Power2Max Powermeter

fran83

Diarmuid wrote: »

Hi! Good ride at the weekend

Have you checked out Power2Max? I have one for the past few months and it works a treat. Had zero issues with it so far and it's far cheaper than an SRM or Quark. You just need to pick the version that matches your BB.

However when I did order it, there was a 6 week lead time. Drop them a mail to see how long the lead time is.

Sorry to rob you tread.

I have been looking to get 1 of the power2max and was worried that they are crap?

Just a few questions on it? Have you raced with it and have you used it in and bad weather conditions?

What model did you get?

Diarmuid

fran83 wrote: »

Sorry to rob you tread.

I have been looking to get 1 of the power2max and was worried that they are crap?

Just a few questions on it? Have you raced with it and have you used it in and bad weather conditions?

What model did you get?

I have the GXP version. I've raced and trained with it non stop since I got it in March (I think). Raced in Donegal in the pouring rain with no issues. Why would you think they are crap?

tunney

Diarmuid wrote: »

I have the GXP version. I've raced and trained with it non stop since I got it in March (I think). Raced in Donegal in the pouring rain with no issues. Why would you think they are crap?

from the indepth reviews and the discussion on wattage there are some questions over the data quality under certain circumstances but those that are concerned are the likes of the guys that write the books on training and racing with power meters. The data isn't *quite* SRM quality but its better than Quarg data.

I'd get one as my next PM (presently wired DA SRMs)

Diarmuid

tunney wrote: »

from the indepth reviews and the discussion on wattage there are some questions over the data quality under certain circumstances but those that are concerned are the likes of the guys that write the books on training and racing with power meters. The data isn't *quite* SRM quality but its better than Quarg data.

I'd get one as my next PM (presently wired DA SRMs)

I didn't spot that but I haven't been following Wattage very closely recently... Any links?

tunney

Diarmuid wrote: »

I didn't spot that but I haven't been following Wattage very closely recently... Any links?

None off hand, should be easy to pick up on the search. Think it was Robert Chung talking about data quality.

Its great the the P2m came out, first new PM in a while. The pedal based ones are going to have severe data quality issues I fear. (both Look/Garmin and MetriVector).

Beasty

Are they only available direct?

Found this review which seems quite positive

tunney

Only direct, and are getting slammed on demand.Delivery now taking until end September.

Not sure I trust that bloke 100% to be honest.

Diarmuid

tunney wrote: »

Only direct, and are getting slammed on demand.Delivery now taking until end September.

Not sure I trust that bloke 100% to be honest.

When you put in an order, or when you email them to inquire, they will tell you the lead time. When I put my order in , in January, they told me 6 weeks and true to their word, I received it 6 weeks later

I'm not surprised demand is high. The pricing is very competitive and the weight penalty on the SRAM rival crankset I replaced was relatively small

Home:Ballyhoura

Thanks for the info on the Power2Max anyway, quick question.

If you were to go for your first power meter which would you go for?

• Power2Max €1100 and ANT+ computer ~ €200 = €1300
• SRM Dura Ace wired version second hand including PC V head unit €760 + import duty etc = €960 (such as this)

There are always Quark's second hand for around €1200 plus an ANT+ computer too?

What ya think?

Diarmuid

Home:Ballyhoura wrote: »

What ya think?

Do you already have a Garmin500? What BB do you have?

For me the best option was the Power2max but depending on what you already have and how comfortable you are with buying expensive second hand equipment the SRM may be what you are after....

TinyExplosions

Home:Ballyhoura wrote: »

What ya think?

I'd rent one from here for a while and see that you are getting the use out of it/which one your prefer, and then decide based on that!

mloc123

TinyExplosions wrote: »

I'd rent one from here for a while and see that you are getting the use out of it/which one your prefer, and then decide based on that!

Nobody that swaps to training with power will go back to HR, renting is a waste of money if he can afford to buy one now.

Giving those options I would go with P2M over an old wired SRM which may no longer be covered by warranty? Also factor in the SRM battery/service costs.. about €200-300 a go.

Home:Ballyhoura

Diarmuid wrote: »

Do you already have a Garmin500? What BB do you have?

For me the best option was the Power2max but depending on what you already have and how comfortable you are with buying expensive second hand equipment the SRM may be what you are after....

No only a basic polar so an additional computer purchase would be necessary! Threaded external bearing English thread BB like shimano dura ace is what I currently have.

Good point, the one I had been looking at has been recently serviced, batteries changed and calibrated but you still don't know with used goods!

mloc123 wrote: »

Nobody that swaps to training with power will go back to HR, renting is a waste of money if he can afford to buy one now.

