Bora Ultra 50 vs. anything faster?

Everything about building wheels, glueing tubs, etc.
Roadrocket
Posts: 169
Joined: Wed Aug 29, 2018 8:43 am
Location: Slovakia

by Roadrocket

I´m currently riding Campagnolo Bora Ultra 50 AC3 tubular and thinking about upgrade after reading some reviews here they feel much slower(being 24.2mm wide) compared to other modern shaped wide rims.
I like the stiffness, low weight and great Campag hubs, but if there´s something significantly faster in 50-60mm category, I´d consider it.

I´ve found some Bora One 50(same rim as Ultra) aero test on Hambini site, and I was a bit surprised, Bora´s result was quite good. At 30kmh only 3W slower than Zipp 808 and at 50kmh 2W slower than Zipp 404 and faster than say Zipp 454 NSW or HED Jet 6.

If this test is trustworthy, why aren´t user reviews so good talking about ,,aeroness´´ ? Are wider rims really that faster, or it´s just kind of placebo then?
Attachments
1.png
2.png

by Weenie


User avatar
kgt
Posts: 7938
Joined: Sun Jun 18, 2006 10:29 am
Location: Athens, Greece

by kgt

Hambini explains all you need to know about the aerodynamics of wheels in his videos. In general narrower rims with narrow tires have less drag. There are a few exceptions but these are rare.
Most (if not all) tests done by manufacturers or Tour magazine etc. are either lacking actual scientific methods or are just marketing platforms. Unfortunately, most users just believe whatever these unscientific tests want them to believe.

Alexandrumarian
Posts: 491
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

I was suprised about Hambinis chart because in the real world I do not find my Bora 35 to be speed monsters. My other wheels are built on DT Swiss 440 rims (tiny 21mm wide 21 mm deep) with (many) Aerolite spokes, 25mm 5000s or Power comps. The classical wheels are about 8-10W, 0.3 to 0.6kph faster for pretty much any speed between 30 and 37Kph. Faster than that I can't reliably ride and compare. But for slower (which I guess is real worls speed for most cyclists (at least going solo)) I have a lot of data. I do alot of cycling on a 3Km closed loop, car free, 4 lane track. The road encircles an abandoned development project, these days used just by a few cyclists, runners and wildlife. Anyway, I have hundreds of laps and I am pretty anal checking the wattage, wind, wheels and my position on the bike. I did some short tests with Rovals CL 50 and Knot 45 also and tbh I was not blown away enough to rush for truly deep stuff. For the best speed nothing beats good legs and reasonably friendly wind.

AJS914
Posts: 3597
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

Roadrocket wrote:
Sun Oct 20, 2019 6:45 pm
I´m currently riding Campagnolo Bora Ultra 50 AC3 tubular and thinking about upgrade after reading some reviews here they feel much slower(being 24.2mm wide) compared to other modern shaped wide rims.
I like the stiffness, low weight and great Campag hubs, but if there´s something significantly faster in 50-60mm category, I´d consider it.
You are talking about a handful of watts in either direction when comparing all 50mm rims. That is what I take from the Hambini charts - that most wheels at the same depth are about the same speed.

Nothing is going be "significantly" faster. How wide are your tires? If your Boras are only 24mm wide and you use a 25mm wide tubular then you are losing a few watts by not having an optimized tire width.

Say you find the fastest 58mm wheel with the most aero optimized tire, then you are only talking about saving 5 watts per wheel @ 50km/hr per the Hambini tests. I wouldn't buy a new wheelset for 10 watts.

User avatar
TonyM
Posts: 3271
Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

Yepp that's always the point "faster" vs. "significantly faster"....

Many new products are just faster but not by that much. Is it significantly faster? Well that depends also on the expectation of the buyer....

Roadrocket
Posts: 169
Joined: Wed Aug 29, 2018 8:43 am
Location: Slovakia

by Roadrocket

kgt wrote:
Sun Oct 20, 2019 7:53 pm
narrower rims with narrow tires have less drag
This really surprised me. So any ,,old school´´ rim, say 21-22mm wide with 20mm tyre on has less drag than 26-27mm wide rim with 25mm tyre? Then the hype about super wide rims is just marketing...

Roadrocket
Posts: 169
Joined: Wed Aug 29, 2018 8:43 am
Location: Slovakia

by Roadrocket

Alexandrumarian wrote:
Sun Oct 20, 2019 8:18 pm
I was suprised about Hambinis chart because in the real world I do not find my Bora 35 to be speed monsters. My other wheels are built on DT Swiss 440 rims (tiny 21mm wide 21 mm deep) with (many) Aerolite spokes, 25mm 5000s or Power comps. The classical wheels are about 8-10W, 0.3 to 0.6kph faster for pretty much any speed between 30 and 37Kph. Faster than that I can't reliably ride and compare. But for slower (which I guess is real worls speed for most cyclists (at least going solo)) I have a lot of data. I do alot of cycling on a 3Km closed loop, car free, 4 lane track. The road encircles an abandoned development project, these days used just by a few cyclists, runners and wildlife. Anyway, I have hundreds of laps and I am pretty anal checking the wattage, wind, wheels and my position on the bike. I did some short tests with Rovals CL 50 and Knot 45 also and tbh I was not blown away enough to rush for truly deep stuff. For the best speed nothing beats good legs and reasonably friendly wind.
Hambini didn´t test the 35s. 15mm in height could do pretty much in difference, you cannot compare that.

