Daytrip

People talk about hills they've climbed with what appears to be precise measurements of the grade, i.e., 5% or 10% or whatever. How do you determine that? I imagine with a GPS you could go back and compare the vertical rise in elevation to the distance for a particular hill, or get the information from a topo map or some other published source. Or is it an educated guess?

ir0nfist

Most people are just making up numbers. I just read the sign if they have one. If you don't have a GPS you can take the length from bottom to summit and then get the difference in elevation and divide. rise over run

waterrockets 

I've been meaning to get a Sky Mounti for a long time.

Flatballer

It's on sale, what are you waiting for? It looks kinda bulky to me, but I don't have anything to compare it to.

nondes 

Find the hill in Google Maps. Use the elevation information to work out the difference in elevation from top to bottom and the "ruler" to measure the distance travelled, and take it from there. Not sure how accurate it is, but it's more convenient than finding a large scale topo map and working with that.

Soil_Sampler

https://www.tiltmeter.com/

GamecockTaco

or they just look at their Garmin and use the highest number it showed.

RubenX 

That looks like a mountain biker's gadget. I like it tho... MTBers have a lot of nice gadgets.

bbattle

I use the USGS number for the major climbs in my area. On other climbs I've done, I've used Google maps but cite this because some have said Google maps isn't the most accurate. I've ridden with people that have Garmin gps units and they report the grade but someone else told me the humidity or barometric pressure affects them so you need to check the grade several times and get the average. A couple of riders have those spirit levels on their handlebars but they don't have much faith in them and just report a range.

CharlieWoo

https://www.coloradocyclist.com/product/item/VDOQAYGY

waterrockets 

Yeah, it wouldn't be on the bike full-time anyway. Once you know your local hills, you don't need it any more unless you travel.

JoelS

Gps

curiouskid55

https://www.mapmyride.com

umd

I have all the data recorded with my Garmin. When reviewing the data later, you have to sometimes take the instantaneous numbers with a grain of salt, as their are usually spikes. But if you take the grade over slightly longer distances (at least a few sample points) I think it is pretty accurate. I do belive that a lot of people make up their numbers though. And as far as the signs go, those are maximum grade for a road, not sustained.

pjcampbell

For specific hills you can go on Google Earth and find the bottom elevation and top elevation. I use the distance from my bike computer and I would say its quite accurate, at least for the hill where I do repeats.

Allegheny Jet

Maybe my math skills are flawed but here is how I determine grades. Two weeks ago I rode a 1.2 mile hill that gained 610 feet in elevlation (according to Map my ride)

610' (elevation gained) divided by 6,336' (distance 5,280' x 1.2) = .096% or 9.6% grade.

I hope I'm right because that hill did cause me to suffer and knowing the grade was anything less would only make me suffer more.

umd

^^^ that is correct

waterrockets 

Yeah, GPS, altimeters, and internet tools all have accuracy issues. A bubble level is going to be spot-on if it's properly zeroed.

waterrockets 

Not quite. The distance was the hypotenuse, not the base of the triangle.

daytonian

toporoute is your friend

Allegheny Jet

Is that hypontenuse good or bad for my self esteem? Maybe the hill is > 10%? cool, less and I'm crushed.

dunningrb

It doesn't matter much for small angles. Use the Pythagorean theorem to get

x^2 = (6336^2) - (610^2) => x = 6307.

That's only a 0.4% difference.

banerjek

How times have a changed....

Seems to me that just a year or two ago, a bunch of Road Nazis were saying how that very gizmo WR pointed to will be on every Fred's Xmas list (and no, I didn't waste time trying to search for the thread). I'm not saying this to bust WR's balls, but just observing since I don't expect anyone to call him one.

And he is right that if you want accurate instantaneous readings, a bubble level is a good way to go. The problem with mathematically calculating grade is that average grade is a very misleading figure. 6% ain't bad if it's steady, but it can be really bad if it's just the average.

donheff

I just made this simple gradiometer yesterday and measured a couple of slopes on my ride today. Takes about five minutes to build and works great.

waterrockets