Who is using GPS ??

I haven't bought one yet, but it's on the list. I want to do more long distance riding, and it seems it would be very helpful. That's a great service your providing too.

I use a Garmin 305. Love it. Mostly its just a fun little toy, but it gives some good info too. I'll check it out.😄

Everyone who wants to give some feedback or just his/ her opinion can send me an email: [email hidden]

I really like this trip. It's a trip of some one who climbed the Galibier in France:

ttsm.comtripview.php5Open ↗

I'll try once 🙄

Reintje said:

Everyone who wants to give some feedback or just his/ her opinion can send me an email: [email hidden]

I really like this trip. It's a trip of some one who climbed the Galibier in France:

ttsm.comtripview.php5Open ↗

I'll try once 🙄

GPS is great for post ride analysis. I use my PALM with a bluetooth GPS to collect data. I can calculate my speed, acceleration, elevation/slope, and esimated power. The power calculation I found to be very useful and consistant. As a result, I can gauge my training improvments. I do all of my calcuations in a spreadsheet.

I can also graph the elevation of the course to see how much climbing I did. Finally, I usually overlay my route on a satellite photo of my area. There are lots of tools on the web to do all of this.

I love numbers, and like to keep an archive of rides for future analysis.

Thanks

digi-bike said:

GPS is great for post ride analysis. I use my PALM with a bluetooth GPS to collect data. I can calculate my speed, acceleration, elevation/slope, and esimated power. The power calculation I found to be very useful and consistant. As a result, I can gauge my training improvments. I do all of my calcuations in a spreadsheet.

I can also graph the elevation of the course to see how much climbing I did. Finally, I usually overlay my route on a satellite photo of my area. There are lots of tools on the web to do all of this.

I love numbers, and like to keep an archive of rides for future analysis.

Thanks

How do you calculate power? Thanks 🙂

azdroptop said:

How do you calculate power? Thanks 🙂

May be he checks his calories. You are using your garmin 305. There's a heartbeat device included, isn't it? 🙄

I'm cylcing without heartbeat :o . What's the additional value of it? And how do you use it?

azdroptop said:

How do you calculate power? Thanks 🙂

I want to attach the spread sheet I was talking about, but this fourm does not allow me. Therefore, I will try to provide as much in detail as possible.

Steps to achieve estimated Power (watts) from collected GPS track data.

1. Ride you bike and collect GPS track data that collects no sooner than every 10 seconds.
   
2. Convert GPS track data to spreadsheet format: goto gpsvisualizer.comgpsvisualizer.comOpen ↗ and choose "Convert a File". Upload your data file, and select "Slope" & "Speed".
   
3. Import the spreadsheet into MS Excel, and "save as" a *.xls file.
   
4. Your spreadsheet file should have the following:[font=Arial]time[/font][font=Arial]latitude[/font][font=Arial]longitude[/font][font=Arial]alt[/font][font=Arial]speed[/font][font=Arial]slope[/font]
   
5. Determine your weight (you & bike combined) in Kg, and add a "weight" column.
   
6. Calculate "velocity" and create another column with the following equation: "=(SPEED*1000)/3600".
   
7. Calculate :power" (watts) and create another column with the following equation: "=(SPEED*((0.5*1.18*(SPEED*SPEED)))/2)+(WEIGHT*9.806*(0.006*COS(ATAN(SLOPE/100))+SIN(ATAN(SLOPE/100))))". Note: this assumes a delta time of 10 seconds per a GPS measurement.
   
8. Each Power calculation is independent of other measurements.
   
9. Compute Average, Min & Max or whatever.
   
10. ENJOY!
    

Wow! Great info there. Sounds a bit out of my league speedsheet wise, but I'll try it out.

Quoted post said:

May be he checks his calories. You are using your garmin 305. There's a heartbeat device included, isn't it? [img]cyclingforums.comrolleyes.gifOpen ↗[/img]

Estimating watts/power from calories? The garmin calorie count is WAY off. Overestimates by at least 30%. Along with HR the garmin gives cadence, avg cadence, speed, avg speed, speed per lap, distance, elevation, current grade, auto lap, Full GPS, courses, uploadable to Google earth and so much more. Check out www.motionbased.com in the forum section under garmin 305 and you'll see what they can do. Most of it is just plain fun, but with the motionbased software you can get as detailed as you like for training. With out power of course.

I have to admit that I am a engineer which specializes in GPS. I wanted a Power measurement, but I do not want to spend the money on the equipment (I am cheap). The calculations of Power do assume some things, for simplification, and is not accurate but is consistent. For the layman cyclist, consistency is what counts. The results of my rides are very consistent. Therefore, I can "gauge" myself on performance improvement. However, I feel that this formula for Power is as good as it can get.

Have fun

azdroptop said:

Wow! Great info there. Sounds a bit out of my league speedsheet wise, but I'll try it out.

Estimating watts/power from calories? The garmin calorie count is WAY off. Overestimates by at least 30%. Along with HR the garmin gives cadence, avg cadence, speed, avg speed, speed per lap, distance, elevation, current grade, auto lap, Full GPS, courses, uploadable to Google earth and so much more. Check out www.motionbased.com in the forum section under garmin 305 and you'll see what they can do. Most of it is just plain fun, but with the motionbased software you can get as detailed as you like for training. With out power of course.

digi-bike said:

I have to admit that I am a engineer which specializes in GPS. I wanted a Power measurement, but I do not want to spend the money on the equipment (I am cheap). The calculations of Power do assume some things, for simplification, and is not accurate but is consistent. For the layman cyclist, consistency is what counts. The results of my rides are very consistent. Therefore, I can "gauge" myself on performance improvement. However, I feel that this formula for Power is as good as it can get.

The major issue with this GPS based scheme is that you can not take into account of air resistance, which is a major component of power expenditure when your speed picks up.

sogood said:

The major issue with this GPS based scheme is that you can not take into account of air resistance, which is a major component of power expenditure when your speed picks up.

Valid point. However, I do take that into account, and is one of my assumptions for simplification. Since I usually ride in a loop, I can assume a wind resistance of zero. However, if you do not ride in a loop (unidirectional) and want to factor in wind resistance, follow the additional additional steps:

1. [font=Verdana]Determine the average wind speed for the direction you were riding, in metric. Just look up a local weather web site.[/font]
   
2. [font=Verdana]Use the following modified formula for Power:"=(SPEED*((0.5*1.18*[font=Verdana]((SPEED+WIND)SQR[/font]))/2)+(WEIGHT*9.806*(0.006*COS(ATAN(SLOPE/100))+SIN(ATAN(SLOPE/100))))". [/font]
   

[font=Verdana]I also assume a rolling resistance of 0.006, which relates to a thin-med high pressure road tire.[/font]