Classified hub - Is this the new big thing?

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

by TobinHatesYou

BigBoyND wrote:
Sat Feb 25, 2023 3:16 pm
TobinHatesYou wrote:
Sat Feb 25, 2023 12:50 pm
BigBoyND wrote:
Sat Feb 25, 2023 11:22 am

You need to look at range as a whole. Big-small to small-big. For the same drivetrain range, AXS requires bigger % jumps in the rear.

The tradeoff for fewer compensation shifts is larger jumps, is greater gearing overlap between big ring and small ring. This goes for any given top and bottom gearing you need.

You don't get it.

10-11-12 = 10%-9.1%
11-12-13 = 9.1%-8.3%

The jumps are larger in percentage because of the 10t cog. It's got nothing to do with the difference up front.
And because smaller rings are used, the absolute changes in gear-distance are not far off.

The decision to go with a 13t jump is driven by the use of the 10t cog. Going 13t up front didn't drive any changes in itself.
Lol you say I don't get it while missing my point about system range. I'm not talking about the 1t jumps (which are also bigger with Sram, as you pointed out). I'm talking about the fact that a smaller range at the front (13t vs 16t) requires greater range at the rear. The greater range at the rear requires greater jumps (more teeth) in the middle and top of the cassette.

If you want a 1:1 low gear and a 4.6:1 high gear, for example, these are your options:
Shimano 50/34 with 11-34
Sram 46/33 with 11-33

These are the jumps on the cassette:
Shimano 9.1%, 8.3%, 7.7%, 7.1%, 13.3%, 11.8%, 10.5%, 14.3%, 12.5%, 11.1%, 13.3% (ave. 10.8%)
Sram 10.0%, 9.1%, 8.3%, 7.7%, 7.1%, 13.3%, 11.8%, 10.5%, 14.3%, 16.7%, 17.9% (ave. 11.5%)

You understand gear-distance right?

BigBoyND
Posts: 1350
Joined: Mon May 31, 2021 1:51 am
Location: Berlin, DE

by BigBoyND

TobinHatesYou wrote:
Sun Feb 26, 2023 12:07 am
You understand gear-distance right?
It was a typo. It's 10-33 for sram (the calculations were correct). But yes, I realize % should rise up the cassette if thats what youre getting at.

And still i don't get what you're arguing. Shimano jumps are smaller in the rear and that was my point. That is enabled by bigger jump at the front. Keep it going as a mental exercise. As you decrease the front difference from 16t, 13t, 5t, 1t the rear cassette must grow at one end or shrink at the other if you want to maintain the same gearing range.
Last edited by BigBoyND on Sun Feb 26, 2023 7:44 am, edited 1 time in total.

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TobinHatesYou
Posts: 12458
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

BigBoyND wrote:
Sun Feb 26, 2023 7:38 am

It was a typo. It's 10-33 for sram (the calculations were correct)

You understand gear-distance, right?

BigBoyND
Posts: 1350
Joined: Mon May 31, 2021 1:51 am
Location: Berlin, DE

by BigBoyND

TobinHatesYou wrote:
Sun Feb 26, 2023 7:44 am
BigBoyND wrote:
Sun Feb 26, 2023 7:38 am

It was a typo. It's 10-33 for sram (the calculations were correct)

You understand gear-distance, right?
You've got quick fingers. I was editing my response above

TobinHatesYou
Posts: 12458
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

BigBoyND wrote:
Sun Feb 26, 2023 7:45 am

You've got quick fingers. I was editing my response above

You don’t understand gear-distance. If you reduce chainring sizes the absolute “gear-inches” jumps get smaller even though the ratio differences remain the same. Everything you think the 13t jump up front is responsible for is actually enabled by the 10t cog.

BigBoyND
Posts: 1350
Joined: Mon May 31, 2021 1:51 am
Location: Berlin, DE

by BigBoyND

TobinHatesYou wrote:
Sun Feb 26, 2023 7:48 am
BigBoyND wrote:
Sun Feb 26, 2023 7:45 am

You've got quick fingers. I was editing my response above

You don’t understand gear-distance. If you reduce chainring sizes the absolute “gear-inches” jumps get smaller even though the ratio differences remain the same. Everything you think the 13t jump up front is responsible for is actually enabled by the 10t cog.
What difference does that make?

