Measuring your hill's percentage figure

[flecc]

Do you get puzzled over all this talk of 5% or 12% hills, all just mumbo jumbo, or even if you understand it, do you know how to classify your hills to compare them?

Here's how, the easy way.

You need a spirit level, you may have one already in a set square or separately, but if not, buy a cheap one from a DIY or tool shop. If you haven't got one, also get an extending rule with centimetres on it. Then get a strip of straight metal or wood and cut it to exactly 100 centimetres long. Place the spirit level on the top surface of your straight strip and secure it firmly with tape or rubber bands.

That's your measuring apparatus complete. If the hill you want to measure isn't at home, you can tie that strip to your crossbar to ride to your destination.

Now on a representative sloping part of the hill, rest one end of your strip on the road surface with the spirit level above and the bubble kept centralised. With the other hand, hold the rule extended and vertical against the road directly above the other end of the strip and note the centimetre measure where it meets the underside of the strip right at the end. Thats the percentage measure of your hill, it's as easy as that, just the distance from the road surface vertically to the 100 cm point on the underside of your strip. If it's 11 cm, it's an 11% hill. Just make sure the bubble is central as you read the measurement.

If you want the whole thing more compact, use a 50 cm strip and measure in half centimetres.

Now all over Britain people will be wondering where all the surveyors have sprung from!

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[Miles]

Or, if you want to know your inclination, at all times: Sky Mounti Inclinometer - $17.50 at BikeTiresDirect.com

 

[flecc]

Yes, they're nice, but I thought the practical way would help the understanding. Also, my method is automatically correct, that device can be set up on ground that's not quite level and will always be wrong then.

Me, I just knocked up my own inclinometer since it's only needed once for each hill, and so far we don't have too many earthquakes to change things. (Touch the wood of my inclinometer )

 

[rsscott]

Something that might be useful on the site is a diagram showing various hill gradients and then each bikes theoretical speed for each gradient.

Obviously there are lots of variables (rider weight, battery condition etc) but it could give at least an indication of what could be expected in the stated conditions.

Would anyone else find this useful ?

 

[flecc]

I'll have to have a think about this Russ, it might be incredibly complex given the number of bikes on the market. It's not easily possible to group them, since the power variations are considerable between bikes that look to have the same spec. For example, these three bikes are listed as 200 watts:


eZee Quando, peak output at 8.7 mph, 576 watts

eZee Torq, peak output at 12 mph, 576 watts

Powacycle Windsor, peak output at 8 mph, 270 watts

All three have very different hill climbing abilities, the Torq much less than the Quando because of the higher speed at which the peak power appears, so the available power per metre travelled is less by the compounded proportion of the speed change.

In turn the Windsor is much less again, but this time due to very low peak power from the motor in the interests of long range. This also illustrates the huge power variation I've referred to.

It could all get horribly complicated and need brain exercises.

 

[ITSPETEINIT]

How steep is your hill

to all those who, like me, hate hills:
I purchased one of those INCLINOMETERS from Brands Cycles and Fitness USA.
I should have approached the matter more scientifically being not unfamiliar with Spirit Levels.
The scale of the meter is horizontal, on a gentle curve, so that the negative grade (downhill) is nearer the rider. The positive scale is thus further away from the rider and poses some lack of clarity.
The scale is quite small - 1 graduation = 1% of gradient = a little more than 1 millimeter
Because of the way one must level the thing on the handlebar (probably the most likely point of attachment), the positive scale seems to have a sort of parallax which brings the scale markings closer together when viewed from the saddle.
The best way to view it would be whilst stationary, standing above it. Reading it on the move, especially if some effort is required to ride the hill, does not help accuracy (as with cycle computers there could be a warning for that inattentive-to-the road moment).
It would be better read going downhill on that chosen hill.
The current price is US$ 22-99.
The service provided by Brands was good - just a few days. They take most credit cards. When ordering there is no advice, on checking out, of the Shipping Cost to non US addresses. You are advised that the cost of shipping wil be emailed to you for acceptance. I was advised that it would be US$13-00: I was somewhat surprised to note from the packaging that the actual postage was US$ 2-50.
I emailed them some 'feedback' but I have yet to receive a reply.
Peter

 

[flecc]

That's my main objection to it Peter, the near impossibility of getting an accurate reading while moving due to that tiny scale. I wish they'd designed it with half the curvature and only reading uphill, as that would have doubled the size of the divisions.

