Help Build Powertap into Marvic Cosmic Carbon (2003)

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#1
Hi,

anyone know if it's technically possible to build a Powertap (G3) into an existing Cosmic Carbon Wheelset?
I assume challenges are spoke-count and spoke-length...

Malte
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#2
YES !

I know this as my first powertap was built in to a Cosmic Carbon rim, you just need to make sure that the spoke counts are the same :D

By the way are MaRvic's some Chinese clone of the Mavics? :D
 
Last edited:

GSAstuto

Maximum Pace
Oct 11, 2009
945
242
103
tokyo
www.roadfixie.com
#4
Assuming you have the 20H version (most popular) Mavic use a DS 10x2X and NDS 10x0X lacing and drilling alignment. PowerTap torque hub reverses, essentially, DS and NDS roles. So just be aware of that when you build it. And build the freebody opposite side into the Mavic DS side and the freebody PT side into the Mavic NDS side. Oh yeah, its also a good idea to follow Mavic's original spoke configuration of 2.5mm blades on the radial side and 3.0mm blades on the DS. One thing to watch for is that if you choose alternate lacing patterns, the carbon fairing of the Mavics will likely interfere with the spokes. In general this is no issue other than you might get some clicking and scratching noises as the spokes rub against the fairing.
 

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#5
Assuming you have the 20H version (most popular) Mavic use a DS 10x2X and NDS 10x0X lacing and drilling alignment. PowerTap torque hub reverses, essentially, DS and NDS roles. So just be aware of that when you build it. And build the freebody opposite side into the Mavic DS side and the freebody PT side into the Mavic NDS side. Oh yeah, its also a good idea to follow Mavic's original spoke configuration of 2.5mm blades on the radial side and 3.0mm blades on the DS. One thing to watch for is that if you choose alternate lacing patterns, the carbon fairing of the Mavics will likely interfere with the spokes. In general this is no issue other than you might get some clicking and scratching noises as the spokes rub against the fairing.
But if I would choose same (but reversed) lacing then there should be no rubbing, right?
How would I source matching aero spokes and how to figure our the right length?

Thanks,
Malte
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#6
But if I would choose same (but reversed) lacing then there should be no rubbing, right?
How would I source matching aero spokes and how to figure our the right length?

Thanks,
Malte
I didn't have an issue with rubbing, also most mavic dealers will be able to order in the correct spokes for you.
 

GSAstuto

Maximum Pace
Oct 11, 2009
945
242
103
tokyo
www.roadfixie.com
#7
@Malte -

1) The 'same' lacing will not work on a PowerTap. It is 2X DS and 0X NDS.
- a) The PowerTap 'drives' from the side opposite freebody, hence the 'DS' is actually a common hub's 'NDS'. It must be laced 2X (according to PT's own instructions) to ensure correct response to the strain gauge system and also to transmit torque properly through the shell. And, actually, with the large diameter flange , it's a bit difficult to lace 3X.
- b) Lacing 0X (radial) is not suggested on the PT due the strength limitations of the flange, (Again, from PowerTap) They always suggest 2X, though, from experience, 1X has proven no issues to many builders including myself.

2) You could lace it simply 2X / 2X and in that case , you'll likely get some interference by the fairing on the <new> NDS. But , hey, the worst that will happen is it just cuts into the carbon a bit and makes an annoying squeaking noise when you ride.

3) Mavic 3mm SP blades come in the following sizes -
Mavic part number 32390401 291mm
Mavic part number 32390401 307mm
Mavic part number 32390501 289mm

You'll need appx 297mm to build PT - I usually custom cut and thread to do this.

Oh, but one more thing ---

Your Cosmic Carbone probably has straightpull spokes, no? The PowerTap G3 series uses J-Hook. Another option there is the new PowerTap which uses the DT straightpull hub shell.

So - if you want ~3mm blades, then you need to order either Pillar XTRA 1425 (2.5mm) or CX-Ray (2.2mm)