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I guess this would be a buyer beware. I forked over a considerable amount of money to get the power tap several months ago, and have had a miserable experience with the product. Much to my dismay, my experience seems to be the norm for the product--constant instability, awful customer service and overall discontent. Here is the summary: 6 rides, dead battery. 4 more rides, calibration requirements. 2 more rides, calibrations no longer sufficient--wheel sent back to Graber (they own Power Tap). Two weeks later..still no word, "it's not our policy to notify the senders when the wheel arrives nor when it is delivered." Nice. Fortunately for me, I'm in tight with a bike shop and they gave me a brand new wheel to use in the interim. This wheel is experiencing the same problems after 7 rides...

Not that anyone out there asked, but I would absolutely NOT buy this product especially from this company. Go to roadbikereview's heart rate monitor section and read from another user--same story.
 

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Back in '98, I got sick of HR training and wanted a powermeter. The Powertap had just appeared at Interbike and I thought it was an elegant and affordable alternative to the SRM. But I couldn't wait a few more months so I bought an SRM. I also thought that since they'd been around for several years and their stuff is used by lots of pros logging thousands of training miles, it was a mature product. Since then I've had to change the battery twice at $9 a pop. I'm glad my impatience and willingness to rack up credit card debt lead me to the SRM.

I thought the PT Pro was significantly improved but I guess people's experiences aren't universal.

The PowerTap tech support forum:

http://www.topica.com/lists/wattage/read
 

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I seem to only get around 250-275 miles on mine before the HR function starts to drop out and the head unit battery dies. So the battery thing is common, even with older non-pro units like mine, but the hub going out is really lame.

I've gotten consistent reading with mine from day one and it now has around 2k on it. Again mine is the standard powertap not a pro. I had heard of a number of problems/issues with the pro before I bought mine and that's why I stayed away from it.
If you've got the bucks, an SRM or Ergomo is probably the way to go although both have their own set of issues.

Good luck
 

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Cat 1 said:
I guess this would be a buyer beware. I forked over a considerable amount of money to get the power tap several months ago, and have had a miserable experience with the product. Much to my dismay, my experience seems to be the norm for the product--constant instability, awful customer service and overall discontent. Here is the summary: 6 rides, dead battery. 4 more rides, calibration requirements. 2 more rides, calibrations no longer sufficient--wheel sent back to Graber (they own Power Tap). Two weeks later..still no word, "it's not our policy to notify the senders when the wheel arrives nor when it is delivered." Nice. Fortunately for me, I'm in tight with a bike shop and they gave me a brand new wheel to use in the interim. This wheel is experiencing the same problems after 7 rides...

Not that anyone out there asked, but I would absolutely NOT buy this product especially from this company. Go to roadbikereview's heart rate monitor section and read from another user--same story.
My experience could not be more different. I've had Power Taps since the first Tune prototype units and while there were some problems early on, I've had nothing but good experiences with the Pro. Battery life is long enough that I when I do have to replace a CPU battery, I've forgotten how long it's been in there. Customer service has also been excellent. They've answered questions readily, and when I've had problems, have been very willing to work out solutions. On two occasions, they've sent replacement units immediately and only asked I return the defective ones after the replacements had arrived.

You say you have to do frequent calibration. I'm not sure what you mean by this. Are you talking about resetting the zero for torque? The zero may fluctuate with sudden changes in temperature but resetting the zero is no big deal requiring only a few button pushes.
 

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I second that

I just picked one up a couple of months ago, and it has been good to me so far. I purchased mine on the recommendation of a friend who has run one on both road and mountain bike for a couple of years.

After a few hundred miles, I have not had any battery troubles, and a few instances of dropping the heart rate under high tension power lines. I talk to one of the guys at graber regularly, and they are always looking for input.

Would you rather be riding an SRM that has to be sent back everytime the strain gauges go out of calibration? The ability to zero the unit on the fly is one of the selling points for the unit.

And I am riding with a used one.
 

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The strain gauges don't go out of calibration. The slope sometimes changes as it settles from the factory setting. That predominantly affects cranks made at a certain period when they switched epoxies or something. I've had mine since '98 and the new slope is 99.2% of the factory slope.

In all that time, the cranks have never been sent anywhere for service nor have they had a single data dropout. If you read the wattage mailing list, using a PT sounds like a nightmare though some people get lucky. There isn't a day that goes by where there isn't someone asking for help with their PT. There was one person who kept having interference when riding on a trainer. One suggestion was a Faraday cage or something to that effect. I don't know about you but building a Faraday cage to ride in is a little more trouble than I'm willing to go through.

You can calibrate SRMs yourself using known weights. I get slopes that are only a fraction of a percent different. It's very repeatable. In addition to calibration, you can also "zero it on the fly."

Dr. Coggan, who's something of a power training pioneer, started with a PowerTap and then got an SRM Pro. I also know of someone who was sponsored by PowerTap but was so frustrated by it that he sold it and bought an SRM.
 

