Cycling UK Forum

mattheus wrote: ↑12 Apr 2024, 1:24pm

Vorpal wrote: ↑12 Apr 2024, 1:22pm

mattheus wrote: ↑12 Apr 2024, 1:15pm
Man-hours?

staff hours or person-hours, please

I was waiting for that ...

Fair point, of course, but I stuck with the old term, as doing so fits the spirit of the thread, and IMO the question!

(kilometres are so woke, doncha think?? )

And here, I thought that my request fit the spirit of the thread

Man-hours or person-kiloseconds.

Vorpal wrote: ↑12 Apr 2024, 1:29pm ...
And here, I thought that my request fit the spirit of the thread

After 27 pages, I've lost track, sorry!

nirakaro wrote: ↑12 Apr 2024, 12:41pm Sheets of plywood (but not sheets of plasterboard), threads on plumbing fittings, bicycle chain pitch. Square studs on socket wrenches? What else is still universally sized in imperial units?

Draught beer and milk (but only if it comes from a cow). Car wheels (diameter and width) but not car tyre width. Metric diameter wheels were tried on 1980s cars, like Metros and some BMWs, and turned out like Betamax.

Shimano tried to introduce a 10mm pitch chain sometime in the past (early '80s?) but it too was Betamax.

Bmblbzzz wrote: ↑14 Apr 2024, 1:22pm Shimano tried to introduce a 10mm pitch chain sometime in the past (early '80s?) but it too was Betamax.

My mate Jochen in the workshop showed me yesterday some information he'd printed and laminated for reference. There was a diagram of a chain showing the pin spacing as 12.7 mm.

Seems correct to me.... ?

It is, because an inch is now defined as exactly 25.4mm. Before 1959 it would have been a far less precise fraction, since the two measuring systems had evolved independently.

rogerzilla wrote: ↑19 Apr 2024, 8:23pm It is, because an inch is now defined as exactly 25.4mm. Before 1959 it would have been a far less precise fraction, since the two measuring systems had evolved independently.

Can we not now, post-Brexit, revert to 1/36th of the distance from the King's nose to his outstretched fingertip?

Anyone know (of course someone will ) why the metric equivalent of miles per gallon is litres per 100km, rather than km per litre?

VinceLedge wrote: ↑20 Apr 2024, 8:40am Anyone know (of course someone will ) why the metric equivalent of miles per gallon is litres per 100km, rather than km per litre?

And then again, BEVs tend to quote Wh/mile. Why not m/J?

Or, in the UK, perches per btu.

sjs wrote: ↑20 Apr 2024, 9:00am

VinceLedge wrote: ↑20 Apr 2024, 8:40am Anyone know (of course someone will why the metric equivalent of miles per gallon is litres per 100km, rather than km per litre?

And then again, BEVs tend to quote Wh/mile. Why not m/J?

Yes, everyday descriptions of energy do seem very sticky. I think that one's got caught on both miles (for obvious reasons) and kW hr because that's how we describe domestic consumption and national generation and consumption.

You can feel the tension whenever we discuss the energetics of eBikes.

Jonathan

VinceLedge wrote: ↑20 Apr 2024, 8:40am Anyone know (of course someone will) why the metric equivalent of miles per gallon is litres per 100km, rather than km per litre?

It isn't a proper ISO unit but it fits everyday life. But I don't know why it's done that way round. I'll do some reading.

It's the most common example of conversion requiring something other than a factor of proportionality... because the two measures are inversely related. This makes the calculation much more difficult to do in your head, but can while away a few km. : - )

Jonathan

VinceLedge wrote: ↑20 Apr 2024, 8:40am Anyone know (of course someone will ) why the metric equivalent of miles per gallon is litres per 100km, rather than km per litre?

Km per litre gives nice sensible numbers but it measures fuel economy, not fuel consumption, which is a frequent criticism of mpg.

Litres per km measures fuel consumption but gives silly small fractions, hence the clumsy use of 100km.

What I don't know is why we don't use miles per litre in the UK, since these are the two.units used for road distances and fuel dispensing. I suppose it's (a) tradition and (b) a horror of mixed systems.