Kurt Kinetic Power Computer a worthwhile training aid?

bigpikle

I have a Road Machine TT and will be using it extensively over the winter like many people. Right now I have no power meters or equipment, just a 705 & HRM , and I just cant afford to buy a PT or anything else right now. Also, with several bikes I just cant find a solution that would work with all of them if I rented etc...So.....

Is it worth £50 to get the Kurt power computer for use on the trainer? My goal would be more targeted training using power rather than HR, and being able to test myself to measure progress. It seems the Kurt is pretty accurate as TT power computers go, but as you cannot download any data and it only shows max, av and current power, is there enough data to make it worthwhile?

My thinking is that if I can calculate the power zones I want to target (using the Kurt) for different intervals etc then being able to train against these zones must be more helpful than using HR data alone?

Before I splash the cash would someone tell me if I am wasting my time. Please dont recommend a PT etc as its just not going to happen for a long time yet!

MatthewBulmer

Don't buy the KK Power Computer. All it does is measure rear wheel speed. It then uses the known power curve of the KK Road Machine to translate this speed into a power reading.

Assuming you have the speed sensor for your 705, then you are already able to measure your rear wheel speed. After your turbo session simply use the equation quoted on the KK website to work outy our power readings for any workout. The 705 is actually better for this as you can work out ave power for individual intervals - you can't do this on the KK power computer. Indeed, you can in effect set up power zones on the 705 using the speed zones function. Done this all year and it works great.

None of the above is to say that this method is anywhere near as accurate/consistent as using a proper power meter. However, it is a good way of ensuring that your training intensity is roughly where it should be.

swaman

if you have any computer that will show speed then you don't need a kurt computer

you can download and print out the power curve from the kurt website, it will show power against speed

i use my garmin 705 on the bike and when I upload my speed after a session i can see where i was in relation to power

easy to do power intervals, just look at the speed you need to do and keep it in the relative speed zones during your workout

i also have an i-magic which does gave power and all the extras but rarely use it, the Kurt power figures are more realistic to road figures, the kurt is easier to set up, and it rides much better

hope this info makes sense...

if you want to have an all-fangled system with all sorts of power data and graphs etc then then you need the powertap

but if you just want to set power targets, do power sessions on the turbo, and keep a l diary of your progress, then the kurt kinetic linked with a computer that shows speed will do a great job

bigpikle

thanks guys - I obviously need to get my head round this speed/power equation and plot a curve...

So, if I use the 705 lap feature to record each interval then I can find av speed per lap/interval and hence av power per lap/interval. By the same process I can also identify the speed range that corresponds with the target power range and work to stay in that speed range...

Seems to make sense if I can work the equation then.

swaman

you can use the equation or use the power curve chart, you will find it here

http://www.kurtkinetic.com/documents/Po ... ves419.pdf

makes life a lot easier...hope this helps

bigpikle

thanks - I managed to reproduce it in Excel so I can print the graph etc and have it by the machine. My next job was some algebra to see if I could calculate the speeds for a particular power level? Been a while since i tried that though....

Slow1972

Bigpikle wrote:

thanks - I managed to reproduce it in Excel so I can print the graph etc and have it by the machine. My next job was some algebra to see if I could calculate the speeds for a particular power level? Been a while since i tried that though....

That's what I've done. I self tested to find avg speed at threshold, converted that into power. I've then used excel to calculate the corresponding speed for varying percentages of threshold power. I've then just knocked up a table which gives me the speed on the Kurt for different % of threshold from 50% through to 140% in 5% increments. I just have it taped on the wall next to the turbo. I just use a cheapish Cateye computer with rear wheel mounted speed sensor, I found the signal on my Garmin sensor seemed to keep dropping out a bit which was adversely affecting the averages I achieved.

bigpikle

Slow1972 wrote:

That's what I've done. I self tested to find avg speed at threshold, converted that into power. I've then used excel to calculate the corresponding speed for varying percentages of threshold power. I've then just knocked up a table which gives me the speed on the Kurt for different % of threshold from 50% through to 140% in 5% increments. I just have it taped on the wall next to the turbo. I just use a cheapish Cateye computer with rear wheel mounted speed sensor, I found the signal on my Garmin sensor seemed to keep dropping out a bit which was adversely affecting the averages I achieved.

can I ask what you did to find your speed at threshold? This is the last pice of the puzzle for me as I cant work out how best to find the training zones?

