Rotor LT powermeter offer

jgsi

If you are thinking of a powermeter..from Rose
http://www.rosebikes.co.uk/article/roto ... tAodgGAAfg

excellent price for Advent as the Germans name it.

StillGoing

It's over twice the cost of the 4iiii system still and only measures left crank arm like the 4iiii.

jgsi

Personal choice, but the 4i is a bit home diy for my taste... when it gets to be on sale of course

StillGoing

Well the one's I ordered are due early January.

cswitch

philthy3 wrote:

It's over twice the cost of the 4iiii system still and only measures left crank arm like the 4iiii.

...though you do get a £300 crank with the Rotor and I don't have to run the battery down on my phone. 4iiii could be great if it works as expected (and it works with a garmin) but right now all looks a bit budget. Also the fatigue test results are all incomplete or N/A - not sure exactly what that is but sounds like it needs confirming before buying one. However it's good another cheapo option is coming to market to help drive down typical powermeter costs.

cswitch

more info here on the 4iiii. Actually sounds like a good start considering it was prototype that was tested.
http://www.dcrainmaker.com/2014/09/4iii ... ision.html

StillGoing

cswitch wrote:

philthy3 wrote:

It's over twice the cost of the 4iiii system still and only measures left crank arm like the 4iiii.

...though you do get a £300 crank with the Rotor and I don't have to run the battery down on my phone. 4iiii could be great if it works as expected (and it works with a garmin) but right now all looks a bit budget. Also the fatigue test results are all incomplete or N/A - not sure exactly what that is but sounds like it needs confirming before buying one. However it's good another cheapo option is coming to market to help drive down typical powermeter costs.

Why would I need to run the battery down on my phone? As you've pointed out, the 4iiii device is ANT+ and connects to a Garmin device for use. The 4iiii device is compatible with any smooth crank arm so no need to replace your existing crank set. It's one set back from what I read is the inability to remove it to fit to another crank arm. But, the price of it means two devices to give you left and right read outs make it cheaper than just about all of the other devices out there and which only do left arm reading at the price.

However, if you really want Rotor, then it's at least close to Stages prices.

cswitch

I wasn't pointing out that it is ANT+, I meant it 'could' be great if it worked with a Garmin...I wasn't aware it did (or didn't for that matter) when I posted...there were a couple of articles referring to an android app for the 4iiii...which is likely to suck power if the screen is constantly on - not great for anyone doing long rides. As it is Ant+ then all good on that front.

For me it's not about really wanting Rotor, its about the added value of a power meter that comes with a £340 crankset. I actually have a Rotor twin sided PM and that certainly hasn't been without flaws. Anyway I hope the 4iiii is a success and if so it certainly has a place - I for one have a Red 22 crankset that I would consider putting a 4iiii on once I know they work without major flaw.

StillGoing

cswitch wrote:

I wasn't pointing out that it is ANT+, I meant it 'could' be great if it worked with a Garmin...I wasn't aware it did (or didn't for that matter) when I posted...there were a couple of articles referring to an android app for the 4iiii...which is likely to suck power if the screen is constantly on - not great for anyone doing long rides. As it is Ant+ then all good on that front.

For me it's not about really wanting Rotor, its about the added value of a power meter that comes with a £340 crankset. I actually have a Rotor twin sided PM and that certainly hasn't been without flaws. Anyway I hope the 4iiii is a success and if so it certainly has a place - I for one have a Red 22 crankset that I would consider putting a 4iiii on once I know they work without major flaw.

That's exactly the way it's intended for me. I have Rotor 3D cranks on one bike but prefer the Red cranks I have on the main bike and where the 4iiii PM is going. The flaw with the 4iiii is it can't be fixed to a non-flat crank arm. Yet. I doubt it will have the precision of the likes of SRM etc, but the figures for my level of riding are well within acceptable tolerances and preferable to riding on HR readings. As for Rotor; I don't believe their device is any worse than the SRAM Quarq Riken and is a hell of a lot cheaper, and is also, for me anyways, a better deal than Stages for the money.

mulletmaster

Of course it's inferior to the Quarq, it's single sided.

cswitch

mulletmaster wrote:

Of course it's inferior to the Quarq, it's single sided.

