Trek Speed Concept Aerobars – keep breaking


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.

Thanks for comments

Thanks for people who leave comments sharing their experience with the bolts shearing off. It shows it is a widespread problem and not just due to inadequate set up.

Also, it seems that Trek’s response is inadequate, with no-one able to get a satisfactory solution. Trek just seem to try and fob riders off.


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.”


35 thoughts on “Trek Speed Concept Aerobars – keep breaking”

  1. Hi Tejvan

    Try replacing the bolts with ordinary (but good quality) non-stainless ones. Assuming they are stainless steel bolts, they will be inherently weaker than non-stainless, hardened steel ones.

  2. Did you ever get this problem resolved? I have a friend that has the same problem and the Trek shop has not been able to fix it. He has had it in the shop five times in five weeks

    • sorry no. Trek were not particularly helpful when I enquired. Last summer I ordered a whole replacement set of nuts and bolts, but it never arrived.

  3. Does anybody have an update on the top cradle bolts snapping? Mine have snapped/sheared 4 times. Each time, they have been replaced with the Trek replacement bolts and torqued to spec. I do not live near a Trek dealer so having trouble getting any useful information about this. Thanks.

  4. Hello – I recently had this same issue occur during an Ironman event. I fortunately was not hurt/did not wreck as we approached speeds of over 50mph on the downhills but it did cause me to ride aero-less for a little less than half the distance. The design is on a very high shear point and the bolt’s flat out are failing as they are what i suspect the inappropriate grade for the tensile force applied. The bike is currently at my LBS and I am waiting to hear back the manufacture – if they simply replace the assembly with the same material I will conduct the proper testing to see what replacement hardware is needed to survive in this environment.

    • Hello, thanks for the reply. I have just had my 6th bolt shear and am beyond frustrated. If you have Found a good solution, kindly share here. I am at the point where I no longer feel safe on this bike. Thanks!

      • Nicole,

        The manufacture replaced the entire assembly kit with the same bolt and T anchors. I am doing my own testing at this point on the bike as the original assembly was performed at the Trek dealership and not myself. I have completely disassembled and reassembled the system with the new provided anchors and bolts with Trek recommended specifications and locktite. If the bolt fails again I will than look further into a different clamping system and bolt material (IMO its a matter of when not “if”).

        When designing the bolt and anchor they ovalized the allen bolts to act as a pivot based on where the base bar is set and Anchor angle. The shear rate I can only assume is so low as Trek has quite the warranty on Carbon Fiber components and with components such as this I only assume they designed a bolt to fail before a mono extension carbon failure.

        When speaking directly to Trek the simple answer given was it was an isolated case and unsure of the exact failure. This is a very dangerous situation IMO and I am not 100% certain that a off the shelf bolt can appropriately work to solve the issue.

        The best advice I can give to any hesitant or concerned athlete/owner at this time is to simply sell the bike and look for an alternative as at this point in time the issue does not seem to be resolved from the manufacture (Owner of 3 – 700 series carbon bikes)

  5. My bolts sheered off last Saturday while I was riding at 26mph. Luckily I only suffered a crushed helmet and fractured scapula. This sounds like an on-going problem for sure.

    • And again 11/07/2020 at mile 60 of Ironman Florida. Had to ride back to transition on my base bar into a headwind upright. Cost me at least an extra hour.

      I’m pissed… Probably will see all three of my treks.

      • Omg that sucks! I had to ride my “backup bike” (QR) in Ironman Florida because my Speed Concept has been in the shop over a month due to the broken bolt issue, faulty Di2 wiring n a shitty Project One paint job on a bike I’ve had barely over a year. Trek said they wouldn’t cover any of it! Ugh!

  6. My rear bolt sheared off on a downhill, 30 mph at Ironman Hawaii 2017. I keep my bars level to 1 degree upward tilt which probably increases the stress on the rear bolt, especially downhill with more weight on the front end. I hit a small transverse seam in the road and bang. The aerobar pitched forward and swivelled side to side. Nearlly crashed. Bike in the shop now.

    • Larry – sorry to hear this. I also suffered the same failure during Kona 17 which resulted in a DNF and a broken hand. Glad to hear you did not crash..!

  7. hey All,

    I may have found a solution, but like all of you have conveyed only time will tell.Hang in there with me as i describe what i have done… I have taken off the screw closest to you (the rider), and added a spacer so that the handle bars lay flat, and eliminate the angle that is the root of this design flaw.

    So far it has accomplished two things. First, it allows us to be in a more aero position, and secondly it eliminates the stress put on the screw due to the incorrect angle.

