Gear ratio 520% &#x...
 

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Gear ratio 520% 😳!!

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What does it actually mean?

I’m sure my Eagle cassette says 520% on it but I’ve just been playing about with the Sheldon Brown gear calculator says that it’s only 420% That’s a whole 100% less.

So who’s wrong and what does it mean anyway?

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[url= https://i.ibb.co/Sst2sxF/A202896-A-BCD7-4508-95-A9-8-D33-EA49879-A.jp g" target="_blank">https://i.ibb.co/Sst2sxF/A202896-A-BCD7-4508-95-A9-8-D33-EA49879-A.jp g"/> [/img][/url]

🤷🏻‍♂️


 
Posted : 31/10/2022 10:14 am
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By my reckoning 52/10 = 520/100 = 520%


 
Posted : 31/10/2022 10:19 am
 5lab
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Depends if you count a singlespeed as having 100% ratio or 0 I think


 
Posted : 31/10/2022 10:25 am
 DrP
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i guess from teh smallest teeth sprocket (10) to the largest teeth sprocket (52) it's an increase of 520%

DrP


 
Posted : 31/10/2022 10:39 am
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It all depends …. 52 is 520% of 10 but the range 52 to 10 is 420%


 
Posted : 31/10/2022 10:49 am
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It pains me to say it but Sheldon is wrong (or more likely you are reading it wrong, because, well, Sheldon is never wrong)

As a ratio its 520%, a ratio is a multiplier so 10*5.2 = 52

It is however a 420% gap or increase (which so would be a sum, not a multiplier)

Depends if you count a singlespeed as having 100% ratio or 0 I think

Definitely a ratio of 100%, a ratio of 0% would be no teeth.

It's all a bit weird though as you should really express it as a ratio of the chain ring (or gap in the cassette) so a 32 tooth chain ring on a 10 52 gives 31.25% to 162.5% that is a 520% increase between the two (320% would give the 32t sprocket and 100% ratio)


 
Posted : 31/10/2022 10:54 am
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Just the mech that says it can do 520%...unless the cassette also says that...


 
Posted : 31/10/2022 10:57 am
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i guess from teh smallest teeth sprocket (10) to the largest teeth sprocket (52) it’s an increase of 520%

DrP

DrP has unwittingly nailed it, by stating something incorrect.
It's not an increase of 520%, its a multiplier of 520%
An increase of 420%

Basically what dangerbrain said.


 
Posted : 31/10/2022 11:02 am
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THey should never have used percent...

5.2 gear range explains the concept perfectly fine.

And dont get me started on when the cassettes went from 50 to 52 tooth (and so 500% to 520% in their language) and it was touted as a "20% increase in range"


 
Posted : 31/10/2022 11:25 am
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What does it actually mean?

Not sure TBH, it's not my kind of thing.

I just let my legs tell me if I've got enough range.


 
Posted : 31/10/2022 11:50 am
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And dont get me started on when the cassettes went from 50 to 52 tooth (and so 500% to 520% in their language) and it was touted as a “20% increase in range

Well it is, because its relative to the spread regards the chain ring not the cassette.

So if you've a 20t or a 56t chainring doesn't matter, your range changes from
1:n to 1:5.0n
To become
1:n to 1:5.2n

That's a 20% increase on the ratio from bottom to top

I'm guessing you think that's a 4% increase?


 
Posted : 31/10/2022 11:51 am
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Not sure TBH, it’s not my kind of thing.

I just let my legs tell me if I’ve got enough range.

Me neither and even less so now that I have read everyone’s explanations 🤣

I was actually trying to decide whether going from a 46 to 52 cassette would actually make much difference, after my legs told me 46 wasn’t enough 😬


 
Posted : 31/10/2022 11:57 am
 J-R
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going from a 46 to 52 cassette would actually make much difference

It will make a significant difference, but only you will know of it makes enough difference.


 
Posted : 31/10/2022 12:02 pm
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Pah, you and your measly 520% range! 😁 It's all about the 600% 😉


 
Posted : 31/10/2022 12:03 pm
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Well it is, because its relative to the spread regards the chain ring not the cassette.

So if you’ve a 20t or a 56t chainring doesn’t matter, your range changes from
1:n to 1:5.0n
To become
1:n to 1:5.2n

That’s a 20% increase on the ratio from bottom to top

Nonsense.


