Power meters

richwestover
Just wondered if any one had experience of training with a power meter?

I'm trying to decide between the Power2max Rotor 3D crank based system or the Garmin Vector pedal based system.

Both seem to be able to provide reliable data from what I've read, but having no experience of using one I don't know of what other factors to look out for that might come up after you've been training with one.

The Power2max Rotor system apparently had a few issues around the temperature change when beginning a ride which is now resolved as it's a couple of years old, and the Garmin system is fairly new.

Thanks!
Neil H's picture
Neil H
Are you going to be using this on one bike only, or is interchangability (is that a word???) a factor? I would imagine that the Vectors would be a damn sight easier to swap between bikes, but I don't know too much about the Power2Max.

The only other thing that I can think of is weight; I think the Power2Max comes in quite heavy? Depends if that kind of thing bothers you or not.

Powermeters are also pretty sensitive pieces of equipment, so it would be worth looking into the aftersales or costs of repair. For example, the torque tube in my old powertap pretty much gives out at some point each year, and if it's outside of the 1 year warranty it is around £350 to replace. It's just gone again so I now have the option of replacing it or just getting a new system. Currently the Stages is the top of my list, but just waiting on further reliability reports...



Neil H's picture
Neil H
The other thing I thought of (as I was considering the Vectors too) was that you would have to change your pedal system across all bikes, or have a separate pair of shoes for the Vectors (if you wanted to swap them between bikes that is). Also you need to buy a special torque wrench to install them, as they have to installed to a specific tightness otherwise they aren't accurate. Basically - for me - what seems like a simple, interchangable system is actually a bit of a ball-ache.
Tony_LaMoury's picture
Tony_LaMoury
I was tempted by the flexibility of the vectors and, the good reviews they have had so far by the mags. I have yet to speak to anyone who as actually used them and swapped them between bikes. My enthusiasm has been dampened however when a well respected chap in my local bike shop told me that they built in to a pretty basic pedal (Exhauster I think) so, the reliability of the pedal bits questionable long term ?
richwestover
thanks for the thoughts. changeability isn't too important, it'll mainly just sit on my race bike i expect.

that's interesting about the weight of the Power2max system though, definitely important and hadn't heard that mentioned anywhere before. big negative against that one then, i like climbing hills!

the pedal system isn't an issue as i'm using the look cleats on all my shoes anyway.

not sure about the battery system on the garmin though, will have to look into it. As it comes in so many bits though, apparently each individual part isn't too expensive to replace if damaged, e.g. the pods, as far as i know.

do you know which exustar model that is which they've used as the pedals tony?

I've found someone who is using the vectors on a training camp this week though and they're going to let me know how they get on once back, will let you know their thoughts, will be interesting to see how they work in real life.
richwestover
another positive review..... http://triathlete-europe.competitor.com/2014/01/30/gear-review-garmin-vector-power-meter
Tony_LaMoury's picture
Tony_LaMoury
Yes, I would be very interested in the feedback you get. I don't know what the pedal model is unfortunately and, I haven't actually seen them for myself either. I really like the concept of these and am a big Garmin fan so, a positive report would be good! Coincidentally, a lady at turbo last night was using them and said she was pleased so far but, I didn't actually see them as she was clipped in!
Martin_Brown's picture
Martin_Brown
This is the web site to go to for power meters FAQ and Reviews
http://www.dcrainmaker.com/product-reviews/power-meters

Personally waiting for the beans to land and then Stages for me.
Tony_LaMoury's picture
Tony_LaMoury
Good website Martin - thanks! Not sure about stages - looks a bit "add on" but, good enough for Brad and Froomie so must be alright. No good for me though - not a Campag crank in sight!!!
Timgrinsted
Just purchased stages Ultergra. I haven't done it yet, but it apparently is easily interchangeable. Early days, but I like it.
Tony_LaMoury's picture
Tony_LaMoury
Did you sell your Vector pedals in the end Tim ?
Neil H's picture
Neil H
Done a bit more looking into this and it seems that the power2max has come down in weight since the 1st iteration; now lighter than an SRM. So that is back on my list of 'possibles'...

My brother has just bought the Vectors and is having a lot of initial problems getting them to produce consistent readings.

Looks like it's Stages or Power2Max for me. Emailed Power2Max today about availability on the 'S Type' (their new power meter) and if I ordered today, they would be sent w/c 3rd March. So there's few weeks lead time, in case you were thinking of buying them.

