Author Topic: Rim Wear Indicators for Mavic Ksyriums?  (Read 3795 times)

Rim Wear Indicators for Mavic Ksyriums?
« on: July 26, 2011, 01:34:07 PM »
Have I lost the plot?

Many manufacturer's rims have a safety marking or groove to indicate the level of wear.  I can find no such thing on my Mavic Ksyrium SLs.

So what do I do, feel the rim for the degree of concave wear and stick my fingure in the air and hope for the best?
Taking bookings for the Sunrise & Snowdrop Express. 21st Feb 2015.   http://www.beaconrcc.org.uk/audax/express/index.html https://www.facebook.com/groups/expressaudax

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #1 on: July 26, 2011, 01:42:48 PM »
yes.

If you are really worried, remove the tyre and inner tube, and use a vernier gauge to measure the thickness.  You will need a small non-compressible block to place on the inside of the rim, just below the hook, so you can measure the thickness of rim + block (then subtract thickness of the block).

I reckon once a rim is starting to feel distinctly concave, then it is on it's way out (thinks of rim on front of current bike).
<i>Marmite slave</i>

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #2 on: July 26, 2011, 03:24:26 PM »
I've got a rim wear gauge you can borrow Philip. You just need to be aware that on some rims the thinnest part might not be accessible for measurement - there's a thread here somewhere with photos illustrating this.

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #3 on: July 26, 2011, 04:00:32 PM »
I've got a rim wear gauge you can borrow Philip. You just need to be aware that on some rims the thinnest part might not be accessible for measurement - there's a thread here somewhere with photos illustrating this.

Thanks Steve.  I shall take you up on that.
Taking bookings for the Sunrise & Snowdrop Express. 21st Feb 2015.   http://www.beaconrcc.org.uk/audax/express/index.html https://www.facebook.com/groups/expressaudax

Polar Bear

  • aka Michael
Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #4 on: July 26, 2011, 04:12:42 PM »
Of course, if you were a rim manufacturer, would you set the indicator right at the safe limit, or maybe a few fractions of a mm before this so as to maximise your profit margins on further sales so as to show genuine concern for the safety of cyclists?

Professional McKenzie Friend and Paralegal.          goodem2@gmail.com     07802 709337.

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #5 on: July 26, 2011, 05:33:03 PM »
Here's a pic of my rear Ksyrium rim which was retired after approximately 13,650 mostly dry miles. The bearings were I think in a worse state than the concavity of the braking surface - and were the real reason for its retirement.
The concavity you can see is probably < than 1mm.
I have digital Verniers and turners calipers, but because of the hollow construction of the rim section it is not possible to take a measurement of the thickness of the rim at it's point of greatest wear. At least not without the use of a hacksaw which, one day, after this wheel has languished in my shed for long enough, I'll bring myself to do.

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #6 on: November 25, 2011, 05:38:14 PM »
In the interests of thread necromancy......

Today I took the plunge hacksaw and gave the rear rim of my retired Ksyrium maximum elbow. It didn't take long.



According to Mitutoyo, the braking surface at its thinnest point (just above the web, on the left of the pic) is 0.72mm  :o
At its thickest (just above the bead retaining ridge on the left of the pic) is 1.32mm.

I'm comfy with the notion of having replaced the wheels when I did.

Interesting things Jurek found when dismantling the wheel:
The nipples (which cannot be separated from the spokes) have (what measures up as) an M7 thread, with a really steep pitch and (there's more) a LH thread. So - looking from the hub outwards towards the rim, you'll be turning the nipples, somewhat counter intuitively, clockwise to loosen spoke tension. The nipples screw directly into holes threaded into the rim rather than onto the spokes.

The rim was full of dry, crystalline, powdery stuff which I took to be dried up thread locker.

Manotea

  • Just 1 sob, Vassily
Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #7 on: November 25, 2011, 05:52:44 PM »

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #8 on: November 25, 2011, 06:00:29 PM »
0.72mm? That's barely broken in...

Yeah I know, but I have an aversion to sudden loud noises  :D

Rhys W

  • I'm single, bilingual
    • Cardiff Ajax
Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #9 on: November 25, 2011, 07:10:42 PM »
I think the white, crystalline powder is aluminium oxide - salty water gets in around the nipples and causes corrosion in areas that are not anodised (the spoke drillings).

Here's a deceased Open Sport after a post-mortem:



Notice how one side is much more worn than the other. Even on the worn side, most of the wear indicator is intact. The lesson here is make sure your brakes hit the rim evenly on both sides and in the right part of the wall.

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #10 on: November 25, 2011, 07:17:08 PM »
Loads left on that yet :-)

I take the rim gauge to mine occasionally and wll change them at 0.5mm  :demon:

Re: Rim Wear Indicators for Mavic Ksyriums?
« Reply #11 on: November 25, 2011, 07:31:05 PM »
I think the white, crystalline powder is aluminium oxide - salty water gets in around the nipples ....

It does. Many is the time I've heard sloshing sounds coming from the rim following a wet ride.
Take off the tyre and tube, and you can release most of the water via the valve hole.