Powertap.. wired vs wireless

mloc123

I have had a look around for the cheapest source on a powertap. Best I have found is the old wired pro on ebay from the US. Full kit with head unit etc.. and comes in over £100 cheaper than an elite+ wireless. I have a garmin already so either of these would be an option.

Have the old wired models any disadvantages apart from being wired? I had read before that Garmin use 'smart' recording for power values but it is not all that smart.

Diarmuid

I've previously used a wired now a wireless. I'd imagine battery life is a bit shorter but that wouldn't be a deal breaker IMHO. They last ages as is. I think the cheapest wireless one is heavier than the wired one but you can check that. I prefer the wireless one for asthetics and flexibility.

tunney

Don't own a powertap but wires on PMs suck.

Lumen

I would rather go used than wired.

tunney

mloc123 wrote: »

Have the old wired models any disadvantages apart from being wired? I had read before that Garmin use 'smart' recording for power values but it is not all that smart.

Just noticedthis - Garmin use "smart" (read sh!te) recording for everything bar power. They got ripped apart and it became obvious that no one was going to use the units for power and had to change to per second. The way it should be for everything

mloc123

Hmmm, I'll think some more about it. It seems like a decent saving and the hub is slightly lighter than an elite+... I could live with having wires taped to my frame.

Ryaner

tunney wrote: »

Just noticedthis - Garmin use "smart" (read sh!te) recording for everything bar power. They got ripped apart and it became obvious that no one was going to use the units for power and had to change to per second. The way it should be for everything

You can see it to per second recording. In this mode everything gets written out every second. Spent enough time inside the tcx files to know this

tunney

Ryaner wrote: »

You can see it to per second recording. In this mode everything gets written out every second. Spent enough time inside the tcx files to know this

From 310xt on??? Would be very interested in this if true!!!

Lumen

tunney wrote: »

From 310xt on??? Would be very interested in this if true!!!

As I understand the TCX format (from my 705), you can't have smart for one thing and per second for another.

Short extract:

<Trackpoint><Time>2010-08-15T16:26:27Z</Time><Position><LatitudeDegrees>53.383085</LatitudeDegrees><LongitudeDegrees>-6.393650</LongitudeDegrees></Position><AltitudeMeters>70.232</AltitudeMeters><DistanceMeters>20961.961</DistanceMeters><HeartRateBpm><Value>135</Value></HeartRateBpm><Cadence>75</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>160</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:28Z</Time><Position><LatitudeDegrees>53.383071</LatitudeDegrees><LongitudeDegrees>-6.393748</LongitudeDegrees></Position><AltitudeMeters>70.220</AltitudeMeters><DistanceMeters>20968.721</DistanceMeters><HeartRateBpm><Value>135</Value></HeartRateBpm><Cadence>77</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>149</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:29Z</Time><Position><LatitudeDegrees>53.383058</LatitudeDegrees><LongitudeDegrees>-6.393849</LongitudeDegrees></Position><AltitudeMeters>70.258</AltitudeMeters><DistanceMeters>20975.639</DistanceMeters><HeartRateBpm><Value>135</Value></HeartRateBpm><Cadence>78</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>139</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:30Z</Time><Position><LatitudeDegrees>53.383046</LatitudeDegrees><LongitudeDegrees>-6.393948</LongitudeDegrees></Position><AltitudeMeters>70.297</AltitudeMeters><DistanceMeters>20982.420</DistanceMeters><HeartRateBpm><Value>134</Value></HeartRateBpm><Cadence>81</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>159</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:31Z</Time><Position><LatitudeDegrees>53.383034</LatitudeDegrees><LongitudeDegrees>-6.394045</LongitudeDegrees></Position><AltitudeMeters>70.319</AltitudeMeters><DistanceMeters>20988.916</DistanceMeters><HeartRateBpm><Value>134</Value></HeartRateBpm><Cadence>81</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>159</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:32Z</Time><Position><LatitudeDegrees>53.383022</LatitudeDegrees><LongitudeDegrees>-6.394144</LongitudeDegrees></Position><AltitudeMeters>70.396</AltitudeMeters><DistanceMeters>20995.648</DistanceMeters><HeartRateBpm><Value>134</Value></HeartRateBpm><Cadence>82</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>139</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:33Z</Time><Position><LatitudeDegrees>53.383010</LatitudeDegrees><LongitudeDegrees>-6.394244</LongitudeDegrees></Position><AltitudeMeters>70.444</AltitudeMeters><DistanceMeters>21002.391</DistanceMeters><HeartRateBpm><Value>134</Value></HeartRateBpm><Cadence>82</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>139</Watts></TPX></Extensions></Trackpoint>
<Trackpoint><Time>2010-08-15T16:26:34Z</Time><Position><LatitudeDegrees>53.382997</LatitudeDegrees><LongitudeDegrees>-6.394346</LongitudeDegrees></Position><AltitudeMeters>70.467</AltitudeMeters><DistanceMeters>21009.455</DistanceMeters><HeartRateBpm><Value>134</Value></HeartRateBpm><Cadence>83</Cadence><Extensions><TPX xmlns="http://www.garmin.com/xmlschemas/ActivityExtension/v2"><Watts>203</Watts></TPX></Extensions></Trackpoint>

tunney

Lumen wrote: »

As I understand the TCX format (from my 705), you can't have smart for one thing and per second for another.

Hence the "310xt on" comment. Since then its power per second, everything else smart. I'd love to be wrong on this one.

Lumen

tunney wrote: »

Hence the "310xt on" comment. Since then its power per second, everything else smart. I'd love to be wrong on this one.

