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Cracked rear rim on Raven sports tour

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paulhipwood:
Hi All
Have just washed my bike and noticed that there are many cracks at the nipples - about 15 of the 32 nipples holes have cracks - these generally are radial along the rim and about 10 mm long. The wheel is still running true and the spokes feel at the correct tension.
I have done about 3000 miles on this rim, I bought the bike second hand and it had done about 1000 miles by the other owner.
The rim is a Mavic 717 and I use Schwalbe Marathon plus 1.3 (smartguard) at 80 psi. Have never had a puncture and never run with low pressure.
I have not noticed these before and usually wash the bike every couple of weeks.
I use the bike for commuting and Sunday runs. I ride along the canal during my commute.
I am about 85 kg and carry no more than 10 kg in the rear panniers.

Has anyone else had this problem and what do you think has caused the cracks?

What would you recomend as a replacement?

best regards
paul

paulhipwood:
http://aolpictures.aol.co.uk/galleries/paulhipwood

Thought I would put these on to illustrate the cracks.
Sorry about the aol adverts!!!!

regards
paul

stutho:
Not Good,

After reading about your problems I went to check my rims.  I've got 4 mavic rims, 2 * 717, 1 * 717 ceramic and 1 * 517? Ceranic. All rims are 32 hole.  I have always being an advocate for mavic rims however the 517 rim (ceramic - rear) is cracked badly.  It has got about 6000 miles on it.  Luckily all my other mavic rims (717s) are fine - they have varying mileage of up to 4000 miles.

Oddly the wheel is still true (I put it in the stand to check! I use the bike mainly for commuting along with some UK touring (I am never very far from help).  Therefor I am not planning to replace the rim any time soon.

As for what to replace it with – up until now I would have said another mavic.  Don’t know what to advise any more.

PH:
Oh dear, Mavic rims had a reputation for this, especially when the spoke tension was high.  My LBS assured me it was in the past and I’ve recently had my rear rim replaced with the same 717.  Just been to look and no cracks yet, though it’s only done around 2,000 miles.  
As for replacements, the Sun CR18 I originally had was OK, I was a bit disappointed with how long it lasted, probably to be expected with a lightweight rim.  On my old commuting hack, Rigida Sputniks lasted well and were cheap, they are a good bit heavier, not that I ever noticed.

paulhipwood:
Hi all
The spokes are double butted and the cracks are from both sides of the hub.
I have checked the Rohlof manual and checked the lacing and it is correct for the nipple hole orientation.

I spoke to Thorn and told them of my problem. They said they had heard of this happening before with Mavic rims.
The bike is nearly three years old and there are to many unknowns with its history - honest I have never gone down a pot hole.
So I will get a new rim fitted, I will probably take it to Thorns and get them to fit it. They recommended a Sun CR18.
I am not too sure if any local bike shop has seen a Rohlof, so I do not want to risk it.

regards
paul

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