Giving those options I would go with P2M over an old wired SRM which may no longer be covered by warranty? Also factor in the SRM battery/service costs.. about €200-300 a go.

Ya those service costs are one thing I hadn't really factored in. I have been told the wired SRM's are a bit fiddly to work with?

Fazz

You might want to wait until interbike is done as Garmin are due to have a pedal based power meter etc coming out I think.

Power meters will get much better priced from next year I gather and I wouldn't buy one now tbh.

May be an option to rent a computrainer until then if needed?

Lumen

Fazz wrote: »

You might want to wait until interbike is done as Garmin are due to have a pedal based power meter etc coming out I think.

Power meters will get much better priced from next year I gather and I wouldn't buy one now tbh.

That's been the story for years now.

Power metering is hard. Power metering anywhere but the crank or hub is even harder.

Beasty

Lumen wrote: »

That's been the story for years now.

Power metering is hard. Power metering anywhere but the crank or hub is even harder.

I think that's exactly the point - if it was easy they would have perfected it a long time ago. Clearly there are issues that are taking time to resolve.

One concern i will have about any pedal system is the scope for "wear and tear" - all the clipping in and out, and the pedal is often the first thing to hit the deck in a crash/fall ...

Lumen

Beasty wrote: »

I think that's exactly the point - if it was easy they would have perfected it a long time ago. Clearly there are issues that are taking time to resolve.

One concern i will have about any pedal system is the scope for "wear and tear" - all the clipping in and out, and the pedal is often the first thing to hit the deck in a crash/fall ...

It's not just that though. As Tunney has alluded to, even the established crank-and-hub-based PM engineers seem to spend a lot of time bickering discussing with the failed engineers sports science people the limitations of and compromises within their technology.

I don't know whether arguments about the statistical effects of sample rates and calibration of strain gauges have any relevance in the real world, but power metering doesn't appear to be a "solved problem" even for the easier engineering cases.

My Quarg has been faultlessly reliable from a general operational point of view (lack of lost data, spikes, etc), but there are some race data I've looked back over that leaves me with a sense of unease, and I've found myself using HR stats to sanity check the efforts.

If I could just work out how to consistently reproduce the less mediocre performances...

mloc123

How cheap do people expect powermeters to get?

You can pick up a new wired Powertap for €500? Most people will waste €500 on cycling crap that has no benefit. P2M starts out around €800 for crank based power that is pretty good value IMO...

Lumen

mloc123 wrote: »

How cheap do people expect powermeters to get?

Cheap enough to have one on each bike.

Bambaata

The P2M is what im contemplating at the moment. I said to myself i'd get myself one by year end this year and it is at about the max i am willing (can afford!) to spend. Pity i dont have a notion what most "experts" are saying sometimes when reading reviews :P

Time for reading on how to use it first i think and then decide if it will help me.

Beasty

Lumen wrote: »

Cheap enough to have one on each bike.

They already are, aren't they?;)

(track bike currently excepted)

Morrisseeee

Yep, you can never really have enough PMs :pac:

Bambaata

Hey Diarmuid
I am looking at getting on in the coming weeks. I currently ride a 6700 crankset so i gather this wont do and thus need to chose from the available options on the P2M site - TA Vega, TA Carmina, ROTOR 3D Plus, ROTOR 3D, ROTOR Agilis or SRAM S900. I have a GXP BB spare (brand new!) and currently have the hollowtech BB in for the 6700. From that i presume that narrows the selection down to the ROTOR 3D, ROTOR 3D + or SRAM S900. (Note on the specs page and compatibility page seem to have an error? Rotor3d + on one says BB30 and the other Shimano compatible?) I was wondering which you went for and why? Or does anyone else know much on the available options and how'd they rate. Im after the best but am struggling to find comparative reviews.

Also did you have chainrings yourself or can these be ordered from P2M? I gather the 6700 rings wont work? And since im looking at having a 53/39 i presume its the 130mm version? Sorry, ive not looked into changing anything like these before so new to this end of a bike!

I have a 310XT to use as the computer. I presume now that this has 1sec recording its adequate? Or is there anything the other units do that this doesnt?

Is there anything else i need or is there anything ive forgotten? Cheers

Home:Ballyhoura

Bambaata wrote: »

(Note on the specs page and compatibility page seem to have an error? Rotor3d + on one says BB30 and the other Shimano compatible?)

Also looking at getting one of these soon, I think that the Rotor 3D+ is made for BB30 but is still Shimano compatible if you use adaptor cups on the BB.

Emailed them this morning, current delivery time estimate is 6-7 weeks.

Would also be interested to see what model Diarmuid went for, and maybe a bit of a review? Would you recommend buying chainrings with the P2M at the same time, or does it matter where you get them as you do not need to calibrate the unit to the chainrings you are using from what I can gather. Also picked up the cheap Garmin 500 today so thats the wired SRM option out the window for me.

