Track Cycling: Velodrome Racing and Training Area Looking to enter into the realm of track racing? Want to share your experiences and tactics for riding on a velodrome? The Track Cycling forums is for you! Come in and discuss training/racing, equipment, and current track cycling events.

Which Power Meter?

Old 11-14-18, 08:21 AM
  #1  
FinkFloyd
Member
Thread Starter
 
Join Date: Nov 2017
Posts: 27
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Which Power Meter?

I hope you won't mind me asking a power meter question. I have decided that I'm going all in on the track stuff and training with a view to starting racing next year. I train with power on the road and on the turbo, so it seems to me that this would be a worthwhile investment for the track bike. My main interest on track is the mass-start stuff; I am not ruling out sprinting but it doesn't hold the same interest for me, and I am not particularly concerned about pursuiting. I've read the previous power meter threads and have drawn the following tentative conclusions:

1. Pedal-based systems (and the Stages crank) aren't ideal for the track due to their accelerometer-based designs.
2. SRM is the gold standard.
3. If I want a crank based system, SRM and Power2Max are really the two choices; the Infocrank does exist but doesn't offer any great advantage over SRM.

My questions are therefore as follows:

1. I see that SRM offer two basic iterations: wired, for use with the PCV system, and wireless (each can come with SRM cranks or Rotor cranks). Is there an advantage to the wired system? If I've understood correctly, it has to do with instantaneous data transfer; is there a different benefit that I'm missing?

2. Using the wired system obviously ties me into the PCV head unit. Does this do everything a more modern head unit does (e.g. syncing wirelessly, etc), and is it really worth the expense of buying a new head unit (I gather the wireless SRM will sync with ANT+) compared with sticking to my Wahoo unit?

3. Is the Power2Max system appreciably inferior in any important respect to the SRM? I note that the Power2Max system comes with a rechargeable battery, which seems to me better than the SRM sealed unit solution.

Thanks in advance for any help.
FinkFloyd is offline  
Old 11-14-18, 10:49 AM
  #2  
carleton
Elitist
 
carleton's Avatar
 
Join Date: Jul 2005
Location: Atlanta, GA
Posts: 15,496
Mentioned: 80 Post(s)
Tagged: 0 Thread(s)
Quoted: 1181 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Hi, FinkFloyd. Have a stroll though this thread. Questions you haven't even thought of are covered there.

Training and Racing with Power Meters and other computers

Feel free to ask questions there. Everything there is still relevant. Track PMs don't change much over the years.

Wireless power meters require maybe 3s to start recording data. Wired, with two reed switches, can start after 1/2 a pedal stroke.

This is because Torque data travels with the Cadence data into the head unit which calculates Power. So, when you have cadence, you have power. No cadence, no power. That being said, only standing start specialists (Tam Sprint, 500M, Kilo, etc...) would want wired. Wireless SRM would probably suit your needs.
carleton is offline  
Old 11-14-18, 02:59 PM
  #3  
FinkFloyd
Member
Thread Starter
 
Join Date: Nov 2017
Posts: 27
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks - I saw the previous threads but you've largely confirmed what I took from those info-wise. I suspect that one of the Rotor SRMs might be the way to go (not least because it goes with a standard threaded BB rather than Octalink).
FinkFloyd is offline  
Old 11-14-18, 04:42 PM
  #4  
carleton
Elitist
 
carleton's Avatar
 
Join Date: Jul 2005
Location: Atlanta, GA
Posts: 15,496
Mentioned: 80 Post(s)
Tagged: 0 Thread(s)
Quoted: 1181 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by FinkFloyd View Post
Thanks - I saw the previous threads but you've largely confirmed what I took from those info-wise. I suspect that one of the Rotor SRMs might be the way to go (not least because it goes with a standard threaded BB rather than Octalink).
Octalink uses a standard 68mm bottom bracket. It always has.