I assume you are referring to Quarq's Power Balance - it isn't a twin sided powermeter, only taking power readings from the drive side leg and just guestimating % of power coming from the other leg. At least with Rotor LT you can pick whether you want the measurements taken from the right or left leg. Considering the cost saving over the Quarq I know which one I would go for. Also Quarq's suffer from power drift - I had an Elsa which suffered from it, which was actually a warranty replacement for the previous Quarq model...certainly not superior by any means.

cswitch

[/quote]That's exactly the way it's intended for me. I have Rotor 3D cranks on one bike but prefer the Red cranks I have on the main bike and where the 4iiii PM is going. The flaw with the 4iiii is it can't be fixed to a non-flat crank arm. Yet. I doubt it will have the precision of the likes of SRM etc, but the figures for my level of riding are well within acceptable tolerances and preferable to riding on HR readings. As for Rotor; I don't believe their device is any worse than the SRAM Quarq Riken and is a hell of a lot cheaper, and is also, for me anyways, a better deal than Stages for the money.[/quote]

...I think Rotor LT will be lighter than the RIken too and we've all heard about Stages battery draining problems which as far as the internet shows are still unresolved.

mulletmaster

What are you talking about, Quarqs are spider based and hence measure double sided input rather than measure one and guess the other is equal.

cswitch

Yes they measure all the power going through the spider but are unable to accurately distinguish where the power is coming from. As I said it's not twin sided and hence why it's left right balance calcs are estimations.

mulletmaster

It arguably doesn't matter where it comes from, only that it reaches the spider. That is something a single sided PM cannot demonstrate with accuracy.
Nobody has shown that L/R balance is actionable intelligence.

meanredspider

mulletmaster wrote:

It arguably doesn't matter where it comes from, only that it reaches the spider. That is something a single sided PM cannot demonstrate with accuracy.
Nobody has shown that L/R balance is actionable intelligence.

No-one has come close to convincing me that high accuracy in a power meter is of any value to 99% of us. Precision (repeatability) is far more important. Even then, take a typical FTP test - do you think it is sophisticated enough to need high degrees of accuracy? To me it's like measuring a banana with a micrometer - what's the point? Reliability is important though, given the huge numbers of Stages that have been sold (according to DC rainmaker blog above) I'm also not surprised you find more issues on the Web than for other meters.

xavierdisley

meanredspider wrote:

Precision (repeatability) is far more important.

Which left only power meters don't provide to the same extent.

meanredspider

xavierdisley wrote:

meanredspider wrote:

Precision (repeatability) is far more important.

Which left only power meters don't provide to the same extent.

Based upon what? You've taken away one variable (the other leg). I'm not sure there's any basis to say they are less precise.

cswitch

I assume they aren't that bad otherwise Sky wouldn't have risked going with Stages, though they might be getting through a lot of batteries!

cswitch

meanredspider wrote:

mulletmaster wrote:

It arguably doesn't matter where it comes from, only that it reaches the spider. That is something a single sided PM cannot demonstrate with accuracy.
Nobody has shown that L/R balance is actionable intelligence.

No-one has come close to convincing me that high accuracy in a power meter is of any value to 99% of us. Precision (repeatability) is far more important. Even then, take a typical FTP test - do you think it is sophisticated enough to need high degrees of accuracy? To me it's like measuring a banana with a micrometer - what's the point? Reliability is important though, given the huge numbers of Stages that have been sold (according to DC rainmaker blog above) I'm also not surprised you find more issues on the Web than for other meters.

Yes quite possibly. I was going to get one but I was put off by reports from customers who were on their 3rd unit and still suffering the same issues.

xavierdisley

meanredspider wrote:

xavierdisley wrote:

meanredspider wrote:

Precision (repeatability) is far more important.

Which left only power meters don't provide to the same extent.

Based upon what? You've taken away one variable (the other leg). I'm not sure there's any basis to say they are less precise.

Because left/right balance isn't a constant from day to day, or even within the course of a ride.

meanredspider

xavierdisley wrote:

Because left/right balance isn't a constant from day to day, or even within the course of a ride.

Says who?

And who says it matters?

FWIW my " left only" data is incredibly consistent (within ride and from ride-to-ride) - way beyond anything I need.

Given the popularity of Stages and now the wave of other "left only" products being released, it seems that consumers are voting on this with their wallets.

jgsi

xavierdisley wrote:

meanredspider wrote:

xavierdisley wrote:

meanredspider wrote:

Precision (repeatability) is far more important.

Which left only power meters don't provide to the same extent.

Based upon what? You've taken away one variable (the other leg). I'm not sure there's any basis to say they are less precise.

Because left/right balance isn't a constant from day to day, or even within the course of a ride.

Can you back this up with any references or are you making an opinion?
Just curious as to why companies like Stages, Rotor and Garmin are thus bothering to offer single sided solutions... or is it just their corporate greed?
As s single sided Garmin user, I reckon I can live with any perceived discrepancy.. getting valid numbers is still important however.

xavierdisley

We've seen it in the lab with many riders of different abilities, and it's quite well known that bilatery asymmetry exists:

http://www.ncbi.nlm.nih.gov/m/pubmed/21055708/

Any study which investigates pedalling mechanics will display an difference in torque profile during the pedal stroke left/right too. I built a set of three axis force measuring pedals for the lab, the asymmetry exists in all three axes (something like a Garmin Vector only gives data for two). A typical end consumer who only has a single sided power meter isn't able to detect these kinds of differences. I don't think paying £600+ for a power meter which requires estimation of such a level to be worthwhile - if it was a third of that price then maybe, but people are very unwilling to accept that their single sided power meter has such severe shortfalls. Sky use them because of $$$ from the Nautilus group and have struggled with the limitations - you don't see them using Stages on the track for the UK Sport funded athletes and programs.

