I assume that the grade of a road is the ratio of the distance traveled vertically and distance traveled horizontally which would be the tangent of the angle the road makes with horizontal. In this case, a road at a 45 degree angle would have a 100% grade in that one would climb the same distance as one traveled horizontally.
I have two hills that I climb on my way home from work that are 8 or 9 degrees which I calculate to be 14% to 15% grade. They’re pretty steep and they’re about one to one and a half city blocks long. The rest of my ride pales in comparison.
I have a Coker with stock 6" cranks. I can chug up these hills with confidence now. It used to be that I could chug up these hills without fail but still without confidence. I’m ready to go to shorter cranks I think. Should I reduce to 5.5" or all the way to 5" cranks? What color cranks should I get?
>I assume that the grade of a road is the ratio of the distance traveled
>vertically and distance traveled horizontally which would be the tangent
>of the angle the road makes with horizontal. In this case, a road at a
>45 degree angle would have a 100% grade in that one would climb the same
>distance as one traveled horizontally.
That’s how someone explained it to me this weekend too. But I always
thought it was the percentage that the road was longer than its
horizontal projection. I.e. how much more you travel than the map
indicates. That boils down to (the reciprocal of the cosine) minus 1.
Is anyone sure what the definition is?
My opinion on your actual question would hardly be based on anything.
I think David Stone is the best person to answer.
I have ridden my Coker a lot of miles with the following crank sizes: 6", 5", 4.3", and 4". I’m planning on welding up a pair of 3.5" or 3" cranks too.
Currently my preference is for the 4.3s as I am doing longer rides with fairly steep (8%) hills of medium length (the longest is about a mile).
If I were in your situation, I would go all the way for the 5s, though I don’t think you would regret buying both sizes and trying them both. You can get “disposable” cranks of each size for like $10 a set, find out what you like, then get some nicer ones of that length (Bicycle Euros). These cheapo cranks will probably bend the first time your Coker takes a hard fall.
I hate to plug my handles again, but honestly having a handle has made the difference between riding and walking a lot of hills for me. In extreme cases, I get off the saddle, lock my knees, and pull up on the handle to exert more force.
I like the look of my black Bicycle Euro’s over the chromed cranks I’ve had on before. Here’s a picture, though it doesn’t show the cranks very well:
I had sort of the same question and the right thing to do just depends on
you and the actual terrain you are riding. The steepest hill I have to ride
on my commute is only 250’ long, but is 20% grade. I had gotten to where I
could nail it every time with the 6" cranks, but wanted to go shorter to
increase my average speed. I ended up going with 5.5" cranks, although I
kind of wanted to try 5". With 5.5", I can’t make it up every single time -
have to be mentally powerful! But I do go about 0.5mph faster, both max and
If you are dealing with “only” 15%, then maybe try the 5". I really like the
Bicycle Euro cranks that George mentioned.
“harper” <email@example.com> wrote in message news:firstname.lastname@example.org…
> I assume that the grade of a road is the ratio of the distance traveled
> vertically and distance traveled horizontally which would be the tangent
> of the angle the road makes with horizontal. In this case, a road at a
> 45 degree angle would have a 100% grade in that one would climb the same
> distance as one traveled horizontally.
> I have two hills that I climb on my way home from work that are 8 or 9
> degrees which I calculate to be 14% to 15% grade. They’re pretty steep
> and they’re about one to one and a half city blocks long. The rest of my
> ride pales in comparison.
> I have a Coker with stock 6" cranks. I can chug up these hills with
> confidence now. It used to be that I could chug up these hills without
> fail but still without confidence. I’m ready to go to shorter cranks I
> think. Should I reduce to 5.5" or all the way to 5" cranks? What color
> cranks should I get?
In 3 weeks I’ll be attempting a week long ride over 450 miles. I got my coker 6 weeks ago. Because I don’t have a whole lot of training time, I’ve been playing around with crank sizes in order to find the optimum size for my riding conditions. I would recommend going directly to the 5" cranks. I started out with the stock 6" cranks and went to the 5" cranks two weeks after that. After 3 and half weeks with the 5" cranks I moved to the 4.3" cranks which I am currently riding. Steep hills are definitely manageable with 5" cranks. It is more at first difficult, but with training you will soon become accustomed to the 5" cranks on hills. Smaller cranks pay off a lot with faster riding on level surfaces.
Another big factor in what crank size you can use on hilly riding is whether or not you have a handle. With smaller cranks, you obviously have less leverage. This makes both the hills, and the unexpected bumps much harder to compensate for. Without the GB handle, I could not go up (or down) steep hills. I often find myself gripping the handle firmly when I hit a bump, get hit by a gust of wind, or when I am trying to control my speed going down hill. The rest of the time I use the handle to take weight off the saddle.
