Introducing PowerCal a new kind of Power Meter

[Bike Mob]

As long as it's consistently out that's fine.

 

The reaction time is amazing for this type of equipment.

 

What is more scary is the discrepancy in the two Garmin's Elevation recording! over 1000ft out.

Edited July 30, 2012 by Zilla

[Cyclewizz]

 

What is more scary is the discrepancy in the two Garmin's Elevation recording! over 1000ft out.

 

I agree. If you read those articles you'd see the 2 Garmin's were different on everything.

[BicyclePower]

I see the TSS value for the PC is around 15% lower than the PT. Is this a consistent trend across your rides? Also, is the difference in powers consistent, or is the PC sometimes higher than the PT?

 

 

I am finding that the Power readings are a constant 10-15% lower than the PT however this is where the value of the PC comes in. because it is almost custom to each user due to HR changes etc one could decide to add10% onto each value however I don’t think this would be needed as the target market is more for the recreational rider who wants to track fitness and feels HR is just not sufficient and for around R1000 this is what the product has been designed for.

 

 

However for the more serious riders who want to keep track of fitness with PMC (performance management charts) then they could find out just how much off the PC is then add a fixed percentage. i.e. in my case add 10% to TSS and energy etc.

 

 

TSS will be affected due to the differences in normalized power, here the differences may be a little more because there are a lot more measurable involved in the normalized power calculation.

[Minion]

If you read those articles you'd see the 2 Garmin's were different on everything.

The HR readings are identical except for a 2bpm difference in the one average, which could be due to slightly different start and end times. This would be because they're both getting the same HR data stream.

 

The speed and distance would be different since the PowerTap speed and distance would come from the hub vs. the PowerCal speed that's probably coming from GPS measurements.

 

The PT cadence reading can also come from the hub, while I suspect there was no sensor for the PowerCal (mean, min and max are all 127, suggesting a glitch).

 

The Edge 800 rounds each elevation point to the nearest whole number (if you look at its elevation track, it has a stair-step shape), while older models like the 310 record decimal values (giving a smooth profile). So, while the 310 might record an elevation change from 100.4ft to 100.6ft, the 800 would record 100ft to 101ft. This can cause issues with the cumulative elevation calculations.

[Minion]

However for the more serious riders who want to keep track of fitness with PMC (performance management charts) then they could find out just how much off the PC is then add a fixed percentage. i.e. in my case add 10% to TSS and energy etc.

This is good to know. The PowerCal is looking like it would work very well for what I'd want to do with it. I'll certainly look at getting one once you've got more available.

 

TSS will be affected due to the differences in normalized power, here the differences may be a little more because there are a lot more measurable involved in the normalized power calculation.

TSS ends up being proportional to NP squared, so the error is further magnified, but if it's consistent like with average power, it can also be calibrated out to some extent.

[Bike Mob]

I'm seeing that your NP and ave wattages would be down on the PT because the PC will omit the peaks that PT will record and accumulate. so your 1130w was softened to 900w...those add up on a ride and your Ave suffers.

 

if you are using it for peaked riding then you can expect a variation up to 15% is not much considering.

 

But in a Time Trial for instance where you ride at 300w consistently, there is not much peak to lose and the gap will be small to true value. Similar in MTB where its mostly threshold riding.

[Coenie]

hi, a limited number are due to be dispatched early part of next week from our suppliers, i think enough to supply everyone who has pre ordered. should be due to arrive towards the end of next week or the early the following week.

 

testing should be finished by then on our side.

 

we will be interested to hear how the users find the PowerCal however a second order with larger quantities is not far off.

 

Are those of us who put our names on this tread seen as clients that pre-ordered the PowerCal?

[BicyclePower]

Are those of us who put our names on this tread seen as clients that pre-ordered the PowerCal?

 

yes this is correct.

 

we have not marketed the product in any other way for now, however once we have stock we will do more marketing in other media

[The_Break]

I am finding that the Power readings are a constant 10-15% lower than the PT however this is where the value of the PC comes in. because it is almost custom to each user due to HR changes etc one could decide to add10% onto each value however I don’t think this would be needed as the target market is more for the recreational rider who wants to track fitness and feels HR is just not sufficient and for around R1000 this is what the product has been designed for.

 

 

 

However for the more serious riders who want to keep track of fitness with PMC (performance management charts) then they could find out just how much off the PC is then add a fixed percentage. i.e. in my case add 10% to TSS and energy etc.