Dave Truman's picture
Dave Truman
Another 2p on power....Because of all the other new power options available, Powertap prices are coming down too. You can get the basic model for £525 on Wiggle at the moment. I haven't got as long experience with it as Neil H, but (fingers crossed) mine is fine so far. There are some advantages to wheel based systems:
- they are really easy to change from bike to bike provided you have the same gears on both. Shimano 10 speed swaps over faultlessly between all 3 of my bikes. So ride winter on the hack, summer on the best road and race on the TT all with power.
- you can lend your wheel to someone else to try out power. I've done this with a couple of people. Again very easy to do and a good way for folks to a) try out power and b) try out the Powertap.
- it measures power at the wheel - as close to the ground as possible. Not a big issue . As long as power measurement is consistent between rides it doesn't really matter, but there are transmission losses. I have heard it can be up to 5 Watts.

Biggest disadvantage I've found is you are stuck with one wheel. You don't really want to ride your best aero wheel on your winter hack or your bombproof training wheels in a 10.

Whilst on the subject I heartily recommend Hunter and Coggan's book on training with power. Getting the numbers is just the beginning. It's understanding them and doing something with them that improves performance. Luckily I have people to help with that or I'd be lost!
Dave T
Dave Truman's picture
Dave Truman
Correction. The book is by Hunter Allen and Andrew Coggan and it's called Training and Racing with a Power Meter.
Tony_LaMoury's picture
Tony_LaMoury
I totally echo your thoughts Dave. This is my second "off season" year of training with powertap wheel but, I only ever intended and only do, use it on my turbo bike. I am not using any form of power measurement out on the road but, like to think I can gauge any increase in performance on climbs etc without one!

Neil, is you brother experiencing fluctuating readings changing so rapidly that it is difficult to appear smooth ? The problem is that these devices are so sensitive, they react quickly to the most minor change in applied force.If that is the case (and I found the same) I cured the problem by setting my Garmin to read every 10 seconds which "smooths" the output to your screen so you can follow it much easier.
Neil H's picture
Neil H
The problems he is having is getting them to give consistent readings against his powertap; he is running both in tandem to 2 different Garmins, and for long periods of time the Vectors are out by 20 watts or so (and also getting power drop outs). He's sent them back now and looking for another option...

10 second smoothing? That's quite a lot of lag! I run mine at 3 seconds to get rid of the fluctuations but also enable me to see an relatively instantaneous indication of increased effort.
Tony_LaMoury's picture
Tony_LaMoury
Yes, 10 seconds is a long lag and, it does catch me out sometimes when I look at my upload to see I may have dropped (or increased!) from the target power without knowing it. I will try 3 seconds again although last time the display figures were dancing up and down - perhaps that is me and not the device!
Sorry to hear about the vectors - that is disappointing as, they are really the only option for me as I want to keep my current chainset and wheels.
Neil H's picture
Neil H
Judging by the number of positive reviews for the Vectors, I wouldn't take my brother's experience as the norm; maybe just a dodgy pair.

Pretty certain I'm going for the Power2Max now, and just swapping out my old SRAM Red for SRAM S900. Any chance they cater for your current crankset Tony?

Now just a small matter of finding a spare grand...
Tony_LaMoury's picture
Tony_LaMoury
These look really good and, they cater for Campag which is unusual - good choice! However, I have bought a Campag Bora chainset which is a fully shrouded aero carbon http://www.campagnolo.com/jsp/en/groupsetdetail/item_crankset-bora-ultra_catid_18.jsp so, I can't use any of the crank based systems. To make matters worse, I have also discovered that the Vectors won't fit either because the cranks are too wide - they are bringing out a new version to suit though later this year (or so they say!). So, this season I think I will remain guessing my output on my TT bike!
Neil H's picture
Neil H
That'll teach you for having ridiculously fancy cranks! :-)
richwestover
did you manage to find out the actual weight penalty of the Power2max system Neil?

I'm still leaning very slightly towards the vectors just because there's only about 46g extra by having them on and i can't find anything specific about the quality of the exustar pedals they use on them.
Tony_LaMoury's picture
Tony_LaMoury
Thanks Neil, Yes - it is a fancy crank (should suit me then!). I went to the bike show at the weekend but was disappointed in that, no Garmin stand or anyone displaying the Vectors so I am still to see a pair too!
Neil H's picture
Neil H
Additional weight for the Power2Max Type S is 130g (for the SRAM option). Just of note; my brother reckoned his Vectors came in about 100g more than his 105 pedals (so more if you're running dura-ace, etc). But we're talking differences of 50-100 grams here, which, to be honest, isn't going to make a blind bit of difference. Take less water in your bottle!

