What Power Meter do you use?



daveryanwyoming

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Oct 3, 2006
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Thom_y said:
..... Yet, the early experience of a few with their PT SL 2.4 on this forum is making me hesitant to take the plunge just yet. ....
I don't quite understand the fascination with the PT 2.4. Yeah wireless makes a cleaner bike but a well installed wiring harness isn't that big a deal. That and the 2.4GHz wireless transmitter has to drain hub batteries faster than the current SL or Pro models. I picked up from one of RDOs posts that they've gone to a coded HR strap and new HR receiver electronics with the 2.4 model, that's a nice upgrade but I still can't figure out why everybody's so excited about the new model. The PT SL is very reliable, very light and the wiring harness is pretty darn clean especially if you forego the crank sensor for cadence. The sharkfin wiring harness installs in minutes with a very clean line.

I've picked up PT SL race wheels, training/backup wheels and even a track wheel complete with the Surly fixed gear adapter from riders who just had to have the wireless version. All in all I've saved a couple of thousand dollars and outfitted several bikes with the wired models because folks just needed the wireless version. I don't get it. Heck, I'm not complaining but for those folks sitting on the fence over getting a PM why wait for the bugs to get worked out of the SL 2.4 when you can save some cash get a great and field tested SL or Pro version today? Is a clean and simple wiring harness that big a deal?

On another note, I used the Ergomo Pro PM for about four months and loved it. I'd still be using it if I hadn't scored these incredible deals on PT SLs. I couldn't pass up the chance to outfit my track and road bikes with PMs and couldn't afford Ergomos for all my bikes. But I did get a chance to ride my Ergomo Pro and PT SL side by side for a week or so. They both tracked each other very nicely with the Ergomo reading 10 to 15 watts higher most of the time which makes sense as its an "upstream" PM. The Ergomo real time display and interval functions blow the PT out of the water with real time and AP displayed simultaneously. Real time NP, IF and TSS display and interval on and off switching instead of just the interval on markers you get with the PT. The biggest downside of the Ergomo is the difficulty validating the power readings but you can at least calibrate it if you have access to a known accurate PM whereas you can only check the accuracy of the PT, you can't correct errors if you find them. Anyway, I don't see why you'd be interested in a polar which relies on things like accurate chain weight and vibration modes for accuracy and discount an Ergomo that has signifigantly less black magic in its power measurements. Yeah I know the difficultly validating power readings is a downside, but how do you validate the accuracy of a Polar unit?
 

peterpen

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Jul 29, 2003
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daveryanwyoming said:
I don't quite understand the fascination with the PT 2.4. Yeah wireless makes a cleaner bike but a well installed wiring harness isn't that big a deal. ...

One of the chief problems with the PT system has been the harness + wiring, both of which are notoriously flimsy. Eliminate that, and you eliminate 50% of problems with PTs.
 

daveryanwyoming

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Oct 3, 2006
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peterpen said:
One of the chief problems with the PT system has been the harness + wiring, both of which are notoriously flimsy. Eliminate that, and you eliminate 50% of problems with PTs.
Tell that to the early SL 2.4 adopters who've sent their brand new wireless unit back for repair :)

P.S. I've been a design engineer in the wireless telecom industry for over 20 years. I've yet to see a wireless system yield higher reliability than a similar wired system. MTBF goes down, not up when you add components and complexity. If a company has trouble designing a reliable wired harness I have trouble believing they'll develop a more reliable wireless system.
 

Thom_y

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Aug 16, 2006
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daveryanwyoming said:
Tell that to the early SL 2.4 adopters who've sent their brand new wireless unit back for repair :)

P.S. I've been a design engineer in the wireless telecom industry for over 20 years. I've yet to see a wireless system yield higher reliability than a similar wired system.


Check out this webpage: road magazine blog re: SL 2.4 hub

comparing the 2.4 to the non-wireless they say:

The hub contains a 2.4 hertz antenna that transmits the watts data in packages with only a 1% loss of information. This is in comparison to 3% data loss of the wired PowerTap. The reason for this improvement is the use of an ANT microprocessor.

