibli testing data, as apparently it is only allowed if I will invest heavily into doing a like for like test, which will require me to - for example - buy a CRW handlebar for my Aeroad to get a 34cm position. If those kind of datasets get scrutinized the way they are, with implications about my ‘financial interest’, a non like-for-like comparison may come across as me trying to give unfair beneficial numbers to the VRT. And then there will be another debate demanding on what I should and shouldn’t do. No interest in that, as this venture is for my fun.


I’ll let others share their experiences with the bike, as frames are now being shipped we should get some soon.

[Sakizashi]

Interesting, can you share the appropriate details for the Cervelo claims?

Perhaps I can learn something from how they do it. Always open for feedback.

Cervelo Aspero 5: https://www.cervelo.com/nl-NL/bikes/aspero-5

I would rather you didn't take after Cervelo, as I personally think it's shady. But this isn't about numerical transparency; it's about consistency, and Cervelo is incredibly *consistent* about how they present the Aspero 5. They use the data they have to keep making the same claim. The claim below is from their website:

*Áspero-5 is 37 Watts faster than its predecessor, and 34 Watts faster than the nearest competitor. Cervélo has long led the industry in aerodynamics, and we’ve delivered a gravel race bike worthy of that reputation. The aero handlebar and stem are responsible for nearly 6 Watts of that savings on their own.*

They didn't release public data but instead focused on interviews. The talking points are clear.

• It's 37 W @ 48 km/h vs. the old bike. It's always 37w.
• It's a full bike test, and that number includes tires (both RR and aero gains)
• They made no effort to isolate the frame, wheels, or anything. They are literally testing bikes out of the box.
• They do not mention specific configurations, so we can assume they picked one that was most advantageous for them.
• They do make a specific claim about the handlebars.

The press their PM, Maria Benson, consistently features the same caveats. Here are some from Canadian Cycling (picked because of the lack of a paywall, and english language): https://cyclingmagazine.ca/sections/gear-reviews/cervelo-aspero-5-intriguing-features/

*“We didn’t isolate the frames,” Benson says. “A lot of times, we will isolate the frame and say the frame is x watts faster. In this case, we compared how the bike is delivered to the customer and how fast our complete Áspero-5 is compared to our competitors.”*

*“We know that the smooth tire choice may be disruptive,” Benson says. “The reason we decided to go ahead with it is that it is a very good tire option for the types of races that we targeted. But we were also very aware that tires are a very personal choice and very terrain dependent, so we expect that people are going to put tires on that suit whatever course they’re going to be riding. But this configuration was how we could deliver the fastest option possible to the customer.”*

You have SSE data and could do the same thing, easily reaching the same level of consistency without introducing noise into the conversation about other numbers you won't be verifying. "The VRT is a top-level road bike. It's proven to be just as fast in the wind tunnel as bikes that win the biggest races under top pros." You could probably add in stuff about stiffness too, since I think they usually do some deflection numbers in the SSE reports.

[cdav7193]

I’ve got one coming, and will be the first in Australia. Pretty special for me, as I was deep in the  WhatsApp chat with Peter finessing this bike after I first put it to him as an idea about 8 months ago. Originally proposed making a “lighter” VeloBuild Aerotrace, but it went in different direction.in no way saying I responsible for anything which makes it what it is, but it’s not often you have a bike that has elements you can pin down to a conversation on x date.