Most light weight powermeter?

Discuss light weight issues concerning road bikes & parts.
refthimos
Posts: 175
Joined: Fri May 25, 2012 6:02 pm

by refthimos

dalex wrote:
Wed Jul 18, 2018 9:13 pm
AndreLM wrote:
Wed Jul 18, 2018 8:11 pm
SRM Origin (I have seen different weights online, but not sure if it was for 24mm or 30mm version)
Mine: 662 g all up (30 mm axle, both cranks, Shimano Dura Ace 52/36 rings)
Seems fair to compare crank-based PMs based on arms, spindle and spider and not rings, since those can be swapped. Yes DM rings throw this off, since you lose the spider but then have to adjust with the rings, but I'm not sure there are any crank-based PMs that actually use DM rings (e.g. with the SISL2, you add a PM spider and use normal rings, not DM rings) so I think arms + spindle + spider is a fair way to look at this.

So if those are the ground rules, I believe your Origin would weight approx. 532g (I'm deducting 130g for the Shimano rings). That is just an estimate - I am sure one of you knows the numbers better than I do.

For a SISL2 PM, my research estimates 250g for the arms, 64g for the spindle, and assuming we go with a P2Max NG (not ECO), 157g in 110BCD. That adds up to 471g, or approx 61g less than the Origin. Not sure if the SRM spider for Cannondale cranks is more or less than the 157g for the ECO, so there may be an even lighter SISL2 option yet.
SystemSix | On order | BBQ
EVO Hi-Mod | [WW Project in Process]
P5 | 9070 Di2 | Rotor 2Inpower | Aeolus 7 TLR | Alto Disc
T1 | Power2Max Type S | Rolf Prima FX58/Zipp Super 9 Disc

refthimos
Posts: 175
Joined: Fri May 25, 2012 6:02 pm

by refthimos

AndreLM wrote:
Wed Jul 18, 2018 8:11 pm
A SiSL2 with SRM or P2M is probably one of the lightest, but it is limited to BB30/PF30 frames. Another BB30 alternatives, that are potentially even lighter, and still dual-sided:
- S-Works power crank (with factory-installed 4iiii pods)... for now I think they are only available with new Tarmacs and Venges...
- SiSL2 with Watteam powerbeat pods

(I am not saying they are as reliable as SRM or P2M though...)

Other lightweight spider-based options:
- Easton EC90 SL with P2M NGEco spider (BB386... compatible with everything but Trek BB90)
- THM Clavicula M3 with SRM (BB386... but discontinued?)
- SRM Origin (I have seen different weights online, but not sure if it was for 24mm or 30mm version)
You're right! The S-Works power crank should definitely be a little lighter than a SISL2 w/ SRM/P2Max. That should be the new crank PM to beat, assuming the actual weight is near the 440g claimed for the 172.5mm length.

For me, it's hard to take Wattbeam seriously, solely on the basis that they look super goofy (IMHO).
SystemSix | On order | BBQ
EVO Hi-Mod | [WW Project in Process]
P5 | 9070 Di2 | Rotor 2Inpower | Aeolus 7 TLR | Alto Disc
T1 | Power2Max Type S | Rolf Prima FX58/Zipp Super 9 Disc

by Weenie


AndreLM
Posts: 311
Joined: Tue Feb 05, 2013 11:53 pm

by AndreLM

I know a guy with an S-works SL6 disc (with the power cranks)... I am trying to convince him to take out the cranks so I can check if they fit my frame (the pods are faily chunky). I will post scale shots once I get to weight it.

KevinM
Posts: 37
Joined: Fri Jun 29, 2018 11:37 am

by KevinM

Stueys wrote:
Wed Jul 18, 2018 8:24 pm
KevinM wrote:
Wed Jul 18, 2018 3:46 pm
claus wrote:
Wed Jul 18, 2018 1:58 pm
KevinM wrote:
Wed Jul 18, 2018 11:05 am
The thing about power data is that the numbers only matter as long as theyre consistent.
And then you switch to a new/different power meter... and all the old data is now probably useless.
Exactly! All that matters is the meter you’re using is consistent.
As long as you don’t want to use a smart turbo with inbuilt power meter, or get another bike with a PM, etc, etc. Accuracy and consistency are both important.
You’re fooling yourself if you think there is a smart trainer or pedal or crank or whatever that is more “accurate”. Even two pairs of the same model power meter aren’t exactly the same. If you’re going to use two different power meters (I do: Neo and P1 pedals) and you’re worried about 1% variance, just have two FTPs. Comparing your FTP on a pair of Vectors to my FTP on a different set of Vectors doesn’t make sense. There will always be variance. Until we can both ride on the same exact meter set up with the same exact bike, we’ll never know.

User avatar
ms6073
Posts: 2538
Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

KevinM wrote:
Fri Jul 20, 2018 4:05 pm
I do: Neo and P1 pedals) and you’re worried about 1% variance, just have two FTPs.
Not that I really need a powermeter anymore, but I ahave a Shimano R9100-P (previously SRM DA-9000) and Tacx Neo. While neither are ever going to be in exact agreement, the powermeters and the Neo are on average usually within +/-2% of each other. The one time I overlaid the SRM and Neo power graphs, they were nearly mirror images between the Neo and SRM.
Michael - The Anaerobic Threshold is neither...

Post Reply
  • Similar Topics
    Replies
    Views
    Last post