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How to tell when carbide rims are worn out ?

swayzakswayzak Posts: 38
edited September 2010 in Workshop
Hi

I have Grizzly carbide rims / Shimano Deore V-brake / Swissstop Bluesky pads combination on my Thorne Sterling.

I'm new to this - what sign should I look for to tell me the rims are wearing out ?

Also, is normal for the front wheel to judder when coming to halt in the rain ?

thanks

Posts

  • Monty DogMonty Dog Posts: 20,614
    When rims are nearly worn, they start taking a distinctive concave shape as the pressure from the tyre bead forces it outwards - you may experience irregular braking where the rim feels buckled although it is running straight. A close inspection is likely to reveal circumferential cracking around the brake track. You can also measure rim thickness with a micrometer or caliper - minimum thickness is often detailed on the makers tech docs. If you have one or more of the above suggest you look to replace the rim - when they go it can be sudden and catastrophic.
    Make mine an Italian, with Campagnolo on the side..
  • cougiecougie Posts: 22,512
    Rims should last 1000s of miles though - so its not an immediate worry. Some rims have wear indicators, and when they disappear - you've worn x mm off the rim and should replace. Not aware if yours has them though ?

    Inspect the rims when you clean them. You may find cracks before the rims go.
  • swayzakswayzak Posts: 38
    Thanks both

    These are only 4 or 5 months old - maybe done approx. 1000 miles. Will check for shape & cracks.

    And (probably OT) the juddering of front wheel ?
  • Monty DogMonty Dog Posts: 20,614
    Doubt you'll wear out a rim in 1000 miles - usually takes a good few thousand miles. Re judder, I'm assuming you've got cantilever brakes as they most commonly suffer from judder - it can be due to a combination of factors - flexy brakes, a flexy fork or incorrect pad alignment. If the bike's new it can take a while for them to bed-in. First option is to align the pads with toe-in. Next is to fit a fork-crown fitted cable hanger rather than the more usual one fitted with the top headset. More details of your brake set up will help.
    Make mine an Italian, with Campagnolo on the side..
  • swayzakswayzak Posts: 38
    They're Shimano Deore V -brakes.

    Bike is here ("trekking" spec):


    http://www.sjscycles.com/thornpdf/Thorn ... lowres.pdf
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