SHORTENED BOOM … SOMETHING TO BE AWARE OF


When buying a used trike it is very possible that someone has shortened the boom … cut the end off so that it can go down into the outer tubing further. This is more common than you might think or expect. My own boom has been shortened as it would not go in far enough to adjust to my X-seam. Recently on Facebook Recumbent Trikes Group this picture was posted.

Trident frame crack on boom

Upon taking a close look at it I figured out what happened to cause this. Can you spot it?

No doubt when the boom was extended out it was not noticed that it no longer was inserted back all the way inside the outer tubing … past where the slot is. This greatly reduced the strength of that area of the frame as both the inner and outer tubing need to be together to provide their combined strength. Without the smaller diameter inner tubing the larger diameter outer tubing lacked the strength needed to withstand the stress load placed on it. That is what led to the crack happening. And, of course, the weakest point is right where the crack occurred … at the end of the slot. Indeed, many people would not notice this if they didn’t know about it. That is why I am posting this article about this to help others to know about this and prevent it from happening to them. It is imperative that the boom goes back into the outer tubing far enough to provide this strength needed.

The good news is that Trident is covering this for the owner under warranty. If it would not be covered by the warranty this is a steel frame which can be repair welded rather than have to replace the entire frame. The boom, of course, will either need to be replaced or lengthened by a qualified weldor. It would do no good to repair weld the crack and reassemble it using the same boom as this would only happen again.

Others report that Trident trikes are known for using poor quality steel and having cracking problems. If this is true then it is sad as one should not have to deal with such a thing. Buying any product you should expect it be made of quality material. I assumed that these were chrome moly frames which would be stronger than mild steel, but apparently they are mild steel and therefore not as strong. That is mighty thin tubing to be using if it is indeed only made of mild steel.

I don’t know if this boom had been shortened. This particular trike was sold by a dealer and not purchased used by it’s current owner. It was a “demo” model. If the boom had not been shortened then there is a problem in that it is too short to reach where it needs to back into the outer tubing. Like I said, I don’t know the story on this particular boom. BTW, Trident offers a longer boom for riders with longer X-seam than what the standard boom handles.

Trident reports: “Standard Boom length on all Spikes gives you an X- Seam range of 36 1/4” – 43 3/8”.  Long Booms are available at no charge (exchange for your standard boom) which will give you an X Seam Range of 36 1/4 – 47 1/4 “ In addition your standard boom can be cut down to accommodate X Seams as low as 32 ½” with the use of 152mm Crankarms.”

I do know this … shortened booms happen. Be on the lookout and don’t be a victim. This is not something you want to go thru. We all want to …

KEEP ON TRIKIN’

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About Steve Newbauer

I have a few current blogs (tadpolerider1, navysight, and truthtoponder) so I am keeping busy. I hope you the reader will find these blogs interesting and enjoy your time here. Feel free to email me at stevenewbauer at outlook.com

Posted on August 12, 2015, in construction/design, maintenance/repair, tadpole trikes, tips and tagged , , . Bookmark the permalink. Comments Off on SHORTENED BOOM … SOMETHING TO BE AWARE OF.

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