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Squint said:
The strain gauges don't go out of calibration. The slope sometimes changes as it settles from the factory setting. That predominantly affects cranks made at a certain period when they switched epoxies or something. I've had mine since '98 and the new slope is 99.2% of the factory slope.

In all that time, the cranks have never been sent anywhere for service nor have they had a single data dropout. If you read the wattage mailing list, using a PT sounds like a nightmare though some people get lucky. There isn't a day that goes by where there isn't someone asking for help with their PT. There was one person who kept having interference when riding on a trainer. One suggestion was a Faraday cage or something to that effect. I don't know about you but building a Faraday cage to ride in is a little more trouble than I'm willing to go through.
.

I think saying thepower tap is a nightmare is a gross exageration. First, the nature of the list is such that people will post with their problems to get help but not their satisfactionwhen things are working. If you look through the archives there were long discussions on the epoxy curing problems with the SRM amateur model. This didn't just change the slope over time, but caused the signal to be non-linear with power, something which could not be corrected with calibration. Second, the Faraday cage was a joke; a simple solution was just to move the trainer.

Given the much larger number or power taps in service, it's not surprising more people have problems, more people have trouble free systems as well. I know five users here who've never had any significant trouble. I think the consensus is that the SRM is probably a better system at a higher price. The power-tap is a much less expensive alternative though with some relative shortcomings.
 

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I think the original poster's experience was a nightmare and he's not the only one. I compiled a list of PT/SRM problems for just this month. I counted each experience with each device only once but made note if they were dealing with more than one of the same device. I also differentiated between new problems (which reflect the likelihood something bad will happen to your PT) and people who had similar problems in the past (to get an idea of how unique the problem is).

Dr. Coggan has said that factory slopes differ from the slopes users later derive because the factory either does it differently or it changes. BUT, the slope determined after the factory doesn't change. The amateur model might not be as linear as the pro model but I don't think it's a big problem. When calibrating one, I halved the amount of weight used and got a slope that was 99.97% of the previous slope. The PT probably is somewhat more accurate and more linear but that has little impact on real-world use whereas its serious problems do.

Statistics is a poor excuse for a product that has not fully matured. PT's outnumber SRMs but only by 2.25:1. Also, SRMs have been around much longer than PTs so that they may actually have more total hours of usage. Don't forget the thousands of pros out there who train on SRMs all the time. Look at how many Australians use SRMs, not just for training either.

Ergomo 10.00% (24)
PowerTap 16.67% (40)
PowerTap Pro 26.67% (64)
Polar 27.50% (66)
SRM Amatuer 6.67% (16)
SRM Pro 12.50% (30)

http://www.bicyclewattage.com/modules.php?name=Surveys&op=results&pollID=2&mode=&order=0&thold=0

Here is a compilation of SRM/PT problems posted this month. Each reported problem was counted only once and categorized as either a present problem or a past one. Note that there were no crippling SRM problems in this period.

2/05 PT torque stuck on one value, possible water intrusion (present)
2/08 SRM calibration (2) - new slopes differ from factory (present)
2/09 SRM calibration (past)
2/09 SRM calibration rehashed (factory slope wrong but new slope never changes) (past)
2/15 PT display going blank/not downloading all data (present)
2/15 PT mounting bracket contacts loosening (past)
2/15 PT mounting bracket contacts loosening (present)
2/15 PT no data from hub after ride in humid weather (present)
2/15 PT mounting bracket contacts loosening (past)
2/15 PT bearings need replacing (present)
2/16 PT computers (2) working erratically (present)
2/17 PT with unusually high numbers, possible water intrusion/rebuild (present)
2/18 PT losing time, may need rebuild (present)
2/18 PT timer counting erratically (present)
2/18 PT losing time, $120 rebuild (past)
2/18 PT losing time again (present)
2/18 PT dropouts requiring rebuild of hub by Graber (past)
2/18 PT dropouts due to interference (present)
2/18 PT dropouts due to interference (present)
2/21 PT with unusually high numbers, may need servicing (present)
2/21 PT with unusually high numbers, sent to Graber for servicing (present)
2/22 power and torque stuck at zero, possible moisture intrusion (present)
2/23 PT user reports similar problems (past)
2/23 PT damaged when trying to change battery (past)
2/24 SRM download problem (present)
2/24 SRM download problem due to cable (past)
2/25 PT not downloading all data (present)
2/25 PT not downloading all data (past)
2/26 Computertrainer interferes with PT (present)
2/26 PT download problems due to loose wire (past)
 

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Squint said:
The amateur model might not be as linear as the pro model but I don't think it's a big problem. When calibrating one, I halved the amount of weight used and got a slope that was 99.97% of the previous slope. The PT probably is somewhat more accurate and more linear but that has little impact on real-world use whereas its serious problems do.
I'm not disputing the good performance you're getting from your SRM, but several people have had problems with the amateur model. You might want to check out
http://www.topica.com/lists/wattage/read/message.html?mid=907845085

and especially the data plotted at: http://www.acara.co.uk/srmcalibrations.xls
 
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