How to tell when carbide rims are worn out ?

swayzak

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

Monty Dog

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.

cougie

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.

swayzak

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 Dog

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.

swayzak

They're Shimano Deore V -brakes.

Bike is here ("trekking" spec):


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