 
Posted : 31/10/2022 12:10 pm
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If it goes from 500% to 520% then that's an increase of 20% but not a 20% increase.


 
Posted : 31/10/2022 12:13 pm
 Olly
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is it not what the mech's capacity is?
You could add a double ring into the mix and up your %, and the mech would still be able to handle it?


 
Posted : 31/10/2022 12:14 pm
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That’s a 20% increase on the ratio from bottom to top

That should have been in not on but...

Nonsense

Care to explain our offer an alternative explanation?


 
Posted : 31/10/2022 12:16 pm
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You need one of these!

https://road.cc/content/review/classified-powershift-kit-wheelset-296931


 
Posted : 31/10/2022 12:20 pm
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Care to explain our offer an alternative explanation?

As you said in your post, it's a 4% increase.

For a 29er mtb wheel you get about 1387mm of development with a 30/50 gear

You get 1334mm of development with a 30/52 gear.

Difference of 53mm

Or 4%


 
Posted : 31/10/2022 12:23 pm
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The only time refering to it as "520%" seems to make any sense is with gear inches.

32-52 is 17.8"
x520% makes is 92.8"


 
Posted : 31/10/2022 12:36 pm
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As you said in your post, it’s a 4% increase.

No, its not, its a 4% increase to the top sprocket, even a 4% smaller gear, but the cassette offers a range of gearing.

Its a 20% increase to the range because that is a percentage already -> 4%*500%=20%

--

Is 60% 20% or 25% less than 80%?


 
Posted : 31/10/2022 12:38 pm
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It's not a 20% increase, it's an increase by 20 percentage points


 
Posted : 31/10/2022 9:54 pm
 mboy
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There's a whole lot of confusion going on here because of the way Americans interpret numbers...

It’s not a 20% increase, it’s an increase by 20 percentage points

It's a 20% increase in absolute terms... In relative terms it's only a 4% increase.

It pains me to say it but Sheldon is wrong (or more likely you are reading it wrong, because, well, Sheldon is never wrong)

Sheldon was often wrong... I imagine if you managed to dig him up right now, bring him back to life, he'd look at the bikes we ride now and dismiss us all as Devil worshippers with our flying saucer sized cassettes, 12 speed cassettes, wheelbases almost as long as MX bikes and our dropper posts...

That aside, Sheldon Brown was American. And just as America insisted on bastardising the English language, there's also some real quirks in the way that they teach "Math" (not least, dropping the bloody "s" off the end of it!) over there... I mean, FFS, they still insist on using gear inches over there, or at a push gain ratios... Why can't they just accept Percentages? 🤷🏻‍♂️

To be fair to him though, he even acknowledges the weakness in the way he represents ratio differnces... https://www.sheldonbrown.com/percentage.html

All good...? 🤔👍🏻


 
Posted : 31/10/2022 10:46 pm
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It’s not a 20% increase, it’s an increase by 20 percentage points

It’s a 20% increase in absolute terms… In relative terms it’s only a 4% increase.

This is why the term "percentage points" is preferable, IMHO - the terms absolute and relative don't really help the clarity, for me.

If something is increasing by a proportion, them use the percent symbol. If the proportion is increasing, then use 'percentage points'.

On the subject of American English Vs English English, a lot of the differences are not down to the Americans 'bastardising' things, but more to do with them preserving the language as it was at the time that emigration to America began, whilst we evolved in a different direction.
the Bill Bryson book 'Mother Tongue' covers this in some detail (but the start of the book is very academical, compared to most of his other books, so you have to stick with it)
The spelling of colour/color etc is a prime example of this divergence


 
Posted : 01/11/2022 1:33 pm
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Yawn 🥱🥱🥱🥱 😁


 
Posted : 01/11/2022 6:20 pm
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Yawn 🥱🥱🥱🥱 😁

Well it’s my thread so I feel like I should read it all, but this isn’t how I expected it to go 🤣


 
Posted : 01/11/2022 7:18 pm
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So how many revolutions do the wee legs have to make for the wheel to go around once ?.


 
Posted : 02/11/2022 9:42 pm
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In what gear?


 
Posted : 02/11/2022 9:48 pm

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