Ksyrium stress relieving?

[Cedez le Passge]

Last week I ordered a set of Ksyrium SSC SLs from TotalCycling. They're now being held by US Customs at JFK, but that's another story (something nefarious we don't know about French wheelsets?)

There's some good advice in previous posts about truing and stress relieving Ksyriums before riding, hopefully to avoid becoming another cracked rim horror story.

I've built several sets of wheels using Open Pros, butted DT spokes and 3-cross. But does anyone know whether the stress-relief and truing process is different given the Ksyriums' radial spoking pattern and bladed spokes?

Also, does anyone know Mavic's recommended max spoke tensions for the 04 SSC SLs?

The Mavic metal spoke wrench is now available on-line, BTW.

Many thanks.

J

 

[Cedez le Passge]

I know everyone's been losing sleep over this , so I'll post what I found.

Per Park Tools' website:

Ksyrium SSC

Front wheel: 90 - 110 kgf



Rear Wheel- right side (chain side): 130 - 150 kg

 

[Weisse Luft]

I know everyone's been losing sleep over this , so I'll post what I found.

Per Park Tools' website:

Ksyrium SSC

Front wheel: 90 - 110 kgf



Rear Wheel- right side (chain side): 130 - 150 kg

I would NOT recommend any overtension of the spokes for ANY purpose. Aluminum has no endurance limit and bringing any part of the spoke near yield is potentially harmful to the fatigue life.

The torque transfer hub and low modulus of the aluminum spokes is perfectly suited to the geometry of the wheel. There is some rotation of the drive side spokes from windup but the additional stress is nil as the windup angle is tiny compared to classic tiny hub diameter.

 

[Cedez le Passge]

Thanks Weisse Luft. So your sense is that stress relieving will actually weaken the spokes rather than strengthening the wheel overall?

 

[Weisse Luft]

Thanks Weisse Luft. So your sense is that stress relieving will actually weaken the spokes rather than strengthening the wheel overall?

Yes. Aluminum alloys have very strange stress-strain relationships, most of which do not like to be anywhere near yield. Since the spokes are straight pull, there is no added benefit to be gained by stress relieving.

Now, I know what will be coming later...straight pull stainless spokes. Unless these spokes have a rotating seat like Mavic Ksyriums, the portion of a radial spoke near the hub will go into bending stress if the flange is allowed to wind-up. I know of a few designs where this is a contributing factor to short spoke life.