Internal rim wear indicators

[gregoryoftours]

Found a hole in my Mavic A319 rim, to my surprise it's actually a wear indicator, but internal only, no divot or channel in the outer rim surface. Quite neat! No sign or mark until the rim is ready for replacement

The front rim is not quite there yet:

I remember that I got a real shock once checking somebody's bike over and their rim had a gap the whole way around that you could stick a screwdriver in, due to the design of wear indicators on Rigida rims.

[Brucey]

it isn't a bad design, is it?

[plancashire]

it isn't a bad design, is it?

Not bad? It is far superior to the exterior circumferential groove for two reasons. It doesn't reduce the surface area for braking. It is a positive indication: a hole looks bad. If you never noticed that your rim had grooves and you take it to a workshop and it now has no grooves, is it worn out or just never had grooves?

[Cugel]

it isn't a bad design, is it?

Not bad? It is far superior to the exterior circumferential groove for two reasons. It doesn't reduce the surface area for braking. It is a positive indication: a hole looks bad. If you never noticed that your rim had grooves and you take it to a workshop and it now has no grooves, is it worn out or just never had grooves?

Shoulda got disc brakes.

[Nearholmer]

Smart. Very.

[cycle tramp]

it isn't a bad design, is it?

Not bad? It is far superior to the exterior circumferential groove for two reasons. It doesn't reduce the surface area for braking. It is a positive indication: a hole looks bad. If you never noticed that your rim had grooves and you take it to a workshop and it now has no grooves, is it worn out or just never had grooves?

Shoulda got disc brakes.

Okay... all the disc-ies on that side of the room (look, you can fight about whether or not cable or hydraulics are better, later) everyone else, the other side.... ah, the guys with the lost, bewildered expressions, er.... that's both of you- you must be the drum brake team.. its up to you which side your on, its not like anyone's really listening.....
....okay, everyone just check that no bricks, barbed wire, or explosives have 'magically' appeared in your handbags...
Okay, on the blow of the whistle...

[scottg]

Shoulda got disc brakes.

Specialized is going to reinvent spoon brakes,
but hydraulic.
Never wear out a disc, rim or brake pad again.

[Brucey]

it isn't a bad design, is it?

Not bad? It is far superior to the exterior circumferential groove for two reasons. It doesn't reduce the surface area for braking. It is a positive indication: a hole looks bad. If you never noticed that your rim had grooves and you take it to a workshop and it now has no grooves, is it worn out or just never had grooves?

Shoulda got disc brakes.

naaah, he'd probably have been better off with drum brakes, wouldn't he?.....

[jimlews]

The next big thing:
Wireless electronic braking !
What could possibly go wrong ?

[axel_knutt]

Found a hole in my Mavic A319 rim, to my surprise it's actually a wear indicator

How old is it, they stopped putting those on at least 15 years ago. The T520 I bought in 2002 has them, as does an A719 from 2006, but neither of the A719s I bought in 2009 & 2012 have them. Considering Chris Juden's comments in the CTC mag below, I've always assumed they must have been forced to remove them for infringing someone else's patent.
.

[torrens]

The next big thing:
Wireless electronic braking !
What could possibly go wrong ?

The ABS, if you don’t change the fluid frequently enough?

[gaz]

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Wear indicator, when the whole appears you need a new bike .

[gregoryoftours]

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Wear indicator, when the whole appears you need a new bike .

Oh yes! I didn't realize that it's actually indicated on the label. It is on mine too, I just never noticed.

In reply to the question about the age of the wheels, they are probably at least 15 years old, I got them as a spare set of wheels with an old 90s Dawes galaxy I bought on eBay years ago. They have Cannondale hubs with cartridge bearings . Never got around to using them until a couple of years ago.

I had a couple of A319 in store as replacement and you are quite right, they don't have these indicators. A bit of a shame as they were a very neat and unobtrusive solution. I really don't like the painted channel that runs right around the braking surface of many other rims.

[plancashire]

What is the usual thickness of rims when new? Or is there no such norm? I ask because I have just measured the rims on my old Brompton (2004) and find they are 1.33 mm. They have no wear indicators; hole or groove, but I assume this is safe. If I knew the original thickness I could estimate the rate of wear and predict their remaining lifetime, which could well be longer than mine.

[LWaB]

Somewhere around 0.7-0.8mm remnant thickness is as much as I dare. I have failed a rim that got slightly below 0.7mm.