Mountain Biking - Measuring grades

I found a new fireroad today that is just plain sick ! The entire 3 or 4 miles is insanely steep, but much of it is so steep that it's all but impossible to ride up, and walking it is almost as bad. But it made me wonder, when i hear some of you cite what % a perticular grade is, how are you measuring this? Are there computers that can do this or what? I'd like to be able to know how steep some of the parts are to compare with other rides.

Thanks

feet vertical per 100 feet. ie, 100% grade = 45 degree incline.

oops didn't read the whole post. some really steep roads will have road signs that tell the grade. The steepest I've seen is 12%, but I do live in MD. I wonder if any cyclo computers have this feature. It would be neat to have, but I don't really know how much I would use it, except to brag to friends...

Some computers will tell you altitude change. Given that and distance you could come up with a rough idea of grade - or at least an average grade.

From what I've heard, they measure altitude by air pressure. Changes in wind, weather, or even a car driving by can throw them off. They should be able to give you a reasonably accurate reading though.

Or you could get an inclinometer.

http://www.adv-cycling.org/cgi-shl/webc.exe/advsales/st_prod.html?p_prodid=554&p_catid=32&sid=4l0YJ7Si

Cool ! I think i need one of those ! Thanks.

Many ride-guide type books that include fireroads will already figure the grade out for you.

-Moab

Ciclo sport has a cyclocomputer that figures grades as well as a million other things you thought you would never need to know. Most of the functions are more roadie oriented but hey that doesn't mean that we mountain bikers cannot use it. They also make this crazy navigation system for cyclists to track their routes. Check them out here http://www.ciclosport.de/ it is called the HAC 4.

-Ryan