Rim Wear?

alancash100
alancash100 Posts: 18
edited October 2014 in Workshop
How do I know if my rims are warn? do they explode when worn out? 4 Year old Khamsins and I'm more of a leisure rider, eg; maybe two 35 mile rides per month, for 4 years.

Cheers,

Al

Comments

  • bondurant
    bondurant Posts: 858
    If there are no rim wear indicators, then have a feel of them. If they are concave on the brake track, then it's time to think about new ones. If they go through under braking it wouldn't be pretty.
    viewtopic.php?f=40012&t=12903952
  • racingcondor
    racingcondor Posts: 1,434
    Deflate the tyres and put a ruler against the brake track. If it touches top and bottom but not in the middle you have some wear (not necessarily enough to require replacement though).

    At 2 x 35 mile rides a month you're riding around 1,000 miles a year so around 4,000 miles, you shouldn't have worn them out yet. There is no hard and fast rule but most rims should last twice that.
  • pinarellokid
    pinarellokid Posts: 1,208
    My khamsins have a black bead Al the way round on the braking service, if that is still there and below the rest of the braking surface then they will still be fine.
    Specialized S Works SL2 . Campagnolo Record 11spd. rolling on Campag Zonda wheels

    http://app.strava.com/athletes/881211
  • comsense
    comsense Posts: 245
    as above with ruler/straight edge, and if you can fit a standard business card between the straight edge and rim it is worn. I bought one of these http://ebay.eu/1y1EXQ4 because I had a front rim disintegrate on a descent. I'll never let it happen again. When a rim is going to go you should feel the brakes pulsing.

    p.s pinarellokid, my khamsins haven't got that wear indicator
  • handful
    handful Posts: 920
    Alternative answer if you are looking for an excuse to buy a new set of Zondas is they are definitely knackered, no question. :wink:
    Vaaru Titanium Sram Red eTap
    Moda Chord with drop bars and Rival shifters - winter/do it all bike
    Orbea Rise
  • keezx
    keezx Posts: 1,322
    My general rule for rimwear: if you see 0,5 mm of wear (hollow) , think of replace.
    Test for fitness for purpose: put 2 Bar extra (more then normal) in the tyre.
    When it survives, its okay.
  • rolf_f
    rolf_f Posts: 16,015
    Bondurant wrote:
    If they are concave on the brake track, then it's time to think about new ones.

    No it isn't - that's far, far too soon. Any wear on the rims will result in a concave brake surface - it can't not do so - there is more brake pad in contact with the middle of the braking track than the edges so it wears more in the middle and wears a concave surface. A concave brake track caused by the alloy wearing away is nothing to worry about - what you need to worry about is a concave brake track caused by the rim edges at the bead spreading due to the pressure of the tyre. The former will have been present for many thousands of miles (eg over 10000 miles) before the latter occurs (see below - first two are good, last one is bad!).

    As said, Khamsins tend to have a wear indicator groove (except the newest ones). As long as that is still visible, the rim should be fine but you can check by removing the tyre and inner tube and checking that the internal width across the rim is still 15.5mm. My Khamsins are on at least 15000 miles (maybe more like 18000) and still going strong.

    rimwear_zps40fa316b.jpg
    Faster than a tent.......
  • MichaelW
    MichaelW Posts: 2,164
    Keezx wrote:
    Test for fitness for purpose: put 2 Bar extra (more then normal) in the tyre.
    When it survives, its okay.

    failure mode for proof testing worn rims is catastrophic. Wear hand and eye protection.
  • andrew_s
    andrew_s Posts: 2,511
    comsense wrote:
    I bought one of these http://ebay.eu/1y1EXQ4 because I had a front rim disintegrate on a descent. I'll never let it happen again. When a rim is going to go you should feel the brakes pulsing.
    I've just retired a wheel due to measuring down to 0.6mm rim wall thickness on one of those gauges. Previous rim failures have been at about the 0.6 to 0.7 mm mark, but I've only been running about 80 psi recently.
    When the brakes start pulsing, its because the rim has started to split, and you don't have very long at all.

    Rim wear is very variable. I've had rims fail in as little as 5500 miles.
  • unit
    unit Posts: 1
    Unless you do a lot of braking, I'd say that it's highly unlikely that you could have worn out the rims with so few miles.
  • wishitwasallflat
    wishitwasallflat Posts: 2,927
    andrew_s wrote:
    comsense wrote:
    I bought one of these http://ebay.eu/1y1EXQ4 because I had a front rim disintegrate on a descent. I'll never let it happen again. When a rim is going to go you should feel the brakes pulsing.
    I've just retired a wheel due to measuring down to 0.6mm rim wall thickness on one of those gauges. Previous rim failures have been at about the 0.6 to 0.7 mm mark, but I've only been running about 80 psi recently.
    When the brakes start pulsing, its because the rim has started to split, and you don't have very long at all.

    Rim wear is very variable. I've had rims fail in as little as 5500 miles.

    I had an Open Pro split when it measused just under 1mm with the same guage so take care if running down to 06 (that said I run at 110 R and 95-100F).
  • alancash100
    alancash100 Posts: 18
    Wow thanks everyone - useful. Looks like the consensus is that they are not too worn yet. Just one thing; they do have a wear indicator, but I've got reservations about it. The wear indicator, a groove, stands proud of the concaved surface around it. Shouldn't it all have worn down with the rest of the rim? Its hard to explain; the wear marker groove should wear flat and disappear, but the rim is wearing around it, if you see what I mean?

    help appreciated.

    Al
  • Bobbinogs
    Bobbinogs Posts: 4,841
    The general wisdom on the CTC pages is that failure can occur typically with a rim thickness of 0.7mm & that folks are advised that it is unwise to ride with a thickness less than 1.0 mm. I bought a vernier caliper set to measure rims where no wear indicator is present and, when concave, just take the smallest measure.
  • londoncommuter
    londoncommuter Posts: 1,550
    Just as an alternative brand, I got one of these:

    http://www.proopsbrothers.com/bicycle-r ... -446-p.asp
  • andrew_s
    andrew_s Posts: 2,511
    unit wrote:
    Unless you do a lot of braking, I'd say that it's highly unlikely that you could have worn out the rims with so few miles.
    I've worn rims out in similar mileages on several occasions, including putting on a new wheel and wearing out the rim before the tyre.
    The reasons twofold:
    a) that I was using shimano brake blocks at the time, which are very good at getting bit of grit or glass embedded in them.
    b) that I ride all winter, largely on small country lanes that are frequently pretty muddy, and often fairly steep.

    I dare say that had I confine my cycling to trundling up and down some dual carriageway in good weather, in search of a PB, and training for the same, my wheels too would have lasted longer, but I didn't fancy the tedium of such things.
  • rolf_f
    rolf_f Posts: 16,015
    andrew_s wrote:
    I dare say that had I confine my cycling to trundling up and down some dual carriageway in good weather, in search of a PB, and training for the same, my wheels too would have lasted longer, but I didn't fancy the tedium of such things.

    I think you'll find that plenty of us spend as much time as you riding along muddy country lanes in winter but manage not to wear out our rims in double quick time. :wink:
    Faster than a tent.......
  • cycleclinic
    cycleclinic Posts: 6,865
    Some pads rolf are harsher on rims than others. Everyone has a different experience. Not evryone can replicate the circumatances you have.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.

Categories