Did You Know? The Story Of The Harley-Davidson Softail Frame.

Softail10Introduced in June 1983 as the 1984 Harley-Davidson FXST Softail, the Softail frame was not designed by the Milwaukee factory. It is the creation of Bill Davis, a Harley enthusiast and engineer from St Louis, Missouri. In 1974 and 1975 Davis worked in his garage on the concept of a rear suspension frame where a swingarm was pivoting at the bottom sprung by a top spring shock absorber placed under the seat. He built a first prototype using his own 1972 Harley Super Glide as the base. After patenting his cantilever design swingarm frame he succeeded in meeting with Willie G. Davidson in August 1976. The story says that Davidson he was very impressed by Davis’s new frame concept and replied 6 months later saying that although the company would not use the new design, it was still interested…

SoftailbisDisappointed, Davis continued to improve his design and got the idea to switch his swingarm pivoting point with the shock under the frame and no more at the top, the big advantage being now to be able to place the traditional Harley oil tank under the seat. Then he went the independent route, starting with partners his own company “Road Works” to produce and market his frame design under the name of “Sub Shock”. The partnership collapsed and Harley executive Jeff Bleustein – who later became the company President & CEO – immediately contacted Davis and made him an offer to sell to H-D all his patents, prototypes, jigs and tooling. The deal was signed in January 1982. Nobody knows, except Davis and Harley, what was the exact financial amount of the transaction, but it always has been rumored as being quite low. The frame required special shocks because working in extension, not in compression, like usually.

Launched in 1984, the first Softail model was a great success, offering a chassis close to the lines of a hardtail frame with the benefit of comfort provided by the rear suspension. The Softail line is one Harley’s best selling and redefined the cruiser genre. Because engine is rigid mounted to the Softail frame, it creates more vibrations than in Touring and Dyna models where engine is rubber mounted to the frame. This issue is partly resolved since the use of the dual counterbalanced version of the Harley Twin Cam engine. Many companies use the Softail style frame, at least on some of their models, from Honda to Kawasaki to Yamaha to Victory.

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28 Responses to “Did You Know? The Story Of The Harley-Davidson Softail Frame.”


  1. 1 CHOPMONSTER66 Oct 29th, 2014 at 9:13 am

    sure would like to get one of the first frames

  2. 2 Manxman Oct 29th, 2014 at 9:37 am

    I may me wrong, but I’m pretty sure most normal shock absorbers work in both compression and extension mode and are valved for that purpose. Have you eve. lifted a softail swing arm? Very heavy but they do look cool.

  3. 3 takehikes Oct 29th, 2014 at 9:49 am

    AEE Choppers built a soft tail frame in the early 70’s. It used a leaf spring set up instead of a shock. Sold only a few if that many but they did build a working riding prototype.

  4. 4 1951vbs Oct 29th, 2014 at 11:09 am

    40 years before the Softail, Vincent Motorcycles designed a suspension that utilized under-slung shocks but opted for a design with shocks under the seat instead. The reason: very limited suspension travel with shocks under the bike. Sounds like a Softail to me!

  5. 5 Mr Dick Oct 29th, 2014 at 11:28 am

    Does HD have any of their own brainwaves? Project Rushmore for example, vent in the fairing-Victory, one handed opening bags-Victory, Goofy looking windshield-Klockworks, big metalflake- lots of guys. I love my Hog, but, come on you guys.

  6. 6 mkv Oct 29th, 2014 at 11:55 am

    Look at that suspension travel. I bet the original would have rode a lot better with more than 2 inches of travel in the rear.