You've lost me with the "since then" bit. 705 would include "since then", and the 705 does either everything per second, or everything smart. I can't see how the other devices would be different, unless the TCX format has changed substantially.

Where does your information come from?

edit: sorry, you mean the 305xt is newer?

tunney

Lumen wrote: »

You've lost me with the "since then" bit. 705 would include "since then", and the 705 does either everything per second, or everything smart. I can't see how the other devices would be different, unless the TCX format has changed substantially.

Where does your information come from?

edit: sorry, you mean the 305xt is newer?

Yes - was just off getting release dates. 310xt is two years newer than 705 and heralded the start of the "no turning off smart recording" era.

Lumen

tunney wrote: »

Yes - was just off getting release dates. 310xt is two years newer than 705 and heralded the start of the "no turning off smart recording" era.

Ah, OK. From what I understand (quick Google) the 310XT does per-second when recording power. I understand that it then does per-second for everything. So it's like the "per second recording" switch is enabled by the presence of a power meter.

Yes, it is stupid. However, I think that stupidity has been surpassed by switching to a binary file format in the Edge 500. :rolleyes:

mjth2004

Looking to start training with power, with a power meter now top of the shopping list!

Like mloc123 I think I could live with wires taped to my frame, the basic wired PowerTap Comp in from the states all in for about 650 notes! Or am I fooling myself & should hold out save some more cash & buy a wireless powertab?

Have a set of 404 tubs, should I have the hub built into these or into a training wheel? Does anyone now if there a problem using tubs on a turbo, I have searched online but didn’t come up with any real answers!

Plan for 2011 is a couple of HIM, then hopefully step up to IM in 2012! So if tubs on a turbo is a no-no & I get hub built into a training wheel should I look to sell 404 tubs, spend a little extra on a training wheel build so I can also use as a racing wheel then maybe down the line look at a disc cover for it?

Any advice much appreciated!

blorg

Turbos shred tyres as it is, you really want to use a dedicated turbo tyre which are designed to last on them. Changing a clincher is enough hassle that most people use a dedicated turbo wheel with the tyre already mounted. Changing a tub for each turbo session would not be practical.

Many turbos do power and some people have reported this to be quite accurate after they have calibrated it with another power meter- so that might be an option either. Might be problematic though that you would be using a different wheel and tyre to the one used for calibration.

If I could only have power in a training or race wheel I would go for training- but then I road race primarily rather than TT.

ryan_sherlock

In about 5 weeks I'll be selling my SRM Pro (Wireless) with DuraAce rings (cranks only, I use an Edge 705 or 500 with mine). It will be fresh back from a service from SRM in Germany. Price will be around 1,100.

Personally - I would go with the wireless PowerTap (I have had two, Mel, one).

mjth2004

@blorg – currently have a Tacx Flow that is meant to measure wattage, but on subsequent research when figures were never consistent it works out that it’s not a great tool for measuring power! I was thinking of changing the current tub tyre to a heavier tub tyre to sacrifice on the turbo over the winter, any outdoor spins will be done on a road bike!

@ryan_sherlock – food for thought, have only really been researching the PowerTap, so will now go & do some research on SRM!

ryan_sherlock

Crank based systems are nice in that they are independent of wheels. SRM is the 'gold standard' for power measurement.

The only negative I see is that you always have to carry around the extra weight (not that much though!) even if you don't want the PM there. But me, I would always like the power data...

tunney

blorg wrote: »

Turbos shred tyres as it is, you really want to use a dedicated turbo tyre which are designed to last on them. Changing a clincher is enough hassle that most people use a dedicated turbo wheel with the tyre already mounted. Changing a tub for each turbo session would not be practical.

Many turbos do power and some people have reported this to be quite accurate after they have calibrated it with another power meter- so that might be an option either. Might be problematic though that you would be using a different wheel and tyre to the one used for calibration.

If I could only have power in a training or race wheel I would go for training- but then I road race primarily rather than TT.

Ironically it appears as if when training with power a non-trainer trye(a good quality tyre not a gatorskin) will disapate heat better and slip less thereby getting more accurate readinghs.

DirkVoodoo

ryan_sherlock wrote: »

In about 5 weeks I'll be selling my SRM Pro (Wireless) with DuraAce rings (cranks only, I use an Edge 705 or 500 with mine). It will be fresh back from a service from SRM in Germany. Price will be around 1,100.

Personally - I would go with the wireless PowerTap (I have had two, Mel, one).

Ryan, not popping in front of mjth here, but I'm guessing that those cranks are standard and not compact?

ryan_sherlock

DirkVoodoo wrote: »

Ryan, not popping in front of mjth here, but I'm guessing that those cranks are standard and not compact?

Yeah - standard - get the training in. 11-28 on the back will take you up anything with standard cranks (39x53)

mjth2004

Reckon my plan of action will be to off the 404's, purchase the Elite+ built into a mavic open pro & use as a training wheel! Then come race day I'll lash on a wheel cover to use it as a racing wheel! Think that is my cheapest way around the situation!

My thinking is to run tubs on a turbo will need me looking for a second job!

DirkVoodoo

@Ryan, I just remembered you are quite a tall chap, I don't suppose these are 172.5 mm cranks?

ryan_sherlock

DirkVoodoo wrote: »

@Ryan, I just remembered you are quite a tall chap, I don't suppose these are 172.5 mm cranks?

Yeah - 175mm cranks. I switched directly from 172.5 and couldn't actually tell the difference (although all my MTB ones are 175 - my CX crankset is 172.5 though)