Editing Isle of Man TT (section)

==Format of the races==
[[File:Start Senior TT 2010 IMG P0001185.jpg|thumb|250px|right|Competitors line up at the start of the [[2010 Isle of Man TT|2010]] [[Senior TT]] race]]
The TT Races since the first race in 1907 have been in the format of time-trial. The races held on the [[Clypse Course]] during the period 1954–1959 were the more traditional full grid starts along with the 1924 Lightweight TT Race and Clubmen TT Races from 1948, which were also "mass-start" races. The current format is a "clutch start" and race competitors will be "started singly at 10-second intervals".<ref>''2015 International Tourist Trophy Regulations'' page 22 ACU Events Isle of Man Limited (2015) Isle of Man Department of Economic Development</ref>

===Race procedure===
* Start Preliminaries
**First Signal – 45 minutes before the start with a warm-up of engines in the Race Paddock and assembly area.
**Second Signal – 30 minutes before start.
**Third Signal – 15 minutes before start, race competitors move to the start-line and form-up in qualification order.
**Fourth Signal – 5 minutes before start, signal to clear the grid and race competitors move towards the exit-gate.

===Eligibility===
Entrants must be in possession of a valid National Entrants or FIM Sponsors Licence for Road Racing.

Entrants must also cite pre-filled documentation of completion of a UK driving licence or motorcycle certification, or a driver's licence from a comparable country that is recognised by UK comparable department of transportation standards and may withhold due to any pre race or post race suspensions.

===Race classes===

; Current

* [[Senior TT]] (1909–present)
* Supersport TT (2005–present)
* Superbike TT (2005–present)
* [[Superstock TT]] (2005–present)
* Supertwin TT (2022–present)
* [[Sidecar TT]] (1923–1925, 1951–1967, 1977–present)

; Former

* Singles TT (1907–1908, 1994–2000)
* Twin TT (1907–1908)
* Sidecar 1000 TT (1975–1976)
* Sidecar 750 TT (1968–1974)
* Sidecar 500 TT (1968–1976)
* [[Ultra-Lightweight TT]] (1924–1925, 1951–1974, 1989–2004, 2008)
* Clubman Senior TT (1947–1956)
* Clubman Junior TT (1947–1956)
* Clubman Lightweight TT (1947–1950)
* Clubman 1000 TT (1949–1950, 1953)
* 50 TT (1962–1968)
* Classic TT (1975–1984)
* Formula 1 TT (1977–2004)
* Formula 2 TT (1977–1987)
* Formula 3 TT (1977–1982)
* Production 1500 TT (1985–1985)
* Production 1000 TT (1974, 2002–2004)
* Production 750 TT (1967–1973, 1984–1985)
* Production 500 / 600 TT (1967–1974, 2002–2004)
* Production 250 TT (1967–1974, 1984–1985)
* Production TT (1975–1976, 1996–2000)
* Production A TT (1986–1988)
* Production B TT (1986–1988)
* Production C TT (1986–1988)
* Production D TT (1986–1988)
* Supersport 600 TT (1989–1994)
* Supersport 400 TT (1989–1994)
* Lightweight 400 TT (1999–2004)
* [[TTXGP]] (2009)
* [[TT Zero]] (2010–2019)
* [[Lightweight TT]] (1922–1976, 1995–2004, 2012–2019)

====Superbike TT====
The 2015 specification for entries into the Superbike TT race are defined as:
* Any machine complying with the following specifications:
** TT Superbike: (Machines complying with the [[2015 Superbike World Championship season|2015 FIM Superbike Championship]] specifications)
*** Over 750&nbsp;cc up to 1000&nbsp;cc 4 cylinders 4-stroke
*** Over 750&nbsp;cc up to 1000&nbsp;cc 3 cylinders 4-stroke
*** Over 850&nbsp;cc up to 1200&nbsp;cc 2 cylinders 4-stroke
Minimum Weight {{convert|165|kg|abbr=on}}. Other machines admitted at the discretion of the Organisers<ref>''2015 International Tourist Trophy Regulations''  ACU Events Isle of Man Limited page 5 and page 58 Appendix A</ref>

====Supersport TT====
The [[1911 Isle of Man TT]] was the first time the [[Junior TT]] race took place, open to 300&nbsp;cc single-cylinder and 340&nbsp;cc twin cylinder motorcycles, contested over five laps of the new {{convert|37.5|mi|adj=on}} Snaefell Mountain Course. The first event on the new course was the Junior TT Race contested by 35 entrants, won by Percy J. Evans riding a Humber motor-cycle at an average race speed of {{convert|41.45|mph|abbr=on}}. The [[1912 Isle of Man TT|1912 event]] was the first to limit the Junior TT to only 350&nbsp;cc machines and this engine capacity prevailed until 1976, after which the category was dropped. The event was instead run for 250&nbsp;cc machines until 1994 when replaced by the 600&nbsp;cc Supersport class.

:* 1911 For single cylinder motorcycles not exceeding 300&nbsp;cc engine capacity and 340&nbsp;cc twin cylinder motorcycles.
:* 1912–1948 For motorcycles not exceeding 350&nbsp;cc engine capacity.
:* 1949–1953 FIM World Championship event for motorcycles not exceeding 350&nbsp;cc engine capacity and held on the [[Snaefell mountain course]].
:* 1954–1959 FIM World Championship event for motorcycles not exceeding 350&nbsp;cc engine capacity and held on the [[Clypse Course]].
:* 1960–1976 FIM World Championship event for motorcycles not exceeding 350&nbsp;cc engine capacity and held on the Mountain Course.
:* 1977–1994 for motorcycles not exceeding 250&nbsp;cc engine capacity and held on the Mountain Course.
:* 1995 onwards for motorcycles not exceeding 600&nbsp;cc engine capacity and held on the Mountain Course.

The 2015 specifications for entries into the Supersport TT race are:
:* TT Supersport: (Machines complying with the [[2015 Supersport World Championship season|2015 FIM Supersport Championship]] specifications)

::* Over 400&nbsp;cc up to 600&nbsp;cc 4 cylinders 4-stroke
::* Over 600&nbsp;cc up to 675&nbsp;cc 3 cylinders 4-stroke
::* Over 600&nbsp;cc up to 750&nbsp;cc 2 cylinders 4-stroke

Minimum Weight 161&nbsp;kg<ref>''2015 International Tourist Trophy Regulations'' page 2 & Appendix C ACU Events Isle of Man Limited</ref>

====Superstock TT====
{{main|Superstock TT}}
The 2015 specifications for entries for the [[Superstock TT]], an event for production based motorcycles racing with treaded road tyres, are based on the FIM Superstock Championship specifications, as follows:
* Superstock TT: (Machines complying with the [[2012 FIM Superstock 1000 Championship season|2012 FIM Superstock Championship]] specifications)
** Over 750&nbsp;cc up to 1000&nbsp;cc 4 cylinders 4-stroke
** Over 750&nbsp;cc up to 1000&nbsp;cc 3 cylinders 4-stroke
** Over 850&nbsp;cc up to 1200&nbsp;cc 2 cylinders 4-stroke
Minimum (Dry) Weight 170&nbsp;kg<ref>''International Tourist Trophy Regulations 2015'' page 5/Appendix D page 34 ACU Events (Isle of Man) Limited (2015) Isle of Man Department of Economic Development</ref>

'''Supertwin TT'''

2022 saw the introduction of the supertwin race run over 3 laps on Wednesday the 8th of June, increased to 4 laps the following year. The class is very similar to the lightweight class which last ran in 2019, although with some differences. The maximum capacity has been increased to 700cc allowing the Yamaha YZF-R7 and Aprilia RS660 to compete. In 2022 bikes with capacities of 651cc+ were required to run 10&nbsp;kg heavier than the 150&nbsp;kg limit for the 650cc machines, but 2023 saw this changed and all bikes in the class now have a minimum weight of 150&nbsp;kg.<ref>{{Cite web |title=Technical Director Dave Hagen explains the Technical Tweaks for the 2023 Isle of Man TT Races |url=https://www.iomttraces.com/latest/features/tech-tweaks-for-tt-2023/ |access-date=2023-06-11 |website=www.iomttraces.com |language=en}}</ref>

====Sidecar TT====
{{main|Sidecar TT}}

[[File:2013 Isle of Man TT 14.jpg|thumb|200px|left|Sidecar TT race competitors line up to start the race]]
The [[1923 Isle of Man TT|1923 TT]] was the first time the Sidecar TT race was run, over three laps ({{convert|113|mi|disp=or|abbr=on}}) of the [[Snaefell Mountain Course|Mountain Course]] and was won by [[Freddie Dixon]] and passenger Walter Denny with a [[Douglas (motorcycles)|Douglas]] and special ''banking-sidecar'' at an average race speed of {{convert|53.15|mph|abbr=on}}. For the [[1926 Isle of Man TT|1926 event]] the Sidecar and [[Ultra-Lightweight TT]] classes were dropped due to lack of entries.

The Sidecar race was re-introduced from the [[1954 Isle of Man TT|1954 event]] for Sidecars not exceeding 500&nbsp;cc engine capacity, run on the [[Clypse Course]]. A non-championship 750&nbsp;cc class for sidecars was introduced at the [[1968 Isle of Man TT|1968 event]]. For the [[1976 Isle of Man TT|1976 event]] the race was held over two-legs. From 1975, the previous 500&nbsp;cc and 750&nbsp;cc classes for Sidecars were replaced by a 1000&nbsp;cc engine capacity class.

<br />
The new [[Fédération Internationale de Motocyclisme|FIM]] Formula 2 class for Sidecars was introduced for the 1990 Isle of Man TT.

* 1954–1959 FIM World Championship Event for Side-Cars not exceeding 500&nbsp;cc engine capacity. Race held on the [[Clypse Course]].
* 1960–1976 FIM World Championship Event held on [[Snaefell mountain course|Mountain Course]].
* 1968–1974 Non-Championship event for Sidecars not exceeding 750&nbsp;cc.
* 1975–1989 Sidecars not exceeding 1000&nbsp;cc engine capacity.
* 1990– FIM Formula 2 Sidecar race for two-stroke engines not exceeding 350&nbsp;cc or four-stroke engines not exceeding 600&nbsp;cc.

The 2015 specifications for entries into the Sidecar TT race are:
* Machines must comply with general technical rules as per ACU Standing Regulations and 2015 Isle of Man TT regulations.
** Engine Types
***501 – 600&nbsp;cc, 4 stroke, 4 cylinder, Production based motorcycle engines.

====Senior TT====
{{main|Senior TT}}

[[File:2010 senior TT IMG 1188.JPG|thumb|200px|right|[[Ian Hutchinson (motorcyclist)|Ian Hutchinson]] on the start-line of the [[Senior TT]] Race on 11 June 2010 ]]
For the [[1911 Isle of Man TT]], the first TT event using the [[Snaefell Mountain Course]] or ''Mountain Course'', two separate races were introduced. The first event was a four lap [[Junior TT]] race and a separate [[Senior TT]] race for 500&nbsp;cc single-cylinder and 585&nbsp;cc twin-cylinder motorcycles, over five laps of the new {{convert|37.5|mi|adj=on}} Snaefell Mountain Course. The new technical challenges of the Mountain Course forced changes on entrants and motorcycle manufacturers alike. The American Indian motorcycle factory fitted a two-speed gearbox and chain-drive.<ref>{{cite news| first=Simon| last=Patterson|title=THE COMPLETE BEGINNER'S GUIDE TO THE 2023 ISLE OF MAN TT |url=https://www.the-race.com/motorcycle-racing/2023-isle-of-man-tt-guide-and-schedule/ |access-date=13 March 2024 |work=The Race |date=29 May 2023 |language=en}}</ref> This proved to be the winning combination when Oliver Godfrey won the 1911 Senior TT race riding an [[Indian (motorcycle)|Indian]] at an average speed of {{convert|47.63|mph|abbr=on}}. Fitted with a six-speed belt drive<ref>''Motocourse History of the Isle of Man TT Races 1907–1989'' page 18-19 and 23 (Mick Woollett Technical Notes) Nick Harris © Hazelton Securities Ltd (1990) Graficas Esatalla SA {{ISBN|0-905138-71-6}}</ref> [[Charlie Collier]] riding a Matchless motorcycle finished second in the 1911 Senior TT race and was later disqualified for illegal refuelling. During an early morning practice session for the 1911 Isle of Man TT races, [[Victor Surridge]] died after crashing his [[Rudge-Whitworth|Rudge]] motorcycle at [[Glen Helen, Isle of Man|Glen Helen]], the first death of a competitor on the Snaefell Mountain Course and the first death in the [[Isle of Man]] of a person in an automotive accident.<ref>''TT Topics and Tales'' by David Wright – Amulree Publications (4 April 2006) {{ISBN|1901508099}}</ref>

