Rim Check

What happens when a rim wears out

If you're lucky, you'll be pumping up your tyres nice and hard, you'll hear a crack, then nano-seconds later you'll hear a loud bang. When the dust settles and you've recovered from the shock, you'll notice that a razor sharp aluminium hoop has parted company from your wheel. You'll also notice that your tyre sidewall is probably ripped and your tube is history.

If you're unlucky, the same thing will happen to you when you're out riding. You can fill in the rest...

The image below shows a rim from a customer who didn't know there rim was worn and replaced a tube & this is what happened when he tried inflating the new tube.

IMG_0688[1]

What to look for

Visually inspect your braking surfaces for excess wear. Usually this manifests itself as a concave profile on the rim. The easiest way to see this is by placing a straight edge (e.g. a metal ruler) across the rim surface. You'll see a significant area of daylight between the rim and the ruler if wear is excessive.

Also look for grooving running around the rim, often caused by grit lodged in the brake blocks. These grooves can be the first places that the rim can fail.

Wear indicators

However, don't confuse these grooves with wear indicator grooves found on some rims. These handy features show you when it's time to replace the rims - when the groove disappears, it's time to go shopping. Some manufacturers have other systems to show when rims need replacing, such as indentations or holes that appear at a certain point when the rim needs replacing.

Not all rims are created equal

Some rims, especially lightweight ones, have a very thin braking surface, meaning that they have a much reduced service life. Heavy duty touring rims like Sun Rhynos, Alesa Endeavours and others have a thicker, heavier braking surface which results in much higher mileage between rim replacement. Some high spec rims have a ceramic coating which drastically reduces rim wear and improves braking and are well worth the investment for high mileage riders with deep pockets.

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