Newbie... power meter suggestion

[RedJuliette]

Hi

I'm new here as you can see and want to ask for suggestions on a power meter.

I've lost 30 pounds in the last 4 months (yay! ) to become fairly slender and would like to get in shape to compete in a beginner bicycle race. I have read many threads here including this epic 300 page one and can see how valuable a tool these devices can be. Plus I'm a nerd so there is further appeal.

My budget is modest so I am trying to save money. I read an article online, a sort of 2015 power meter buying guide which helped. Now I am trying to narrow it down.

I have 3 bikes. ..
Older road bike (~6\7 years old) that I got used. It has Shimano ultregra parts but the chainring is a triple.

Newer low end hardtail mountain bike. ..a giant 29er, also with triple chainring

Fix gear for tooling around casually and to pubs (not considering putting Meter on it obviously! )

These aren't great bikes but I think a power meter and formal training would be money much better spent than buying a new bike right now.
Any suggestions on which meter to buy?

Wheel based. . Powertap...
-about 770$ for a basic road wheel with the g3 powertap plus $125 for rush shipping and delivery from wheel builder, else it takes 2+ weeks.
-mtb 29er wheel is $1100 *ouch* not including rush service and shipping
-is this easy to install on my existing bike? I would need to remove& install the cassette on road bike, cassette and disc brake on mtb..
-more expensive than the crank meters

Crank spider. .
Quarq, power2max, powertap c1..
-both of my real bikes have Triple chainring but these crank meters appear to be doubles. Will this work? Or would it be complex mechanically?
-the power 2 max seems like the cheapest unit., even less than the powertap wheel

Crank arms. ..
Stages, rotor, pioneer
-would they be easy to install?
-can transfer between bikes
-good price
-is left only viable and good for training? In the past I have noticed a decent difference in my strength between my legs doing some exercises

Pedals. .
Look, powertap
-most expensive
-only take certain shoes?
-are these accurate?
-looks like easy to transfer between bikes
-will they break in the event of a crash?

I can do some basic mechanical work on the bikes but I'm no expert.

I would say budget, ease of install, accuracy are my top priorities.

Thank you! !

 

[Weatherby]

Powertap wheel is easy to install. I have two of these. I like that I can switch from bike to bike.

I considered the Stages crank arm power meter but then the power meter would be confined to one bike because I definitely would not swap out the crank arm for one ride.

The Google group "wattage" discusses the finer points of accuracy. When people talk about accuracy, there is some confusion and misunderstandings. I will try to explain what I mean in normal, non-geek statistical goobly gook.

On my powertap G3 hubs, I have tested accuracy by hanging a very heavy weight to the crank arm and reading the torque value in the Garmin settings. The variability is very small meaning if I apply the load many times to one of the hubs, the torque value is very consistent. There are ways to check the calibration as well. One of mine is 1% low and the other is 3% high in terms of displayed power level. If you wish to know your power levels exactly rather than just having a consistent, accurate basis to monitor performance, this could be a concern. One is consistently 1% low and the other is consistently 3% high. The spec is plus/minus 1.5%. My 3% is special. It was rebuilt to fool my coach.

BTW....congratulations for getting in shape. Weight loss takes will power.

 

[cyclenthusias44]

Powertap wheel is easy to install. I have two of these. I like that I can switch from bike to bike.

I considered the Stages crank arm power meter but then the power meter would be confined to one bike because I definitely would not swap out the crank arm for one ride.

The Google group "wattage" discusses the finer points of accuracy. When people talk about accuracy, there is some confusion and misunderstandings. I will try to explain what I mean in normal, non-geek statistical goobly gook.

On my powertap G3 hubs, I have tested accuracy by hanging a very heavy weight to the crank arm and reading the torque value in the Garmin settings. The variability is very small meaning if I apply the load many times to one of the hubs, the torque value is very consistent. There are ways to check the calibration as well. One of mine is 1% low and the other is 3% high in terms of displayed power level. If you wish to know your power levels exactly rather than just having a consistent, accurate basis to monitor performance, this could be a concern. One is consistently 1% low and the other is consistently 3% high. The spec is plus/minus 1.5%. My 3% is special. It was rebuilt to fool my coach.

BTW....congratulations for getting in shape. Weight loss takes will power.

I completely agree with you. Willpower is the most important factor that decides your success.

 

[maydog]

I have an old school wired powertap hub whell that I am pretty happy with. It is easy to swap between bikes. I do wish that it had ANT+ communications as I am stuck using the dedicated head unit - so I cannot easily merge GPS and power data.

If I were purchasing new, I would choose either another powertap hub based system or potentially a pedal based solution. Pedals are easy enough to swap, my reservation is that I seem to wear out pedals faster than wheels.

 

[dkrenik]

Your triple requirement all but completely removes a crank/spider-based PM. SRM is the only one I'm aware of that makes a triple PM and it's going to be costly.

Given the above and your priorities, I'd echo what others have said and recommend going with a PT. I'm not a fan of single-side power meters and there are reports of issues with pedal-based PM's on the Wattage forum (most likely could be resolved with firmware updates). PT's are simple and have proven to be reliable over the decades (I've been using an SRM for nearly 10 years).

As your new to training with/by power (congratulations), customer service will also be important to your satisfaction with your PM. I've seen nothing but good reports of Saris' customer support for PT products.

 

[RedJuliette]

So many thanks to each of you for the suggestions!!

I am not attached to having the triple chainring but it does not seem to be a good investment to spend money upgrading an old bike (the road bike) or a low end bike (the MTB) by replacing the crankset and gears just to save a small amount on a power meter.

I also did some more research on the stages crank arm meter and it seems people have problems with these or more than they do with the powertap.

So I took your collective advice here and ordered a power tap wheel from a custom builder. This way when I do get a nice bicycle, I should be able to transfer my wheel --at least to another road bike

Thank you so much