Edit: Also, I have Shimano Ultegra/Dura-Ace bottom brackets on my road bike. Will I need to get Rotor BBs from now on if I go for the Rotor 3D crankset? I see on this Rotor BB product description, that "This BB1 bottom bracket will fit all Rotor and Shimano compatible cranks with a 24mm spindle.", so can I presume this would work the other way around and that my standard Shimano BBs will work ok? I want to be able to swap it over to my TT bike which is running an FSA MegaExo BB at the moment so I presume this will have to be replaced for compatibility issues. Thanks in advance!

Diarmuid

Hey guys

Well my choice was pretty simple. I already had SRAM Rival groupset with a GXP BB so I figured I'd go for the S900 version. I didn't bother looking into reviews of the Rotors, but I'm sure there are plenty of them out there.

For the chainrings I bought Stronglight CT2 rings from xxcycles. I could have recycled my SRAM chainrings but I figured if I was going to sell the Rival chainset (or if I had to replace another chainset) I would buy the chainrings.

Off hand I don't know about compatibility of the Rotors with the Shimano BBs. If you email the guys directly they will be able to fill you in on the details. The P2M is calibrated for the spider only so you can use whatever chainrings will fit. I think if you find Quarq reviews the same principle applies

From my point of view, the installation was simple. The only issue I had was with the BB chainring bolts. I had alloy bolts and they sheared very easily. Apart from that it was a piece of cake to mount the two chainrings and then pop it on the GXP BB. From what I remember I had initially a bit of adjusting to get the shifting perfect but that's to be expected. Once it was on the bike, it was totally transparent. Without looking down I would have no idea if the Garmin was picking up the power from the P2M or the Powertap.

Once on the computer (if I remember correctly) the P2M was measuring a few % more than the PowerTap but that's to be expected (at pedal vs at wheel). However that was just based on my feel for the numbers. I didn't bother borrowing a second Garmin to compare the two power readings. Someone out there on the interweb did it and confirmed the accuracy of the P2M so I couldn't be arsed.

It goes without saying that this is a new powermeter with no history and generally I wouldn't touch the first gen of a product. However so far so good. I haven't read of any major (or even minor) problems with the unit but that doesn't mean it won't fall over after 2 years. So while this review is positive, buyer beware

Diarmuid

AFAIK for both you guys if you want to keep your Shimano BB (non-BB30) then your choice is Rotor 3D and Rotor Agelis

One option that I didn't explore at the time but seems obvious now, would be to buy the S900 (say from CRC) for €185 and send it off to P2M. As result you get the cranks + P2M + chainrings = €875. Saves you a good few quid

Bambaata

Thanks Diarmuid

Fazz

Fazz wrote: »

You might want to wait until interbike is done as Garmin are due to have a pedal based power meter etc coming out I think.

Power meters will get much better priced from next year I gather and I wouldn't buy one now tbh.

May be an option to rent a computrainer until then if needed?

Garmin Vector pedal based power meter announced...
Surely going to be more price conscious than existing options...



http://t.co/EWYSJn2


Edit :


Vector will be available in March 2012 and will have a suggested retail price of $1,499.99.


Makes most sense for me especially as it's pedal based and not dependent on hub etc therefore useful for both training and racing and costing €1k - €1,250

Most of us have the display units anyway I imagine...

drops

Diarmuid wrote: »

AFAIK for both you guys if you want to keep your Shimano BB (non-BB30) then your choice is Rotor 3D and Rotor Agelis

One option that I didn't explore at the time but seems obvious now, would be to buy the S900 (say from CRC) for €185 and send it off to P2M. As result you get the cranks + P2M + chainrings = €875. Saves you a good few quid

I think i am going to go down this route, i just bought the SRAM S900 from CRC. The guys at P2M say they will send out the sensor and the installation is straightforward. However they say it will only work with the older model SRAM S900 (which is currently what CRC have and i presume the discount is because they are trying to get rid of this stock before new model comes in).

Diarmuid

drops wrote: »

I think i am going to go down this route, i just bought the SRAM S900 from CRC. The guys at P2M say they will send out the sensor and the installation is straightforward. However they say it will only work with the older model SRAM S900 (which is currently what CRC have and i presume the discount is because they are trying to get rid of this stock before new model comes in).

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

drops

Diarmuid wrote: »

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

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."

Home:Ballyhoura

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

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

<snip>

Diarmuid

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

El Director

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

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

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

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

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

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

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

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

Haven't read this one before.

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

Lumen

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

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

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

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

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

fran83

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

[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."