I've just ordered the Power2max SRAM. I originally just went through the process to see what exchange rate was offered by paypal, but it seems you don't pay for it straight away... I've left it as I was 100% sure now anyway.
Tony_LaMoury's picture
Tony_LaMoury
Well done Neil, a new bit of kit is such a good motivator! I will be interested to hear what you think of it.
Timgrinsted
In Lanzarote at the moment trialling my stages power meter. So far very impressed. I have Ultegra on my TT bike and 105 on my winter bike. The same crank is interchangeable between the two and literally takes 30 seconds. I had originally bought the Garman Vector, but it was not compatible with the P2. The stages only gives to readout of power generated from the left foot, but for me that is fine. I'm just looking for a number to work with. I think continually changing pedals which you would end up doing with the Vector you are more likely to cause wearing tear ithan changing the crank.
Dave Truman's picture
Dave Truman
Anyone wanting to compare power options could do worse than attend a Thursday night turbo session or two. If you are lucky you will see Power2max on Andy TB, Vectors on Susan F, Powertap on mine, Tacx turbo based systems on Sally M and I think I saw someone had Stages two weeks ago as well.
How to set the Garmin has been discussed at length on the net. Part of the problem I understand comes from the head unit itself. Could have this wrong, but I think Powertap sends data packets with power readings 4 times per second. Joule head units read all of these. Garmins only once per second. That's why it jumps around. 3s Average is the most common setting I've seen. On my 310xt it's that or 30s so it's a no brainer really. My approach is to find a gear and a cadence which gets the power to jump around the target figure. Then I just look at cadence. Chasing the power figure is hopeless it's too stochastic.
Sometimes I think I'd be better off binning all the technology and just riding up a big hill and then repeat as necessary !
Dave
Dave Truman's picture
Dave Truman
By the way. In the Allen and Coggan book and on Andrew Coggan's website it discusses using power meter to calculate Cd - drag coefficient. Anyone tried that with any success?
D
Dave Truman's picture
Dave Truman
Here's the link.....
http://www.trainingandracingwithapowermeter.com
D
Tony_LaMoury's picture
Tony_LaMoury
I changed my Garmin 800 to 3s readings for my turbo this morning. Definitely keeps you in touch with what you are doing but, frustrating to see the power figure (from power tap hub) jumping around and, consequently the power trace on Strava looks like a relief map of the Alps. Think I will go back to 10 s.
richwestover
finally decided i'm also going for the Power2max system - the latest iteration of it looks good now they've integrated the battery and got rid of some weight/ bulk. going for the rotor cranks option which should be lighter than my current ones anyway so with those and some lightweight pedals, should off-set any extra/ be at least comparable with the vectors + i'll have upgraded cranks and pedals - and still cheaper.
Neil H's picture
Neil H
My P2M should be arriving with me on Monday, ready for 5 days in the Majorcan mountains... will let you know how I get on with it
Tony_LaMoury's picture
Tony_LaMoury
Not jealous at all! Have a good time!
dang's picture
dang
good choice on the power2max! I have 2 of the rotor 3d+ versions and they perform very well
Neil H's picture
Neil H
Massive thumbs up for the P2M Type S. Is much, much cleaner than the 2nd Gen P2M, and worked flawlessy out in the mountains (which included some big shifts in temperature). Was also great to have a pacing tool for the final day race up the Puig Major!

