Mavic A319 rims
Greetings all
I've just been fitting new tyres to my tourer (a 2007 Claud Butler Dalesman). The front wheel is the original from when I bought the bike in 2007; the rear I replaced in 2010 with an M:Wheel A319 - appears to be a like-for-like replacement: same rims - Mavic A319, and same hubs - Shimano Deore.
Worryingly, I discovered a couple of little holes in the rim of the front wheel, on the braking surface. What was strange was that they were in the same position on each side. A quick search on google brought up this pdf from Mavic which describes two types of wear indicators: a little hole which appears on each side, in the position pointed at by a yellow arrow on the label; or a groove in the centre of the braking surface which becomes shallower and eventually disappears. There's my answer.
When I inspected the rear wheel however, it doesn't have the yellow arrows on the label, and I don't recall there being a groove in the rim when it was new. It seems strange to me that with two of the same rims, one would have a wear indicator and the other doesn't. Nothing looked amiss on close inspection - no holes, grooves or cracks, although it is slightly concave when I put a straight-edge against it. Does anyone know how I can tell if the rear rim is safe to use? The pdf above says to use a depth gauge to check there is no more than 0.4mm wear - but I don't have a gauge, and don't know the original width to compare mine to!
Thanks!
Iain
I've just been fitting new tyres to my tourer (a 2007 Claud Butler Dalesman). The front wheel is the original from when I bought the bike in 2007; the rear I replaced in 2010 with an M:Wheel A319 - appears to be a like-for-like replacement: same rims - Mavic A319, and same hubs - Shimano Deore.
Worryingly, I discovered a couple of little holes in the rim of the front wheel, on the braking surface. What was strange was that they were in the same position on each side. A quick search on google brought up this pdf from Mavic which describes two types of wear indicators: a little hole which appears on each side, in the position pointed at by a yellow arrow on the label; or a groove in the centre of the braking surface which becomes shallower and eventually disappears. There's my answer.
When I inspected the rear wheel however, it doesn't have the yellow arrows on the label, and I don't recall there being a groove in the rim when it was new. It seems strange to me that with two of the same rims, one would have a wear indicator and the other doesn't. Nothing looked amiss on close inspection - no holes, grooves or cracks, although it is slightly concave when I put a straight-edge against it. Does anyone know how I can tell if the rear rim is safe to use? The pdf above says to use a depth gauge to check there is no more than 0.4mm wear - but I don't have a gauge, and don't know the original width to compare mine to!
Thanks!
Iain
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Comments
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There's been a fair few threads on here search rim wear or similar should bring them up. General consensus is that once the rim reaches <1mm thick they are done regardless of how thick they were to start with. Most seem to be in the 1.3-1.4 range when new so fits with your 4mm wear guide. Measure thickness with calipers some use normal ones with bits of spokes to measure below bead but Iwanson Crown Dental Calipers will fit round the bead.
http://www.ebay.co.uk/itm/DENTAL-METAL- ... 05625716340 -
Thanks, I've ordered one of those calipers and will measure the rear wheel when it arrives.
I'm surprised, with all the searching I've done today, that the front rim has lasted as long as it has! The holes have probably been there for ages and I've been oblivious to it :shock:0
