Electronic Measurment Devices vs. J.O. Counter

I've used Neville's Protegé method in the past.
For me, the biggest plus was being to do the split calculations at home, ride to the course, reset the Protegé to zero, and ride.
Now that I've begun using the UKCM app on my iPhone, that is no longer a problem w/ a JO counter - the app does the calculations on the spot.
The biggest disadvantage I found w/ the Protegé was having to eyeball the wheel revolution fractions during the cal rides, even though my wheel is marked off in 20 segments. Whenever the stopping point was between 2 wheel marks, I never felt confident that I was getting it right.

Thanks, Jim. As an Android user, I am not certain I am ready to get an iPhone just to use UKCM. However, it is tempting based on learning of your satisfaction with it and the other positive comments I have heard.

I assume that your wheel markings were just for the Protege and that you do not have a use for them with the JO?

This makes me think of the "slack" between counts when calibrating. I am certain that on occasion, the only difference between two calibration rides is this slack. I can imagine JO gearing has been discussed in detail in this space in the past. I will look for this discussion. For now, do you know of some practical reason why the JO is not geared in such a way to reduce the "slop" between counts? The only way I know of to deal with this at present is to simply round and record calibration rides to the nearest .5.

Lyman - on my RaceMeasure site, I have an Excel spreadsheet that allows you to put in your Jones start count, and it will tell you where your splits are. There is a free app that will allow you to edit spreadsheets. Kingsoft Office. Disadvantage of this free app is, I don't believe you can edit multiple sheets in one doc. I wasn't able to, and have gone back to using my paid (Documents To go) application. But, put your Jones count in, and all splits calculate, based on your calibration rides entered in the sheet.

I have no issues with judging my .02, or .03 revolution, as each .05 revolution is very close to one Jones click. So, if I am off .01 revolution, I still have more accuracy that a Jones rounded to the nearest click.

The biggest disadvantage I would see with a Protoge is when you overshoot a mark. You cannot reverse the counts in a Protoge. I use an electronic Totalizer from Veeder-Root. It has to be wired, and I had to get a magnet and wire from a cheap cyclometer, along with a couple of small switches, but I can ride my bike with my counter counting down, if I overshoot. Or, I can roll it backwards, after flipping the switch, and it will count down.

The electronic method is not for the faint of heart. It takes time to set up, and you have to get parts from Radio Shack. Also, you cannot stop with the magnet next to the sensor, or you will get spurious counts. That is the most important aspect to be aware of - never stop at "zero" on your wheel.

The JO has "slop" due to gearing inside. There is no way to (relatively) cheaply produce the counter so it has no slack. I also round to the half-click, but if you are not rolling forward to the mark, there will be slack that can impact your counts by a full click. Not the end of the world, but in calibration rides it makes a difference.

Lyman I believe you can use UKCM on an iPod Touch as well.

As long as you roll forward before reading a count the "slop" doesn't matter.

Mark, I have been thinking I should know what you mean about "rolling forward", but I am not certain I get it. My question is this: when we reach an endpoint of a cal course, we have to decide what number to record based on viewing the JO. Often, for me, the reading is between counts, so I just use a .5 reading. What I have noticed that makes me wonder is the non-trivial amount of real estate my wheel covers between counts when I am beginning to calibrate, when I am adjusting the wheel so I am starting exactly on some number. This inaccuracy would be way over the limit for a steel tape cal course measurement. Obviously, this amount of "slop" is of no concern in a course measurement. I am just wondering what inaccuracy, if any, I should be concerned about in a calibration ride. It seems as though I should not be concerned based on what I am reading here. Yet, if the Calibrated Bicycle Method is intended to be an analog of steel-taping, it seems to me that we are working with a somewhat rough estimate right from the beginning of any calibration ride.

From a non-practical, strictly "pie-in-the-sky" perspective, I would guess that a hypothetical JC with one more number dial - that is driven by a gear that turns 10 times for every ones digit turn on the real JC would dispense with any concerns. I can also guess that were it feasible, such a device would already have been tested.

What are your thoughts?

Duane - thank for the spreadsheet.

If I was confident of never again blowing past a split count while dodging traffic, I might give the Protoge a try. I doubt I will ever get to that level. At least measuring in the D.C. area, I won't.

Lyman,
The "slop" I was referring to is the face that if you roll backward to a stop, when you then start rolling forward the jones won't start moving until you have rolled forward a good bit. This is mostly due to the loose connection between the tang of the JC and the spokes, but is also due in some small way to the slack in the gearing of the JC itself, as you say.

But it sounds like what you may be talking about is the lack of precision in reading the Jones count on the dial.

But the way you can eliminate both issues when you calibrate is to mark your wheel and calibrate based on wheel revolutions rather than JC counts.

Lyman,
The best thing to do in calibrating is clamp your brake at each end and don't let go of it when you turn around. This way you're essentially making one continuous measurement of all 4 (or more) rides. Divide the total counts by the number of rides, and whether you misjudge by a part of a count isn't really as important. Of course you should still record the counts at each stop because you want to make sure the rides are consistent.
For more precision I used to number my spokes, and you can estimate to the nearest 0.1 of a spoke interval, ~0.5 cm or 0.25" for a 36-spoke wheel. In fact you can use spokes only with no loss of accuracy. AND with a little concentration you can remember all the intermediate spoke readings and avoid doing any writing between start and end of calibration.
I'm sure that is "illegal" so let's just say I'm speculating that this could be done :-).
If you're thinking about trying electronic measurement with a protege it may be more convenient to number decimal parts of the entire wheel circumference rather than spokes.

Thanks, everyone, for the education. Bob, I do clamp the brake, as you taught me long ago. So it should all even out over 4 or more rides, as you say, so I won't sweat it.

Apropos of nothing, I guess, it is interesting that we use a different logic in establishing a working constant than in using a Sum of Shortest Segments measurement. That is, we do not select either the longest or the shortest calibration ride count. Rather, we use an average of at least 4 good rides. I mention this because by strictly using the same logic as SSS, wouldn't we assume the cal ride with the lowest count total to be the most accurate ride?

Of course, a smaller working constant would result that way, which I assume is one reason we use an average instead. Is my thinking on track?