Needle bearing BB-7700:
https://bike.shimano.com/en-US/produ...0/BB-7700.html

Sealed bearing BB-7710:
https://bike.shimano.com/en-US/produ...0/BB-7710.html

Last edited by carleton; 11-14-18 at 04:45 PM.
carleton is offline  
Old 11-14-18, 04:44 PM
  #5  
FinkFloyd
Member
Thread Starter
 
Join Date: Nov 2017
Posts: 27
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by carleton View Post
Octalink uses a standard 68mm bottom bracket. It always has.
Really? My bad - I thought from the way that the SRM sales materials drew a distinction between them that Octalink must be something different.
FinkFloyd is offline  
Old 11-14-18, 04:47 PM
  #6  
carleton
Elitist
 
carleton's Avatar
 
Join Date: Jul 2005
Location: Atlanta, GA
Posts: 15,496
Mentioned: 80 Post(s)
Tagged: 0 Thread(s)
Quoted: 1181 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by FinkFloyd View Post
Really? My bad - I thought from the way that the SRM sales materials drew a distinction between them that Octalink must be something different.
Added links above.

Also, you don't need the $100+ Dura Ace BB. You can use a $20 105 Octalink 19.5mm BB as well. I've used that as well as the sealed and unsealed Dura Ace.
carleton is offline  
Old 11-14-18, 04:48 PM
  #7  
carleton
Elitist
 
carleton's Avatar
 
Join Date: Jul 2005
Location: Atlanta, GA
Posts: 15,496
Mentioned: 80 Post(s)
Tagged: 0 Thread(s)
Quoted: 1181 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Click "Service Instructions" in the Shimano websites linked above to get detailed info.
carleton is offline  
Old 11-15-18, 11:05 AM
  #8  
gl98115
Senior Member
 
Join Date: Apr 2014
Posts: 631
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 140 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by FinkFloyd View Post
3. Is the Power2Max system appreciably inferior in any important respect to the SRM? I note that the Power2Max system comes with a rechargeable battery, which seems to me better than the SRM sealed unit solution.
Power2Max currently sells two track power meters in NA. The NG has a rechargeable battery while the NGeco uses replaceable coin cell batteries. Neither use magnets for cadence.

power2max NG
gl98115 is offline  
Old 11-16-18, 02:11 AM
  #9  
Dalai
Senior Member
 
Join Date: Jan 2006
Location: Australia
Posts: 2,136
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by FinkFloyd View Post
the wired system obviously ties me into the PCV head unit. Does this do everything a more modern head unit does (e.g. syncing wirelessly, etc).
Nothing with the PCV is wireless. PCV is connected to the wiring harness on the frame. Download of data is via a cable with USB to connect to your PC.
Dalai is offline  
Old 11-16-18, 03:08 AM
  #10  
Dalai
Senior Member
 
Join Date: Jan 2006
Location: Australia
Posts: 2,136
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Also not sure if it matters to you, but the wired track SRM's are not waterproof - not sure about wireless track units as happy with my wired units...

For accuracy and repeatability of data, it is very easy to check the slope of the SRM units yourself with a known weight and then update the crank via the SRM software or PCV. Interestingly PowerMax claim this is unnecessary.

I wouldn't be put off by the battery not being readily replaceable as it lasts a number of years even with regular use.

Note I own two wired track SRM's and a mix of wired and wireless road units too, so if you have any specific questions then fire away.
Dalai is offline  
Old 01-09-19, 06:19 AM
  #11  
Ricovonsuave
Junior Member
 
Join Date: Aug 2015
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Apologies for grave-digging, but if you're still looking at track PMs, Stages did make a DA crank based system which I'd heard some okay reviews of, and for my 2c, I've had good luck with the PowerTap track hub, as has a training buddy of mine. Obviously you don't get to use it when you put a disc wheel on the back for your A races, but for training and geeking out on data purposes it's been good and seems generally accurate - paired with my old Garmin 510 mounted under the saddle, and using GoldenCheetah for analysis. You do have to buy the special White Industries style splined cogs for it, but a 13T and 14T are enough, for most things really... 15T if you want to warm up on it I wish they made a 12T though....
Ricovonsuave is offline  
Old 02-18-19, 09:20 PM
  #12  
DaleG85
Newbie
 
Join Date: Feb 2019
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
What are people's opinions on the Verve Track Infocrank? I got a price last night of $1500.

cheers for the help
DaleG85 is offline  
Old 02-19-19, 08:58 AM
  #13  
Morelock
Senior Member
 
Morelock's Avatar
 
Join Date: Dec 2017
Posts: 385
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The Verve is relatively new (and expensive) so you're probably not going to find a lot of reviews on the track specific model for a while.

