measuring xc courses?

The front wheel only takes a third or less of the total weight and this weight is spread over a wider path, so it does not have to be that bad while at the same time being consistently pressed to the ground.

dukerdog wrote:

I think that the bike does have the advantage of applying a consistent pressure that is not controlled by the person doing the measurement. I'm not convinced though, that the large pressure the bike applies to the ground is an advantage.

But a practical consideration is that the people who manage the golf course are not going to be too happy to see somebody riding down their fairways on a bicycle. In many cases using a bike is not going to be an option.

Mike Rohl wrote:

Use a Gandy wheel and there will not be that kind of error and it will be more accurate then a jones counter in any conditions.

Our course at Mansfield is with in 10m of the 10k and 6k distance listed. GPS multiple times and wheeled multiple times. I am fortunate that I have absolute control of the grounds keeping and can have the grass as short as possible for any race or workout I want to do. I have wheeled almost every course my team runs and will continue. Other then ours I have yet to see a course that has the same start finish line be accurate. And yes is it cross country and time is secondary but I like to know how far the team has really run.

You are wrong that a Gandy wheel is more accurate than a

'Jones counter in any conditions'. Any condtions includes roads. What makes you think your cross country courses are so accurate? If your reply is, 'Because I use a Gandy wheel and it's been GPS measured multiple times', that is hardly sufficient reason to make such an claim. If you've followed this thread you would've seen the difficulty in getting a reliable, across-the-board acceptable measurement from any wheel and GPS is off by at least 1 part in 100.

rekrunner wrote:

Both of my footpods have calibration factors, which should usually bring the accuracy to within 1%.

I'm interested to see how accurante and consistent your calibration can be.

As measure acceleration in the horizontal plane, I wonder if comparison is made with acceleration in the vertical plan, as I feel this would be helpful and provide greater accuracy.

I've just started checking some videos on youtube, and the first one states that cadence is measured, so that's good.

Instantaneous pace graphs with footpod devices are much smoother.

Great.

According to the first video, the footpod is only placed on one shoe. However, the stride from one leg to the other is different in most people. The difference should be consistent, but would need calibration to verify.

Also, what is the minimum price for one of these.

As I said, I think you can get consistently within 1%, but it doesn't come for free. You will need to calibrate with all your shoes on different surfaces, and possibly at different speeds. Plus you need to be sure you fix it tight, and the same way each time. If you manage it less, you may get results more like the Masters student at 3%.

For a hint about how to manage calibration, this guy did more than most ever will:

http://users.telenet.be/wy/sport/S625X/S625X%20Accurate%20Speed-Distance%20Measuremnt.htm

http://users.telenet.be/wy/sport/t6/t6%20Accurate%20Speed-Distance%20Measuremnt.htm

He collected lots of data and screenshots, and really explores all the issues with calibrating footpods.

As far as I know, they only work with watches. The footpod adds about $100 to the price of a watch, and watches start at about $150.

Polar has two generations of footpod: the S1 and the S3. The S1 is bigger, and uses non-coded "analog" transmission (subject to interference from electrical lines), while the S3 is smaller, using "digital" transmission with handshaking. The S625X (described in one of the links above) came with the S1, and as you will see, had a few problems. The RS800CX fixed some of problems.

Looking at Polar's website, costs for a watch with a footpod:

RS300SX SD with S1: $249.95

RS400SD with S1: $369.95

RS800CX with S3: $519.95

Suunto has a few products too. Their footpod compares more to the S3 with digital transmission and handshaking:

T3D: similar to the RS400, if it came with the smaller S3

T4D: like the T3D, but with a "coaching" feature

T6D: more like the RS800CX running watch

I didn't find prices at their website, but I bought the T3C (previous model) for ~$150 and the footpod for ~$100. In my opinion, for $250, this combination is better than the RS400SD. The T6D is likely comparable to the RS800CX.

For distance measurements, there won't be much difference between the models. The main differences have to do with more features: how much data it collects, and the capability to upload the data to PC software.

You may find other brands available for less (e.g. the tester above also tested a NIKE TRIAX ELITE and a Philips Nike MP3run. This one was cheaper, and more accurate than Polar's S625X, but I guess it lacks features).

Why so touchy? What is your experience with a Gandy Wheel?

Thread Follower wrote:

Why so touchy? What is your experience with a Gandy Wheel?

I've never heard of it.

In high school I used to measure running routes by revolutions of the bicycle tire and pedals, which was quite tedious work, and long before the Jones Counter was invented. I had a 600 yard loop around the block, a 2 mile loop that started at the outer edge of the shorter one, and a quarter mile on a really nice dirt road about a 1/2 mile from the house. I ran all of them quite a few times.

jones counter - wikipedia

usata course mapper

Thread Follower wrote:

scotth wrote:

[quote]Mike Rohl wrote:

Use a Gandy wheel and there will not be that kind of error and it will be more accurate then a jones counter in any conditions.

You are wrong that a Gandy wheel is more accurate than a

'Jones counter in any conditions'. Any condtions includes roads. What makes you think your cross country courses are so accurate? If your reply is, 'Because I use a Gandy wheel and it's been GPS measured multiple times', that is hardly sufficient reason to make such an claim. If you've followed this thread you would've seen the difficulty in getting a reliable, across-the-board acceptable measurement from any wheel and GPS is off by at least 1 part in 100.

