Power2Max Powermeter

Home:Ballyhoura · 18-08-2011 04:21PM

Diarmuid wrote: »

Do you not have to send them the S900 for them to calibrate the P2M?

That is what I thought too, I imagined the P2M was calibrated to your crank spider, but maybe its just calibrated to SRAM S900 cranksets in general assuming they are all the exact same in terms of stiffness etc....

drops wrote: »

I emailed them yesterday about that thinking i would have to send it but they said no. Below is the response i received.

"If you have the old model of SRAM S900 as we show then we don't need it for mounting because it's easy. It costs 690.00 Euro additional shipping. But please note: the old S900 must be."

Got the same reply from them when I asked that question! Maybe its not necessary to send it to them after all! Although for €140 more to get the Rotor and stronglight chainrings your almost 200g lighter. Decisions decisions!!

drops · 18-08-2011 04:29PM

Home:Ballyhoura wrote: »

That is what I thought too, I imagined the P2M was calibrated to your crank spider, but maybe its just calibrated to SRAM S900 cranksets in general assuming they are all the exact same in terms of stiffness etc....

Got the same reply from them when I asked that question! Maybe its not necessary to send it to them after all! Although for €140 more to get the Rotor and stronglight chainrings your almost 200g lighter. Decisions decisions!!

Yeah the s900 is on the heavy side alright and the rotor looks nicer, but gonna try and keep the costs as low as i can. If the sensor is 680 plus shipping and the chainset comes in at 180 plus i will need a new GXP BB so the whole lot should come in around the €900 mark.

duffyshuffle · 18-08-2011 05:23PM

<snip>

Diarmuid · 19-08-2011 07:24AM

IS there a 200g difference? That's quite substantial.

El Director · 19-08-2011 11:40AM

Guys good discussion here on a topic I'm only beginning to scratch the surface with. Not that I am in a position currently to be in the market for either but if ye could afford one or the other which would it be? Computrainer or a power meter for your bike?

Chips Lovell · 19-08-2011 11:44AM

El Director wrote: »

Computrainer or a power meter for your bike?

Not in the market myself, but if I was it would be a PM hands down. You can use your PM on the turbo. You can't take your computrainer out on the road.

Home:Ballyhoura · 19-08-2011 01:33PM

Diarmuid wrote: »

IS there a 200g difference? That's quite substantial.

SRAM S900 Chainset including stock chainrings = 830g
Rotor 3D Chainset (530g) + Stronglight chainrings (117g) +10g for chainring bolts = 657g

Difference is 173g here, and as far as I know the Power2Max will be an additional 200g for both configurations. According to this guy anyway "The original Rotor spider weighs 58g. The Power2Max spider weighs 264g, so the extra weight is 206g (130mm version)". Maybe the original SRAM spider might be heavy already so it might not be such a big weight gain when using the P2M spider. Still though over 1kg for the SRAM crankset is quite hefty!! And that doesn't include the bottom bracket

Home:Ballyhoura · 28-08-2011 10:32PM

Can the power2max be re-calibrated at a later date by the manufacturer?
Would swapping the power2max crankset from road to tt bike throughout the season be bad for it, as in affect the accuracy?

Diarmuid · 28-08-2011 11:10PM

Home:Ballyhoura wrote: »

Can the power2max be re-calibrated at a later date by the manufacturer?
Would swapping the power2max crankset from road to tt bike throughout the season be bad for it, as in affect the accuracy?

I think if you change cranks you'd need to recalibrate it, apart from that I wouldn't think so. However as it's a new product, it's best to email the guys who make it.... As for swapping it between bikes, I don't see why it should impact the accuracy...

hf4z6sqo7vjngi · 28-08-2011 11:23PM

Actually paying for mine on Monday a rotar 3d+. I gave them the spec of both my road and tt bike and i need a bb30 for the roadie for it to be compatible but there should be no issue switching between both bikes and with accuracy or calibration (from what they tell me).
Will be handy enough any way as i train on the road bike in winter and tt bike in race season so should be groovy:)

Lumen · 28-08-2011 11:39PM

Diarmuid wrote: »

I think if you change cranks you'd need to recalibrate it, apart from that I wouldn't think so. However as it's a new product, it's best to email the guys who make it.... As for swapping it between bikes, I don't see why it should impact the accuracy...

