Quinn8it

Anybody want to tell me how to set up that watts/Cadence chart in GC?
@carleton ?

carleton

queerpunk, can you help Quinn? I haven't used GC in a couple of years and I don't have it on my computer anymore. Haven't had a power meter since 2013 or so.

queerpunk

when you're in the Activities tab (as opposed to Trends), then, use the "scatter" tab - if you have that tab already there, that's great. if not, you can add it via the hamburger menu on the right side. i think it's usually in there by default, but it might not have the right data columns chosen by default.

once you have a scatterplot, you can hover in the upperleft of the display ("more") or the top border to bring up options for what displays. select "frame intervals" so you can highlight the data points from specific intervals that you select in the left-hand column (or where ever you keep your list of intervals). on the x-axis you can put cadence, and on the y-axis you can put power.

nb that you can also select "AEPF" - average effective pedal force. kiiiind of like torque? what we're talking about in this conversation gets kind of close to the QA chart - that has pedal velocity on the x axis and AEPF on the y-axis - and the threshold is a curving line that cuts through it (it is a product of the two values).

SprintzNKiloz

I feel like with The Golden Cheat it's easier to grab raw data out of the file and puke it into Excel and making my own graphics and such. Per Carleton's point, I'll do just that to see if I can get torque out of the file. I've also pinged Quarq and they claim if I put the unit in "SRM Power Control Mode" it will send cadence and torque data separately. I may post findings and ya'll can mock my watts.

queerpunk

i haven't played with it but GC also has a function labeled "calculate torque values."

Quinn8it

Thanks QP!
Got that set up quick.
I'll have to sit down with it to figure out how to read that chart!

Hida Yanra

uhhh.... may have already happened?
I never looked at my head unit while training- I'm not nearly good enough to keep an eye on the screen while also holding the line I wanted around the track.... but in terms of looking at torque after the workouts and backing out gearing & pacing - yeah, that absolutely happens.

generally related to this thread and another thread currently going on over in road racing - I got to wondering...
"has anyone ever done a study of effective leg length as % of height? in professional cyclists, parsed by speciality?"
you know, lever length being a critical component of position and generation of torque over durations.

If that exists, I'd love see any data that came out of it - you know, for "reasons"


And I avoided getting into this thread earlier, but as a ex-pursuit-dude, having a PM helped me A TON, for training, yeah.
but also, it did all the following: tracked training effort through periodization, is a "free" (ignore sunk costs) wind tunnel" gave specific feedback on selecting crank length for pursuits, and in one thing that I never actually got dialed in - I *think* use of a PM will assist in determining "ideal line" around any given velodrome- because depending on your speed following the black line isn't necessarily the "fastest" line and all velodromes are a different shape ..... but I never got that all the way sorted out, I bet my old coach has figured it out by now, but I haven't talked with him in a while.

MarkWW

What's the verdict for using a quarq on the track? Does it handle the negative torque values well and all that?

I just now realized quarq is making a 165mm version of the Riken AL, so I'm thinking about looking into this more.

tonski 

Power2Max offers a rotor3d 165mm for track too -

queerpunk

I know a bunch of people who used 'em with a 110->144bcd adaptor and it worked great.

Quinn8it

My Quarq/SRAM Red on my road bike would randomly read high, across an entire ride.
I've had to go back and delete rides out of my records once I realized that I couldn't actually replicate the wattage.
Based on a few people I know, I'm not alone on this...
Are people seeing the same thing on the track?

Hida Yanra

I only used my Quarq for pursuits, and only some of the time - but the data lined up pretty well with what was coming off my SRM, so, no issues for me.
That said - there certainly have been documented issues for some users w/ them.


yup- and it's pretty great.
Of note: the Q factor is different than the q factor on Rotor track cranks - it's road width IIRC.

SprintzNKiloz

I run a Quarq Elsa R with this adapter and it's generally been good. I noticed it would cut out on my Felt while I was using a BB mounted magnet at certain cadences. On my Dolan just using putty + magnet it doesn't seem to happen - probably spurious but just my observation.

Track Parts-ADAPTOR

carleton

FYI: The guy that owns that company is a BF regular.

Hida Yanra

HA! he finally made it!
We'd talked about it a few years ago, and he said something like, "yeah, I have the math figured out to do it, but it is such a niche product that it's way down on my 'to-do' list" - I'd lost track of where it was since I got a track-specific SRM - but I'm really stoked to see that it finally a real part.

Tim is a great guy and super, super helpful.

Voodoo76

Bummer, I've got a Quarq sitting in a box but it's 130 BCD.

Quinn8it

Blackspire makes high quality track rings in 1/8th 130BCD...

Hida Yanra

I had one of theirs, it was nice - they look flat out fierce.
I've also used TA Alize and Miche 130 bcd track rings - all worked well.
I know that Gephart makes them, a ton of the nice folks up at Burnaby had them? No personal experience though.

Voodoo76

Appreciate the tip, I'll have to check that out. These are also 172.5, so not ideal. But there is some training I've been doing on the Road bike that I would rather do fixed. Even when I can't make the drive to the closest track to get it done. Been very close to pulling the trigger on the Power2Max Track.

tonski 

That is correct - it's a road crank mated to track spider

carleton

For those who want a good deal on a PowerControl head unit with speed and cadence sensors: https://www.bikeforums.net/sale/10368...head-unit.html

TrackMonkey7

This thread has me convinced that if I'm going to be using a PM, it should be something other than a Garmin - for track use at any rate. I am most seriously considering the Powertap pedals, and the power2max track meter. I am drawn to the pedals for the same reason I was the Garmins: they are easily portable and swap-able between bikes, with the added benefit of not needing as much specific torquing and calibration when said swaps are performed. Additionally, I can experiment with crank length much more easily. I am however, concerned about the fact that they are just road meters and likely have all the drawbacks that road meters have for track use.

I like the power2max given that it is cheaper than the Powertaps, and that they are "designed for fixed gear riding" according to their website. What exactly that means, I know not. They lack an auto zero function, which I think means that you have to zero them manually, since the road versions do this when you stop pedaling.

Does anyone have any input on either of the two models and how they might fare for track use?

Quinn8it

If I could go back in time- I would not use a Powermeter.. Especially on the track.
The year I rode my fastest Kilo was before I had a power meter. You can do everything you need with a simple speedo that records top speed, a stopwatch and an app like Carletons...
Simpler, faster times...

I've never used the P2M, but the Stages is full of issues..
On a budget the PowerTap hub is still the best Track PM
And the best is to find a used wired SRM

carleton

Yeah, I haven't mentioned that in this thread as I didn't want to seem like a naysayer. But, I don't think most people will get any value from using a power meter (myself included).

It's kinda like the 5-bladed razor blades. Yeah, I mean, more blades is sorta better...but is it worth the extra money?

For sprinters, Speed and Cadence are 100x more important to log and chart than Power.

I think the British (who seemed to pioneer using Power Meters on the track for sprinters and enduros) did it in their quest for that extra 1% incremental gains.

Yes, there are isolated examples where using a PM could help (like nailing the windup for a flying 200M), but I really haven't seen a strong case for sprinters using them.

TT Enduros, yes. Sprinters, no. Mass Start Enduros, no.

I'm pretty sure that mass start enduros can be coached based off of cadence and heart rate data (not even speed, as they don't necessarily control their speed as much as the pack does. They simply react to it and occasionally drive it.).

tonski 

Same is true for most roadies, but there's something reassuring knowing that you didn't PR because of wind and not your lack of strength or that you didn't get the PR because you're weak and need to train more