# Why kms?

#### Glow worm

##### Legendary Member
I was thinking I'm happy using either but must admit if someone gives their weight in KGs I have absolutely no idea! And I did once have to take a bike computer back to the shop because I discovered it only measured in KMs when I got it home.

One thing I do struggle with (along with most things in life to be honest!) is hill gradients in %s. Not really a metric thing as such I guess, but does seem to be a relatively recent thing- at least UK. I can easily visualise a 1 in 8 or 1 in 10 hill but a 75% one, no. I just assume it means you can get up 75% before you're knackered. I'm sure it's very straightforward to understand but I have a mental block. Being thick doesn't help either.

Edit- I should add that luckily for me, hill gradients are not things that trouble us here in East Anglia.

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#### Tribansman

##### Senior Member

1-3%: Slightly uphill but not particularly challenging. A bit like riding into the wind

4-6%: Manageable but can cause fatigue over long periods

7-9%: Starting to get uncomfortable for seasoned riders, and very challenging for new climbers

10%-15%: Usually tough and you'll start to get sore (but dependant on gearing), esp if for any length of time

16%+: Very challenging for nearly all riders

Btw, the steepest measured gradient on a paved road is 35% (Baldwin Street, New Zealand)

#### Dogtrousers

##### Kilometre nibbler
No, I disagree. The old measurements were based on human dimensions, but in the vast majority of cases there was no need to be absolutely precise. A foot is about the length of an average adult foot, for example. A mile was a thousand steps (the Roman mille passus), again variable with stride length, but a useful concept. There were plenty of more precise measurements (troy and avoirdupois ounces, drams and the like for commercial purposes, for example) for when accuracy was needed. But for day-to-day transactions, 'about a foot', 'about an inch' and 'about a mile' were adequate. A furlong was originally a 'furrow-long' - the length of an average furrow in a field. In a society where the majority of people worked on the land, that would have been a useful mental image to describe a distance. Again, originally it would have been an approximate distance, and only became defined as 1/8 mile or 220 yards much later. Agreed, the more people needed to calculate rather than estimate, the clumsier and more frustrating the old system became. But its basis in human factors is why I think people feel comfortable with it.
These are interesting historical curios - for which thanks - but they don't give the imperial system any intuitive advantage. No one these days has a clue about the length of a furrow, nor how the Romans counted their steps, nor have most people ever seen a surveyor's chain. I'd also be pretty sure that when most people visualise a foot, they think of a rule and not an actual foot. As such it's no more intuitive than mentally subdividing the distance from the equator to the pole into 10 million. Both systems are equally arbitrary.

The main advantage of the metric system is that it's part of the SI which is a coherent system of units for all kinds of measurement. For everyday stuff then whatever arbitrary thing familiar to you and those you communicate with will do.

Even scientific stuff, when it gets into esoteric areas, diverges from the SI. eg astronomers use parsecs and light years and not, say, yottametres.

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#### ColinJ

##### Puzzle game developer
One thing I do struggle with (along with most things in life to be honest!) is hill gradients in %s. Not really a metric thing as such I guess, but does seem to be a relatively recent thing- at least UK. I can easily visualise a 1 in 8 or 1 in 10 hill but a 75% one, no. I just assume it means you can get up 75% before you're knackered. I'm sure it's very straightforward to understand but I have a mental block. Being thick doesn't help either.
That is a very good example of how easy it is to switch from one system to another. I grew up with (e.g.) 1-in-10 but barely noticed the change to 10%.

#### Dogtrousers

##### Kilometre nibbler
That is a very good example of how easy it is to switch from one system to another. I grew up with (e.g.) 1-in-10 but barely noticed the change to 10%.
I did that but skipped understanding the "X in Y" notation. I still don't quite get it. I just saw a sign with a hill and figured that it meant a hill.

#### matticus

##### Über Member

1-3%: Slightly uphill but not particularly challenging. A bit like riding into the wind

4-6%: Manageable but can cause fatigue over long periods

7-9%: Starting to get uncomfortable for seasoned riders, and very challenging for new climbers

10%-15%: Usually tough and you'll start to get sore (but dependant on gearing), esp if for any length of time

16%+: Very challenging for nearly all riders

Btw, the steepest measured gradient on a paved road is 35% (Baldwin Street, New Zealand)
Not bad. Now are you going to do the fun side: signs on descents??

#### Glow worm

##### Legendary Member

1-3%: Slightly uphill but not particularly challenging. A bit like riding into the wind

4-6%: Manageable but can cause fatigue over long periods

7-9%: Starting to get uncomfortable for seasoned riders, and very challenging for new climbers

10%-15%: Usually tough and you'll start to get sore (but dependant on gearing), esp if for any length of time

16%+: Very challenging for nearly all riders

Btw, the steepest measured gradient on a paved road is 35% (Baldwin Street, New Zealand)
looks like a useful reference thanks.

#### GoldenLamprey

##### Well-Known Member
That's the thing about 'intuitive'. Many conflate it with 'familiar'. Metric is easy enough to visualise once you use it a little. I find it hard to think in mph now, apart from speed limits when driving.

