How to determine percentage of grade?
03-04-10, 01:03 PM
#1
Senior Member
Thread Starter
Join Date: Oct 2009
Location: New England
Posts: 1,001
Bikes: Trek 1.1
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 5 Times
in
2 Posts
How to determine percentage of grade?
Think grade is determined by the ratio of height to length that is, a 10 foot rise in a 100 foot length would be a 10% grade. Is that correct? If so, how does one determine such other than with a rough estimate? Read often of people dealing with a certain percentage of grade but are they just estimating based on experience? Guess they must be. Any thoughts?
03-04-10, 01:13 PM
#2
Senior Member
Join Date: Oct 2007
Location: Medina, OH
Posts: 5,804
Bikes: confidential infromation that I don't even share with my wife
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
You can use a Garmin unit and download the ride data to determine the grades you covered. You can plot your ride on Map My Ride or other simular sites then click the "elevation" box to determine grades and feet climbed. Or if all else fails you can estimate the grade by how hard it felt then add 2 % since it's the internet.
03-04-10, 01:44 PM
#3
Time for a change.
Join Date: Jan 2004
Location: 6 miles inland from the coast of Sussex, in the South East of England
Posts: 19,913
Bikes: Dale MT2000. Bianchi FS920 Kona Explosif. Giant TCR C. Boreas Ignis. Pinarello Fp Uno.
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 5 Times
in
4 Posts
Garmin or a computer that measures similar is the only way- but you have to remember that an average of 10% ride----The 10ft in 100--- is only an average. At times it will be a lot less and if you are lucky enough- there will be some steep bits in the hill aswell.
__________________
How long was I in the army? Five foot seven.
Spike Milligan
How long was I in the army? Five foot seven.
Spike Milligan
03-04-10, 01:48 PM
#4
Banned.
Join Date: May 2008
Location: Southern california
Posts: 3,498
Bikes: Lapierre CF Sensium 400. Jamis Ventura Sport. Trek 800. Giant Cypress.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
If I remember correctly the formula if you don’t have a cycling computer that gives you the grade is:
Elevation gain divided by feet and multiplied by 100.
An 800 foot climb divided by 3 miles would be 800 / 15840= .05050 x 100= 5.050505 or 5.05 percent.
That only gives you a total and in most cases there are places in that climb that will be in excess of 5 percent.
Elevation gain divided by feet and multiplied by 100.
An 800 foot climb divided by 3 miles would be 800 / 15840= .05050 x 100= 5.050505 or 5.05 percent.
That only gives you a total and in most cases there are places in that climb that will be in excess of 5 percent.
03-04-10, 07:20 PM
#5
Banned
Join Date: Sep 2005
Location: Santa Barbara, CA
Posts: 28,387
Bikes: Specialized Tarmac SL2, Specialized Tarmac SL, Giant TCR Composite, Specialized StumpJumper Expert HT
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times
in
2 Posts
Not the only way. You can use a bubble level, you can measure the start and end elevation of hill, you can use known elevations, many popular climbs have their stats published, etc. Ultimately you need to know how much elevation gain and how much distance travelled. How you get that information does not matter.
03-04-10, 07:27 PM
#6
rebmeM roineS
Join Date: Jan 2006
Location: Metro Indy, IN
Posts: 16,216
Bikes: Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 653 Post(s)
Liked 347 Times
in
226 Posts
Google Earth shows altitude at any spot and includes a basic linear measurement tool. You supply the math.
__________________
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
03-04-10, 08:10 PM
#7
Senior Member
Technically, grade is rise over run; but in practice you can use the hypotenuse (the distance on the road itself) and it's close enough for gov'ment work. You can get a bubble level that mounts on the handlebars and is marked for up to 10 or 12% grade, but I can't seem to find a link.
03-04-10, 08:59 PM
#9
rebmeM roineS
Join Date: Jan 2006
Location: Metro Indy, IN
Posts: 16,216
Bikes: Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 653 Post(s)
Liked 347 Times
in
226 Posts
__________________
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
03-05-10, 12:57 AM
#10
Senior Member
Join Date: Sep 2006
Posts: 1,195
Bikes: Kona Cinder Cone, Sun EZ-3 AX
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Right...it's elevation change divided by horizontal distance (and then multiply by 100 to get %), but for small angles, using the distance along the road instead of horizontal distance is close enough. The difference is the difference between sine and tangent of the angle...using horizontal is the tangent, using road distance (hypotenuse) is the sine.
03-05-10, 08:55 AM
#11
Senior Member
Join Date: Oct 2004
Location: Huntington Beach, CA
Posts: 7,085
Bikes: Cervelo Prodigy
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 478 Post(s)
Likes: 0
Liked 87 Times
in
67 Posts
Think grade is determined by the ratio of height to length that is, a 10 foot rise in a 100 foot length would be a 10% grade. Is that correct? If so, how does one determine such other than with a rough estimate? Read often of people dealing with a certain percentage of grade but are they just estimating based on experience? Guess they must be. Any thoughts?
03-05-10, 08:56 AM
#12
Senior Member
Join Date: Oct 2004
Location: Huntington Beach, CA
Posts: 7,085
Bikes: Cervelo Prodigy
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 478 Post(s)
Likes: 0
Liked 87 Times
in
67 Posts
Slope, I think is the technical term. https://cs.selu.edu/~rbyrd/math/slope/
03-05-10, 12:54 PM
#13
Uber Goober
Be warned: If you go measure the 8% hill and can't find a single spot on it that measures over 5%, it won't matter, everyone will still be convinced it's an 8% hill.
One of the steeper places I measured is a little dip in between two hills where you can just coast through it from either direction, and it doesn't occur to anyone that it's steeper than the 5% hill down the way.
__________________
"be careful this rando stuff is addictive and dan's the 'pusher'."
"be careful this rando stuff is addictive and dan's the 'pusher'."
03-05-10, 01:19 PM
#14
``````````````
Join Date: Feb 2007
Location: san jose
Posts: 763
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
www.bikely.com , after plotting a route click Show -> Elevation Profile
www.gmap-pedometer.com , click elevation Large
You still have to do math on these, but they will give you distance and elevation.
www.gmap-pedometer.com , click elevation Large
You still have to do math on these, but they will give you distance and elevation.
03-05-10, 02:47 PM
#15
Senior Member
Join Date: Apr 2005
Posts: 5,866
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 3 Times
in
2 Posts
Technically, grade is rise over run; but in practice you can use the hypotenuse (the distance on the road itself) and it's close enough for gov'ment work. You can get a bubble level that mounts on the handlebars and is marked for up to 10 or 12% grade, but I can't seem to find a link.
Few roads are over 10% for any distance. Excluding Fargo street, a road in Los Angeles where the Wheelman have an annual hillclimb event the steepest I have been on in a bike related situation was 13%.
