Hill Grades?
 

Can someone please explain hill grades to me? There are some rides I would like to do that have the grades listed but I don't really know what it means. Thanks in advance.

Smple slope formula rise/run ex: 100 feet rise an 250 feet distance is steep!

100ft/250ft=0.4 or a 40% Grade, a cliff with a vertical drop is undefined grade because you can't divide by 0, and a 7% grade = 7ft rise in 100 feet traveledhttp://www.madhatter.free.fr/smileys/albert.gif

You need to know both the grade and the length of the grade. Some people brag about 30% grades, but if they are only 10 feet long, they are over in just 1 or 2 pedal strokes. On a long climb, the average grade over 1 mile or more is much more interesting. Few paved roads (anywhere in the world) are steeper than 10% for more than 2 miles. In the USA, I believe the interstate highways and railroad tracks are never steeper than 6% for any distance.

On the other hand, sometimes you see stuff like this on state highways:
http://www.chainreaction.com/images/26percentgrade.jpg
State Highway 108 in eastern California.

+1 explanation. I'd add that a 100% grade is a 45-degree angle, for reference.

Grades are like "fun ratings". If a hill has a 1% grade, it is going to be very little fun. If a hill has a 10% grade, well, that hill will be like 10 X more fun.

Follow?

And a wall is an infinite grade. :D

As a general guide:

5% is a hill (as opposed to a roller, or a slight upgrade)
10% is a steep hill. Most riders will drop down to their lowest gears.
15% is a really steep hill. Even with low gearing (say, 30-25), some/many riders will need to tack back and forth and/or stand
20% is super steep. Almost everybody will have to tack.

Some riders who would be riding their first century might need to walk on a 10%

I give all hills an F. All of them.

F = fun

I give them an F for "Freaking Awesome"

i love hills...too bad I'm not good at climbing them (i'm 245lbs)

come to florida and you will quickly miss the hills...i can ride 50 miles and only gain 250 ft in elevation...it is freaking boring.

Only if you are going down said hill.

Either that or if you are going uphill than a 10% grade means F = F/10

I've had a heck of a time climbing a two mile hill that averages 13.5%....God only knows what the higher percentages are..

What's the road? Two miles at 13.5% is special.

Iowa Hill Rd...just out of Colfax, CA

This weekend I did my first big climb of the year. Pilot Mountain State Park in NC. In two miles the road climbs over 1000 feet. It took me 20 minutes at 90% effort to get up, and less than 5 to get down.

Climbing hills is fun. Who among us has the little voice at the start of a descent that says "It's too steep, you can't get down it."? I don't think so. But how many have found a climb that your little voice tells you you can't do? Then you get out of the saddle, and build up your cadence, and you pump and you gasp for air, and the bike rocks under you and finally, as you start to develop tunnel vision, you crest it and can relax a little. You look back at the hill and say to your little voice "Don't tell me what I can't do. I am unstoppable."