It looks pretty good overall, and with British cycling using it (at least some form) it's going to get good feedback going forward. The cadence method seems a bit murky (From the tech document - Proprietary process for accurate cadence measurement, which does not use magnets or accelerometers in order to achieve accuracy and save battery usage ) and the <2sec startup time could turn off a true sprinter... otherwise it looks solid. The crank length options, especially 155 and 160 is appealing.
Morelock is offline  
Old 02-20-19, 07:45 AM
  #14  
DaleG85
Newbie
 
Join Date: Feb 2019
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Morelock View Post
The Verve is relatively new (and expensive) so you're probably not going to find a lot of reviews on the track specific model for a while.

It looks pretty good overall, and with British cycling using it (at least some form) it's going to get good feedback going forward. The cadence method seems a bit murky (From the tech document - Proprietary process for accurate cadence measurement, which does not use magnets or accelerometers in order to achieve accuracy and save battery usage ) and the <2sec startup time could turn off a true sprinter... otherwise it looks solid. The crank length options, especially 155 and 160 is appealing.

Thanks Mate,
I had been speaking with them the other day and this is what the salesman told me regarding cadence

"An accelerometer is not how the InfoCrank registers cadence, it works from Torque impulses. It is not necessary but you can choose to use the magnets."
DaleG85 is offline  
Old 02-20-19, 09:29 AM
  #15  
Morelock
Senior Member
 
Morelock's Avatar
 
Join Date: Dec 2017
Posts: 385
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
interesting... obviously over my pay grade on the technical side, but I wonder why the option to have magnets if it's not necessary?
Morelock is offline  
Old 02-20-19, 09:49 AM
  #16  
colnago62
Senior Member
 
Join Date: Aug 2014
Posts: 1,272
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 205 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Cyclops Hammer and Magnus work this way. They will do cadence without a sensor. My feeling is it less accurate and a little laggy.
colnago62 is offline  
Old 02-20-19, 04:02 PM
  #17  
Clythio
Senior Member
 
Join Date: Aug 2016
Posts: 79
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 49 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Morelock View Post
interesting... obviously over my pay grade on the technical side, but I wonder why the option to have magnets if it's not necessary?
Powertaps work this way too, clocking each 2 torque peaks one pedal turn, and it's pretty good and accurate if you pedal all the time pushing some torque every pedal move, like on a training session interval.
It doesn't have any lag, but it floats a lot out of reality if you soft pedal, if you stop pedaling on a downhill or inside a group, drafting, like we do on a race peloton, which hurts some metrics like average etc, and lay some crazy high spikes on the file. That's the reason I use Powertaps WITH a dedicated cadence sensor (left crank mag attached).
InfoCrank now uses the same principle - torque peaks from one of the cranks, to count crankset revolutions.
Clythio is offline  
Old 02-24-19, 07:46 PM
  #18  
DaleG85
Newbie
 
Join Date: Feb 2019
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I noticed yesterday the huub wattbike team run infocranks on the training bikes.
DaleG85 is offline  
Old 02-24-19, 07:54 PM
  #19  
Morelock
Senior Member
 
Morelock's Avatar
 
Join Date: Dec 2017
Posts: 385
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Clythio View Post
Powertaps work this way too, clocking each 2 torque peaks one pedal turn, and it's pretty good and accurate if you pedal all the time pushing some torque every pedal move, like on a training session interval.
It doesn't have any lag, but it floats a lot out of reality if you soft pedal, if you stop pedaling on a downhill or inside a group, drafting, like we do on a race peloton, which hurts some metrics like average etc, and lay some crazy high spikes on the file. That's the reason I use Powertaps WITH a dedicated cadence sensor (left crank mag attached).
InfoCrank now uses the same principle - torque peaks from one of the cranks, to count crankset revolutions.

Cool, thanks for the info!
Morelock is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.