Steerer Tube Failures: Trek Responds

After a rash of steerer tube failures, Trek has responded blaming incompatible stems and incorrect installation. Trek advises:

1) Always use a torque wrench, and never over-tighten stem clamp bolts.
2) Always use spacers above and below the stem. Although less obvious than correct torque, a minimum of 5mm and a maximum of 40mm spacers under the steerer, plus a 5mm spacer above the stem are required. Riders should factor in these spacers when sizing their bike.
3) Use only the stem brand and model that came with the bike, because not all stems will work with carbon steerers. Often the lighter the stem, the less chance it will be compatible with a carbon steerer. Weight-relieving cutouts on the stem clamp and steerer interface can create stress risers.

You can read the full article on VeloNews. I'd rather just have a slightly heavier bike and be able to change my stem without fear of crashing.

Fork Fail

Here's one from Samuel:

Here's a picture of my late 90s carbon trek after the front fork snapped off. I was biking up Market Street in San Francisco when it happened. No train tracks, no pot holes... just catastrophic failure :-) Luckily, I was going pretty slow, so there were only minor scratches and bumps as I hit the pavement.

This was an aftermarket fork, which was on the bike when I bought it. I've been riding this bike hard through SF and Oakland for 3+ years, so I am not surprised it failed. Looks like an old design where the carbon was glued to an aluminum bracket. The carbon popped off at this junction.

Even if a fork is old, I'd rather the legs didn't pop off. I've seen modern forks fail in the same way, so I'm not sure this is a solved problem.

Mavic Disc Failure

Not exactly sure what's going on with this disc wheel, but that's more than just the tire falling off.

Even More Mavic R-Sys Failures

When it rains it pours. Here is another failed Mavic R-Sys wheel, this time one of the rear wheels which wasn't recalled. The drive side spokes are aluminum, so the wheel didn't fail completely. Still, it would be nice for $1300+ wheels not to explode when hit by road debris.

Full story at bikehugger.com.

Mavic R-Sys Redux

I've blogged about the Mavic R-Sys twice before, and after being recalled in January they are back and already the carbon spokes are breaking again. Velonews.com Editor in Chief Ben Delaney had his front Mavic R-Sys wheel suffer a catastrophic failure, sending him into the ground breaking his shoulder blade. This wasn't the result of a crash or any impact, it simply failed exiting a corner. Carbon spokes just aren't a good idea.

See the full article for more details and photos.

No Carbon Wednesday: Cranks are Still Falling Off

Olympic rowing gold medalist Malcolm Howard is so powerful he just snaps the cranks off of his bike.

No Carbon Wednesday: Cranks Fall Off

Why are so many cranks falling off? It's an epidemic!

No Carbon Wednesday: Crank Falls Off

Crank arms seem to fall off a lot these days. I've seen it on the road, cyclocross and the track. It's always funny to see somebody try and walk with a crank stuck to their foot.

Spinergy Rev-X

The infamous Spinergy Rev-X. A number of catastrophic failures caused Spinergy to pull these wheels off of the market. This was in the 90s, before digital cameras were everywhere, so there aren't that many good photos of them. The Spinergy Accidents page only exists in the Internet Archive Wayback Machine now. Soon these wheels will be completely forgetten.