I like to ride aerobars facing slightly upwards. The Speed concept bars allow a small degree of angle. I would like more, but this is about as far as it will go.
However, when keeping aerobars at this angle, seems to place great stress on one of the bolts.
Over time the bolt shears and breaks off.
This happened last year and I put it down to a bad angle of set up.
After getting a replacement bolt set, I took great care to place the bolt into the bracket at the right angle (not stressing it). It was very difficult to tighten this bolt as you have to hold the nut from underneath and then screw down. It’s one of those jobs, where you could do with a third pair of hands.
Unfortunately, I had same experience today, about 12 months after last aerobar failure. Again the bolt sheared away, leaving just one bolt holding everything in place.(at bottom, featured below). Of course, the aerobars come loose and wobbly. I was 40 miles from home, but at least it wasn’t in a race.
Once might have been bad luck or poor set up. But, the second time around I tried everything to tighten up correctly. To happen a second time is a real problem. Also, I know it has happened to other riders.
I contacted Trek and they said
“What I believe could have happened is where you have adjusted the tilt of the bar, you have bottomed out the set screw on the top cradle, if this occurs, the force is put onto one bolt rather than spread between the two. please also make sure the bolts are not being over tightened, all torque settings can be found in your speed concept user manual.
I’m not sure what they mean by set screw, but a fellow rider suggested:
“Tightening the bottom bolt (closest to you when sitting) first. This should angle the bars all the way up. THEN tighten the other both (what looks like the broken one).
There is also the extra smaller grub screw that you tighten LAST – this helps stop the bars moving once position is set.”