With the Quarq you have to get it recalibrated if you change chainrings substantially. Some variations are close enough not to need it.

I'd imagine the P2M is the same.

Swapping to another bike won't make any difference.

Diarmuid · 29-08-2011 07:25AM

Lumen wrote: »

With the Quarq you have to get it recalibrated if you change chainrings substantially. Some variations are close enough not to need it.

Well they sell it to you with no chainrings or without any specs for said chainrings....

Lumen · 29-08-2011 09:48AM

Haven't read this one before.

http://jibbering.com/sports/power2max-review.html

Lumen · 29-08-2011 09:53AM

Diarmuid wrote: »

Well they sell it to you with no chainrings or without any specs for said chainrings....

Here is an example of advice from Quarg about chainrings:

http://www.quarq.com/forum/thread/213/

"SRAM TT rings in 54/42 are compatible but there is a 3.5% difference in calibration between them and SRAM RED 53/39 rings. Your head unit's display and your data files will show 3.5% less power with the TT rings fitted. You can have your powermeter recalibrated at the Quarq factory or by using Qalvin, our new iPhone app."

I hadn't heard of this app before:

http://www.quarq.com/qalvin

It might be worth asking the P2M people about chainrings. I don't understand how it can affect the Quarg and not the P2M.

Home:Ballyhoura · 29-08-2011 09:54AM

Lumen wrote: »

Haven't read this one before.

http://jibbering.com/sports/power2max-review.html

I've read it, but from someone who owns a quarq power meter what do you think of the p2m based on that review? Any comments as you would have more experience with all that technical stuff and a better perspective altogether.

Lumen · 29-08-2011 10:04AM

Home:Ballyhoura wrote: »

I've read it, but from someone who owns a quarq power meter what do you think of the p2m based on that review? Any comments as you would have more experience with all that technical stuff and a better perspective altogether.

The most important thing about working with power is that you have confidence in the numbers.

I've done races with both a PowerTap and Quarg (not at the same time) where I distrusted the numbers enough to look at the HR. That in itself is indicative of something, possibly that I'm not doing the calibration consistently enough.

Collecting power data from races is useful and interesting, but my pre-race "routine" usually involves quite a lot of faffing and (if I have time) a warm up. Calibrating my power meter is the last thing I'm thinking about, so often I forget, or I do it but forget whether I've done it.

In this respect, the P2M is appealing because (as I understand it) you don't have to recalibrate before each session/race to account for temperature.

I probably should spend more time RTFMing. Given the legendary effort you spent getting your wheel decals right, you're probably organised enough to manage it.

In summary: it seems like P2M and Quarg are more or less as accurate as each other if used according to instructions, but I'd get a P2M over a Quarq because it appears to be cheaper and less hassle to keep accurate.

For me, SRM is just too much money and I hate sending stuff away. Presumably you still need to do that with the SRM when the battery goes.

Home:Ballyhoura · 29-08-2011 11:12PM

Thanks for that Lumen, looks like a power2max will be the way to go for me soon in the near future. I emailed them and it is possible to be sent back for re-calibration at any stage if necessary which I was afraid was not possible. If the Rotor 3D cranks are as easy as the Dura-Ace ones to remove and install then it shouldn't be too much hassle to swap between bikes seeing as they are both compatible with the same bottom brackets.

Also, after my heroic effort to get lovely matching new corima decals this is what my race wheel set up looks like...damn Gorey crashes

Diarmuid · 02-09-2011 03:48PM

Looks like there are a good few more crank options now available on the P2M powermeter and an MTB version too!

fran83 · 04-09-2011 09:38PM

Check this out it looks like saris (powertap) are going to be bring a crank based system out.

This is only applying for a patent so might not make the market.

SRM patent is up so over the next couple of year there will be a lot mire carnk based systems due on the market.

http://www.patentgenius.com/patent/7975561.html#

Lumen · 04-09-2011 09:47PM

[QUOTE=fran83;74211159http://www.patentgenius.com/patent/7975561.html#[/QUOTE]

I for one welcome our new 199-word-sentence overlords.