Why so touchy? What is your experience with a Gandy Wheel?

Touchy? You read too much into my reply. I have no experience w/a Gandy Wheel. However, I went online and looked them up - they're just like every other measuring wheel that's been discussed. Which means: it's an inferior measuring tool to the Jones-Reigel counter mounted on a bike - on the road.

scotth wrote:

Thread Follower wrote:

Why so touchy? What is your experience with a Gandy Wheel?

Touchy? You read too much into my reply. I have no experience w/a Gandy Wheel. However, I went online and looked them up - they're just like every other measuring wheel that's been discussed. Which means: it's an inferior measuring tool to the Jones-Reigel counter mounted on a bike - on the road.

Great Logic! Hopefully your measuring skills are better than your research and reasoning.

What Gives wrote:

Great Logic! Hopefully your measuring skills are better than your research and reasoning.

His reasoning and logic are fine. The Gandy wheel is no different than any other measuring wheel, and the reasons why measuring wheels are inferior to a calibrated bicycle wheel for measuring road courses have been covered in the previous 11 pages of this thread (which I'm sure you haven't read).

This thread is sounding like the movie Groundhog Day!

dukerdog wrote:

What Gives wrote:

Great Logic! Hopefully your measuring skills are better than your research and reasoning.

His reasoning and logic are fine. The Gandy wheel is no different than any other measuring wheel, and the reasons why measuring wheels are inferior to a calibrated bicycle wheel for measuring road courses have been covered in the previous 11 pages of this thread (which I'm sure you haven't read).

Mike Rohl makes a valid point about the wheel used in the test that had the differences. He points out a better product, and with no testing by the Jones Clickers he is wrong as is anyone who agrees with him. Classic!

The simple fact that some people believe all measuring wheels are the same shows ignorance and bias.

David Katz wrote:

This thread is sounding like the movie Groundhog Day!

David -

I was hoping you would add something productive to this thread since it is my understanding that this is your passion and you make money measuring.

Could you please respond to my questions from page 7 of this thread? I think many people could learn a great amount from posters like yourself if you responded to questions like mine instead of asking for this thread to disapear.

I found this evidence that proves the gandy wheel really works!

http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Sus_scrofa_avionica.png/220px-Sus_scrofa_avionica.png

Sorry David-

I was actually hoping you could answer the questions from page 8 of this thread.

incontrovertible truth wrote:

I found this evidence that proves the gandy wheel really works!

http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Sus_scrofa_avionica.png/220px-Sus_scrofa_avionica.png

and my Dad's bigger than your Dad!

What Gives wrote:

scotth wrote:

Use a Gandy wheel and there will not be that kind of error and it will be more accurate then a jones counter in any conditions.

You are wrong that a Gandy wheel is more accurate than a

'Jones counter in any conditions'. Any condtions includes roads. What makes you think your cross country courses are so accurate? If your reply is, 'Because I use a Gandy wheel and it's been GPS measured multiple times', that is hardly sufficient reason to make such an claim. If you've followed this thread you would've seen the difficulty in getting a reliable, across-the-board acceptable measurement from any wheel and GPS is off by at least 1 part in 100.

Why so touchy? What is your experience with a Gandy Wheel?

Touchy? You read too much into my reply. I have no experience w/a Gandy Wheel. However, I went online and looked them up - they're just like every other measuring wheel that's been discussed. Which means: it's an inferior measuring tool to the Jones-Reigel counter mounted on a bike - on the road.[/quote]

Great Logic! Hopefully your measuring skills are better than your research and reasoning.[/quote]

First, I appreciate dukerdog backing me up on my 'finding'.

Second - I've got your logic for you - the Gandy device is a measuring wheel. It is like every other measuring wheel that's been discussed on this thread - a device that a human being pushes along the surface to be measured. There is nothing about the Gandy wheel that makes it better than any other measuring wheel by comparison to a Jones-Reigel counter mounted bike for measuring a road race. Measuring wheels are NOT acceptable devices to be used for certification by USATF - the national governing body for the sport in the United States of America. I trust this line of logic is easy enough to follow.

There are click wheels, electro magnetic wheels, gear driven wheels, and belt driven wheels. They all perform the same function but accuracy varies dramatically. The Jones-Reigel unit is just a typical gear driven devise from what I have seen. The tolerances and gear mechanisms may be the best in the world but I have seen no date to prove such a statement or no data to prove it as superior to any other gear driven push wheel.

The American Congress on Surveying and Mapping (ACSM) does not recognize the Jones-Reigel counter as an acceptable devise for any measuremnt purposes.

Didn't David Katz also say the JR Counter is not an accurate measuring tool?

[quote]What Gives wrote:

Mike Rohl makes a valid point about the wheel used in the test that had the differences. He points out a better product, and with no testing by the Jones Clickers he is wrong as is anyone who agrees with him. Classic!

The simple fact that some people believe all measuring wheels are the same shows ignorance and bias.

I hereby challenge Mike Rohl to a measuring contest. The course will be a straight 200-meter course on grass measured by steel tape. I will use my piece-of-crap $25 plastic measuring wheel calibrated on a 100-meter steel-taped course on the same surface. He will use his uncalibrated magic Gandy wheel.

Not completely sure I'd win, but I'm 99% sure I won't lose.

How do you know he didn't calibrate his Gandy Wheel?

Do you own a JR Counter?