Split rim - possible cause ?

[Señor Chris]

While touring during the summer, the rim of my rear wheel split
lengthways either side of the valve hole. I had to fix a puncture at
about the same time as I first noticed a problem with the rim and
vaguely remember using a tyre lever near the valve - not something I
would normally do but I was in a hurry.

Would this have been enough to split the rim or would there have to be
an existing weakness ?

Chris.

[Martin Dann]

Señor Chris wrote:
> While touring during the summer, the rim of my rear wheel split
> lengthways either side of the valve hole. I had to fix a puncture at
> about the same time as I first noticed a problem with the rim and
> vaguely remember using a tyre lever near the valve - not something I
> would normally do but I was in a hurry.
>
> Would this have been enough to split the rim or would there have to be
> an existing weakness ?

I very much doubt that just using a tyre lever near the
valve would be enough to split the rim.

It is more likely to be rim wear combined with that either
that is where the weld is, or fatigue.

[Don Whybrow]

Martin Dann wrote:
>
> It is more likely to be rim wear combined with that either that is where
> the weld is, or fatigue.

Welds are usually opposite the valve hole, at least they were on the
last set of wheels I made up.

--
Don Whybrow

Sequi Bonum Non Time

One tentacle, one vote.

[Martin Dann]

Don Whybrow wrote:
> Martin Dann wrote:
>>
>> It is more likely to be rim wear combined with that either that is
>> where the weld is, or fatigue.
>
> Welds are usually opposite the valve hole, at least they were on the
> last set of wheels I made up.

When I have built wheels, the weld is opposite the valve
hole, but on cheap rims this might not be the case.
I have a rim in my garage with a couple of splits on the
weld, luckily I caught it just in time.

I also expect the valve hole would be a weak point on a
rim, and subject to more fatigue than the rest of the rim.
(This is just speculation though).

[Zog The Undeniable]

Señor Chris wrote:
> While touring during the summer, the rim of my rear wheel split
> lengthways either side of the valve hole. I had to fix a puncture at
> about the same time as I first noticed a problem with the rim and
> vaguely remember using a tyre lever near the valve - not something I
> would normally do but I was in a hurry.
>
> Would this have been enough to split the rim or would there have to be
> an existing weakness ?

How many miles did the rim have on it? Assuming rim brakes, it probably
just wore out.

[Pete Biggs]

Zog The Undeniable wrote:
> Señor Chris wrote:
>> While touring during the summer, the rim of my rear wheel split
>> lengthways either side of the valve hole. I had to fix a puncture at
>> about the same time as I first noticed a problem with the rim and
>> vaguely remember using a tyre lever near the valve - not something I
>> would normally do but I was in a hurry.
>>
>> Would this have been enough to split the rim or would there have to
>> be an existing weakness ?
>
> How many miles did the rim have on it? Assuming rim brakes, it
> probably just wore out.

Sidewalls wear out. Doesn't sound like that's the bit that split.

Anyway, the tyre levering wouldn't have been to blame.

~PB

[Señor Chris]

Pete Biggs wrote:
> Zog The Undeniable wrote:
>> Señor Chris wrote:
>>> While touring during the summer, the rim of my rear wheel split
>>> lengthways either side of the valve hole. I had to fix a puncture at
>>> about the same time as I first noticed a problem with the rim and
>>> vaguely remember using a tyre lever near the valve - not something I
>>> would normally do but I was in a hurry.
>>>
>>> Would this have been enough to split the rim or would there have to
>>> be an existing weakness ?
>> How many miles did the rim have on it? Assuming rim brakes, it
>> probably just wore out.
>
> Sidewalls wear out. Doesn't sound like that's the bit that split.

Correct, the split is in the same wall as the valve hole.

>
> Anyway, the tyre levering wouldn't have been to blame.
>

I think you're probably right, although I have seen rims severely
damaged by over-enthusiastic levering.

[Señor Chris]

Martin Dann wrote:
>
> When I have built wheels, the weld is opposite the valve hole, but on
> cheap rims this might not be the case.

It's a Mavic X517 and the weld is opposite the valve.

[Rob Morley]

In article >, Señor Chris
says...
> While touring during the summer, the rim of my rear wheel split
> lengthways either side of the valve hole.
>
Presta valve with locknut screwed up tight?

[James Thomson]

"Señor Chris" > a écrit:

> It's a Mavic X517

These rims are known for cracking. Mine have failed at the spoke eyelets,
but there seems to be a tendency for them to fatigue in the spoke bed and
rim face and crack along the axis of extrusion. I still have a couple
surviving as front wheels, but all those I've built as rears have cracked
before wearing out.

If you're looking for a sturdy replacement, I like the Alesa/Rigida Sputnik.

James Thomson