"A chain ring torque sensing assembly for use with a bicycle, the bicycle including a plurality of power input components including a crank arm and one or more chain rings, theassembly comprising: a sensor ring having a first set of mounting points on the sensor ring for coupling to a first one of the power input components and a second set of mounting points on the sensor ring for coupling to a second one of the power inputcomponents such that the sensor ring is positioned between and interconnects the first and second power input components through the first and second mounting points, wherein the first and second mounting points are at a common radius relative to acenter of the sensor ring, and wherein the sensor ring has a closed body and includes at least one force transmission area defined at least in part by a void area in the sensor ring; and at least one strain sensor associated with the at least one forcetransmission area of the sensor ring and adapted to measure strain in the force transmission area resulting from power applied to the crank arm by a cyclist during riding of the bicycle."

Bambaata · 28-10-2011 04:30PM

So my P2M arrived yesterday and i have it fitted. Just before i go at it with the sand paper i wanted to check with someone who might have had to sand down the chain catcher slightly on account of having aero rings. Is there anyone here with them? And if so am i right in saying this is the chain catcher part they speak of:

fran83 · 28-10-2011 10:12PM

Hi Bam,

It is that part. If you take off the battery cover it makes life a bit easier to do it.

What one did you buy?

I got mine a couple of weeks ago and I have to say there great value for money.

hf4z6sqo7vjngi · 28-10-2011 11:10PM

Riding with the power meter the last 3 weeks and i have to say a great piece of kit.

Bambaata · 29-10-2011 12:20AM

thanks for that fran83. I got the rotor 3D+ with 53/39 aero Q-Rings. looks the bizz! Now i hope it will help me preform as well!

Home:Ballyhoura · 29-10-2011 03:25AM

Bambaata wrote: »

thanks for that fran83. I got the rotor 3D+ with 53/39 aero Q-Rings. looks the bizz! Now i hope it will help me preform as well!

Please throw up a picture if you don't mind, looking at getting the same model!

fran83 · 29-10-2011 03:41PM

Bambaata wrote: »

thanks for that fran83. I got the rotor 3D+ with 53/39 aero Q-Rings. looks the bizz! Now i hope it will help me preform as well!

Got a Rotor 3D myself looks good just put some old rings on for the winter will change to the new rings when my new bike arrives for next season. The powermeter alone wont make you preform well you need a good training plan and a **** load of hard work put in! Enjoy the pain of training with power!

duffyshuffle · 31-10-2011 06:38PM

Ok, i've been cycling plenty but i'm an absolute noob to power and no idea on details. I've got a Trek Equinox 7 (2007) Large frame, all same kit as when I bought it, gonna buy a power2max PM, but don't know which one, and what size and what crank size. What should make me decide? I'm in to long course tri racing if that makes a difference? Or someone let me know about any other details that they'd need to answer the question! I was gonna get a Vega and the part from CRC for it, any help very appreciated :-)

Beasty · 31-10-2011 07:06PM

It's quite an investment for something where you have not done much research (although I'll freely admit to something similar when I bought my first PM)

There are a few threads going into the merits of PMs, which you can do a search for. I find mine most useful for tracking overall fitness and pacing TTs, and if you're into longer distance Tris you will probably ultimately find it an invaluable tool

In terms of match - check your existing bottom bracket and crank length - the different P2M versions mainly reflect different BB options

duffyshuffle · 31-10-2011 07:14PM

Beasty wrote: »

It's quite an investment for something where you have not done much research (although I'll freely admit to something similar when I bought my first PM)

There are a few threads going into the merits of PMs, which you can do a search for. I find mine most useful for tracking overall fitness and pacing TTs, and if you're into longer distance Tris you will probably ultimately find it an invaluable tool

In terms of match - check your existing bottom bracket and crank length - the different P2M versions mainly reflect different BB options

Thanks Beasty, i understand how they work and the value of them, but my brain doesn't seem to want to understand the differences between them and my wallet does :-) I'm defiantly buying one and reviews seem good on p2m, i've been looking at getting one for a bit, but its all the bike parts that i've no clue about, i'm not joking when I say i'm gonna have to google what a bottom bracket is and how to measure it

and how to measure the crank, also just because the crank is a certain length doesn't mean its the right length does it? Any info and crank lengths and the why of them?

Cheers for the info

fran83 · 31-10-2011 07:19PM

Hi duffy,

If you take a picture of the cranks and bottom bracket are I can tell you what one will fit.

Power2Max Powermeter

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