Thursday, October 15, 2015

Broken Crank Brackets

Broken Crank Brackets
As I mentioned several times, I’ve been fairly busy lately and this prevented me from riding regularly.  Last weekend was the Thanksgiving holiday in Canada and I was looking forward to riding my DF.  I had noticed that my crank had moved forward about 3 to 4 cm and wanted to move it back to the right place.  Aluminum has a tendency to slide on carbon fiber.  The same problem occurs on a road bike when you have a carbon fiber seat post on an aluminum or steel frame.  The seat has a tendency to slowly lower and you need to adjust the height from time to time.  Manufacturers have created a compound to provide better grip between the two materials.

Before leaving for the weekend, I opened the hatch and loosened the four bolts to move the cranks to the proper place on the boom.  In the process, I found that the two brackets were broken.  To some extent, I was not surprised, in the past couple of weeks, I read several posts from DF riders who had the same issue.  Their description was not unfamiliar to me including the movement of the crank on the boom, creaking noise when pedaling or sluggish feeling when pedaling.  I had noticed two symptoms: the sound and could not identify the source and the forward movement of the crank on the boom. 

I contacted Randy at Bluevelo and he’s sending me a new set of brackets.  Unfortunately, as a result I had to abandon my plans for riding over the weekend.

The question remains however: why are there so many failures of these brackets?  The same system has been in use for many years on the Quest and Strada but while a few fail from time to time, the number of failures on the DF is much greater.  I wonder if the difference of the much stiffer carbon fiber boom in the DF compared to the aluminum boom in the Quest and Strada put too much strain on the brackets.  The small flex experienced in the Quest and Strada may provide some protection to the brackets.

Notwithstanding the cause, it looks like a redesign will be considered.  Daniel Fenn has already produced a new stiffer boom for the DF but it is not part of the production, it is a special part used for racing.  The boom is drilled and the crank is installed inside the boom, not on top of the boom.; once installed, it cannot move.  This means that you would probably need to change the position for another rider for example; you would probably need to purchase and install a new boom, as it may not be a good idea to drill several large holes in the same boom.  This would most probably affect the stiffness.

Several alternatives to the current brackets are being discussed including manufacturing the brackets using another stronger material including steel or costly titanium.  Using a round pipe clamp and nylon inserts with square sides to adapt to the square crank mount and boom.  The round shape can withstand a lot more pressure than the current brackets without breaking and they may also be lighter.


Theo van andel announced a price increase due to higher purchasing costs and improvements to the standard equipment of velomobiles. While cost for components have gone up improvements like 3 x10 speed is now standard and so is higher quality color finish with automotive paint, lithium batteries dimmable lights, lower weight full carbon shells and more.

The Strada now has lights, flashers and horn like the Quest.

The price increase will take place November1st.  If you want to beat the price increase, you have until October 30th. Do you want to buy the old price then order for 30 October!


Wim Schermer reported that a new suspension is being tested for the VeloTilt.  It should address some of the shortcomings identified during testing.

Terra Cycle

Terra Cycle is testing a new 23T Sport Idler that could replace the current idler in the IntercityBike DF and DF-XL velomobiles.


  1. I believe the number of broken brackets in Stradas and Quests is quite substantial too, as this topic regularly appears in blogs. At least in my own Strada both brackets broke, and I now always carry two steel DIY replacements in my vm bag.

    Erwin and Tante Lies (my Strada, named after my great-aunt)

  2. Erwin:

    Thanks for the comment. You may be right and a substantial amount of brackets in Quest and Strada may have been broken, I've also read account of this problems. What makes it worse for the DF in my opinion is the number of broken ones in such a short time for the number of DF velomobiles on the road.

    1. Dear Luc,

      Then maybe it's a good idea to make some steel brackets and take these with you. Especially useful if a bracket breaks during a trip.

  3. How feasible would it be to make the brackets from CF? I wouldnt think is would be much extra money since the brackets are so small a piece.

    About the CF boom for racing.Can one order this as an option for a daily runner?

    And hopefully the Idler works out for the better.

  4. Tim, these are good questions, I'm not a carbon fiber expert so I will not speculate but if someone has an opinion, please chime-in. The brackets could also be made of a stronger alloy without any weight penalty bu the cost may be higher. I don't think that the race improvements like the boom or the wheel pants have been made available to the public yet but you would have to ask ICB for sure, these were not available a few months ago when I asked Ymte.

    I'm still waiting for delivery of the brackets, hopefully in the next day or two. then I can test the idlers but the first snow come down today so I may not have much longer to ride this year.

  5. I've broken my brackets too on my Quest XS.
    Theo Van Andel told they had one series with the wrong aluminium alloy. I'm surprised because I bought my Quest 3 years ago... so maybe they have 3 years of brackets production with the wrong aluminium alloy?

  6. I've enjoyed your post and got some valuable tips from your article.Thank you for your post.


  7. My 2014 Quest XS, with 7400 miles on it, broke a bottom bracket clamp about a week ago. It took me time to figure out the problem, and I didn't get it until you pointed me in the right direction, Luc. Checking price & availability at BlueVelo, and considering building a replacement set myself.

    1. Following up on my comment - I have access to a milling machine at work. A retired Ford racing engineer showed me how to operate it, and I made a new pair (2 complete brackets) for my Quest XS from thicker aluminum. I've put about 1,000 miles on them since, and no problem.

    2. Thank you Doug for the update. I'm still waiting on the upgraded brackets designed by a rider in Germany. Hopefully, they will be produced and shipped soon!

    3. Am now up to about 3,000 miles on the replacement brackets, and all's well. I don't think they'll fail, and they were extremely simple to make. Weight went up by a few ounces.