If I my cadence changes 15% due to a rear shift, I don't care whether I'm in 60-40 or 30-20 gear.

In the sram case, if you increase the entire system size by 10% then it will feel exactly the same. Since we have to round to the nearest tooth, there will be some small difference as in the 10-11-12 vs 11-12-13 case.

The only difference resulting from gear distance that I can think of is that the 13t jump feels like an effective 14.3t jump in a 11t system.

And that is still much smaller than 16t. So 13t jump on 10t system has to result in greater cadence changes somewhere on the cassette if you want to maintain the same gearing range. 13t on SRAM is like ~14.3t on Shimano.

Nickldn
Posts: 1868
Joined: Mon Mar 25, 2019 12:35 am

by Nickldn

TobinHatesYou wrote:
Sun Feb 26, 2023 7:48 am
BigBoyND wrote:
Sun Feb 26, 2023 7:45 am

You've got quick fingers. I was editing my response above

You don’t understand gear-distance. If you reduce chainring sizes the absolute “gear-inches” jumps get smaller even though the ratio differences remain the same. Everything you think the 13t jump up front is responsible for is actually enabled by the 10t cog.
Yes this is true. I raised this when AXS was first released and there was a negative reaction to the 10t cog.

Yes the absolute jumps in % terms between cogs on the AXS cassette are slightly larger, but they do not feel as large due to the smaller chainrings. Imagine the chainring size acting like a 'scaling factor' to the cassette. The bigger the chainring the higher the jumps will be in real life. Even if the same cassette is used jumps will feel smaller with a 50t than a 53th chainring and smaller still with a 34t chainring.

I am not going to offer any maths here, you can use gear inches calculator to work out numbers.
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Sock3t
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Joined: Mon Jun 11, 2018 2:20 am

by Sock3t

TobinHatesYou wrote:
Sat Feb 25, 2023 5:17 am
Sock3t wrote:
Sat Feb 25, 2023 4:34 am

Yeah I'm not a pro. I'm a Cat 3 and I don't think the neutral car is going to have a wheel with a derailleur in the hub.

How often do you take neutral wheels? The only time I've ever had real neutral support in a lower category race was at Sea Otter. At Cascade Classic, "neutral wheels" meant anyone who put a spare in a SAG vehicle had access to anyone else's wheels if they flatted. With disc this was a problem because at the time I was set up with a 140mm rear. I was the only person who put disc wheels in the car so I was supposed to be the only one permitted to take my disc wheels. Instead the SAG driver let someone use both my spare wheels even though he was set up for 160mm rear.

Anyway if you are lucky enough to have a follow car, then it's on you to bring a spare wheel that works for your drivetrain…doesn’t matter if it’s Classified or 9-speed or AXS or what.
I've not used neutral wheels in a while but suffered the same issue as you in the past; I've had a buddy borrow a wheel or so in the past and then I come up with a flat (this was in a crit) and I had to snag a neutral wheel because my front was being used. No harm, but this was in the days of rim brakes so it wasn't a big issue.

Now I'm racing disc and have a second set of wheels and ponder the same lessons.

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Lelandjt
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by Lelandjt

Hambini said it will have too much drag in the "small ring". Classified wasn't happy with that and invited him to visit and take a closer look. This should be good....

cajer
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Joined: Sun Jul 14, 2013 1:26 am

by cajer

Lelandjt wrote:
Thu Mar 16, 2023 10:18 pm
Hambini said it will have too much drag in the "small ring". Classified wasn't happy with that and invited him to visit and take a closer look. This should be good....
This should be good. Physics dictates a 4-5% loss. I don't see how having him visit will change anything. It's not like he can learn anything unless they give him one to send to test himself or at a third party

crlincoln
Posts: 157
Joined: Sat Dec 08, 2018 7:42 am

by crlincoln

cajer wrote:
Fri Mar 17, 2023 12:25 am
Lelandjt wrote:
Thu Mar 16, 2023 10:18 pm
Hambini said it will have too much drag in the "small ring". Classified wasn't happy with that and invited him to visit and take a closer look. This should be good....
This should be good. Physics dictates a 4-5% loss. I don't see how having him visit will change anything. It's not like he can learn anything unless they give him one to send to test himself or at a third party
Maybe similar approach to Colnago with Tom Boonen, come visit us, test it, rather than just say it's $hit without actually having one or testing it..