meanredspider

During cycling, bilateral differences are frequently found and vary with the competitive situation, pedaling cadence, exercise intensity and exercise duration. Regardless of the variability of asymmetry index between subjects, few suggestions are available to overcome lateral differences. Most of the research suggests that bilateral pedaling asymmetries decrease as the workload increases, however the relationship to injury risk was not clearly addressed

Which tells us what, exactly? Absolutely nowt. It doesn't even tell us anything from a precision point of view. Even for those people for whom it varies ("frequently" isn't exactly a precise word in itself), we then need data to show that this variability isn't consistent before we can draw anything from a precision point of view.

You say it matters? Why exactly? I'm bored with reading stuff on here that people post that has no basis in reality or usefulness. I read about FTP tests that will inevitably have large variability in them in any case. But that's great because I've measured the car park with a vernier. Nonsense.

mulletmaster

Then keep your random number generator and be happy with it. Just don't try and tell people with PhDs in exercise physiology that single leg measurement is as precise or accurate as spider based measurement. Whether the more accurate data is worth the meagre price increase (if any) compared with a power2max or quarq is up to you. If the price differential was £500 or the only spider system was SRM I would be with you but as prices stand they are a total false economy to me.

meanredspider

mulletmaster wrote:

Then keep your random number generator and be happy with it. Just don't try and tell people with PhDs in exercise physiology that single leg measurement is as precise or accurate as spider based measurement. Whether the more accurate data is worth the meagre price increase (if any) compared with a power2max or quarq is up to you. If the price differential was £500 or the only spider system was SRM I would be with you but as prices stand they are a total false economy to me.

Well, if we're going to trade qualifications, I'm a Fellow of the Institution of Mechanical Engineers with over 15 years of medical device engineering including 10 as quality director for an IVD manufacturer. My ex-colleague (a professor from Cranfield) runs a human performance testing company here in the Highlands with the coach of one of Britain's foremost athletes on his team - we were discussing all of this stuff only the day before yesterday. He's in my camp. His team have PhDs in pretty much anything relevant - I used to work with them all.

All I'm asking is that you show me that left-leg measurement is "a random number generator" and explain to me why the accuracy and precision of two leg measurement actually makes any real difference in the real world. So far nobody has been able to do this. I'm a reasonable guy just asking for some proof* rather than references to papers that mean nothing. In the meantime I'll use the device that actually works with the bikes that I have.

* ETA - good luck with that. We don't even properly understand how fitness works in a broad population so trying to argue that two-leg measurement makes a real difference is going to be a challenge.

imposter2.0

meanredspider wrote:

All I'm asking is that you show me that left-leg measurement is "a random number generator" and explain to me why the accuracy and precision of two leg measurement actually makes any real difference in the real world. So far nobody has been able to do this.

They have - you just haven't been listening....

xavierdisley

Here's one example - you can't aero test with a left only power meter, as the variability within session is too high. A normal power meter I can get <3w resolution for aero testing in the field with athletes, with a left only power meter you can't test even within ~10w because of the variability, sometimes it's worse. For a £600+ piece of equipment that isn't good enough in my opinion. Better than a Powercal, for sure, and I'm sure you can train with one and see improvements, but not worth it at the current prices.

meanredspider

Imposter wrote:

meanredspider wrote:

All I'm asking is that you show me that left-leg measurement is "a random number generator" and explain to me why the accuracy and precision of two leg measurement actually makes any real difference in the real world. So far nobody has been able to do this.

They have - you just haven't been listening....

Instead of quoting me, quote them then. Part of my job is satisfying FDA that medical devices do what they say. If anyone gets close to half that level of proof, I'll be happy. I've seen NOTHING that would convince the guy down the pub.

meanredspider

xavierdisley wrote:

Here's one example - you can't aero test with a left only power meter, as the variability within session is too high. A normal power meter I can get <3w resolution for aero testing in the field with athletes, with a left only power meter you can't test even within ~10w because of the variability, sometimes it's worse. For a £600+ piece of equipment that isn't good enough in my opinion. Better than a Powercal, for sure, and I'm sure you can train with one and see improvements, but not worth it at the current prices.

Good - an example. Aero testing isn't anything I'd ever considered doing with mine. I'm guessing you need to be a TTer before you worry too much about this and, even then, looking for some reasonable sized improvements if field testing is going to show them. Next time I want to do aero testing, I'll rent/borrow a meter

You seem hung up on the price. Given the combination of bikes I have, I was going to get nowhere near the utility I get from the Stages at anything close to that price.