revchuck 

I'm also a Cat 5, and an older guy to boot; decided to start racing at 61. I got a PT via eBay and had it built into a rear wheel I already had. For longer intervals, such as the 20 minute TT intervals you mentioned, HR works pretty well. Where HR comes up short is in shorter intervals, where HR doesn't have time to react. Also, HR drift is real; last Saturday I did a series of longer intervals at 92% of FTP, and my HR noticeably increased with each interval, even though the power levels were the same.

If your finances are such that you'd have to choose between getting a Powertap or paying bills (and we've all been there), stick with HR. However, if it's a choice between a Powertap and a cool new wheelset, get the PT - it'll make you faster than the wheels would, assuming you've either done the homework to create a good training plan or have signed on with a good coach. It's a tool, not a talisman.

Another route to check into is a used wired SRM power meter. It's about the same cost as a PT, and doesn't require having a wheel built.

jsutkeepspining

I personally really dislike hr. It is affected by way too many things to be "useful" outside of looking at it post workout and seeing big trends. When I'm really training, and doing a ton of miles, and a ton of intensity my hr goes into catatonic mode (for example my z2 hr is between 158-168, but during periods of high training at say x watts i might be at 150 versus a more "predicable" 160-165, and dont get me started on post ride coffee versus no coffee). I would personally rather use RPE for intervals and just use hr for post ride analysis to see how my body reacted to the work (remember hr is an reaction to an effort).

I would say go for it. Having power teaches you a lot about yourself that you cant find out just by riding (racing, on the other hand, will show you the majority of the things power will). For example, I used to think i was a bad sprinter due to genetics, it turns out i just had to work on positioning and choosing the right gear (and that each year i gain like 100 watts to my max power ).

UmneyDurak

Got my 6-7 year old SRM replaced with latest one. I sent it for service and they discovered a crack that is unrepairable. Gave me a nice deal on new one. So figured why not? Went for a ride yesterday, just cruising along it seems to read z1/2 power 20-40W higher. When I started doing ON/OFF power seemed kind of inline with how I felt. Although maybe have been higher also. What a heck? I linked srm7 computer with crank. I have slope to be detected automatically, and when I downloaded a file it was the same value that is printed on the crank, I set zero offset before starting a ride, but in computer it set to automatic. Is crank not calibrated at the factory correctly?

misterwaterfall

When was the last time your old crank was calibrated? It would be my guess that the old crank was low, not your new crank is to high

UmneyDurak

Hmm, I think couple years ago? Although I had a power test done late last year on computer trainer and power output on my computer corresponded to power displayed on the trainer.

rbart4506

Is there a trick to removing the battery in a Quarq? I got the lid off, but the batter isn't simply popping out... Don't want to ham fist anything...

Racer Ex 

I've seen SRM USA miss on calibration, once they missed by quite a bit and I experienced what you're getting now. Verifying with a known weight is simple, and cheap and a must do in the long run.

Drop me a PM and I can explain further and send you the spreadsheet you'll need.

waterrockets 

[don't own a quarq: beware]

Doubled-over duct tape on the square end of a bic pen?

Shop vac?

[/don't own a quarq: beware]

UmneyDurak

PM sent, thanks.

merlinextraligh

The battery is sitting down on steel spring tabs. Press down gently on the edge on one side, and then use a fingernail, or small screwdriver etc., to pry up the other edge as it pops up.

Or turn the bike sideways, and shake it a bit.

rbart4506

Thanks guys...

I utilized the aid of my wife, she has fingernails...

BTW, that is one big battery...

rkwaki

You wife has an aid? Is she a politician? If so what else does she help you with

rkwaki

Anyone want to change the battery in my SRM and re-calibrate it? I'll pay you....

Jandro 

In what...?

rkwaki

The same thing I paid you in last time to continue my nonsense...

semaj

How do you guys plan to obtain a certain CTL, ATL, TSB mix at a certain period of time? I currently use an excel spreadsheet and I'm wondering what other ways people track their progress.

Ygduf

I don't worry about anything but TSB. I look on Monday at my TSB and rest Monday, maybe ride Tuesday, rest Wednesday and decide on Thurs/Fri/Sat around where my TSB is and whether the race is Saturday or Sunday. I want to be anywhere from 0 -10.

I don't use any calculators or spreadsheets, just the history in the PM to judge how it moves in response to stress, and I trust my legs over the TSB anyway.

aaronmcd

Question:
I would love to track power, but don't have a ton of money to spend, and have to seriously overhaul my bike or buy a new one for next season.
Options are:
1) Continue without power. Try to be ok with the fact that I'll keep going by RPE, don't know my weaknesses, don't know how much I am improving, etc. But it's free!
2) Get a trainer with a power computer just for testing, and to help know what different watts feel like. Costs a bit, but I could randomly spin while bumming around the apartment, and warm up more thoroughly at races.
3) Stages power meter. Train with power always available. Have a thorough power profile and track everything. Finally find out my 5 second to 1 minute power. Expensive, and it doesn't help me warm up like a trainer would. Also I might get dependent and loose the ability to go by RPE as well.

Are any of these off base? Am I missing anything?

Side question: Anyone know the sample rate of stages power meters?

misterwaterfall

Get a cheap powertap rear wheel for ~$300 and use that on and off the trainer. I bought my trainer for $40 off of craigslist and it has worked for me for quite a few hours.

rkwaki

Agreed on the Powertap. There are a few available on that 'try-athlete site right now.

ovoleg

Hey guys quick question. I don't know much about this so I thought to ask. A friend did a VT test(Ventilatory Threshhold) and the wattage output was a bit on the high side(I expected 30-40W lower based on our riding together). How accurate is this test? I guess a good way is to test on the road and then to compare but what have you guys heard?

Just curious.

Wylde06

Ordered a Quarq yesterday. It needs to hurry up and not be backordered.

aaronmcd

How are the old wired powertaps? There is one on Craigslist near me for $350 with stuff that I assume I need. https://sfbay.craigslist.org/sby/bik/4107988861.html
I like the idea of Stages (easy, and can change wheels) but this is much cheaper.
Or... wireless wheelset. More expensive, but I dented my front rim and should get a wheel anyway before something bad happens.

shovelhd

Don't compare yourself to others.

mattm

I'm no expert on those but it seems like a bit much for an old/used wired one.

You can get new/wireless full builds for around $600 I think. (meaning if you wait/look around more you should be able to find a newer wireless one for at least as much)

Did you try slowtwitch?