Power2max - which crank?
GGBiker
Posts: 450
Close to buying a power meter, deciding between powertap rear wheel and a power2max crank based system.
Thought the powertap was an obvious choice given that I want to change it between 2 bikes fairly regularly and this would be easiest way to achieve this. Only downside is the weight 1150g for the powertap pro rear wheel (which I believe has a DT swiss 465 rim and dt swiss competition spokes, 32 hole).
I want to use it for training, racing and short TTs (max 10miles).
The alternative suggested by a poster here previously was the power2max crank based system.
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Obviously I would need to change this between bikes so my question is which of their cranks would make this easiest? I have campagnolo Centaur on both bikes so the crank needs to be compatible with this. One of the bikes has a FSA gossamer crankset so I could use the chainrings and non drive crank (it's supplied without these I think).
Is the fsa gossamer a doddle to switch between bikes or would one of their other options be easier (eg rotor 3d)?
Would want something very easy to switch so that I actually use it!
Thought the powertap was an obvious choice given that I want to change it between 2 bikes fairly regularly and this would be easiest way to achieve this. Only downside is the weight 1150g for the powertap pro rear wheel (which I believe has a DT swiss 465 rim and dt swiss competition spokes, 32 hole).
I want to use it for training, racing and short TTs (max 10miles).
The alternative suggested by a poster here previously was the power2max crank based system.
On
Obviously I would need to change this between bikes so my question is which of their cranks would make this easiest? I have campagnolo Centaur on both bikes so the crank needs to be compatible with this. One of the bikes has a FSA gossamer crankset so I could use the chainrings and non drive crank (it's supplied without these I think).
Is the fsa gossamer a doddle to switch between bikes or would one of their other options be easier (eg rotor 3d)?
Would want something very easy to switch so that I actually use it!
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I've ordered a power2max and don't remember seeing a campag version on the site. I chose the crank system as I wanted to easily swap between bikes (all run SRAM) and this seemed the easiest way whilst allowing any wheels to be used.
If you order with the cranks it will include both arms but no chainrings. My suggestion would be to buy with cranks and then convert the bottom brackets on the bikes it'll be used with so you can swap them. Rotor 3D uses a standard Shimano external BB so you can choose from a few manufacturers. If you have an FSA already this may be an option although it's Shimano standard BB as well, at least you have a compatible BB and would only need to buy one more for the second bike.0 -
Cycleops emailed me April 2012 to say they use Velocity A23 rims.0
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It could be a hub, built up to a wheel by the PT seller.FatTed wrote:Cycleops emailed me April 2012 to say they use Velocity A23 rims.
Bob Tobin at Cyclepowermeters sold me a 28H track PT already built onto a DT565? Rim. I would have preferred the hub on its own & had it built into a wheel by Derek @ Wheelsmith, but it was his last one @ £600, it was too good an offer to pass up. Derek told me It is not the best rim, heavy & not that stiff, & I'll change it sometime, but it works just now.0 -
I started out with a PT. It was fine for training but made the bike feel very unresponsive when putting the hammer down. For me no good for racing though I see many at the start line so they must be okay for them. I then went with a quarq cinqo on a rotor 3D which was very good and easy to swap over. That was until it stopped working however within 5 days I had received replacement, a brand new Quarq Elsa which so far seems really good, pretty light and stiff. In winter I bought a Power2max and put it on a 3D+ crank. I was very disappointed with the huge drift in numbers. It was so bad I had absolutely no faith in the numbers it was putting out. I would start out doing 200w and within 30mins it was saying 120w for the same speed. Also 3D+ crank is a little more finicky than the 3D cranks due the extractor method of removal but no biggy. After returning a couple of times (expensive) I got rid. I'm sure many owners have got on with them but for me they're cheap for a reason and lots of comments out their about drift.
Personally I would put in an order for the Rotor power cranks. It wil work out a little motte expensive but while you are waiting (on back order) you can save the difference.