TOO BAD, not all of the bugs have been eliminated !!
 

Thom_y

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Aug 16, 2006
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Also on the same Road Magazine blog mentions a new hub -- the SLX:

"The wireless PowerTap that Landis rode during the Tour was an upgraded version of the wireless model currently available. Dubbed the SLX, the hub used ceramic bearings, a carbon fiber axle, and a carbon fiber cap, which saved a total of 40 grams. This type of technology usually trickles down pretty quickly, so you probably won’t have to wait too long to purchase your own SXL model. Bartholomew did tell me that owners of the current PowerTap would be able to send in their hubs for that upgrade when it becomes available."
 

Steve_B

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Dec 31, 2006
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Thom_y said:
Check out this webpage: road magazine blog re: SL 2.4 hub

comparing the 2.4 to the non-wireless they say:

The hub contains a 2.4 hertz antenna that transmits the watts data in packages with only a 1% loss of information. This is in comparison to 3% data loss of the wired PowerTap. The reason for this improvement is the use of an ANT microprocessor.

TOO BAD, not all of the bugs have been eliminated !!
That's probably "packets" (of data) not "packages", and it's 2.4 GigaHertz, not Hertz. (Giga is 1,000,000,000.) It's same frequncy band used for many portable devices, such a cordless telephones. It's also close to the frequency of microwave ovens.

I question the veracity of the quoted statement above because I can't imagine where I'm losing 3% of my data on my wired systems. I don't lose 108 one-second samples in one hour (3600 seconds) of riding. They are overstating things a bit.
 

daveryanwyoming

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Thom_y said:
...The hub contains a 2.4 hertz antenna that transmits the watts data in packages with only a 1% loss of information. This is in comparison to 3% data loss of the wired PowerTap. The reason for this improvement is the use of an ANT microprocessor...TOO BAD, not all of the bugs have been eliminated !!
Be careful when it comes to marketing hype. Time will tell whether the SL 2.4 is more or less reliable than the existng SL model. There's also hardware reliability problems such as the first generation wiring harness trouble with PT units and some of the early 2.4 failures versus communication link reliability in the field. As Stev_B mentions the 2.4 GHz ISM band is an unlicensed band filled with cordless phones, 802.11b/g wireless LAN equipment and other consumer devices. How well the SL 2.4 link holds up to that interference environment remains to be seen. I've used a number of wireless cycling computers and HR monitors over the years and even the coded versions tend to drop out predictably in certain places such as near power substations. A good spread spectrum radio can reject a certain amount of interference but not all.

In fairness the existing PT units like the Pro and SL already have a wirless link to the sharkfin sensor so it's not really fair to use the analogy of fully wired systems to wireless systems. Maybe they've really nailed the design and the SL 2.4 will blow away the existing units, but I'd give it some field time before I jumped to the conclusion that reliability will skyrocket.

Thom_y said:
..."The wireless PowerTap that Landis rode during the Tour was an upgraded version of the wireless model currently available. Dubbed the SLX, the hub used ceramic bearings, a carbon fiber axle, and a carbon fiber cap, which saved a total of 40 grams. This type of technology usually trickles down pretty quickly, so you probably won’t have to wait too long to purchase your own SXL model. Bartholomew did tell me that owners of the current PowerTap would be able to send in their hubs for that upgrade when it becomes available."
Now that's more interesting and more to the point of my original question: Why are folks so focused on the SL 2.4 system with potential early bugs when the existing SL system is available, less expensive and has gone through it's teething pains? Still this SXL technology isn't currently available, may or may not be offered as an upgrade to all PT units and saves a whopping ounce and a half although the bearings sound better.
 

