Classified hub - Is this the new big thing?

Discuss light weight issues concerning road bikes & parts.

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Lina
Posts: 78
Joined: Sat Sep 01, 2018 9:09 pm

by Lina

tjvirden wrote:
Thu Apr 08, 2021 10:22 am
aeroisnteverything wrote:
Thu Apr 08, 2021 9:27 am
4 percentage points isn't great. But I still don't get the comparison. Are they comparing Ekar to Classified in it's low gear config? That's not quite right since most of the time, you'd be riding in the equivailent of a big ring, with zero losses - a configuration where Classified should be more efficient than Ekar.

The real apples-to-apples needs to be a comparison vs the standard Dura Ace or Ultegra 2x11 set up accross the cassette range with a compact or semi-compact crank. I think it's fair to say that if Classified looses 4% to the small ring of a 2x setup, then they have work to do. If it's more like 2-2.5% loss or less vs small ring, then that may be entirely tolerable and might be largely offset by the aero gain from loosing the FD.
Would you care to put a number on the "aero gain" from no FD?
Is there going to even be a real aero gain from no FD since the efficiency losses only happen on the small chainring ratio. And when you're on the small chainring you aren't going that fast.

aeroisnteverything
Posts: 548
Joined: Fri Aug 24, 2018 4:43 pm

by aeroisnteverything

Lina wrote:
Thu Apr 08, 2021 10:55 am
tjvirden wrote:
Thu Apr 08, 2021 10:22 am
aeroisnteverything wrote:
Thu Apr 08, 2021 9:27 am
4 percentage points isn't great. But I still don't get the comparison. Are they comparing Ekar to Classified in it's low gear config? That's not quite right since most of the time, you'd be riding in the equivailent of a big ring, with zero losses - a configuration where Classified should be more efficient than Ekar.

The real apples-to-apples needs to be a comparison vs the standard Dura Ace or Ultegra 2x11 set up accross the cassette range with a compact or semi-compact crank. I think it's fair to say that if Classified looses 4% to the small ring of a 2x setup, then they have work to do. If it's more like 2-2.5% loss or less vs small ring, then that may be entirely tolerable and might be largely offset by the aero gain from loosing the FD.
Would you care to put a number on the "aero gain" from no FD?
Is there going to even be a real aero gain from no FD since the efficiency losses only happen on the small chainring ratio. And when you're on the small chainring you aren't going that fast.
The gain is hard to measure because it depends on the frame, yaw angle, etc. A frame with an uncovered FD mount migh give very little gain,while a frame designed for 1x from the get go should show a pretty decent one. In any case, the gain is there - hard to see how it couldn't be! People have measured that flush skewers save a handful of watts, so I'd say around 4-5w at 40kph for a frame sans FD is in the realm of reasonable.

I don't get the last comment though. The aero gain is going to be there for all ratios, since the FD is gone permanently. The additional drivetrain loss is only there for the time that you are in the "small ring" on classified system. So if you are only riding in "big ring" or are in the big ring 90% of the time, then the classified system should be a definite net positive. If you are climbing a lot, then this is a lot less clear.

by Weenie


pmprego
Posts: 1173
Joined: Mon Jan 21, 2019 3:16 pm

by pmprego

aeroisnteverything wrote:
Thu Apr 08, 2021 9:27 am
Cycomanic wrote:
Thu Apr 08, 2021 8:11 am
TobinHatesYou wrote:
Tue Apr 06, 2021 11:58 pm
Please clarify. 93.5% efficient compared to what, a baseline 2x drivetrain or input wattage at the crank?
Tour is a bit unclear with their language in the test. They write 93.5% drivetrain efficiency, which indicates that is input wattage to wattage that drives you forward. In the text they have a sentence:
"Der classified Antrieb verursacht zwischen 2,5 und 4 Prozent zusätzliche Reibung im Vergleich zum Ekar-Kettengetriebe. Der Wirkungsgrad fällt von 96 auf bestenfalls 93,5 Prozent"

