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 rider’s 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?

 

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.

 

 

Don't worry about it.. While the new bikes are stiffer, there is still plenty of flex.. The good thing is, no rubber mounts.

 

@Max Headflow, I have never owned a rubber mounted bike. I rode a 2017 Lowrider which was nice. What do you not like about rubber mounts?

 

Yup. The Marathon was 12 inches longer than the regular Checker model used as a cab. Weighed 3 tons. Had a 405 V8. It was an unkillable beast.

 

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.