 

 

 

TSS will be affected due to the differences in normalized power, here the differences may be a little more because there are a lot more measurable involved in the normalized power calculation.

This totally contradicts things. If the power values are based on HR then how on earth can it be for the recreational rider who feels that HR is not sufficient. He will end up with a less accurate training aid than just using HR alone. I have still to see how this product is more accurate than HR and you are avoiding my questions. Is it because I am correct? Would love to hear as if you are going to marekt the product in an open forum you should be willing to answer ALL questions that come your way.

[Minion]

This totally contradicts things. If the power values are based on HR then how on earth can it be for the recreational rider who feels that HR is not sufficient. He will end up with a less accurate training aid than just using HR alone. I have still to see how this product is more accurate than HR and you are avoiding my questions. Is it because I am correct? Would love to hear as if you are going to marekt the product in an open forum you should be willing to answer ALL questions that come your way.

It would appear that it's not just HR, but also includes HR variability (based on an answer to an earlier question I asked). Presumably you're paying for the algorithm and research that map HR and HRV to power in the cycling context and not just a HR monitor strap.

Given your own raw HR and HRV data, it should be possible to generate your own algorithm to make this estimate. The downside being that HR monitors that can record HRV are comparatively expensive and data intensive.

[Coenie]

yes this is correct.

 

we have not marketed the product in any other way for now, however once we have stock we will do more marketing in other media

 

Good to know. Looking out for my message/mail...

[BicyclePower]

so arrival is expected very veru soon :clap: :clap:

 

dont worry i will let everyone know as soon as they have arrived and been bought into stock, might be sooner than expected

 

here is a really good youtube video from the well respected DR Allen Lim as to why you should go for PowerCal:

 

 

then onto this here is another video, please note this in this video they use the incorrect working, PowerCal is not a Power Meter but a Power Calculator!!!

 

[LOOK695]

I just have one more question which has been asked but not answered. Got me thinking again this morning when I was doing intervals. How are the power readings affected when your legs are fatiqued and your HR is higher than normal on a specific stretch of road with your speed being the same. eg your HR is 70% at 30km/h when rested. When fatiqued, your HR might be 75% at 30km/h. Would the PowerCal show a higher power level for the higher HR? This would also apply when doing hill repeats/intervals. How would your power levels compare from the start and the finish of your training session where you need to work harder (higher HR) to maintain the same speed towards the end, but your ave speed stays constant for the intervals

Edited August 1, 2012 by LOOK695

[BigGuy]

I just have one more question which has been asked but not answered. Got me thinking again this morning when I was doing intervals. How are the power readings affected when your legs are fatiqued and your HR is higher than normal on a specific stretch of road with your speed being the same. eg your HR is 70% at 30km/h when rested. When fatiqued, your HR might be 75% at 30km/h. Would the PowerCal show a higher power level for the higher HR? This would also apply when doing hill repeats/intervals. How would your power levels compare from the start and the finish of your training session where you need to work harder (higher HR) to maintain the same speed towards the end, but your ave speed stays constant for the intervals

Here is my opinion (again). It does not work for interval training, HR is a reaction and will always be. You need the real deal, as do most of the people who comment on this thread. Let me use an analogy: I go to the gym and do leg presses. I have a plan on what I want to achieve, and it is based on the weight. I know I pressed 100kg last month and I need to increase the weight with 5%, ie now I should press 105kg. If I do not increase the weight then I will still be pressing 100kg in 12 months' time. I cannot go by feel, because one day I am more rested than the other, have more or less stress, maybe dehydrated a little; there are just too many variables I cannot control, so I need to control one thing, and that is the weight. I do not get hung up on multiplying sets and reps with weight to calculate the total work I have done, as it does not give me an accurate view of progress. What I need is the mental awareness of pressing 105kg iso 100kg, which gives confidence and affects neuro-muscular change. And this is my point (eventually), that you need to know exactly what you are doing at that specific point in time, otherwise you will not know whether you are doing enough to stimulate progress. You have gone through the effort of warming up, and you need to make those intervals count. Trying to figure out afterwards whether you have done enough does not make sense to me.

[NotSoBigBen]

Cycle Nation ‏@Cycle_Nation

And in other news, Cycleops PowerCal Power Meter is finally available from @CycleOpsJHB starting at R1095

 

[Bike Mob]

just got that too...where's mine?