Rolling resistance/aero/weight net gain

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romanmoser
Posts: 573
Joined: Sun May 06, 2018 8:30 pm

by romanmoser

@hambini
hey ! the light bicycle 56mm super wide ( 23mm internal 30 30,5 external ) that you tested from my memory ( may be wrong )
with a conti GP4000S2 25 so as wide as a GP5000 28mm , close to 30mm measured
was beating for 1 watt the zipp 404 right ?
Been using them LB56, it's quite comfy, it rolls nice, but it's not that reactive,
and even if side winds is not a problem thanks to the smooth transition
front winds and when you are 40 45km/H on the flat pushing, it's not as slippery as a 23mm or 25mm tire on narrower rims ...
Otherwise they would all be on 28mm tires on Time trial, das rite ?


Really can see both kind of wheels/tires coexist
Depending on the training or racing and kinds of roads
You would either ride the 25mm tire optimized pair of wheels
or the 28mm tire optimized pair of wheels

LB56 and these 48mm Hunt are nice especially because :
- no *f##k* internal nipples ( I know the theorical structural betterness of Internal Nipples but don't want them )
- able to run a 25mm tire in theory ( will be hard on tumbs ? )

I've messaged Hunt wheels to know more about the wheels, especially rim weight. They say they were able to reduce rim weight by 50 gr by using this polymer to fill the upper part instead of going full carbon. BUt not rim weight annonced.

I am partial to rim weights, lower isnt always better, for example my venn 507TCD were a bit more stable V shape ( only with the 25mm tire )
and more reactive, better uphill despite being 495gr each for 50 mm, instead of the 460gr rim LB56mm that are wider.
How much is tire related and how much rim related, that's the question.
Ceramic bearings well, I am with hambini on that too, they can sell me these with super high quality STEEL bearings, don't want no Ceramic Speed bullshit thanks.

alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Hexsense wrote:
Sat Jun 22, 2019 3:52 pm
68kg rider, using 56mm depth here. No problem with cross steady wind. My bike can move a bit in gusty surge wind but nothing scary yet.
The only thing i don't like about this depth is that there isn't a just right valve length exist.

If it is 50mm deep, i can use 60mm michelin latex tube. It's perfect fit.
If it is 64mm+, using 80mm valve or short valve+extender look about right.

But for 56mm, 60mm valve is too short, 80mm is too long. Short valve+ extender still isn't quite the right size as 60mm valve on 50mm deep rim.
Try standard 48mm tubes and use 20mm extenders. The added bonus is lower weight (less steel, more alloy) and you can have a nice looking all black valve if you so choose. :thumbup:

For your weight 30mm wide rims will cost you a few watts unless you ride on terrible roads.

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romanmoser
Posts: 573
Joined: Sun May 06, 2018 8:30 pm

by romanmoser

If clinchers
Latex tubes
Or tubeless
The rest ( butyl inner tubes meh )

Or Tubulars :)


I am 65kg 1m87 and indeed while I was playing with the srm ( don't have it anymore, plan for a ng eco ) , they cost you a few watts, especially climbing
They are better than 28mm tires on rims not designed for 28mm tires, but still not as fast as rims designed for 25mm tires.

I like to try new things, but for most of us on a race road bike ( or gran fondo ) optimized for 25mm nominative tires rims will be faster

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kgt
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Joined: Sun Jun 18, 2006 10:29 am
Location: Athens, Greece

by kgt

hambini wrote:
Sat Jun 22, 2019 10:00 pm
I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".
Shaking my head...
Unfortunately marketing always wins at the end...

hambini
Posts: 580
Joined: Tue Nov 15, 2016 8:13 am
Location: Cologne, Germany

by hambini

kgt wrote:
Sun Jun 23, 2019 8:16 am
hambini wrote:
Sat Jun 22, 2019 10:00 pm
I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".
Shaking my head...
Unfortunately marketing always wins at the end...
You are probably right.

Quite scary...
Hambini Aeronautical Engineer, Polluting YouTube since 2016 - views expressed are my own...

alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

hambini wrote:
Sun Jun 23, 2019 8:48 am
kgt wrote:
Sun Jun 23, 2019 8:16 am
hambini wrote:
Sat Jun 22, 2019 10:00 pm
I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".
Shaking my head...
Unfortunately marketing always wins at the end...
You are probably right.

Quite scary...
Your aerodynamic wheel tests have helped a lot of people, including me. Thank you very much.

I had a quick question that may relate to this topic. One of the fastest wheels tested and a wheelset that sticks out as being very efficient for it's depth, were the bontrager xxx 6 wheels.

These have a 21mm inner width which would indicate they are wider than some 17-20C wheels that are out there. Still they perform above the rest and rival deeper wheels even.

Sure there are many factors involved but the width maybe isn't the be all and end all for speed. Any thoughts?

spdntrxi
Posts: 5789
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by spdntrxi

XXX6.... outers are only 28mm.. so maybe the rim shape and the particular tires used ended up being a good match... My Rovals are nearly 29mm and my Enve's 5.6 are 28+ and Enve 4.5 are 30+ outer.
Last edited by spdntrxi on Mon Jun 24, 2019 5:40 am, edited 1 time in total.
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LeDuke
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Location: Front Range, CO

by LeDuke

hambini wrote:I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".

Shaking my head...
Here’s the question I’d ask you:

You’ve conducted aero tests, and they are of value to many here. That said, how do you quantify overall speed as a function of aerodynamics, grip, rolling resistance and comfort from aerodynamic qualities alone?


