rim wear indicators

[Alan Moffatt]

This is the first set of rims that I've had (Mavic T224s) with the internal
wear indicators, which are now becoming visible. Does anyone know how much
warning they give you, as the rim doesn't seem nearly as worn as I would
previously have let it become? I'm obviously planning for a new wheel, but
should I be panicking?

Alan

 

[elyob]

"Alan Moffatt" <[email protected]> wrote in message
news:[email protected]...
> This is the first set of rims that I've had (Mavic T224s) with the
> internal wear indicators, which are now becoming visible. Does anyone know
> how much warning they give you, as the rim doesn't seem nearly as worn as
> I would previously have let it become? I'm obviously planning for a new
> wheel, but should I be panicking?
>

Is it normally a face plant?

 

[Pete Biggs]

Alan Moffatt wrote:
> This is the first set of rims that I've had (Mavic T224s) with the
> internal wear indicators, which are now becoming visible. Does anyone
> know how much warning they give you

I don't know but would be interested in the answer too. You could measure
your sidewalls to find out. A bearing ball on the inside is handy as a
spacer when measuring with ordiniary calipers.

~PB

 

[normanwisdom]

It's a daft question really. Obviously there will be a margin of safety
designed in - the rim isn't just about to collapse at the point where
the indicators appear so you needn't panic. But the longer you ignore
the indicators
the greater the risk of getting it wrong and having a breakdown on the
road. This might be sooner rather than later if you hit a big bump or
something.

cheers
Jacob

 

[dkahn400]

normanwisdom wrote:
> It's a daft question really. Obviously there will be a margin of safety
> designed in - the rim isn't just about to collapse at the point where
> the indicators appear so you needn't panic. But the longer you ignore
> the indicators
> the greater the risk of getting it wrong and having a breakdown on the
> road. This might be sooner rather than later if you hit a big bump or
> something.

It's worse than that, Jim. The rim is likely to fail explosively. It's
happened to me twice - once fairly recently. If you happen to be going
fast at the time, or cornering, or riding in the vicinity of a motor
vehicles, or even all three, that could be very nasty. Big bumps don't
come into it. The rim may fail without warning while you are simply
riding along on a smooth surface. There may be enough bits of rim
sticking out to stop the wheel from rotating, and even if it does keep
going round the tyre will almost certainly come off if you are going at
any kind of speed.

The appearance of the wear indicators means that the rim needs
replacing. The question is, how soon. If they're just beginning to
appear you're probably OK for the time being. Once they are clear all
round the rim I really think you should stop riding on it.

--
Dave...

 

[dkahn400]

Alan Moffatt wrote:
> This is the first set of rims that I've had (Mavic T224s) with the internal
> wear indicators, which are now becoming visible. Does anyone know how much
> warning they give you, as the rim doesn't seem nearly as worn as I would
> previously have let it become? I'm obviously planning for a new wheel, but
> should I be panicking?

You don't need a whole new wheel, but you do need a new rim.

--
Dave...

 

[normanwisdom]

dkahn400 wrote:
> normanwisdom wrote:
> > It's a daft question really. Obviously there will be a margin of safety
> > designed in - the rim isn't just about to collapse at the point where
> > the indicators appear so you needn't panic. But the longer you ignore
> > the indicators
> > the greater the risk of getting it wrong and having a breakdown on the
> > road. This might be sooner rather than later if you hit a big bump or
> > something.
>
> It's worse than that, Jim. The rim is likely to fail explosively. It's
> happened to me twice - once fairly recently. If you happen to be going
> fast at the time, or cornering, or riding in the vicinity of a motor
> vehicles, or even all three, that could be very nasty. Big bumps don't
> come into it. The rim may fail without warning while you are simply
> riding along on a smooth surface. There may be enough bits of rim
> sticking out to stop the wheel from rotating, and even if it does keep
> going round the tyre will almost certainly come off if you are going at
> any kind of speed.
>
> The appearance of the wear indicators means that the rim needs
> replacing. The question is, how soon. If they're just beginning to
> appear you're probably OK for the time being. Once they are clear all
> round the rim I really think you should stop riding on it.
>
> --
> Dave...

Theres only one indicator each side (a cut-out from the inside) on my
ex-rims (mavic 221? or something) on a dawes galaxy.
I had a MA40 rim collapse once. It first showed as bumpy braking and I
noticed the rim spreading sideways from a circumferential crack in the
middle of the braking area of the rim. We were about 15km from the
Roscoff ferry. Just made it but the bike was un-rideable when we got to
Plymouth. Another 5km distance and we would have had a tedious problem
- and it was belting down with rain!
On the other hand if you just pootle about gently not far from home you
could risk delaying replacement a bit longer but you might not get any
warning when it finally goes.

cheers
Jacob

 

[dkahn400]

normanwisdom wrote:

> I had a MA40 rim collapse once. It first showed as bumpy braking and I
> noticed the rim spreading sideways from a circumferential crack in the
> middle of the braking area of the rim. We were about 15km from the
> Roscoff ferry. Just made it but the bike was un-rideable when we got to
> Plymouth. Another 5km distance and we would have had a tedious problem
> - and it was belting down with rain!

I've had one go like that as well - a relatively new rim with little
brake wear. If they start to do that you can let some of the air out of
the tyre to reduce the risk of an explosion. A couple of the people
here might remember it from last year's York Rally. I'd ridden the last
20 km or so with the rear brakes disconnected to allow the bulge to
pass the brake blocks. Of two Ambrosio Evolution rims I bought at
around the same time, one developed this bulge on the way to York and
the other, on the front, exploded without warning at the Severn Bridge.
Earlier in the ride I'd got within a gnat's whisker of 50 mph so I can
count myself extremely lucky it didn't happen then.

--
Dave...

 

[dkahn400]

normanwisdom wrote:
> dkahn400 wrote:

> > The appearance of the wear indicators means that the rim needs
> > replacing. The question is, how soon. If they're just beginning to
> > appear you're probably OK for the time being. Once they are clear all
> > round the rim I really think you should stop riding on it.

> Theres only one indicator each side (a cut-out from the inside) on my
> ex-rims (mavic 221? or something) on a dawes galaxy.

Jacob is correct. Some Alesa rims, for example, have as a wear
indicator a groove that appears all the way along the braking surface.
That's what I was thinking of. However, I've just checked a Mavic
technical manual, and their indicator is a little hole that appears in
one spot where there are 2 yellow arrows on the sticker, opposite the
valve hole. There's one on either braking surface but the manual warns
that as soon as one of them appears it could be dangerous to continue
using the rim. So, Alan, you should not really assume that there's any
safety margin.

--
Dave...