Might be worth discussing your needs with Bob at Cyclepowermeters. Very helpful.0 -
Errr... The P2M drift issues have been sorted with the latest software revision. I also have no issue with the 3D+ cranks as it takes me two minutes to swap my PM between bikes.English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg0
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Powertap ordered, thinking about bottom bracket experience in the past they are an item that should be left alone unless strictly necessary to mess about with them. The power2max just seems a bit too new to the market to be reliable, powertap has an established rep and the overall wheelset weight I will have at 1750g is reasonable for the training and club racing I do.
Thanks for everyone's input.0 -
GGBiker wrote:Powertap ordered, thinking about bottom bracket experience in the past they are an item that should be left alone unless strictly necessary to mess about with them. The power2max just seems a bit too new to the market to be reliable, powertap has an established rep and the overall wheelset weight I will have at 1750g is reasonable for the training and club racing I do.
Thanks for everyone's input.
I'm sure you'll be happy with the PowerTap until the torque tube fails and Paligap want £425 to fix it.
FWIW I've had a P2M since Sept 2012 and after a couple if initial software bugs (that P2M fixed straight away) it's been superb. Mine is the SRAM S900 version and I swap it around on an almost weekly basis. It takes a couple of minutes and I really can't see how this would cause issues with the bottom bracket (and even if it did mean replacing the bb more often, they only cost about £20).
So if you can live with one wheel for all your riding then I'm sure you'll be happy with the PowerTap, but I've owned both a PowerTap and P2M and I'd much rather have a P2M.More problems but still living....0 -
Grill wrote:Errr... The P2M drift issues have been sorted with the latest software revision. I also have no issue with the 3D+ cranks as it takes me two minutes to swap my PM between bikes.
Errr...well it wasn't sorted on mine which was the latest version with the software update. And if you look into the first edition, it seems not everyone had drift issues then too. Clearly I'm not speaking for all users but just sharing my experience. I also gave the product a good 2-3 months of heavy use...it wasn't an assumption from a couple of rides. I hope it is now sorted as the more PM suppliers the better.
'a little more finicky' were the words I used. No mention of an issue with extracting the crank. 3D+ = 2 mins v 3D = 1min
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Which P2M crank for 11 speed Campagnolo and English Bottom Bracket?
the SRM is crazy expensive!0 -
edten wrote:Grill wrote:Errr... The P2M drift issues have been sorted with the latest software revision. I also have no issue with the 3D+ cranks as it takes me two minutes to swap my PM between bikes.
Errr...well it wasn't sorted on mine which was the latest version with the software update. And if you look into the first edition, it seems not everyone had drift issues then too. Clearly I'm not speaking for all users but just sharing my experience. I also gave the product a good 2-3 months of heavy use...it wasn't an assumption from a couple of rides. I hope it is now sorted as the more PM suppliers the better.
'a little more finicky' were the words I used. No mention of an issue with extracting the crank. 3D+ = 2 mins v 3D = 1min
Sounds like you're just unlucky. There isn't a single PM on the market (SRM included) that always works for everyone.English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg0 -
edten wrote:Errr...well it wasn't sorted on mine which was the latest version with the software update. And if you look into the first edition, it seems not everyone had drift issues then too. Clearly I'm not speaking for all users but just sharing my experience. I also gave the product a good 2-3 months of heavy use...it wasn't an assumption from a couple of rides. I hope it is now sorted as the more PM suppliers the better.
How have you established that there's significant drift that leads to a noticeable error in the power readings? The ZO will always change with temperature, but if yours is working properly the ZO will be modified by the auto-zero algorithm as temperature changes. Unfortunately you can only check the ZO by doing a manual zero so you don't really know what the auto-zero is doing. This is obviously not unique to the P2M, but the same for any power meter with an auto zero function (e.g. PowerTap). It would be great if the P2M and other power meters would start sending the ZO value via ANT+ as an extra data field so you could check the value on your head unit. As it is you have little idea of how well the auto-zero works unless there are huge temperature changes that lead to errors in the power readings of tens of Watts.