BTW, there has to be loss somewhere.. along with all the other inefficiencies on a bike... never mind the average lump, definitely including myself, this is the largest inefficieny on the bike,,

cajer
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Joined: Sun Jul 14, 2013 1:26 am

by cajer

Test riding it does not make ineffiencies go away.

ichobi
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by ichobi

4 years have passed since sram axs came out with 10t sprocket and there's still no good test about how inefficient the 10t really is, at least compared to the equivalent level of product. And don't quote me that Velonews graph. What we know with SRAM stuff is that the flattop chain is slower than campag and shimano's but not really about the 10t. (the slow chain doesn't help).

I am not putting my hope up that there will be a good illuminating test re the efficiency of Classified anytime soon.

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C36
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by C36

ichobi wrote:4 years have passed since sram axs came out with 10t sprocket and there's still no good test about how inefficient the 10t really is, at least compared to the equivalent level of product. And don't quote me that Velonews graph. What we know with SRAM stuff is that the flattop chain is slower than campag and shimano's but not really about the 10t. (the slow chain doesn't help).

I am not putting my hope up that there will be a good illuminating test re the efficiency of Classified anytime soon.
What? Man you need to dig into old friction facts data (the one you had to pay for, prior ceramic speed purchase). Overall data exist since Moser hour record and has been refreshed since then.

Not published but it has been tested at least by Trek teams with Mapei-sport science team. That is one of the reason it lead to pro-only big chainrings, to use less the 10t (and cross less the chainring).

On top of my head there is a bit less than 1% (0.7) loss going from 11 to 10. Then as you mention, you add the poor SRAM chains on top of this.
Last edited by C36 on Fri Mar 17, 2023 9:24 am, edited 1 time in total.

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RoadDonk82
Posts: 38
Joined: Wed Feb 08, 2023 2:43 pm

by RoadDonk82

It seems to me there is a lot of confusion about how gear ratios work in this thread. Let me comment on a few and offer my view on why SRAM cassettes are just a bad design and some Shimano cassettes are terrible as well along with one objective way to measure it.
You don’t understand gear-distance. If you reduce chainring sizes the absolute “gear-inches” jumps get smaller even though the ratio differences remain the same. Everything you think the 13t jump up front is responsible for is actually enabled by the 10t cog.
Gear inches is an irrelevant concept for the discussion as we keep wheel diamater the same. What is left is only ratio of number of cogs in front to numbers of cogs in the back.
Yes the absolute jumps in % terms between cogs on the AXS cassette are slightly larger, but they do not feel as large due to the smaller chainrings. Imagine the chainring size acting like a 'scaling factor' to the cassette. The bigger the chainring the higher the jumps will be in real life. Even if the same cassette is used jumps will feel smaller with a 50t than a 53th chainring and smaller still with a 34t chainring.

I am not going to offer any maths here, you can use gear inches calculator to work out numbers.
Again, using gear inches in this discussion is a sign of confusion. It doesn't matter how big rings are in front, only gear ratio matters.
As an example: if you have 32 in front and 11-32 cassete and compare it to 34 in front and 11-34 casette the only reason the last jump feels bigger in 32 system is because 32/28 is a bigger number than 34/30. 32/28 is 14.3% jump while 34/30 is a 13.3% jump. It has absolutely nothing to do with the front ring being bigger.
If you want a 1:1 low gear and a 4.6:1 high gear, for example, these are your options:
Shimano 50/34 with 11-34
Sram 46/33 with 10-33

These are the jumps on the cassette:
Shimano 9.1%, 8.3%, 7.7%, 7.1%, 13.3%, 11.8%, 10.5%, 14.3%, 12.5%, 11.1%, 13.3% (ave. 10.8%)
Sram 10.0%, 9.1%, 8.3%, 7.7%, 7.1%, 13.3%, 11.8%, 10.5%, 14.3%, 16.7%, 17.9% (ave. 11.5%)
Yes, although average jump is not the best metric as it will always be the same in the cassete of the same range. You need to measure standard deviation of jumps to see which cassette has more equal jumps. I've written small script for that. Here is the output for some popular cassettes:

