The weak point in the Strida bike for many Strida owners is the rear hinge joint. This hasn’t always been the case. Older Strida bikes rear hinge joints were constructed with better quality fasteners. This post introduces the Strida TriLock rear hinge join system.
What is the Strida Rear Hinge Joint?
The Strida rear hinge joint is the bolt and washers that hold the bottom tube to the seat tube at the Strida rear wheel. When folding the Strida these two tubes swivel on the end of the axle held in place by a bolt, a small washer and a cup or spring washer. As the video shows what can go wrong with this joint is when the sharp edge of the steel cup spring turn against the soft aluminum tube and it then wears a grove in the aluminum tube. This can happen over time and is more likely to happen with a stronger or heavier rider.
There is a lot of pressure at this point as compression of the cup spring holds this joint tight. Compressing the cup spring provides movement so that the bottom tube can be slipped into the front tube when folded. This last sentence may only make sense to a person who has folded a Strida bike!
What Goes Wrong
Two things go wrong with the current design. One, the small washer that is meant to pivot on the top of the cup spring is too soft and quickly deforms. Two, the result of the small washer deforming often means the cup spring moves on the bottom tube resulting in groves cut into the tube. This combination results in loss of tension and can produce a noticeable sound of creaking when pedaling the Strida bike. And severe damage can be done to the bottom tube over time.
What you need to look for in this video is that the cup spring is turning against the tube. This will cause wear and is not good.
The pivot point should be between the small washer and the top of the cup spring.
Some Good News
Myself and many others have been concerned about this issue for many years. I have made available a rear hinge upgrade kit in the past. It has been successful but not necessary the easiest to install. But now we have the TriLock rear hinge system. Designed by Mark Sanders, the original designer of the Strida bike more than 30 years ago.
Strida TriLock Rear Hinge System
Designed by Mark Sanders, manufactured and packaged in Austria, the new Strida TriLock rear hinge system solves an issue many Strida owners have struggled with, a loose and creaky rear hinge joint. Product and information can be found here.
The TriLock hinge system uses a plastic thrust washer to protect the aluminum bottom tube. On top of the thrust washer is a stainless steel cup spring held in place by the TriLock nut. Three set screws hold the Trilock nut tight as they tighten against the end of the axle. A 8mm set screw threaded into the axle is what holds the TriLock nut in place.
Installation Instructions
Notes
Please note,
#1 in the instructions, no glue or Locktite. For added security Locktite can be used.
#3 in the above instructions, the original Strida spring washer will not fit.
#5 in the instructions, the spanner needed is 22mm.
#5 in the instruction, with the Strida EVO three speed bikes the bottom tube is heavier, as such it is difficult to adjust the tension so the tube does not drop.
Link to my blog post of a few years ago that explores the Strida rear hinge joint problem.
