Is Flexural Rigidity a bad thing?
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Intermediate
Joined: May 2017
Posts: 44
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From: Cherry
Is Flexural Rigidity a bad thing?
The 2018 M8 Softail frames are supposed to be 34% stiffer than the older Harley's, tho are still designed to flex in certain areas. I remember before 2009 there were stabilizers being sold for the touring models on this issue. To my knowledge frame flex and fork flex have always been a negative design and can cause "death wobble."
Article on 2018 Softails
Cycle world- "A bike with a flexy chassis transmits less of the riders steering effort to the front wheel while the rest gets lost in chassis, handlebar, and fork flex. - Harley-Davidson"
I know sport bike and other companies design flex sports in frame, just thought Harley Softails to be more rigid.
Is it impossible to create a bike with no flex or would that cause significant problems?
Article on 2018 Softails
Cycle world- "A bike with a flexy chassis transmits less of the riders steering effort to the front wheel while the rest gets lost in chassis, handlebar, and fork flex. - Harley-Davidson"
I know sport bike and other companies design flex sports in frame, just thought Harley Softails to be more rigid.
Is it impossible to create a bike with no flex or would that cause significant problems?
Grand HDF Member
Joined: Jun 2010
Posts: 4,584
Likes: 918
From: coast to coast
My '74 Checker Marathon survived 159,000 miles of NYC potholes because it was designed to diffuse jolts and turbulence through frame flex based on 747 airline chasis design. I'm no engineer, but with zero flex you are asking for metal fatigue and fracture as well as transmitted stress of other parts and systems.
Last edited by Thingfish; Nov 10, 2017 at 02:28 PM.
Seasoned HDF Member
Joined: Aug 2010
Posts: 5,173
Likes: 177
From: East Coast
My '74 Checker Marathon survived 159,000 miles of NYC potholes because it was designed to diffuse jolts and turbulence through frame flex based on 747 airline chasis design. I'm no engineer, but with zero flex you are asking for metal fatigue and fracture as well as transmitted stress of other parts and systems.
Grand HDF Member
Joined: Jun 2010
Posts: 4,584
Likes: 918
From: coast to coast
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,899
Likes: 8,006
From: poway
They wear out, cause vibration, handling issues and require maintenance. They are nice because of lower vibes when functioning correctly. Go over to the dyna section and look at the discussions on mounts.
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