MatthewBulmer

Useful reads:

http://alex-cycle.blogspot.com/2008/05/ ... -sins.html

http://alex-cycle.blogspot.com/2009/07/ ... ftp-2.html

In the context of the KK, just read 'speed' for 'power'. A mainstay of my training is the typical 2*20 workout. I do these sessions as hard as I can. I then use the ave power over the 2 intervals as a rough indication of my threshold power.

As stated above, this is not the most accurate way of assessing threshold power, but for my purposes it does fine.

Murr X

This is a good conversion table for the KK Roadmachine. Print it out and have it in view when on the turbo.


MPH - WATTS

17.0mph=183.34w
17.1mph=185.53w
17.2mph=187.74w
17.3mph=189.98w
17.4mph=192.23w
17.5mph=194.51w
17.6mph=196.80w
17.7mph=199.12w
17.8mph=201.46w
17.9mph=203.81w

18.0mph=206.19w
18.1mph=208.59w
18.2mph=211.01w
18.3mph=213.45w
18.4mph=215.91w
18.5mph=218.39w
18.6mph=220.89w
18.7mph=223.42w
18.8mph=225.96w
18.9mph=228.53w

19.0mph=231.12w
19.1mph=233.73w
19.2mph=236.36w
19.3mph=239.02w
19.4mph=241.70w
19.5mph=244.40w
19.6mph=247.12w
19.7mph=249.86w
19.8mph=252.63w
19.9mph=255.42w

20.0mph=258.24w
20.1mph=261.07w
20.2mph=263.93w
20.3mph=266.81w
20.4mph=269.72w
20.5mph=272.65w
20.6mph=275.60w
20.7mph=278.58w
20.8mph=281.58w
20.9mph=284.60w

21.0mph=287.65w
21.1mph=290.72w
21.2mph=293.82w
21.3mph=296.94w
21.4mph=300.09w
21.5mph=303.26w
21.6mph=306.45w
21.7mph=309.67w
21.8mph=312.92w
21.9mph=316.19w

22.0mph=319.48w
22.1mph=322.80w
22.2mph=326.15w
22.3mph=329.52w
22.4mph=332.92w
22.5mph=336.34w
22.6mph=339.79w
22.7mph=343.26w
22.8mph=346.76w
22.9mph=350.29w

23.0mph=353.84w
23.1mph=357.42w
23.2mph=361.03w
23.3mph=364.66w
23.4mph=368.32w
23.5mph=372.01w
23.6mph=375.72w
23.7mph=379.46w
23.8mph=383.23w
23.9mph=387.03w

24.0mph=390.85w
24.1mph=394.70w
24.2mph=398.58w
24.3mph=402.48w
24.4mph=406.42w
24.5mph=410.38w
24.6mph=414.37w
24.7mph=418.39w
24.8mph=422.44w
24.9mph=426.51w

25.0mph=430.62w
25.1mph=434.75w
25.2mph=438.91w
25.3mph=443.10w
25.4mph=447.32w
25.5mph=451.57w
25.6mph=455.85w
25.7mph=460.16w
25.8mph=464.49w
25.9mph=468.86w
26mph=473.26w


With a bit of work I had got it amazingly close to my SRM Pro from 250-350 watts. Make sure that the tire pressure is always identical and the unit is tightened to the same degree (app 3 revolutions for mine, after contact with the tire) each time as this will greatly affect the accuracy and consistency.

Also it must be warmed up, however due to the fluid used in the resistance unit above a certain temperature it is very stable and in my experience does not suffer from reduced viscosity and therefore does not overestimate power output above this temperature.

The KK is a very good piece of kit and as just mentioned can be surprisingly accurate with a bit of effort, but it is not great if improperly set up.


Murr X