If you're convinced there's an issue with your P2M then I'd send it back to Germany for investigation.More problems but still living....0 -
Having been an owner of a powertap, 2x quarqs I had never experienced the same amount of drift regardless of change of temp. The Powertap was the most stable out of all, just a shame it is in a wheel! Establishing the drift on the P2M was quite easy, speed kept very constant throughout the whole ride on rollers or turbo. Yes clearly a change in temperature as the room warmed up (even the oil in the trainer) but as I noticed the drift I kept stopping and re-calibrating but the power still drifting, I'm not talking 10w here but more like 50+ and also noticeable that riding on feel metrics were dropping. A re-calibrate would result in it raising again but then it would gradually get less and less over the next 20-30mins until I re-calibrated even when the temp in the room had stabilised. Regardless of the temperature the P2M as I understand it measures the temp and adjusts, maybe something amiss with the adjustment. A Quarq Cinqo did not replicate the drift used in the same kind of temps / time of day.0
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Sounds like you maybe got a bad P2M. If mine was like that I'd send it back and insist on a replacement.
How many points was the ZO value changing by each time you recalibrated? Mine sits at around -880 in the house and drops to a low of around -865 when it's sub-zero outside. It always settles after about 15-20min after going from cold-hot or hot-cold. I was obsessive about doing manual ZO when I first got it and I'd stop several times, but after finding it always settled after about 15mins, I generally only do a manual ZO at the start of a ride and occasionally 20min or so in.More problems but still living....0 -
Hmm, I'm not sure. I did use to check but I can't remember. Yes probably a bad'n. Very happy with my new Quarq Elsa though which was a warranty replacement for a Cinqo...but that's another story altogether!0
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I've recently swapped from Powertap(s) to Power2max. So far it's been really impressive. Reliable and hassle free, numbers look perfect. I wish BikeRadar would update their review.
Running Campag 11 and Rotor 3D+ with normal round chainrings. Shifting is excellent. Removing the Rotor 3D+ involves removing the crank bolt and then reversing the outer bolt which acts a self extracting tool to remove the non-drive side crank. Pretty easy once you get the hang of it. Any crank based system is a bit of a faff to swap but I guess if it's a couple of times a year then it's not too bad.0 -
do you know what diameter crank spindle your campag runs? i thought it was 25mm where as the rotor3d+ is shimano sized 24mm.magliaceleste wrote:I've recently swapped from Powertap(s) to Power2max. So far it's been really impressive. Reliable and hassle free, numbers look perfect. I wish BikeRadar would update their review.
Running Campag 11 and Rotor 3D+ with normal round chainrings. Shifting is excellent. Removing the Rotor 3D+ involves removing the crank bolt and then reversing the outer bolt which acts a self extracting tool to remove the non-drive side crank. Pretty easy once you get the hang of it. Any crank based system is a bit of a faff to swap but I guess if it's a couple of times a year then it's not too bad.
i have a problem where my shimano bikes - road is running a fulcrum chainset (same as campag ultratorque 25mm) and my TT is FSA running 24mm.
ideally i`d like to keep the fulcrum chainset and put the same BB on the TT, but P2M dont do a campag setup.
cheers
beni need more bikes0 -
No idea, it was a Super Record Ultra Torque. The Rotor 3D+ has a 30mm spindle (It's a BB30). I've also changed the cups to the BSA30 outboard cups also made by Rotor. Basically enables you to run BB30 chainsets on a normal BSA threaded bike.
The reason Power2Max don't do a Campagnolo chainset is that Campag's don't have removable spiders like the Rotor. The Power2max replaces the Rotor spider.
Cheers0 -
magic... more reasearch to be done.
didnt know you could run bb30 on bsa68
maybe i need 2 new chainsets...i need more bikes0