#### Tribansman

##### Senior Member
Not bad. Now are you going to do the fun side: signs on descents??
I'd just suggest 'Weee' for 1-3% and adding an extra 'e' for every 1% from there

#### Dogtrousers

##### Kilometre nibbler
I'd just suggest 'Weee' for 1-3% and adding an extra 'e' for every 1% from there
And change to "waaah" at about 20%

#### Glow worm

##### Legendary Member
That is a very good example of how easy it is to switch from one system to another. I grew up with (e.g.) 1-in-10 but barely noticed the change to 10%.
Sounds easy enough. so with a 16% hill, apart from avoiding it, that would be about 1 in 6 and a 1/4 ?

On another note- I've heard bookies have started, or are to start doing odds in %s rather than just saying 8 to 1 or 60 to 1 etc. The world is rapidly becoming way too complicated for me. And on that note- I'm off for a hill/ betting free ride

#### ColinJ

##### Puzzle game developer
Sounds easy enough. so with a 16% hill, apart from avoiding it, that would be about 1 in 6
That's right.
... and a 1/4 ?
25% (we do have some round here!)

I might as well do all the obvious ones (rounding some to whole numbers)...

2% = 1-in-50
3% = 1-in-33
4% = 1-in-25
5% = 1-in-20
6% = 1-in-16
7% = 1-in-14
8% = 1-in-12
9% = 1-in-11
10% = 1-in-10
11% = 1-in-9
12% & 13% = 1-in-8
14% & 15% = 1-in-7
16% & 17% = 1-in-6
20% = 1-in-5
25% = 1-in-4
33% = 1-in-3

#### classic33

##### Legendary Member
Oh come now, it's not that difficult. A metre is defined as the distance travelled by light in a vacuum in 1/299,792,458 of a second; how is that not easy to visualise? *

Now THERE is an imperial animal - measured in hands (4 inches) and raced over furlongs and miles.
That's the old(1983) definition!
2019 definition:
The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299792458 when expressed in the unit m⋅s−1, where the second is defined in terms of the caesium frequency ΔνCs.

#### RichardB

##### Slightly retro
These are interesting historical curios - for which thanks - but they don't give the imperial system any intuitive advantage.
I don't think I ever said that the Imperial system was better or had an intuitive advantage. I was just having a few thoughts about how the system came about (i.e. it's not as barmy as it looks) and why some people find it hard to let go. I don't disagree that the SI system is far superior for all practical purposes in the world we live in. I was taught all the rod/pole/perch nonsense at primary school and metric was a relative novelty at secondary school, but even I use metric for most purposes today, and feel comfortable with it.

Weight - grams and kilos (except for general statements about bodyweight, when st/lb)
Volume - cc, litres, cubic metres (firewood and water metering), haven't thought of gallons in years, but beer in pints ALWAYS
Distance - mm/cm/m except in informal conversation, miles for journey distances, km otherwise.

#### I like Skol

##### I don't think so, sonny!....
Weight - grams and kilos (except for general statements about bodyweight, when st/lb)
Volume - cc, litres, cubic metres (firewood and water metering), haven't thought of gallons in years, but beer in pints ALWAYS
Distance - mm/cm/m except in informal conversation, miles for journey distances, km otherwise.
Funny thing about buying liquids isn't it. Milk and beer still commonly traded in pints while nearly all other consumable liquids are sold in millilitres or litres. I suppose saying "give me half a litre" in a pub doesn't quite roll off the tongue the same as "I'll have a pint"? Like wise with milk. I still buy it in pints (albeit 4 pint cartons at the supermarket) . The metric version of the 4 pint milk carton always feels like a bit of a con to me, like I am being short changed! Mrs Skol tries to buy the filtered Cravendale shoot if she can get away with it because she thinks it is 'better' (don't ask me why, we use the normal milk at a fair rate of knots so it never has time to go off ) and I grumble and complain about the expense! Her excuse is that it isn't much more expensive, which would be right if they were like for like, but the several pence more for her carton of boutique milk is in reality considerably more than several pence when you factor in the reality because her carton is 2 litres while mine is 4 pints (2.272Ltr).
The pint is an oddity, but the mile is still the official unit. If pubs stopped selling beer in pints and changed to half and quarter litres I bet 'the pint' as a unit of liquid would quite rapidly fall out of use (apart from for CAMRA members ).
Miles and mph would also soon fall out of use if the kilometre was made the official unit. Mpg will probably be more resilient, as clinging to its use allows us to compare modern vehicles against ones that we owned 'back in the day'. I buy fuel in litres but convert this to gallons to calculate fuel consumption in mpg. Mpl seems just wrong and litres per 100km also involves converting one of the metrics between imperial and metric (I felt it was necessary to insert a link explaining the difference between a metric and the metric measurement system..... sorry). Once distance is measured in km and fuel in litres then a natural adoption of the ltr/100km will be inevitable.

As I have said previously, I and many like me are not resisting the metric system. We are simply working with what we have until the switch is properly completed.