Which roughly translated means: "The classified drivetrain causes between 2.5 and 4% additional friction compared to the Ekar drivetrain. The efficiency therefor falls from 96% to 93.5% in the best case"

I think the correct words would have been the drivetrain causes 2.5-4 percentage points (not percentage) more additional friction. I interpret this to mean that in the best case (for classified) Ekar has 96% efficiency and Classified 93.5% (a 2.5 percentage points or 2.6% less efficient) and in the worst case Ekar has 96% and Classified has 92% (which would be about 4% lesss efficient) or Ekar has 97.5 % efficiency and Classified has 93.5% or somewhere in between. They also say that the bike with Classified was consistently slower on 4 paired testrides.

Considering that the Ekar drivetrain is slightly less efficient than a 2x12(11) in some gears because of the chain line, the picture looks even worse for road use. I was actually quite excited when I saw the first announcements (especially considering the efficiency numbers), but I guess the realities of physics are hard to beat.
4 percentage points isn't great. But I still don't get the comparison. Are they comparing Ekar to Classified in it's low gear config? That's not quite right since most of the time, you'd be riding in the equivailent of a big ring, with zero losses - a configuration where Classified should be more efficient than Ekar.

The real apples-to-apples needs to be a comparison vs the standard Dura Ace or Ultegra 2x11 set up accross the cassette range with a compact or semi-compact crank. I think it's fair to say that if Classified looses 4% to the small ring of a 2x setup, then they have work to do. If it's more like 2-2.5% loss or less vs small ring, then that may be entirely tolerable and might be largely offset by the aero gain from loosing the FD.
oh... if you start goinf that rabbit hole... it's deep. For comparison then you'd have a distribution of the common gears used (kind of what they do for testing aerodynamics with a distribution for yaw angle). If it' gets too complicated they will simply not do the analysis.

But I agree they should be very clear with their testing protocol.

Lina
Posts: 78
Joined: Sat Sep 01, 2018 9:09 pm

by Lina

aeroisnteverything wrote:
Thu Apr 08, 2021 11:27 am
Lina wrote:
Thu Apr 08, 2021 10:55 am
tjvirden wrote:
Thu Apr 08, 2021 10:22 am
aeroisnteverything wrote:
Thu Apr 08, 2021 9:27 am
4 percentage points isn't great. But I still don't get the comparison. Are they comparing Ekar to Classified in it's low gear config? That's not quite right since most of the time, you'd be riding in the equivailent of a big ring, with zero losses - a configuration where Classified should be more efficient than Ekar.

The real apples-to-apples needs to be a comparison vs the standard Dura Ace or Ultegra 2x11 set up accross the cassette range with a compact or semi-compact crank. I think it's fair to say that if Classified looses 4% to the small ring of a 2x setup, then they have work to do. If it's more like 2-2.5% loss or less vs small ring, then that may be entirely tolerable and might be largely offset by the aero gain from loosing the FD.
Would you care to put a number on the "aero gain" from no FD?
Is there going to even be a real aero gain from no FD since the efficiency losses only happen on the small chainring ratio. And when you're on the small chainring you aren't going that fast.
The gain is hard to measure because it depends on the frame, yaw angle, etc. A frame with an uncovered FD mount migh give very little gain,while a frame designed for 1x from the get go should show a pretty decent one. In any case, the gain is there - hard to see how it couldn't be! People have measured that flush skewers save a handful of watts, so I'd say around 4-5w at 40kph for a frame sans FD is in the realm of reasonable.

I don't get the last comment though. The aero gain is going to be there for all ratios, since the FD is gone permanently. The additional drivetrain loss is only there for the time that you are in the "small ring" on classified system. So if you are only riding in "big ring" or are in the big ring 90% of the time, then the classified system should be a definite net positive. If you are climbing a lot, then this is a lot less clear.
I meant that the aero advantage of 1x won't help when you're losing watts to the hub since you only have losses in the "small ring". If we take it as 4.5 W at 40 km/h that's 1.5% loss if we're assuming 300 W output to go 40 km/h. And that's only when going 40 km/h. On normal speeds the losses are a lot less. The "small ring" losses would have to be less than that for it to be worth it.