Roadrocket
Posts: 169
Joined: Wed Aug 29, 2018 8:43 am
Location: Slovakia

by Roadrocket

In Hambini´s test there´s a handful of watts not only comparing 50mm wheels, but across the whole range:

50kmh examples:
Bora 50mm: 593W
F6R 60mm: 592W
HED Jet 60mm: 595W
Zipp 404 58mm: 591W

That´s pretty much similar results considering some user reviews say the Boras are much slower than more ,,aero´´ or deep wheels.

Even when considering some extra deep(TT) and fast wheels there´s not that much differences:

Yoeleo 88mm: 591W - 2W faster
Enve 7.8 71mm: 585W - 8W faster
Zipp 808 80mm: 581W - 12W faster

The results at 30kmh are even more closer than 50kmh. Maybe the tyre width makes the difference in the test, I doubt he used the same tyres on all wheels.



Btw. I ride 23mm tubulars on the front and 25mm tubs on the rear on my Boras.

blaugrana
Posts: 65
Joined: Wed May 24, 2017 9:49 pm

by blaugrana

In any case, the differences are so small that there is simply no chance for a user to determine that a wheel is faster just by feel or by comparing watts while going at about the same speed. The margin of error for tests regular riders can do on the road is simply much higher than these differences. The placebo effect, however, is a completely different story.

rides4beer
Posts: 199
Joined: Wed Nov 28, 2018 5:27 am
Location: SC

by rides4beer

Roadrocket wrote:
Mon Oct 21, 2019 7:58 am
This really surprised me. So any ,,old school´´ rim, say 21-22mm wide with 20mm tyre on has less drag than 26-27mm wide rim with 25mm tyre? Then the hype about super wide rims is just marketing...
In a wind tunnel maybe, but then there's the real world. I'm faster on a 28mm tire (that actually measures at 30mm), than I was on a 23mm tire, because I'm more comfortable and confident on crappy roads. Strong legs don't matter if you're holding back because you're getting beat up. I'm also violating the 105% rule and haven't noticed any negative effects, so I'll stick with wider tires on wider rims. My only exception will be the TT setup, where I am running skinny tires on deep wheels, but that's with good pavement and optimizing every aero piece that I can. But for road racing, A group rides, etc., I'll stick with the 28's.

alanyu
Posts: 136
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

Roadrocket wrote:
Mon Oct 21, 2019 7:58 am
kgt wrote:
Sun Oct 20, 2019 7:53 pm
narrower rims with narrow tires have less drag
This really surprised me. So any ,,old school´´ rim, say 21-22mm wide with 20mm tyre on has less drag than 26-27mm wide rim with 25mm tyre? Then the hype about super wide rims is just marketing...
What you gain from a 26mm rim with 25mm tyre than an old school combo is a better balance between aero, RR, comfort and control. See what those track bikes are using with the demond of only aero and RR.

Alexandrumarian
Posts: 491
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

Roadrocket wrote:
Mon Oct 21, 2019 8:01 am

Hambini didn´t test the 35s. 15mm in height could do pretty much in difference, you cannot compare that.
Tbh I did imagine the 35 would look similarly good (or bad) as the 50s if tested. In any case I do not blame the difference in the wheel profile but on the tubulars. And i don't use slow tape, but as little as possible mastik. I guess Campa were onto something when they didn't bother with a tubular version for the WTO. Anyway, I am definitly not hating on tubs here. They still feel the best, are arguably safest and lowest weight for hills.

honeybunner
Posts: 11
Joined: Thu Oct 10, 2019 7:55 pm

by honeybunner

Keep in mind that Hambini's testing was done with 23c tires and has a stated error margin of +/-2.5% (~5W). The only real conclusions you can draw from his testing are that you want a narrower tire than rim (he tests this specifically) and that deeper wheels are faster.

User avatar
C36
Posts: 718
Joined: Fri Mar 03, 2017 3:24 am

by C36

honeybunner wrote:Keep in mind that Hambini's testing was done with 23c tires and has a stated error margin of +/-2.5% (~5W). The only real conclusions you can draw from his testing are that you want a narrower tire than rim (he tests this specifically) and that deeper wheels are faster.
People Keep mixing accuracy (that in absolute has very limited importance) and repeatability. From earlier discussions repeatability of the system was way higher (as usually expected from measurement systems). The variability of the guy on the bike remain another topic.


Envoyé de mon iPhone en utilisant Tapatalk

by Weenie


User avatar
C36
Posts: 718
Joined: Fri Mar 03, 2017 3:24 am

by C36

You have the “faster” / “significantly faster” debate and “faster” / “feel faster” debate.
In terms of feel, on blind-tests, heavier wheels are usually felt as faster by people, then very light wheels for their height like the Boras will somehow feel slower... but at the same time snappier (helped by really good stiffness). It’s always surprising how inertia feeling is totally decorrelated from real measurement on the ground.




Envoyé de mon iPhone en utilisant Tapatalk

Post Reply
  • Similar Topics
    Replies
    Views
    Last post