11 speed ultegra 11-30:
11 speed cassette
['11 ', '12 ', '13 ', '14 ', '15 ', '17 ', '19 ', '21 ', '24 ', '27 ', '30 ']
['1.091', '1.083', '1.077', '1.071', '1.133', '1.118', '1.105', '1.143', '1.125', '1.111']
average jump: 1.106
Std dev: 0.023
11 speed ultegra 11-32:
11 speed cassette
['11 ', '12 ', '13 ', '14 ', '16 ', '18 ', '20 ', '22 ', '25 ', '28 ', '32 ']
['1.091', '1.083', '1.077', '1.143', '1.125', '1.111', '1.100', '1.136', '1.120', '1.143']
average jump: 1.113
Std dev: 0.023
11 speed ultegra 11-34:
11 speed cassette
['11 ', '13 ', '15 ', '17 ', '19 ', '21 ', '23 ', '25 ', '27 ', '30 ', '34 ']
['1.182', '1.154', '1.133', '1.118', '1.105', '1.095', '1.087', '1.080', '1.111', '1.133']
average jump: 1.120
Std dev: 0.030
10-33 SRAM:
12 speed cassette
['10 ', '11 ', '12 ', '13 ', '14 ', '15 ', '17 ', '19 ', '21 ', '24 ', '28 ', '33 ']
['1.100', '1.091', '1.083', '1.077', '1.071', '1.133', '1.118', '1.105', '1.143', '1.167', '1.179']
average jump: 1.115
Std dev: 0.034
10-36 SRAM:
12 speed cassette
['10 ', '11 ', '12 ', '13 ', '15 ', '17 ', '19 ', '21 ', '24 ', '28 ', '32 ', '36 ']
['1.100', '1.091', '1.083', '1.154', '1.133', '1.118', '1.105', '1.143', '1.167', '1.143', '1.125']
average jump: 1.124
Std dev: 0.026
11-34 ultegra cassette has a huge jump between 11 and 13 (18.2%!) I am not sure what the justification for that design was. Probably it was just more convenient to manufacture for whatever reason. Here is a sample cassette that improves over it:
[11,12,13,15,17,19,21,24,27,30,34]

and the output of my script for it:
11 speed cassette
['11 ', '12 ', '13 ', '15 ', '17 ', '19 ', '21 ', '24 ', '27 ', '30 ', '34 ']
['1.091', '1.083', '1.154', '1.133', '1.118', '1.105', '1.143', '1.125', '1.111', '1.133']
average jump: 1.120
Std dev: 0.021
As you can see average jump is the same as with the old one (it always is) but standard deviation is lower meaning less variance in jump sizes. It's worth noticing Shimano rectified that mistake with 12 speed which is exactly the same as my improved 11 speed cassette starting from 15 cog. Whatever "reason" there was for a bone headed design in original 11-34 no longer applies apparently.

As to SRAM cassettes let's take 10-33 for example. It could be improved like this:
[10,11,12,13,15,17,19,21,24,27,30,33]
['10 ', '11 ', '12 ', '13 ', '15 ', '17 ', '19 ', '21 ', '24 ', '27 ', '30 ', '33 ']
['1.100', '1.091', '1.083', '1.154', '1.133', '1.118', '1.105', '1.143', '1.125', '1.111', '1.100']
average jump: 1.115
Std dev: 0.021
Or if you positively hate the idea of jumps in the back getting smaller relatively speaking then like this:
[10,11,12,13,15,17,19,21,23,26,29,33]
12 speed cassette
['10 ', '11 ', '12 ', '13 ', '15 ', '17 ', '19 ', '21 ', '23 ', '26 ', '29 ', '33 ']
['1.100', '1.091', '1.083', '1.154', '1.133', '1.118', '1.105', '1.095', '1.130', '1.115', '1.138']
average jump: 1.115
Std dev: 0.021
Both designs have much lower standard deviation between jumps than the original one and thus would feel much smoother - you would need narrower cadence range to ride it.

SRAM designed their cassettes with mountain biker philosophy of going up the hill whatever way, preferably chilling and talking to your buddies and then having fun bombing it downhill. The problem is that in road cycling you spend 3x or 4x as much time climbing and that's where the biggest time differences arise - where the races are won and lost. If you want to spin comfortably up the hill you need closer jumps at the back. It's not like the hill is going to be 7% all the way up. It's going to be sometimes 5%, sometimes 8.5%, sometimes 11% and sometimes 15%+. I doubt SRAM designers ever rode in the mountains without taking a bus to the top.

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