merlinextraligh

Currently have a Powertap SL. I'd like to get a wireless ANT+ power meter to pair with a Garmin 705.

Options are SRM ($3000, without the head unit) Quark $1195, plus $300 or so for a new crank. Or 2009PowertapSL 2.4 (around $1500 I'm guessing).

Or possibly upgrade my current SL. (I've seen it suggested that this can be done for $500, but not sure if that is correct.)


I'm leaning toward the Quark, figuring I can sell a PT SL Zipp 404 wheel, and a Dura Ace crank, for just about what the Quark and crank will cost.

Any thoughts?

waterrockets 

Given the choice, I'd probably choose the Quarq. SRM is proven, but I've always considered it overpriced. PT messes with your wheel choices (though I'm happy with mine).

wanders

I was dead set on the 2009 Powertap until our resident wheel expert's comment makes me want to reconsider^^^. I'm not doing anything until Dec. so hopefully an early adopter *ahem* Merlin *ahem* will help me make up my mind.

umd

I like my Quarq so far, the only thing that has be concerned is the lack of a torque based calibration. To be fair, that seems to be the problem of using the Garmin as the head unit and not the meter itself. I imagine an SRM or PT with the Garmin would have the same problem. Talking to Tom (aka TnA) has led me to believe that it is reporting low but I don't have any way to check it except to compare it to another meter. Fortunately he is going to let me wire up his extra harness and test with his wheel.

rizz

I was leaning towards an iBike Pro as it's easy to move between machines and relatively inexpensive, then I saw how far off the sub-one minute data is when compared to the meters with strain gauges. Oof. Sorta' defeats the purpose when you can use a heat rate monitor to almost the same effect for those longer distance efforts.

Go with a PT and you'll end up needing two hubs for your road and TT rigs, unless you use 404s on both.

SRM and CinQo would require two cranks in the same situation but at least the CinQo costs less.

So many options.

umd

You can swap the cranks between bikes like you can swap wheels, just takes a few minutes longer. It took me about 15 minutes to swap my Quarq onto my wife's bike, but most of that was because hers was a compact so I had to readjust the FD, and I also had to swap the pedals.

I'm also looking into getting the adapter for my Tarmac that will allow a standard BB to be fitted (it is BB30) so that I can use my Quarq for my race, although my long-term goal is still to get the s-works crank model when it comes out...

waterrockets 

We'll have to see the actual 2009 PT pricing and configurations. If someone wants to get into training with power with a system that is accurate, reliable, and as inexpensive as possible, you absolutely can not beat a used PowerTap. End of story.

When you start talking about the bling bling 705 integration, the economics level out a little bit, so you have to consider other factors... you're moving from a $600 complete solution to a $2000 complete solution. The value is in the power data, and a used PT delivers that as well as anything else out there.

Adding $1400 to the price of entry for GPS data and elimination of wires is a big jump with little return, but it's not clear that PowerTap is the best or least expensive way to get there.

umd

I agree. The Quarq fit the bill for what I wanted, but certainly not the cheapest out there. WR, I'm assuming that's for the wired version built to a standard wheel like an OP?

merlinextraligh

True. But in my case I already have the Garmin, and use it on the tandem,(for which there really isn't a power meter answer, other thna perhaps an Ibike.) So part of my purpose is to get more use out of the Garmin.

In addition to adding GPS, and eliminating wires, the Garmin gives you some more data points including elevation and grade.

Also being able to customize the screens to display any combination of data is pretty cool.

But I'd agree with your basic point, a basic wired powertap is going to be the most cost effective method to get the training data you actually need.

waterrockets 

Yeah, I've got two friends with carbon-windowed SLs built into Open Pros for $600. Mine cost me $680 shipped about 6 months earlier (including brand new wheel parts I got to build myself), so I think the prices have dipped $50 or so this year.

waterrockets 

Regarding the tandem, wouldn't it make sense to run a crank-based system on the front and a PowerTap or Polar on the rear? In post-processing, you could isolate the stoker's power by subtracting the captain's. I haven't been keeping up with all the hub widths available in PowerTaps though...

Phantoj

Are you thinking single-sided drive, or putting the crank on backwards (would probably require special firmware to measure reverse torque)?

merlinextraligh

I don't think there's a 145mm wide Powertap, and I'd be concerned about how robust the hub would be with a team weight of 330-340.

As for the crank set up, you could run a single sided setup with an SRM or Quark, but youd have all the problems with a single side set up.

I'm thinking you could also run an Ergomo if you used a Davinci crank for the captain.


ASU_GT has a tandem set up with dual SRMs in a single side drive setup and a custom Powertap wheel in the back. But it's for medical research, and he has grant money.


I was tempted to get an I Bike for the tandem, mostly so I could post files showing 2300 watts peak 5 second power.

waterrockets 

Track SRM for the captain. It sounds like folks have hooked up a standard SRM for the stoker.

SpongeDad

I'm waiting to see what Shimano does. At that point, it think all the price points and compatibility issues that I care about will be covered. (If Campy comes out with a power meter, it doesn't really matter to me.)

merlinextraligh

^^ you'd need to do something about the pedal threading with the Track SRM installed backward, if you did it with a corssover setup. Would it read torqued in the opposite direction?

waterrockets 

I'm still waiting for an announcement for a Cat Eye (Vetta? Others?) head unit. Right now, the only planned unit that will just do ANT+Sport power and cyclocomputer functions is (presumably) the 2009 PowerTap Cervo ($350).

waterrockets 

Sounds like blue loctite was all that was needed, and the SRM read fine.

merlinextraligh

Let's see, $6000 bucks for 2 SRM's and another $500 for another head unit.

Empirical proof my stoker's slacking, priceless.

waterrockets 

:d

Phantoj

In that series of messages, they are talking about a tandem event where a powermeter was not used:

so the two guys at the event that you might associate most with powermeter usage went with no powermeter. We didn't even run a cyclocomputer (I already knew the course, so I didn't really need to see distance), Andy had on a wristwatch for "data". We didn't even run aero wheels.

And then there was speculation about how a tandem could be set up with power meters. I didn't see anything in that thread where someone said they used a tandem power setup successfully.

waterrockets 

Hmm. mis-read

There is a thread from 2004 where a PowerTap was running on a tandem with some custom spacing. 250 lb team though.

asgelle

https://forum.slowtwitch.com/cgi-bin/...engine#1968832

merlinextraligh

I'm wondering if that Calfee's built to 130 mm spacing.

cslone

I just ordered my Quarq.

:noes: