Harley-Davidson Fat Boy

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Harley-Davidson Fat Boy
ProductionSince 1990
  • Evolution (1990–1999)
    1,340 cc (82 cu in)
  • Twin Cam (2000–2017)[1]
    1,450 cc (88 cu in)
    1,584 cc (96.7 cu in)
    1,690 cc (103 cu in)
  • Milwaukee-Eight (2018–2019)
    1,746 cc (107 cu in)
    1,868 cc (114 cu in)
1,868 cc (114 cu in)
TransmissionChain (Primary) / Belt (final drive)
Wheelbase1,636 mm (64.4 in)

The Harley-Davidson Fat Boy, is a V-twin softail cruiser motorcycle with solid-cast disc wheels.[2] Designed by Willie G. Davidson and Louie Netz, Harley-Davidson built a prototype Fat Boy in Milwaukee for the Daytona Bike Week rally at Daytona Beach in 1988 and 1989.[3][4] Fat Boys produced from 1990-2017 are coded FLSTF, and FLFB (& FLFBS) from 2018.

An oft-repeated false etymology claims that the name comes from a contraction of Fat Man and Little Boy, the atomic bombs dropped on Japan during WWII, as a symbolic insult to Japanese motorcycles.[5] This has been debunked, as the name "Fat Boy" actually comes from the observation that the motorcycle is somewhat wider than other bikes when viewed head-on.[6][5] In a 2015 interview, Scott Miller, Harley-Davidson's vice president of styling and product development, confirmed that the name was simply descriptive and had nothing to do with Harley's Japanese competitors.[7]

History and development[edit]

The Fat Boy's frame is derived from the 1984 "Softail" which appears to have a rigid hardtail chassis but which in fact has a swinging arm with concealed springs that was originally designed in a Missouri garage in the 1970's by a mechanical engineer named Bill Davis and later Patented in 1976.[8] Willie G the grandson of Harley-Davidson co-founder William A. Davidson originally turned down engineer Bill Davis' softail concept; but the company later relented, buying the rights and designing its own softail frame in-house.[9]

  • After 1994, the exhaust was made seamless.
  • In 1996 the master cylinder and switch gear were revised.
  • In 1999 a new 1,450 cc (88 cu in) Twin Cam engine for the 2000 model year was used. This necessitated a bespoke engine variant and changes to the frame.
  • In 2002 bullet-style indicators, alarm and immobilizer were added.[10]
  • In 2005 a 15th Anniversary version was sold with a "Screamin' Eagle" engine, special paint and custom wheels.[10]
  • In 2007 the displacement was increased to 1,584 cc (96.7 cu in)[10] and the transmission changed six speeds.[9]
  • The 2010 "Fat Boy Lo" FLSTFB had the lowest ever Harley seat height.[2]
  • In 2012 the Fat Boy received the new 1,690 cc (103 cu in) Twin Cam engine along with the rest of the softail range
  • The 2018 Fat Boys have a redesigned softail frame with Showa front and rear suspension and new twin-counterbalanced Milwaukee-Eight engines. The two 2018 variants comprise:
  • The FLFB 1,746 cc (107 cu in) with 109 lb⋅ft (148 N⋅m), and
  • The FLFBS 1,868 cc (114 cu in) with 119 lb⋅ft (161 N⋅m)[11]

The 2018 Softail frame has a modified swingarm with a Showa rear monoshock suspension mounted beneath the seat, replacing earlier twin shocks. So as to provide a more comfortable and better controlled ride with improved handling, the front forks contain a Showa "Dual Bending Valve" (SDBV),[12] a cartridge simulator using two valves to control compression and rebound damping, giving linear damping characteristics proportional to fork stroke speed. Harley-Davidson claims the 2018 chassis is stiffer and lighter than earlier Softail and Dyna platforms.[13] Further upgrades include an LED headlight and 18-inch "Lakester" rims, with wider 160mm front and 240mm rear tires.[14][15]

For 2020, the Fat Boy is only available with the Milwaukee-Eight 114 engine. Harley-Davidson also produced a 30th Anniversary edition for 2020.[16]

It is one of Harley-Davidson's best selling models and has appeared prominently in a number of TV shows and movies.[3] The Fat Boy earned a place in American pop culture after appearances in the movie Terminator 2: Judgment Day. One of the motorcycles used in Terminator 2 is displayed at the Harley-Davidson Museum. It appeared again in Terminator Genisys.[2][17][7][18]

See also[edit]


  1. ^ "MOTO USA". Retrieved 25 October 2016.
  2. ^ a b c "Harley Fat Boy History". Harley-Davidson. Retrieved 25 October 2016.
  3. ^ a b "Fat Boy a Harley bestseller and Hollywood favorite for 25 years". Milwaukee Wisconsin Journal Sentinel. Retrieved 28 October 2016.
  4. ^ "Vehicle Profile:25 Years of the Harley-Davidson Fat Boy". Harley-Davidson. Archived from the original on September 20, 2017. Retrieved May 28, 2017.
  5. ^ a b Luckhurst, Tim (14 November 2006). "Harley-Davidson FLSTF Fat Boy". The Independent. Archived from the original on 2022-05-09. Retrieved 13 December 2021.
  6. ^ Mikkelson, David (8 November 2000). "Harley-Davidson Fat Boy". Snopes.com. Retrieved 13 December 2021.
  7. ^ a b Barrett, Rick (5 August 2015). "Harley Fat Boy a screen and street star". The Detroit News. Retrieved 13 December 2021.
  8. ^ Masker, Mark. "Three decades of Softail". Hot Bike. Bonnier Corporation. Retrieved May 21, 2019.
  9. ^ a b "Harley Fat Boy Launch". Sump Magazine. Retrieved 25 October 2016.
  10. ^ a b c "Harley Fat Boy Development". Hogrides. Retrieved 25 October 2016.
  11. ^ Cameron, Kevin (August 22, 2017). "2018 Harley-Davidson Softail Cruisers Tech and Development". Cycle World. Retrieved September 17, 2017.
  12. ^ SDBV image [1]
  13. ^ "2018 Harley-Davidson Softail Cruiser Lineup". Cycle World. 2017. Retrieved September 9, 2017.
  14. ^ MacDonald, Sean (August 22, 2017). "This Is The New 2018 Harley-Davidson Softail Fat Boy". Cycle World. Retrieved July 9, 2018.
  15. ^ MacDonald, Sean (August 22, 2017). "This Is The New 2018 Harley-Davidson Softail Fat Boy". Cycle World. Retrieved July 9, 2018.
  16. ^ "2020 Harley-Davidson Fat Boy 30th Anniversary Unveiled". UltimateMotorcycling.com. Ultimate Motorcycling. 3 February 2020. Retrieved 18 February 2020.
  17. ^ "'Terminator' Fat Boy preserved". Motorbike Writer. 6 February 2014. Retrieved 26 October 2016.
  18. ^ Hinton, TJ (January 12, 2018). "Low Seat Height, Butt-Friendly Saddle, And A Smooth Ride". Top Speed. Retrieved July 9, 2018.

External links[edit]