Gradient......

[BinBag]

Did a search on here and couldn't find anything conculsive.

What's the formula/calculation for working out gradient? And, if you've got something, does it work to the same rules of the road signs you see out and about?

I've often wondered if the hills I'm going up (Cragg Vale nr Hollingworth and Long Lane in Buxton) are challenging hills, or would be considered easy.

Cheers - Binbag

 

[HLaB]

Distance Up/ Distance Across = % Gradient, 1 over X it for 1:X style.

On twisty roads however its often easier to let a package such as Bikehike calculate it for you, its not 100% accurate but its faster. Just click at the start and end of your route (or in between also if needed), tick the 'Show Elevation Box' and then the 'Gradient' box

 

[BinBag]

Thanks for that. I've tried numerous elevation/gradient calculators, but I can't be sure they;re accurate - like the bikehike one, the gradient varies a lot from .01 of a mile etc. Yet at the bottom of a climb the signpost will read 10% for example, is this the average gradient for that climb?

What I really want to know is, do the %'s on the signs use the same calculation/rules as the ones on bikehike?

 

[HLaB]

Thanks for that. I've tried numerous elevation/gradient calculators, but I can't be sure they;re accurate - like the bikehike one, the gradient varies a lot from .01 of a mile etc. Yet at the bottom of a climb the signpost will read 10% for example, is this the average gradient for that climb?

What I really want to know is, do the %'s on the signs use the same calculation/rules as the ones on bikehike?

I guess the signs will use the same basic rules it just depends where they take a reading and over what distance and its max I believe they are quoting. Another site I've been cross referencing with is RidewithGPS I was a bit sceptical about its accuracy at first but it seems to be improving

 

[zacklaws]

Sometimes I look at the profile of a hill using this website, but once again, I do not know how accurate it is, but at least it gives you a rough idea of what your up against:-

http://www.heywhatst...m/profiler.html

As for RidewithGPS, I was not too happy with its profiling as on one ride, the gradient was only about 14%, but when it was displayed on the Garmin, it showed up as an overhang towering over me as I climbed it and another hill was displayed as a vertical climb, but that was in the early days so the site may have improved and got rid of its bugs, it was also a bit inaccurate with its speeds, as it had me doing the ride averaging about 270mph with some parts of the ride exceeding 2000+mph if I recall.

Just done some trials with the website I have posted with some hills that I know and it is not that accurate, and it can vary each time you do the same hill.

 

[jimboalee]

Some simple pointers.

If you suspect there is a hill on your route, check the OS pathfinder on Streetmap.co.uk.

For a hills without a chevron, your bike will need a gear below 40".
For a hill with one chevron, you will need a gear below 30".
For a hill with two chevrons, you will need a gear below 20".

Another pointer.

A 'lump' starts to become a 'hill' when there are four 5m contours involved.