A rash of carbon fork steerer breakages has some concerned.
A small but concentrated group of mid-Atlantic road racers have recently broken the carbon steerers on their 2010 Trek Madone 6-Series bikes. While the regional nature of the reports is probably a coincidence, there does appear to be a pattern indicating that incorrect stem installation — and even stem choice — could lead to catastrophic failure. And at least one racer whose fork broke mid-race is convinced that the 6-Series Madone steerers are prone to breakage even when all of Trek’s instructions are followed.
Trek says installation and compatibility problems are at fault and notes that the same concerns apply to carbon steerers from other manufacturers. The company is working with the Consumer Product Safety Commission on a consumer alert, and has made a running change to add material to 6-Series Madone steerers.
In recent years, the CPSC has announced recalls of carbon road or ‘cross forks from Giant, Salsa, Felt, Novara, Raleigh, Redline, Cervelo and Reynolds, although it’s not clear if any of these recalls involved steerers breaking at or below the stem, as with the recent 6-Series Madone failures.
All owners of forks with carbon steerers should pay attention to the concerns raised and installation instructions when installing or buying aftermarket stems.
The cracks begin to appear
Saturday, May 15, began like any other race weekend for Washington, D.C.,-area Category 2 road racer Bryan Vaughan. He suited up and spun to the start line of the Poolesville Road Race on his 2010 6-Series Madone. The race traverses a rolling 10-mile road circuit with a 1.5-mile stretch of gravel and dirt road. The Pro/1/2 field was slated to do seven laps.
On lap 4, shortly after entering the dirt,Vaughan pulled up on the bars to accelerate. He felt the handlebars come off in his hands and crashed hard into the gravel.
Vaughan’s steerer had sheared off just below his FSA stem.
The next week, one of Vaughan’s teammates stood on the pedals of his 2010 6-Series Madone to pull away from the start line of the Bike Jam Pro/1/2 criterium in Baltimore. His bar and stem suddenly separated from the bike and he crashed, although at a much slower speed than Vaughn. As with Vaughan’s, the steerer tube had sheared just below the stem.
The list of broken 6-Series Madone steerers grew by one when Paul Wilson’s broke during the Wilmington (Delaware) Grand Prix on May 22. With five laps to go in the Category 3 field, Wilson was hoping to earn the last few upgrade points he needed to move up to the 2s.
“There are small manholes and cracks in the road,” related Wilson. “I hit one of those and I heard a … it sounded like metal clanking together … I got out of the saddle and felt the handlebars move,” he continued. In fact, his steerer tube had cracked.
Vaughan has begun a mini crusade to get to the bottom of the issue.
Riders on another Trek-sponsored team told him they had experienced two steerer tube failures in just one weekend in April.
Since then, Vaughan turned to Trek, the media, and the Consumer Products Safety Commission in an effort to bring the issue to light.
Trek points to incompatible stems, incorrect installation
Trek says over-tightening stem bolts, incorrectly placing spacers above and below the stem, and using incompatible stems can all cause point loading (uneven clamping force) on the steerer tube, weakening it and causing it to break.
“As the technology going into today’s bicycles has increased, so has the responsibility of the mechanic and rider to follow the manufacturer’s installation instructions exactly,” reads Trek’s statement. “This issue is not unique to Trek, but is specific to carbon steerers from every manufacturer.”
According to Trek, there are three keys to safe and successful installation of a stem on a carbon steerer:
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.
Vaughan’s FSA stem was incompatible with the steerer, Trek said.
(RELATED: More on Vaughan’s situation)
Last fall Trek warned its dealers about compatibility and installation issues, which also are covered in bike owners manuals and on the company Web site.
Trek’s Ben Coates said Team RadioShack has used 6-Series Madones and Bontrager stems all season without incident.
(RELATED: The entire Trek statement)
Finding fault with FSA?
Trek said Vaughan’s FSA stem was “not compatible with any carbon steerer from Trek and most likely any carbon steerer from any bike company.”
But no one at FSA was aware, until told by VeloNews on June 8, that Trek disapproved of their stems. FSA isn’t convinced they’re to blame and points to poor installation as the more likely culprit.
“To say that it’s not compatible is a little odd to me,” said Max Ralph, FSA marketing manager. “There are lots of stems on the market that are designed similar to ours.”
Ralph also felt that Trek’s categorical disapproval of FSA stems wasn’t fair. “We have stems on the market that are designed very similar to Bontrager’s, with clamps that wrap fully around the steerer.” He added, “The way we see it, every stem we make is ‘carbon friendly.’ We are all riding FSA stems on bikes with carbon steerers, daily, here at the office,” he said. Ralph also pointed to FSA-sponsored ProTour teams like Liquigas riding bikes (in their case, Cannondale) with carbon steerers and FSA stems.
Furthermore, Ralph is concerned that to his knowledge, there’s no remedy in place for riders using an FSA stem that might walk into a bike shop only to be told that Trek doesn’t approve its use.
Trek marketing director Dean Gore elaborated on Trek’s stance regarding FSA stems, saying, “Trek does not ‘approve’ stems from anyone outside of the original stem that came with the bike. There are far too many stems on the market with too many variables that change too often.” He said that using the service bulletin guidelines should help customers determine which stems would be safe and “carbon-friendly.”
(more on page 2 – Installation as critical as design)