And back to the weight issue... we weighed some bikes out there and Phil Kitto's Canyon came in at 6.05kg, but 8.35kg with 2 water bottles. So kind of puts the 50-100g argument into perspective!
Martin_Brown's picture
Martin_Brown
Yes the weight conundrum, have gone from the 7.25KG dry weight Look to my 16KG wet weight (2x750mm bottles) commuting bike. It is about the bike....
Dave Truman's picture
Dave Truman
A question for you power users.. My FTP measured on turbo 2 months ago was 200w (not great, but that's what it was). This week I did a 20min climb in Mallorca. The result is a new FTP of 238w according to Strava. So the question is what to use on the turbo as FTP? Do I now have two FTPs or do I just have to work a lot harder on the turbo?
Dave
Neil_Colvin
Stick with 200w on the turbo. It's common to find power is lower on the turbo although your difference does seem quite high Dave. One reason could be that your turbo training is indoors and heat can't be dissipated adequately. Have you got a decent fan? Different muscles groups are used as well which could also help explain. Maybe you find it easier to push yourself harder on the road than on the turbo.
You may find this interesting - http://alex-cycle.blogspot.co.uk/2009/01/turbocharged-training.html
As a non power user I can't comment on my own performance though.
Neil H's picture
Neil H
Agree with everything that Neil said. Another thing is to make sure that you are calculating FTP in exactly the same way for both. Coggan & Allen use 20 minute power (CP20) * 0.95, but Strava may have it's own calculation for FTP.
How did you measure your FTP on the turbo? It could be that you need to do another 20 minute test on the turbo as your power could have gone up.

For what it's worth, I reckon I lose about 5% on the turbo compared to on the road, and I have a decent fan. So I take 5% off my target power for intervals if I'm doing them indoors.
Dave Truman's picture
Dave Truman
Thanks both Neil's that makes sense. I calculated FTP as 20min max average power * .95 on the turbo. If I do the same for the number from the climb it is very close to what Strava says. I probably should do the test again on the turbo, although I can't say I would look forward to that. I have NO fan, which could explain a lot.
It seems like I am going to end up with 3 FTPs - turbo, flat road and hill. Also I now see why my ironman pacing strategy was so far off last year - I used the turbo FTP which was too low.
There's a lot to this power stuff isn't there?
Dave
Tony_LaMoury's picture
Tony_LaMoury
Ah - very interesting the last few posts that I have only just seen. I have never measured my power on the road as my powertap wheel stays on the turbo with a non road tyre on it but, reading this, I may try out of interest. What is really startling (and as a prolific sweater - I am talking being literally drenched after a turbo) is the cooling effect from a decent fan - Like Dave I don't use one, just rely on being half dressed in the garage. Better research fans of wind tunnel proportions as,perhaps there is a few more watts to be had!!
Neil_Colvin
When you are passing through the air on the road you create your own cooling effect. A fan I'm sure would help and also keep the sweat from dripping in your eyes. Ideally we could do with some fans at the hall on a Thursday. Maybe something to ask the committee for next season.
Neil H's picture
Neil H
I have a decent 80w fan, but will be upgrading to something like this in preparation for the summer... (I reckon floor fan is better when in TT position as it blows air up into the body)
http://www.bodyshop-tools-supplies.co.uk/product_view.php?id=8033&gclid=COOu1IfLxr0CFSkewwod_5MA9g
Jon_Hollidge's picture
Jon_Hollidge
Take a look at a drum fan. It blows the air forward with out any loss. I use a 48in drum fan and have zero complaints.
Jon_Hollidge's picture
Jon_Hollidge
Take a look at a drum fan. It blows the air forward with out any loss. I use a 48in drum fan and have zero complaints.
Jon_Hollidge's picture
Jon_Hollidge
Take a look at a drum fan. It blows the air forward with out any loss. I use a 48in drum fan and have zero complaints.
Neil_Colvin
Thanks for info Neil and Jon. For use in the hall for group sessions of 10 - 15 people would one suffice or would we need a couple do you think? The hall is approx 8m x 15m. We don't carry on during the summer but it does get hot in there especially during April.
Neil H's picture
Neil H
Christ! I'm surprised you can hold onto the bike with that blowing at you Jon!

Neil, I don't know the layout of the room but you would definitely need more than one fan. The fan is more required for blowing air directly at the rider to cool them down, rather than to cool the room down. Reckon 3 at the front in a kind of semi-circle would work. Depends what fans you go for though - my current one has to be right in my face, but John's one would probably do the whole room!
Dave Truman's picture
Dave Truman
Did I read that right? 48ins fan? That's 4 feet across! Jasus!
Neil. Lots of fans = lots of noise. May not be the best. It's bad enough with all the turbos thundering away.
Corporal Mortleman has my Powertap for tonight's turbo session. Please keep an eye on him and make sure he doesn't smash it with those outsize pistons he calls legs!!
Dave
Jon_Hollidge's picture
Jon_Hollidge
My mistake... Had a grey moment. 24 inch
Neil_Colvin
Your powertap was still intact at the end of the evening Dave despite the Corporal putting it under considerable more pressure than it's used to :-)