  7. 7 TJ Martin Oct 29th, 2014 at 12:47 pm

    1951 is spot on with his Vincent analogy . It was and still is for all practical purposes a soft tail . Albeit a much better handling and riding soft tail than the underslung bunch can even hope for … never mind equal . But then again .. Vincent did a lot of things back in the 40’s 50’s that have yet to of been equaled by much of anyone . Proof you say ? Have a look at what a Vincent twin’s architecture is capable of with just a few metal and alloy update/upgrades . e.g. The new Godet and Irving Vincent motors 😉

  8. 8 Sean Oct 29th, 2014 at 2:01 pm

    Good to know the story

  9. 9 domino Oct 29th, 2014 at 5:25 pm

    I did not know this history … thankyou …
    When the softails first came out I wanted one so bad cuz of how cool they looked … then I test rode a softail and an FXR back to back … I still have my FXR …

    Domino Dave

  10. 10 john reed Oct 29th, 2014 at 6:05 pm

    Didnt Derek Whitehead the original owner of Santee own the name SOFTAIL

  11. 11 Woody's Oct 29th, 2014 at 6:34 pm

    or maybe the AMEN Savior was the earlier softail?

  12. 12 James just another crazy Kiwi Oct 29th, 2014 at 7:02 pm

    I remember seeing somewhere that Bill ended up working for the factory.
    But that could be my bewildered brain not recalling things correctly.
    Does any one know what happened to him ?

  13. 13 Steve Carr Oct 30th, 2014 at 5:51 am

    Manxman,

    I would challenge you to re-think your post. A “standard” shock absorber in its idle state will rest in an expanded condition, only meant to be compressed, not expanded. Example: Dyna Shock

    The Softail shock works exactly opposite. It’s idle state will rest in a “compressed” condition, only meant to be expanded, not compressed. Example: a Bungie cord

    Hope this helps

    Steve Carr

  14. 14 Trainiac Oct 30th, 2014 at 5:59 am

    The AMEN frame was a variation of the plunger type rear suspension which Inidian actually had way before. There were a couple of companies I believe were making frames like this back in the 70’s or so. (excuse the brain fog) Also, the AMEN frame (I think they called it the Savior?) used a centrally mounted rear axle sandwiched vertically between two coil springs. I never rode one but I would think there was a lot of stiction in that setup

  15. 15 Trainiac Oct 30th, 2014 at 6:01 am
  16. 16 takehikes Oct 30th, 2014 at 7:23 am

    I left out in my previous post that I own a yamaha Road Star which has a softtail type suspension (great bike by the way). I’ve ridden tons of different types and styles of bikes over 40 plus years and frankly the suspension in it is about like something out of the 70’s. Just no room for any kind of stroke at all, Pretty easy to bottom it out…heavy bike and not much stroke is a bad thing. First thing most owners do is put in a progressive spring to try to help things out. Many are adapting air shock set ups or going full boat air suspension including air bags. No way around it, soft tail looks cool but thats it, not very good riding nor handling.

  17. 17 MAGNET MAN Oct 30th, 2014 at 8:09 am

    Interesting History lesson, thank you, Cyril as always.

  18. 18 James Oct 30th, 2014 at 8:38 am

    Back in the day I was running a 66 Shovel on a goose neck Savior frame. It had a 12 over glide frontend. Had the “floating” axle run through blocks sandwiched between lower and upper springs. Seemed a bit crude but it helped with the ride. Ended up going back to stock rake and added some springs under the solo seat.

  19. 19 Woody's Oct 30th, 2014 at 10:06 am

    @trainiac yup, I have that setup in my ’72 CB750 AMEN Savior http://my.execpc.com/~gwoods/.photos/CB750Chopper/34RtFt.jpg and it is actually a rather smooth operating setup IF you keep it well lubed and replace the bushings before they have enough wear to let the carrier cock & stick. Combine it with a springer like I used and you have a bike with springs but no shocks-get the right road conditions and you are on a pogo stick ☺ I was only bringing it up because I remember folks calling them “soft tails” before the H-D trademark and wondered if that was the first use of the term.