Steve_B

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daveryanwyoming said:
As Stev_B mentions the 2.4 GHz ISM band is an unlicensed band filled with cordless phones, 802.11b/g wireless LAN equipment and other consumer devices. How well the SL 2.4 link holds up to that interference environment remains to be seen.
I totally agree. WiFi is small stuff. Wait until WiMAX rolls out more in the coming years in the same band. (Think: WiFi/Wireless internet but with up to 30 km range.) There are two more bands slated for that service but the first roll out in North America will be in the same band as the PT SL 2.4.

I'm not going to be an early adopter of the PT 2.4.
 

JTE83

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Jan 28, 2004
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Steve_B said:
I totally agree. WiFi is small stuff. Wait until WiMAX rolls out more in the coming years in the same band. (Think: WiFi/Wireless internet but with up to 30 km range.) There are two more bands slated for that service but the first roll out in North America will be in the same band as the PT SL 2.4.

I'm not going to be an early adopter of the PT 2.4.

If this is true then the PT SL 2.4 will really be messed up by interference.

I validated my Polar watt data with theoretical computed speed at it turned out ok. This for instantaneous constant speed and watts.

Besides PT does not have altitude.
 

Steve_B

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JTE83 said:
If this is true then the PT SL 2.4 will really be messed up by interference.
Oh, it's true that WiMAX is coming (I'm working on stuff for it). Whether it produces gross intererence with the PT 2.4 remains to be seen. We won't know for a while yet.

In a dense urban environment such as my neighborhood, where I can get usable wireless signals on my laptop from as many as six routers today while sitting in my living room, there's potential for problems.
 

cuocciom

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Jan 13, 2006
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Thom_y said:
I don't have a PM yet ... I want one based on my research to date, but this forum is making selection confusing.

SRM is more than I want to spend, leaving me to consider PT SL (preferably 2.4 wireless) or possibly the new Polar CS600. Won't consider erogmo now and iBike doesn't seem a viable alternative. Would love to hear more about the MicroSport Revolution, but suspect it is nothing more than vaporware for a while.

I realize that there is an inherent bias that problems are more likely to show up on forums like this, while happy customers are probably too busy riding to post anything positive about their device. Yet, the early experience of a few with their PT SL 2.4 on this forum is making me hesitant to take the plunge just yet.

I am curious are people out there who are happier than pigs in **** with their new PT SL 2.4's ??

Whereas I would hate to spend > 1500$ to get a PT SL2.4 wheel and have it **** out a week later, I am anxious to hear reports about the Polar CS600 once it is available to see how it tracks against the PT, hear about reliability, ease of set up, problems, indoor use on trainer etc. Does the limited memory 2 hour 50 min (for HR, speed, cadence, power) with 1s sampling make it a nonstarter for some ? Is it likely to be any more reliable than iBike ?

Seems there is a real love-hate relationship with the original Polar device.
I bought a PowerTap Pro SL in December 2005. I used it all 2006, and I saw significant improvements in my race performances. Of course, I also paid for coaching for five months, so I can't claim that a tool made all the difference. Unfortunately, I spent a LOT of down time with the PowerTap. I now am on my fourth and fifth modules. Both of them (like the three before them) are malfunctioning: total loss of heart rate recording; "blackouts" of 5-15 seconds every minute or two; total loss of data recording; etc. I also had to ship the wheel/hub back to Saris for new seals after one ten minute rain storm. Saris has been very good about replacing defective parts, but I think they're getting sick of me. I'm not happy with the product quality. I don't abuse the equipment, and there is no reasonable explanation for the frequent failures. Oddly, I'm considering buying a 2.4 wireless model because I appreciate the training benefits and the clean installation, but only if Saris repairs or replaces one of the two defective modules I have now.
Mark Cuoccio
 

Ollli

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Dec 30, 2006
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Just got my CycleOps PowerTap SL for 930 Euros and i am very happy. After testing a Polar Power Meter with broken cables and a never ending setup i am very happy now. Although i had to sell my Tacx I-Magic to get the Powertap :-( but i think the spring is with me :)