Omiar
Posts: 307
Joined: Wed Dec 14, 2011 8:20 pm

by Omiar

Why aren't they selling just the hub (with cassette)? Is it somekind on demand/production issue?
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aeroisnteverything
Posts: 548
Joined: Fri Aug 24, 2018 4:43 pm

by aeroisnteverything

Lina wrote:
Thu Apr 08, 2021 1:01 pm


I meant that the aero advantage of 1x won't help when you're losing watts to the hub since you only have losses in the "small ring". If we take it as 4.5 W at 40 km/h that's 1.5% loss if we're assuming 300 W output to go 40 km/h. And that's only when going 40 km/h. On normal speeds the losses are a lot less. The "small ring" losses would have to be less than that for it to be worth it.
Whether it's "worth it" depends on how much time you spend in the small ring though, doesn't it? Just for the sake of argument, if you gain 4w in the big ring and that holds true for 90% of your riding, and then loose 6w in the "small ring" but this is only 10% of your riding, you still gain on a weighted average basis.

This will vary widely from context to context obviosly.

jfranci3
Posts: 1187
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Omiar wrote:
Thu Apr 08, 2021 1:22 pm
Why aren't they selling just the hub (with cassette)? Is it somekind on demand/production issue?
I'd assume it's to make it easier for early adopters and control everything they can to ensure their reputation stays intact while they build up production and make engineering changes. They want to know what might have gone wrong.

Lina
Posts: 78
Joined: Sat Sep 01, 2018 9:09 pm

by Lina

aeroisnteverything wrote:
Thu Apr 08, 2021 2:40 pm
Lina wrote:
Thu Apr 08, 2021 1:01 pm


I meant that the aero advantage of 1x won't help when you're losing watts to the hub since you only have losses in the "small ring". If we take it as 4.5 W at 40 km/h that's 1.5% loss if we're assuming 300 W output to go 40 km/h. And that's only when going 40 km/h. On normal speeds the losses are a lot less. The "small ring" losses would have to be less than that for it to be worth it.
Whether it's "worth it" depends on how much time you spend in the small ring though, doesn't it? Just for the sake of argument, if you gain 4w in the big ring and that holds true for 90% of your riding, and then loose 6w in the "small ring" but this is only 10% of your riding, you still gain on a weighted average basis.

This will vary widely from context to context obviosly.
But you aren't loosing 4 W on the big ring. You're only losing that when going 40 km/h. And I'd argue that outside of TTs the 4 watts of power are less important when you're going 40 km/h than they're when you're going 15 km/h up a hill.

TobinHatesYou
Posts: 7498
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

aeroisnteverything wrote:
Thu Apr 08, 2021 2:40 pm


Whether it's "worth it" depends on how much time you spend in the small ring though, doesn't it? Just for the sake of argument, if you gain 4w in the big ring and that holds true for 90% of your riding, and then loose 6w in the "small ring" but this is only 10% of your riding, you still gain on a weighted average basis.

This will vary widely from context to context obviosly.

You're not just losing 6W in the lower ratio, but an additional 4% of your input wattage compared to a more standard drivetrain. I'd have to be in Z1 to only lose 6W.

Races also aren't won based on averages, but key moments. I'd be losing 15-20W on a 5min climb compared to someone with a 2x11 drivetrain. Let that sink in.