    Process: It involves removing the undercover of the handle bars (three screws), which allows for manipulation of the top side and addition of the spacer (which eliminates the challenge)

    Again only time will tell if this will really work, but as my buddy(an engineer) and I evaluated it, this may be the ticket. Kind of a bummer that we have to collaborate like this given the bike we all own, but i don’t like reading about fellow triathletes getting injured, and possibly hurt much worse.

    Wishing all of you a safe ride. Hope this helps.



  8. I had the same failure. It was in a race but fortunately I stayed upright. I have the bars angled upwards but I don’t really understand why this overstresses that bolt or what I can do about it.

    I’m about to switch over to the alternative aerobar setup (at great expense) which allows you to use generic poles and, therefore get far more upward adjustment. Will this fix the problem?

  9. Hey to all of you;
    I‘ve had the same problem with my new Trek speedconcept during an ironman in Vichy (France) 8/2018.
    The aerobar untightens by itselfs after 25 Miles und i couldn‘t use the aeroposition during the race!!! I‘ll bring it to my bikedealer next week.

  10. I don’t believe there’s a fix for this common issue of the bolts shearing. Mine broke at 32 mph going downhill and I was amazed I didn’t crash. As I wheeled my broken bike into the Trek store a woman was bringing hers in with the same broken bolts!! Mine had been serviced by experienced techs at a Trek store and was only one year old.

    Do a Google search and you’ll find numerous examples. Not sure what to do about this with an expensive bike I like otherwise (except for the rear brake sticking).

  11. This is very concerning. Had the same issue with the aerobar bolts becoming loose. Just recently crashed when the aerobar bolts sheered and during IM Chat had to stop twice to correct loose bolts. At LBS now. I will update post when I get bike back. I’m very concerned and frankly not confident riding the bike.

    • How about Trek providing a solution? What if this was a car and the steering wheel randomly would fall off? I’ve have 3 snap in three years. And my bar is level, not in the praying position. I don’t feel like spending $8k on a new bike. Huge design flaw.

  12. It’s interesting to find that during 2019 Trek changed the design of the Mono bar (and the alternative Mono Plug-in) to accommodate 6mm bolts and T-nuts in place of the original 5mm bolts and T-nuts. Trek also changed the design of the Mono slider to suit the larger bolts. The replacements are referred to as ‘6mm hardware’ versions.
    Mono bar straight W582442
    Mono bar long W582443
    Mono bar short W582444
    Mono bar S bend W582445
    Mono Plugin – W582446
    6mm bolts and T-nuts – 596164
    Mono Slider – W582447
    Officially, the only way to upgrade is to replace all three parts with the new parts although it might be possible to widen the slot in the original 5mm mono bar/mono plug-in and just replace the bolts, T nuts and slider?

    Perhaps unsurprising that Trek appear to have never accepted that the original 5mm hardware was prone to break.

    • Apparently Trek revised the design after collecting the feedbacks on the previous one. If I were to just replace the whole set of basebar + extension bar with a different brand, do you have any suggestion of brands & models that can retrofit into the Speed Concept?

  13. I have 2021 purchased SC and just recently got the issue in race. Bolt was not broken but got loose and could not ride on aerobars. Though I had messed it up myself but maybe not…

  14. Anyone ever get a good answer to this? My rear bolt sheared during Ironman Waco this weekend going down a hill. Amazing I didn’t crash.

  15. I have a 2020 speed concept. Had this issue last year (2022) and had it replaced to specs at a bike shop with locktight. It happened again, less than a year later in a race. All I’ve heard so far, is “use locktight” and it won’t happen again. I’m beyond frustrated.

  16. I wish I had found this post and would have decided not to purchase this model/year of the speed concept. the bolts on mine snapped as well, and thankfully I was slow enough to land my forearms on the handlebars and control to avoid a fall. Now I will be looking for a model with 2 supports instead of the mono. too risky not knowing when the bolts can snap again

  17. This is a thread I wish I found awhile ago. I came up with a simple solution. I placed a third bolt with washers in most front part of the bars. I don’t knownhow to explain this with out pictures but here goes. Imagine having a third bolt that when the bars are that the most prayer like angle and without the standard mono bolts tightened, the extra bolt stops the bars from leveling out. I consider this to be a support bolt. Then I tightened the standard bolts. This way there are 3 bolts that share the load and not just 2…happy to explain further if anyone needs more info. Hopefully this might help someone who still has this bike and suffers this issue.

    • Kris, how did place a third bolt with washers on the front (farthest from the rider’s body)? Did you use the existing channel where the mono brackets are used? Or, did you drill into the mono-plug?


Leave a Comment