All the Best, Oliver
 

Piotr

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Jan 29, 2007
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Well, I had my first experience with my new shining PT SL this weekend. Everything great so far. I opted not to install the cadence wire for now, but noticed something interesting about the hub cadence values. Namely, if you push on the pedals it reads OK, but as soon as you start pedaling smoothly in a more circular motion it overestimates the values. Perhaps this is already known to all, but just FYI, it became apparent to me that the hub cadence calculates based on power variances in the pedal stroke. IOW, if your pedal stroke is rather smooth you're better off installing the additional cadence unit.
 

betulla

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Mar 15, 2004
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acoggan said:
What's up with all the people responding "other not listed"? With the exception of the old LOOK MaxOne, all the rest are on the list.

What about the Computrainer?
 

WhitWyatt

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Mar 25, 2007
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I have used powertaps for years. First the SL, then the 2.4

On the Sl's I went through at least 4 computers, as all of them eventually lost the heartrate signal completely. (I think I missed the water problem era)

My neighbor went through 3 computers for various problems, and two hubs, on which he bent the axles (he is a biggish guy)

Then went to the 2.4 wireless, and right out of the box had 16 dropouts of heartrate in a one hour ride, you all know the story of course.

So now I am the proud new owner of a SRM pro, which was financed by the sale of a whole raft of powertap stuff.

I have to say, the powertap is a fairly good product, but plagued with reliability and quality control issues. (at least in my experience). I am tired of waiting for them to get it right.

After reading the 155 page SRM manual - several times - and getting it on the bike and adjusted correctly - and going out today for a quick 40 minute spin just to check it out, I have to say I am really impressed with it.

The number of parameters you can change is incredible, the display is much easier to read; the amount of thought that went into the design and execution of this product seem to be head and shoulders above the powertap equipment.

All I have to do now is ride it for a year or two and see how it holds up!

Whit
 

NORECUMYET

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Apr 28, 2007
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JTE83 said:
What Power Meter do you use? Vote on the poll!

Me - 4 Polar Power meters, next one might be an ergomo pro if the new Polar Power meter does not have enough 1 sec memory.

Sorry, I forgot to put SRM science in the poll!
I voted "Other" but I don't really think what I have is a power meter. I've got the Garmin Edge 305. It measures more types of data then I'll probably ever use but I don't know if I can take what it does record and use it correctly. I'm sure there's formulae that make it possible to convert calories used, distance, speed, %grade, feet climbed, cadence, etc., into watts but I wouldn't know what to do with it. I'm kind of a data junkie so any info people can help with would be appreciated.
I am brand new to road biking by the way.
 

vascdoc

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May 7, 2005
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NORECUMYET said:
I voted "Other" but I don't really think what I have is a power meter. I've got the Garmin Edge 305. It measures more types of data then I'll probably ever use but I don't know if I can take what it does record and use it correctly. I'm sure there's formulae that make it possible to convert calories used, distance, speed, %grade, feet climbed, cadence, etc., into watts but I wouldn't know what to do with it. I'm kind of a data junkie so any info people can help with would be appreciated.
I am brand new to road biking by the way.
The Edge 305 is not a PM. Regarding the data - for purposes of training, the only data useful on the Edge is HR. I think it is clear that PM are superior to HR for training purposes. For recreational riding, however, the Edge is a very nice unit. I own one and enjoy it. I have been thinking about a PM, but the price, and reliability factor complicate the matter. I am also a recreational rider with a "competitive" streak. Purchase of a PM just to collect one more piece of data that goes unused does not make sense. I have a computrainer and appreciate the use of power for training in the winter. My reliability for sticking to a training schedule conflicts with my unpredictable work schedule. Thus I sit on the side lines dreaming of a PM but realizing that it is icing on the cake. Reduction of calories and a trim figure is probably more important!
 

PaulMD

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Jul 26, 2006
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Since yesterday I have a Powertap SL 2.4 in combination with a zipp 404 wheelset :)

Today I am going to buy rimtape and I hope to test ride it tonight.