Tandem Cycling - Handlebars sheared off on right side of stem.

Couple on the OCW Tandem ride today got lucky. Just as they stopped because one of the single bikes broke a spoke the right side of the bars sheared off right at the stem. Next turn would have been a damp 40mph downhill.
Santana Team AL that they bought used. My guess is these first were built around 1996???
Original bars and they did crash the bike a few years ago I think.
Just imagine how ugly that would have been on the downhill with a pack of Tandems and singles?:eek:
Check your equipment often!:thumb:

I can hardly believe it. I've never seen handlebars fail.

I can hardly believe it. I've never seen handlebars fail.
Like I said it had crashed sometime back but these are the Modolo that Santana puts on all their bikes.

We had the same issue while climbing a steep road. Ours was a new Santana with the Modolo bars. In our case the stoker's quick reaction save the day. We reported the issue here:

http://www.bikeforums.net/showthread.php?t=134833&highlight=santana+modolo

Years ago, my aluminum handlebars on a single bike sheared off right beside the stem just as I mounted it. The sudden loading as I put my weight on them was the last straw I guess. And I'm only 140 lb., never raced. The bike did have a minor crash several years before when I lost control running onto a gravel shoulder and dumped. I suppose the handlebars took some impact, but I never really thought about them after that. Also saw a bar break in the same place when the rider mounted and settled onto the bike, same mechanism. Crash history unknown.

Check your handlebars for sag. If the centre-to-centre distance at the drops is not the same as when you bought them, they have bent somewhere. We know how much aluminum likes bending, because a bend is really a crack. And replace them when you crash.

Is this the result of an over-torque issue? I don't think there would be a torque spec unless there was some chance of damaging the AL handlebars. How many of us (or how many LBS) use a torque wrench on the stem? I think I'll go over our daVinci tomorrow and retorque a few bolts.

Seen a 'tana fork break as couple came to a stop to rest after topping a steep climb several years ago.
Have personally broken tandem frame at 50,000 and one more time at 56,000 miles. Broken one experimental tandem fork blade after 15,000 miles. Neither caused accident/injuries.
Pays to to keep an eye on your equipment. Metal fatigues and stuff happens quite unexpectedly.
Pedal on TWOgether!
Rudy and Kay/zonatandem

Had the same thing happen to me once, was going slow in the neighborhood, walked home no one hurt. Just thinking of what happened to George Hincapie at Paris Roubaix a couple years ago OUCH.
It can happen fast not much you can do.

We(I) cracked our Modolo handlebars on out Santana. The problem was that I torqued the aero bars too tight when I installed them, or at a later date. One day I found 4 horizontal cracks while doing a routine inspection. I don't know how long they were like that. They hadn't failed. and I replaced them immediatly.

Rick

Some people suggest that handlebars be replaced every 20 to 25 K miles because fatigue could cause a sudden break. I do think that tandem handlebars get more stress than the bars on a single bike. Maybe the 31.8 clamp diameter is less likely to break.
Sheldon Hall
Greenfield, IN

I do think that tandem handlebars get more stress than the bars on a single bike.
Sheldon Hall
Greenfield, IN

It takes more upper body strength at the bars to climb a steep/slow hill on the tandem than on a single.

Is there such a thing as a tandem specific handlebar? Seems to me that I do "load" the handlebars a lot more on the tandem than on my single. Just keeping the bike upright when we're at a traffic light requires a heavier hand, since we've decided to keep the stoker clipped-in (so I'm statically balancing her weight when stopped). I have also noticed that tandeming is definitely a bigger upper body workout than riding a single.

My wife and I are new to tandems, but it shouldn't require much effort at all to balance the bike at a stop. I assume you're still clipped in with your start leg. The down leg ought to be doing what little work is required to keep the shiny side up.Is your stoker leaning perhaps?

Very little use of the bars for us at a stop. All the balancing takes place between my right leg on the ground and my left hip against the saddle. I always have at least one hand on the bars and a brake just for safety.
Helps that my wife sits quietly and centered.

Is this the result of an over-torque issue? I don't think there would be a torque spec unless there was some chance of damaging the AL handlebars. How many of us (or how many LBS) use a torque wrench on the stem? I think I'll go over our daVinci tomorrow and retorque a few bolts.

Unlikely, Aluminum handlebars are designed to take a fair amount of force where they are designed to be clamped (the post below about aerobars is a different issue because you're clamping the aerobars to a place not originally intended to be clamped). For about 100 years people have been clamping AL handlebars without torque wrenches.

Most likely the bar simply failed from cummulative fatigue, probably accelerated by unseen damage from the crash that was mentioned.

Aluminum does not have a fatigue limit (unlike Steel and Ti.) This mean that every time an aluminum part is stressed, (even a minor stress) it is one cycle closer to its ultimate failure.

Aluminum handlebars do fail just from normal use. Also they can corrode under the tape from heavy sweating, particularly in humid climates, and or used on trainers. So you need to periodically inspectyour handlebars, and the 25k replacement policy would not be a bad idea.

The July issue of Velo News has an interesting article on aluminum handlebars. In the last two years the implementation of European Standards have changed aluminum handlebar design. The weights are all over 230 grams, an increase of 30 grams. These changes make the tubing thicker, many eliminate cable groves, and drop and reach were shortened to reduce weight and decrease leverage. The changes should make aluminum handlebars stronger and last longer.

The July issue of Velo News has an interesting article on aluminum handlebars. In the last two years the implementation of European Standards have changed aluminum handlebar design. The weights are all over 230 grams, an increase of 30 grams. These changes make the tubing thicker, many eliminate cable groves, and drop and reach were shortened to reduce weight and decrease leverage. The changes should make aluminum handlebars stronger and last longer.

True, however, the handlebars in question were certainly beefier than the handlebars Velonews was testing.

I think there are very good reasons that the new road bar standard is 31.8mm. Just like in frame tubing, larger tubes are stiffer and stronger, and are even lighter. Small tubing is cheap to manufacture, jig, and weld. Even the boutique Italian handmade frame craftsmen (Colnago, Olmo, and others) started using oversize thinwall steel tubing in the late 80s early 90s before going over to carbon and aluminum.

I always get the current Santana and Co-Motion catalogs every year because I like to see how the spec for tandems changes over time.

Every year since I've gotten into tandeming I've felt that what gets spec'd on a Santana tandem has more to do with profitability than performance. Santana bikes are just dripping with components you wouldn't want on a $1500 Shimano 105 equipped single. Modolo used to make very high end stuff in the 70s & 80s, including some of the best brake levers and brakesets around. Even Mavic sourced some of their brakesetsf from Modolo. They make very cheap price point stuff now.

It wasn't a month ago and we saw the steerer tube on a Santana fail, and luckily again no one was hurt. It turns out that the sleeve that Bill McReady says came on every 1" tandem including the prototype only went up a couple of inches into the steerer. Guess where their steerer tube broke, yep, right above where the sleeve ended.

Take this opportunity to upgrade the controls if you own a Santana tandem. They are very good at marketing, not so good at making great tandems, and apparently, safe tandems.

I had exactly the same experience on my commuter bike about a decade back. I had just pulled away from a stop sign when the bar simply collapsed on the right side. I was lucky and didn't even fall. If I had made it another 1/4 mile down the rode I would have been on a long, steep, fast descent. I was spooked for years afterwards thinking about how they might have worked out. I have made it a point since then to buy good quality bars and not keep them too long. I imagine the newer 31.8 mm are much less prone to this kind of failure.