Naismith's rule? - but for cyclists?

[Tigerbiten]

On tour with my full trailer over the hills, I was working on taking 1.5 hours to cover 10 miles.
On the flat I could get upto 10mph average.
If it was very hilly it could drop as low as 6 mph.

Luck ...........

 

[Ticktockmy]

Hillwalkers amongst you may be familiar with "Naismith's rule" which is a handy guide for working out time to complete a given walking route:

In it's original version:
20 minutes per mile + 30 minutes per 1000 ft ascent.

Or in metric units:
12 minutes per km + 10 minutes per 100 m

Personally I find that "generous" so long as the path is reasonable, whereas over Pennine peat groughs it's tough going, but with modifications its a useful planning tool.

Tranter's Corrections allow for the bad sections like grough, etc.

I am not sure, if anyone has written a "Cycle Naismith rule" but as it a rule I guess some wise soul out there has done so.

 

[jimboalee]

Another aspect of bicycle riding which the online calculators are sadly lacking is....

They don't know where the newsagents and Tesco Metros are, and how long the cyclist waits in the queue to buy a can of Coke.

 

[HLaB]

I've never really paid attention to it but Memory Map has got some sort of journey time planner built in; it concerns average speed the number of minutes added per 10m of climb and the number of minutes lost per 10m of climb. To get it accurate though you've got to accurately plot the route via every twist in the road.

 

[jimboalee]

I've never really paid attention to it but Memory Map has got some sort of journey time planner built in; it concerns average speed the number of minutes added per 10m of climb and the number of minutes lost per 10m of climb. To get it accurate though you've got to accurately plot the route via every twist in the road.

So you tell the sofware how fast you can ride on the flat. How does it know how determined you are and how much extra effort you are willing to give climbing a hill? Will it know I am a lazy B and get off and walk at the first molehill?

 

[Sheffield_Tiger]

Need to account for the concave hill effect.....you know, when you've just done a longish climb and you are barrelling along glad to be on the flat...then you realise that you're actually still climbing

 

[jimboalee]

Need to account for the concave hill effect.....you know, when you've just done a longish climb and you are barrelling along glad to be on the flat...then you realise that you're actually still climbing

That's called a 'False flat'.

 

[Sheffield_Tiger]

That's called a 'False flat'.

Whatever it's called, I love it

 

[HLaB]

So you tell the sofware how fast you can ride on the flat. How does it know how determined you are and how much extra effort you are willing to give climbing a hill? Will it know I am a lazy B and get off and walk at the first molehill?

LOL, If you're honest and say that every 10m on average takes you 10 minutes longer it might work, as long as you are consistent

 

[PpPete]

Naismith rule is that 1 unit of vertical travel is equivilent to 7.92 units of horizontal. (use miles, kms, feet, inches, bananas as you wish.)

Analysis of cycling data suggests a similar rule (1:8.2) for cycling on mountainous roads and tracks.

So going up 2000m is equivalent to adding an extra 16km. no matter how steep.

However, going down speeds you up much more on a bike than on foot and this is unaccounted for in Naismith.

any help?

Interesting stuff hubbike, thanks for the link.
the difference between 1:7.92 and 1:8.2 is probably irrelevant in view of the inconsistency in descending speed. After all, most of us are happy enough at 50 kph on a long straight downhill with good surface & good visibility, but with twists & turns we might be pumping the brakes trying to hold it down to 20 kph.

And these are Average values too... different people will have different ratios for sure.

Interestingly... walking on the level my wife & I are similar speeds, uphill she goes away from me easily.
Cycling I'm a tadge faster on the flats, she gets up hills faster
so maybe there is good read across

I'll have to go away & analyze some tracklog data see if I can work what our own particular ratios are.

 

[jimboalee]

At 16kmh, I'll cover 16km in an hour.

Give me a 10" gear and I'll climb a 50% gradient at 1 kmh. To rise 2000m up a 50% is a 4 km road.

4 km at 1 kmh is four hours.

If I rode the 16 km flat road at 4 kmh, it would take me four hours.

BUT, riding at 4 kmh on the flat requires 20 kCals/hour. Riding up a 50% hill at 1 kmh requires 480 kCals/hour.

Half way up the hill, I would be gagging for some sandwiches and drink, so I will stop which would take ½ hour, so the theory is flawed by human endurance capacity.

As I said earlier, the calculations don't take into account stopping for refreshments.

 

[snorri]

That rule wouldn't work here

You're right of course, I was thinking rural.

 

[Globalti]

Not completely irrelevant to this discussion: a good way of estimating distance from an OS map is to follow your route counting every time it crosses a blue grid line. This means EVERY time so even if the road dives across a grid line then back again that counts as two. Then halve the total and you have the distance in miles. The further you go the more accurate it is; don't ask me how it works but it does.