I use the GB handle on a Miyata seat base. However, after using the handle on the normal plastic seat base it soon became evident that the platic Miyata base would not hold up for much longer. George Barnes installed a metal plate which goes on top of the plastic seat base, and bolts to both the seatpost and the handle. The handle is now very firm and I can now push/pull as hard as I want without fear of a broken seat. If George starts to supply the metal reinforcement plate to unicycle.com, I would recommend the plastic Miyata seat base, reinforcement plate, and GB handle combination.
Another thing to consider is the pressure on your knees. My training started off slow, but now I’m training 5 times a week. With the sudden increase in mileage, I’ve had some knee pain. However, with cheap knee braces ($10 a piece from a drug store) and some rest when needed, my knees are getting stronger and can take the increased force that smaller cranks demand on the hills.
One last note. United cranks develop a lot of character after one UPD. If you don’t want bent cranks, I strongly recommend purchasing Bicycle Euros as they are much more durable.
Thanks for all the info. I think I’ll go with throw-away 5" and try it out with my plastic Miyata air seat and just see how it goes. If I can’t take it I’ll buy some Bicycle Euro 5.5" cranks. If my poor, 50 year old knees don’t explode testing the throw-aways, I’ll buy the high quality 5" cranks.
I would really like to smooth out the fast, flat sections with short cranks but those two hills may demand nothing shorter than 5.5’s.
I’m sorry, I don’t know the name of the instrument I used. It has a slot for a steel rule in the base like a tri-square has. It has a level bubble mounted on a rotating disc. The disc rotates inside a protractor scale. You set it down and rotate the disc until the bubble indicates level and read the angle off the scale. The resolution of this device was coarse with 1 degree increments.
> email@example.com wrote:
> > *Does anyone know of a good way to measure road grades?
> > What kind of an instrument would I have to borrow or purchase?
> > *
> I’m sorry, I don’t know the name of the instrument I used. It has a slot
> for a steel rule in the base like a tri-square has. It has a level
> bubble mounted on a rotating disc. The disc rotates inside a protractor
> scale. You set it down and rotate the disc until the bubble indicates
> level and read the angle off the scale. The resolution of this device
> was coarse with 1 degree increments.
> harper - Gearhead
> -Greg Harper
> “The Unstoppable Killing Machine”-Max Dingemans’ new uni
> harper’s Profile: http://www.unicyclist.com/profile/426
> View this thread: http://www.unicyclist.com/thread/19085
> rec.sport.unicycling mailing list - www.unicycling.org/mailman/listinfo/rsu
"The grade of an incline is its vertical rise, in feet, per every 100 horizontal
feet traversed. (I say “feet” for clarity; one could use any consistent
length measure.) Or, if you will accept my picture below,
o | y
R Theta |
Grade = y/x (Multiply by 100 to express as a percentage.)
Theta = arctan(y/x)
So a grade of 100% is a 45 degree angle. A cliff has an infinite grade."
Actually, after doing a web search, I discovered the
word ‘inclinometer’, which can be built with a protractor
and a plumb line for perhaps $1. I understand that some of
the more recent 4x4 SUV’s have inclinometers built in, to keep
drivers from tipping them over.
A web search also indicated that a French company considered
building such a capability into one of their bicycle
speedometer/odometer/heart rate monitors, but probably
discovered that the heart rate monitor was more accurate!
At 01:09 PM 7/3/02 -0700, John Foss wrote:
>> Does anyone know of a good way to measure road grades?
>A heart rate monitor?
You can do the same using a protractor and a short (shorter than the radius
of the protractor) piece of string with a weight on it. Line the protractor
up so it is at the same angle as the road and then hang the weight from the
middle of the protractor and see what it hangs at.
If you want a percentage grade then do some trigonometry to convert it.
> What kind of an instrument would I have to borrow or purchase?
I believe a clinometer would do what your asking ( not to sure on the
spelling tho my English- Danish dictonary has it spelt that way , so it
must be right). These can be made using a protractor and a plumbline (
string with weight on the end). Or you could try and borrow a basic one
from a high school ( where I used them back when I studied
geography). There is some maths that goes with it, but I forgot that.
Basicly you set up two poles with identical hieght markings, often red and
white strpes at set intervals. place one pole at bottom of slope and one
at top. Line up clinometer with one of the height marks on the bottom
pole. Sight along it to the SAME height marker on the other one and read
off the angle of the slope from the protractor like bit. add that info to
the measurement on the ground between the two poles.Do the maths and hey
presto, you have the gradiant of the slope.
Unicon 11 ~ Washington USA.~ July 25 - Aug 2 2002
The world unicycle convention and championships. http://www.nwcue.org
I purchased an inclinometer at Orchard Supply Hardware (owned by
Sears) for about $10. It may be accurate to about 1 degree, which
may be the best you can do unless you want to spend a lot more
money or do a lot more work.