  20. 20 Manxman Oct 30th, 2014 at 4:00 pm

    Steve Carr,
    I hear what you are saying but I think your explanation is a little off. I should have said a typical auto/motorcycle shock instead of normal shock absorber and in fact at rest under load the typical auto/motorcycle shock absorber is in the compressed state (sit on most motorcycles and the shock absorber, already compressed from the sprung weight of the motorcycle, compresses from the weight of the rider) at rest. According to Monroe’s white paper on shock absorber design there is more resistance designed into a shock absorber for extension than for compression in order to best handle rebound from the tremendous stored energy from a coil or leaf spring. So it works both in compression and extension. The idle state of a softail shock is indeed in extension, not compression. When you set on a softail the shock absorber extends even more until it reaches the point where the spring balances the weight. But the shock also works in compression on rebound as well. Your analogy of a bungie cord is a little ambiguous because a bungie cord is a spring not a shock absorber. Shock absorbers are not springing mediums but may be a platform for coil-over designs. In reality a shock absorber doesn’t really compress or extend (like a spring) – it simply moves oil from one side of the piston through a hole to the other side of the piston damping the spring oscillations. In my previous post I was just making a comment that it wasn’t rocket science to re-engineer valve design in a shock absorber to work in extension at rest. Thanks

  21. 21 skinny denny Oct 30th, 2014 at 4:10 pm

    Shock absorbers work much better in a vertical rather than horizontal figment. That being said, people generally buy Softails for the pseudo rigid frame look, not ride quality. The Evolution motor and the Softail frame saved H-D from going under. From a merchandising angle the Softail frame was sheer genius. If you want ride quality buy a Road King.

  22. 22 skinny denny Oct 30th, 2014 at 4:12 pm

    Should read fitment, not figment.

  23. 23 Steve Carr Oct 30th, 2014 at 6:17 pm

    Manxman,

    My friend, please….again ….please stop and think about what you are saying… again slow down and visualize this, and you will see how these shocks differ and work.

    I am not trying to make s debate out of this because I understand this stuff.

    Thanks

    Steve Carr

  24. 24 Dan Leger Oct 31st, 2014 at 8:59 am

    So basically what they did with him was steal his ideas and screw him like Harley-Davidson has done with countless other people that have had a good idea. Bought them out for peanuts probed their minds and threw them under the bus. I don’t think HD has really done anything innovative and new for a really long time. The public is finally getting wise. Look how well Polaris is doing. Electric motorcycle hahahaha. About half the motorcycles in China have been electric for a long time….

  25. 25 Woody's Oct 31st, 2014 at 10:35 am

    @ DL, if he sold the idea for peanuts, didn’t he screw himself?

  26. 26 Aeromachiist Nov 1st, 2014 at 12:24 pm

    Re: Shock Absorbers

    A differentiation has to be made between “shocks” and “springs”. In motorcycle rear-suspension context we usually think of them together, as a unit (“coil-over” shocks + springs). But they are obviously different, as the common example of an older automotive rear suspension incorporating leaf springs and a separate shock absorber neatly illustrates.

    In the normal “coil-over” setup used for motorcycle rear suspensions, the SPRING works in COMPRESSION. The spring actually is under a bit of compression even when the rear wheel is unloaded (spring pre-load). In fact, since in the normal setup the springs are simply sandwiched between plates at each end, if there isn’t at least a little bit of preload the spring will rattle around. The SHOCKS on the other hand, do nothing at rest and work equally well in both directions, though typically they have different valving for when the shock is being compressed versus when it is extending (rebound), typically more damping for compression than rebound.

    In a “Softail” setup with the shocks/springs under the bike, the key manufacturing difference is the springs are loaded in TENSION. That necessarily changes the spring construction – instead of simply being sandwiched between plates at each end, the springs have to be positively fixed to each end. Physically, you cannot simply put a normal SPRING in the “Softail” and make it work. The SHOCKS, on the other hand, would work, though again one might want the valving reversed so it has more damping in extension than compression.

  27. 27 Blackmax Nov 3rd, 2014 at 7:22 pm

    No I did Not !!!!
    Thank you Cyril for the enlightenment

  28. 28 Randall Massey Nov 4th, 2014 at 1:25 pm

    I think I own the first frame he made. It has a mono shock under the seat, and is made out of a Paucho frame. I ve had it since 1980.

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