The other thing is that it needs to be set up standing alongside a long builders level with centralised bubble. It's amazingly difficult to judge what is a flat road. Many people cannot detect a change of 2%, and that can be greater when the surroundings set up an illusory effect, making the error 3 or more %. Hence the need to use a long builders level as well, say 120 or 180 cm as used by bricklayers.

 

[Miles]

I use the angle head from an old combination square. Adjust until the spirit-level bubble is centered and then read off the angle.

 

[flecc]

Yes, that's good if you have one. What's certain is that some other form of level is needed if it's to be accurately set up.

There's a long stretch near me which almost everyone, motorists and pedestrians alike, are convinced is flat. Cyclists know different though, it's surprisingly easy one way and a nasty surprise the other! In fact it's just over 2% in parts, but the surroundings make it impossible to judge accurately by eye.

 

[halfmedley]

Regarding RSScott's post earlier in this thread: this got me thinking about how to compare the performance of bikes so that buyers could make informed decisions. Perhaps there should be a standard route based test in the manner of the Urban/Extra Urban thing used for cars which could involve a long flat section, a hideous long hill and so forth? The result could be given in time taken and battery charge remaining? Of course you'd need a robot to do the cycling to maintain consistency, otherwise some manufacturers might employ Miguel Indurain to do their testing!

 

[flecc]

That would be great halfmedley, and may come one day when the market matures.

One unfortunate byproduct of doing that at present would be the number of bikes that couldn't even complete the test to arrive at results! There'd be some well known names there too. No, I won't tell which ones (Sigh of relief in certain quarters!).

It certainly wouldn't do much for some of the newer battery technologies, though NiMh would come out well.

 

[MaryinScotland]

The other thing is that it [inclinometer] needs to be set up standing alongside a long builders level with centralised bubble. It's amazingly difficult to judge what is a flat road.

Would it be practical to set it up with the bike standing on a kitchen floor? Perhaps after some experimentation with a ping-pong ball to make sure the floor doesn't slope?

Mary (who owns a small spirit level and a 1-metre ruler, but not a builder's level)

 

[flecc]

That should be ok Mary, and can be quite accurate. There's a good chance that the floor in a fairly modern property is very level anyway (but not guaranteed, typed as I look up at a 1967 ceiling that runs markedly downhill from the rear of the room towards the window end!).

 

[ITSPETEINIT]

The Inclinometer - initial levelling

Hi all who are interested:
I set mine up in the garage having first checked that the floor was actually level. Well, you know what builders are! Notwithstanding my NHRBC 10 year guarantee.
The real skill in setting it up is not to KNOCK IT ABOUT once it is on the bike.
I tried it the other day on hills up to 6% and notwithstanding my previous remarks about parallax it read quite well on the move (both up and down dale).
I can't quite enthuse about the difference bewtween, say 5% and 6%. It's the 14%ers that scare the watts out of me.
Pete

 

[flecc]

Tell me about it Pete. I face a 14% with every bike trip I make, including when towing the trailer.

It'll kill me one of these days!

 

[ITSPETEINIT]

How steep is the hill to the eye

I entirely agree with Flecc about the human eye's judgement of the grade of hills.
Flecc does not mention the famous ELECTRIC HILLS notorious for appearing to be UP when in fact they are DOWN.
I believe such a hill is 'Rest and be Thankful' somewhere in Scotland on the way to Fort William. A bit far to test this particular hill's theory.
Do we have any posters in Scotland?
Pete

 

[flecc]

I've heard of that Pete, but never seen it.

Because my routes are regular and I rarely meet new territory, I'm happy with measuring when stationary with a level as I first described since that leaves no room for error. I've made a 50 cm one now based on a strip of angle alloy with a set-square spirit level and extending rule taped on with PVC insulating tape, each half centimetre indicating a degree. Easy to carry on the carrier or in a tall pannier.
.

 

[Miles]

Just noticed that digital inclinometers/protractors are starting to appear, now.

Bevel Box : Buy Bevel Box at Axminster Power Tool Centre

Digital Inclinometers - With Readout Display

Miles

 

[flecc]

Thanks Miles, I'd hunted for those previously without finding them. I like the look of the first one, small enough for a bike and cheaper and more accurate than the bubble job from the States.

That second company are where I am, Croydon area, notice they're careful to hide the prices though. They look expensive.
.

 

[Miles]

Hi flecc,

If you click on "Please click here for more information" for the Smart Tool one, it gives the prices, etc. (£95....)

I agree, the first one looks neat - I want one for my workshop