Sorry...no.

I've looked into porting the software to the Mac, but it would be a huge project (I estimate around 1000 hours). Given the Mac's small market share, and my other time committments (a full time job, a new relationship, and my bikes), I just can't justify the effort at this time.

However, I've heard rumors that with Apple's recent decision to use Intel chips, it may someday be possible to run Windows programs on Mac's.

Well, I'm confused, but all I need is someone to let me know which, of all these formulas posted, give the most accurate result.

Right now, instead of the one quoted above from you, I'm using this one:

=(ATAN((Rise/Distance)*180/PI()

All info is in feet. So, is your's better?

Also, using the Delorme software to give the average grade (apparently only uses whole numbers), it shows the steepest short block of my three steepest I've ridden is 15%. Near as I can tell, the software must be using the formula of the rise/distance (gradient). According to the formula for degrees listed above, it would be about 8.6 degrees.

Hope I haven't gotten confused over all these things!

FWIW, DeLorme software is notorious for overestimating the amount of climbing. I suspect it's because their software interpolates too much up and down between their data points, and also because their software follows the hill contours, rather than the actual road contours (which tend to smooth out all the minor ups and downs).

In my experience, their estimates for total climbing are typically 10-25% too high.

As for formula - the simplest one (Elevation Gained / Distance Ridden) x 100 is about as accurate as the more complex formula. For most road grades, the difference is entirely negligible (and well within the margins of error for the data).

My formula gives the exact result. The others are approximations.

Which is better? That's up to you!

That's good to know - but if I understand you correctly, the error would be in the distance traveled? I can, of course, measure that on my rides. The critical issue for me would be the starting elevation and the final elevation. I can do the other calculations myself.

I understand your point about the "simplest" formulas being, essentially, good enough, especially considering inherent error on any climb. But I figure that since the computer is doing all the work, might as well be as accurate as possible. The inherent errors could go either way so it is still a benefit to use the best formulas.

Thanks.

Bob

But the difference is negligible, especially given the inherent inaccuracy in "elevation gained".

For instance, a climb of 5 miles, with a 7% grade will have 1,843 feet of climbing.

Your formula will yield 7.00% grade.

But, the simpler formula (1843 / (5 x 5280)) x 100 yields 6.98% grade...virtually the same, and much easier to calculate if one is just using a calculator.

However, I understand your committment to accuracy, which is why I use the "Atan" formula in the Climbing Calculator in CycliStats.

The "approximations" are nearly identical for most climbs, and much easier to calculate with a calculator.

For instance, assume a climb with 1843 feet of elevation gain in 5.0 miles of riding.

The more accurate "Atan" formula shows that the average grade is 7.00%.

But, the "approximation" (Elevation Gained / Distance Ridden) x 100 shows an average grade of 6.98%. Given the inherent inaccuracy in the "Elevation Gained" variable, the approximation is every bit as accurate as the "Atan" formula.

That said, I understand your obsession with numerical accuracy, and that's the formula I use in my CycliStats Climbing Calculator.

Arrrgh! Sorry for the double post - I checked 4 times after posting the first reply, and it seemed to have gone missing.

As a retired highway engineer, much of what I've read here is nit-picking.

First off, highway grades are frequently a combination of grades or in the case of old roads, erratic grades at best. Using topo maps will yield an average grade but won't account for those short stretches of leg searing pitch or transitional vertical curves. Measuring points with a level or other gradient device is only accurate at that point and may change a 100' up the hill.

In other words, significant digits past a whole number, or a tenth at the most is all that one can accurately expect without surveying equipment. Having said that, either formula given in previous posts will yield a percent grade more than accurate enough for real-life purposes.

I had a cyclist in my area ask me the grade of a local road and I went out with a 10' level and an engineering rule to take some quick and dirty measurements. I measured the 1/2 mile grade in three places and got grades of 7.8, 9.2, and 10.5. All that in less than 1/2 of a mile on a relatively new road. So is it a 7.8 or a 10.5% grade? Is it an average of the three? Regardless of what one calls its grade, it's still going to ride the same.

Yeah, those grades do keep changing - I particularly hate the switchbacks on the long 5 mile climb I sometimes do when I'm on the inside of the curve. They can really be tough compared to the rest.

Ultimately, the main thing I want to be able to do is make comparisons to others, even if less than perfect. I mean, think how many times people talk about how they had this "big" hill or "long" hill or "steep" hill, etc - even comments about how strong the wind is.

At least with distance, you can get some specific numbers from a few posters. But few really know the changes in elevation they are doing. Still, sometimes a person will give the percent grade and now that I can at least approximate my grades, I can tell how I compare a bit better.

This may mean more to me than to some others because I'm almost always riding alone so I don't get to make direct comparisons to other riders.

Thanks for the insights.

Bob

Hi All,

I had this really accurate and scientific type graph that I knocked up in paintshop that describes exactly what you are after, but it didn't want to attach, so here's the science behind the math, behind the graph:

You take the Length of the hill climbed (L) , divide it by the Time In Total Seconds (TITS) , multiply by the Average Speed Sustained (ASS) , divide by the Average Number of Spanners in a Sidchrome Toolkit (ANSST) , minus the time taken to drink a standard beer (BEER) . I draw your attention to the vital element of the equation here - beer.

GRADE = ((((L / TITS) * ASS) / ANSST) - BEER)

And that's the science behind the math behind the graph. I hope this clears things up.

Colonel

p.s. Just in case I need to spell it out for some - this is commonly referred to as HUMOUR, and yes, I understand that the OP wanted answers, and he already has them in spades. And to you maths nerds out there - don't question the formula, it is infallable.
p.p.s. I like the cyclistats climbing calculator - it looks sexy.

Thanks, Colonel!

I focused on climbing this season, and added that tool to the program when I was doing some planning for the
Death Ride, and the Bicycle Tour of Colorado.

I have to know -- how are you measuring these distances to tenths of a foot? 0.1 feet = 1.2 inches.

DeLorme TopoMap. Don't know what they use to specify an exact spot - maybe the middle of an intersection? Take it with a grain of salt...

As an exercise in Java, I've written an experimental program to calculate hill distance, rise, elevation, climbing rate, duration, etc. The good news is that it is written in Java and should run anywhere. The bad news is that it is written in Java 1.4 and you will probably need the latest JVM (1.4 or above) available from https://java.com/en or from Apple (for Macintosh users).
Anyone interested can PM me with their email address.

Here is a website that will do the math for you.
Slope and Distance Calculator