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Hexsense
Posts: 3269
Joined: Wed Dec 30, 2015 12:41 am
Location: USA

by Hexsense

alcatraz wrote:
Sun Jun 23, 2019 3:25 am
Try standard 48mm tubes and use 20mm extenders. The added bonus is lower weight (less steel, more alloy) and you can have a nice looking all black valve if you so choose. :thumbup:

For your weight 30mm wide rims will cost you a few watts unless you ride on terrible roads.
It is essentially the case, my state's road condition rank among the worst in the US. Also, it is nearly as flat as Florida, thus extra weight doesn't really matter.

hambini
Posts: 580
Joined: Tue Nov 15, 2016 8:13 am
Location: Cologne, Germany

by hambini

alcatraz wrote:
Mon Jun 24, 2019 12:52 am
hambini wrote:
Sun Jun 23, 2019 8:48 am
kgt wrote:
Sun Jun 23, 2019 8:16 am
hambini wrote:
Sat Jun 22, 2019 10:00 pm
I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".
Shaking my head...
Unfortunately marketing always wins at the end...
You are probably right.

Quite scary...
Your aerodynamic wheel tests have helped a lot of people, including me. Thank you very much.

I had a quick question that may relate to this topic. One of the fastest wheels tested and a wheelset that sticks out as being very efficient for it's depth, were the bontrager xxx 6 wheels.

These have a 21mm inner width which would indicate they are wider than some 17-20C wheels that are out there. Still they perform above the rest and rival deeper wheels even.

Sure there are many factors involved but the width maybe isn't the be all and end all for speed. Any thoughts?
Whoever designed the bontrager considered the wheel, tire, spokes and interactions as a complete system. A lot of the other wheels on test are a random selection of hubs with spokes and rims. The Mavic setup with the rim strips is also another good example (albeit banned).

The Bontrager has almost perfect attachment/reattachment characteristics, so the "trip" (some people call this a tripwire) that is caused by the brake track/bead is shaped to keep the air attached. It is either by blind luck or more likely that someone thought about it to get it to work like this. By "thinking" about it, that might be copying a NACA shape and meddling with the track - I don't know and I doubt Trek would offer that info up.

A lot of the other wheels have allegedly CFD optimized shapes for airflow but their models neglect spokes and the turbulence that comes from them - FLO, Hunt. That is getting on for 25% of the drag so neglect it at your peril.

Hope that helps
Hambini
Hambini Aeronautical Engineer, Polluting YouTube since 2016 - views expressed are my own...

hambini
Posts: 580
Joined: Tue Nov 15, 2016 8:13 am
Location: Cologne, Germany

by hambini

LeDuke wrote:
Mon Jun 24, 2019 3:16 am
hambini wrote:I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".

Shaking my head...
Here’s the question I’d ask you:

You’ve conducted aero tests, and they are of value to many here. That said, how do you quantify overall speed as a function of aerodynamics, grip, rolling resistance and comfort from aerodynamic qualities alone?


Sent from my iPhone using Tapatalk
This is totally dependent on how fast you are going and the terrain. For flat terrain.

1. Optimize position unless you are going very slowly
2. Rolling Resistance (because this a loss at any speed)
3. Weight, linked to item 2

For hilly terrain, swap item 1 and 3 around.
Hambini Aeronautical Engineer, Polluting YouTube since 2016 - views expressed are my own...

Lugan
Posts: 191
Joined: Wed Oct 26, 2011 9:02 pm

by Lugan

hambini wrote:
Mon Jun 24, 2019 1:36 pm
LeDuke wrote:
Mon Jun 24, 2019 3:16 am
hambini wrote:I'm reading these comments with utter disbelief that the cycling industry has done such a good job on people they think "wider is faster".

Shaking my head...
Here’s the question I’d ask you:

You’ve conducted aero tests, and they are of value to many here. That said, how do you quantify overall speed as a function of aerodynamics, grip, rolling resistance and comfort from aerodynamic qualities alone?


Sent from my iPhone using Tapatalk
This is totally dependent on how fast you are going and the terrain. For flat terrain.

1. Optimize position unless you are going very slowly
2. Rolling Resistance (because this a loss at any speed)
3. Weight, linked to item 2

For hilly terrain, swap item 1 and 3 around.
I'd add a 1a: Wear tight clothing.

mikemelbrooks
Posts: 345
Joined: Wed Jun 16, 2010 10:58 pm

by mikemelbrooks

Lugan wrote:
Mon Jun 24, 2019 7:57 pm


I'd add a 1a: Wear tight clothing.
Image

Lugan
Posts: 191
Joined: Wed Oct 26, 2011 9:02 pm

by Lugan

mikemelbrooks wrote:
Mon Jun 24, 2019 8:44 pm
Lugan wrote:
Mon Jun 24, 2019 7:57 pm


I'd add a 1a: Wear tight clothing.
Image
Hah! Except I suspect 'before' will be faster because of the obvious blunt airfoil shape with bulge in the middle.

by Weenie


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peted76
Posts: 433
Joined: Mon Jun 23, 2014 10:30 pm

by peted76

@Hambini and anyone else.. I'm in the lucky situation about to buy a new set of wheels, I wanted deeper but not too deep, (rolling terrain, road races etc), and I'd found the LightBicycle 46mm's (internal 21mm external 28mm width) as sort of perfect shape/weight/price.... apart from the depth, initially I was looking at the 56mm ones (internal 23mm external 30mm), but I'm concerned ref 1) maneuverability and 2) width including how close they would be with brake calipers width wise.. I'm 70kg's btw and would run either 23mm or 25mm tubeless tyres.

Does the collective believe I would miss out on a significant amount of speed by going for the 46mm deep wheels over the 56mm ones?
Or does the collective think there's a better answer available for me with my £1k /$1.2k currently burning a hole in my pocket.

(I had considered a F/R 46mm/56mm set up, but I'm not sure I could cope with the unbalanced look of it on my bike.)

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