Shimano Deore BL-T610 brake levers | broken

[Nicholas]

Hello, bike riders!
Our community member Gabriel has shared his unpleasant experience with Deore T610 brake levers: "After 2 years of very limited use ... I'm still trying to understand why is there so many holes in such a critical place"

Can anyone help by explaining the reasoning for such lever design and what might be the cause of the particular break (material quality, usage, design flaw)?

   

[Nicholas]

Community member John has shared his personal view:

"Well for a start it is only cast aluminium and the tensile strength of the majority of cast metals is limited dependent on the alloy content and casting process etc, that can have minuscule defects (bubbles) in the metal casting reducing the strength...

Though to be honest it is possibly due to a combination of "issues" that caused such a failure, one of them being that the bar securing band hex screw was over tightened...remember that according to the Shimano docs for this lever this should be between 6-8Nm torque and doesn't need to be 'gorilla tight'...!

NB: before anyone asks, yup I always use a torque wrench set to the manufactures recommended setting to nip up bike components, especially on cast alloy fittings...!"

See page 121
https://si.shimano.com/pdfs/dm/DM-GN0001-23-ENG.pdf

[G_M]

Always a good idea to have a glance at torque specifications table!