User avatar
pdlpsher1
Posts: 3116
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

As cassette cogs keep getting bigger and bigger the number of FD shifts have gone down. One simply just ride on the big ring longer. The small rings is only used when the climb is steep or very long. We are now seeing the pros start using larger cassettes, evens in ITTs. Nowadays we just don't use the FD as much as we used to when cassettes were 11-23 or 11-25. I don't see the value of this technology. Also, drivetrain efficiency is more important on the road than it is on the trail. On the trail we have 1x. It would be interesting to see people giving honest feedback on drivetrain losses when they are finally released to the public.

talltales
Posts: 170
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

It might be a nice spare wheel for a 1x bike, for the occational steep hill ride, but Id rather keep my 2x for a permanent installation. Also it requires a special cassette, that may add expense and possible non availability in the future.

talltales
Posts: 170
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

Lina wrote:
Thu Apr 08, 2021 1:01 pm
aeroisnteverything wrote:
Thu Apr 08, 2021 11:27 am
Lina wrote:
Thu Apr 08, 2021 10:55 am
tjvirden wrote:
Thu Apr 08, 2021 10:22 am

Would you care to put a number on the "aero gain" from no FD?
Is there going to even be a real aero gain from no FD since the efficiency losses only happen on the small chainring ratio. And when you're on the small chainring you aren't going that fast.
The gain is hard to measure because it depends on the frame, yaw angle, etc. A frame with an uncovered FD mount migh give very little gain,while a frame designed for 1x from the get go should show a pretty decent one. In any case, the gain is there - hard to see how it couldn't be! People have measured that flush skewers save a handful of watts, so I'd say around 4-5w at 40kph for a frame sans FD is in the realm of reasonable.

I don't get the last comment though. The aero gain is going to be there for all ratios, since the FD is gone permanently. The additional drivetrain loss is only there for the time that you are in the "small ring" on classified system. So if you are only riding in "big ring" or are in the big ring 90% of the time, then the classified system should be a definite net positive. If you are climbing a lot, then this is a lot less clear.
I meant that the aero advantage of 1x won't help when you're losing watts to the hub since you only have losses in the "small ring". If we take it as 4.5 W at 40 km/h that's 1.5% loss if we're assuming 300 W output to go 40 km/h. And that's only when going 40 km/h. On normal speeds the losses are a lot less. The "small ring" losses would have to be less than that for it to be worth it.
Sorry, didnt read every post, but just wanted to point out that an additional ~3W drive train loss is is infact worse than adding 1kg(!) to the bike if you are ascending 1000m per hour. At 500m/hour its like adding 2kg. I magine that! :-)

tjvirden
Posts: 108
Joined: Sun Nov 22, 2020 9:21 pm

by tjvirden

talltales wrote:
Fri Apr 09, 2021 8:03 am
Sorry, didnt read every post, but just wanted to point out that an additional ~3W drive train loss is is infact worse than adding 1kg(!) to the bike if you are ascending 1000m per hour. At 500m/hour its like adding 2kg. I magine that! :-)
Hehe - it's a good comparison.

talltales
Posts: 170
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

tjvirden wrote:
Fri Apr 09, 2021 8:59 am
talltales wrote:
Fri Apr 09, 2021 8:03 am
Sorry, didnt read every post, but just wanted to point out that an additional ~3W drive train loss is is infact worse than adding 1kg(!) to the bike if you are ascending 1000m per hour. At 500m/hour its like adding 2kg. I magine that! :-)
Hehe - it's a good comparison.
It is and its not hyperbole. It takes 2.73w to raise 1kg, 1000m in one hour. Therefore loosing a few additional watts in the drive train is eqúivalent to adding a lot of weight to the bike. Havnt done the math on acceleration on the flats, but im betting its the same thing.

by Weenie


SCJKJ
Posts: 56
Joined: Tue Mar 17, 2020 1:25 am

by SCJKJ

Cycomanic wrote:
Mon Mar 29, 2021 5:33 pm
Tour magazin tested the efficiency of the classified and unfortunately it does not look that great. They found 93.5% efficiency in the easiest gear. Compared to ekar that was 2.5% to 4% less efficient (dependent on gear). So if your riding up a mountain at FTP of let's say 300 W and your friend is riding ekar next to you they only have to push 287W. Compared to a 2x12 that difference will be even bigger because it's even more efficient.

Sent from my LYA-L29 using Tapatalk
Do you have a link? Somehow I can't find this.

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