:* 1911 For single cylinder motorcycles not exceeding 500&nbsp;cc engine capacity and 585&nbsp;cc twin cylinder motorcycles.
:* 1912–1939 For motorcycles not exceeding 500&nbsp;cc engine capacity.
:* 1947–1948 For motorcycles not exceeding 500&nbsp;cc engine capacity and a ban on engine supercharging.
:* 1949–1976 FIM World Championship event for motorcycles not exceeding 500&nbsp;cc engine capacity.
:* 1977–1984 for motorcycles not exceeding 500&nbsp;cc engine capacity.
:* 1985–2004 for motorcycles complying with ACU TT Formula 1 rules not exceeding 1,010&nbsp;cc engine capacity.
:* 2004 onwards for motorcycles complying with ACU/FIM Superbike rules not exceeding 1,000&nbsp;cc engine capacity.

The 2015 specifications for entries into the Senior TT race are:
* TT Superbike: (Machines complying with the 2015 FIM Superbike Championship specifications)<ref>''2010 International Tourist Trophy Regulations'' page 2 ACU Events Isle of Man Limited</ref>
** Over 750&nbsp;cc up to 1000&nbsp;cc 4 cylinders 4-stroke
** Over 750&nbsp;cc up to 1000&nbsp;cc 3 cylinders 4-stroke
** Over 850&nbsp;cc up to 1200&nbsp;cc 2 cylinders 4-stroke

:*Supersport [[Junior TT]] (without limitation of tyre choice)
:** TT Superstock (without limitation of tyre choice)
:** Other machines admitted at the discretion of the Organisers.

===Discontinued race classes===

====Clubman TT and Production TT====
The Clubman races with Lightweight, Junior and Senior classes were held for production motorcycles from [[1947 Isle of Man TT|1947]] until [[1956 Isle of Man TT|1956]].<ref>[http://www.iomtt.com/TT-Database/Events.aspx?meet_code=TT47%20%20&era=2 1947 TT races, overview] IoM TT.com. Retrieved 26 September 2015</ref> A Senior 1000&nbsp;cc class provided an opportunity for [[Vincent Motorcycles|Vincent motorcycles]].<ref>[http://www.iomtt.com/TT-Database/Events/Races.aspx?meet_code=TT50&race_seq=1 1950 Clubman TT 1000&nbsp;cc class results] IoM TT.com. Retrieved 26 September 2015</ref> The riders were little-known, but as the stars were barred from entering the class, it provided a stepping-stone for future-stars but resulted in less spectator-interest. The series became dominated by one model – the [[BSA Gold Star]],<ref name="recce" /><ref>[http://www.iomtt.com/TT-Database/Events/Races.aspx?meet_code=TT56&race_seq=2 1956 Clubman TT Junior class results] IoM TT.com. Retrieved 26 September 2015</ref><ref>[http://www.iomtt.com/TT-Database/Events/Races.aspx?meet_code=TT56&race_seq=1 1956 Clubman TT Senior class results] IoM TT.com. Retrieved 26 September 2015</ref> and with little competition from other manufacturers, was discontinued. When previewing the impending re-introduction of a specification-controlled, roadster-based class in March 1967, ''David Dixon'' wrote: "''lack of inter-make rivalry probably put the final nail in the coffin''".<ref name="recce">[[The Motor Cycle|''Motor Cycle'']], 9 March 1967, pp.284–286 ''Roadsters on the Magic Lap. A Production-TT Recce in Manxland'' by ''David Dixon''. Accessed 26 September 2015</ref>

Writing in UK monthly magazine ''Motor Cyclist Illustrated'', racing journalist Ray Knight, who had achieved a lap speed of nearly 88&nbsp;mph on a [[Triumph Tiger 100]] [[Standard motorcycle|roadster]]-based racing motorcycle in the [[Manx Grand Prix]],<ref>[http://www.manxgrandprix.org/Mountain-Course-Database/Events/Races.aspx?meet_code=MGP63&race_seq=2 1963 Senior race results, Competitor Ray Knight, Hughes Triumph] {{Webarchive|url=https://web.archive.org/web/20160304035517/http://www.manxgrandprix.org/Mountain-Course-Database/Events/Races.aspx?meet_code=MGP63&race_seq=2 |date=4 March 2016 }}, Manx Grand Prix.Org official website, Retrieved 19 October 2015</ref><ref>[http://www.manxgrandprix.org/Mountain-Course-Database/Events/Races.aspx?meet_code=MGP64&race_seq=3 1964 Senior race results, Competitor Ray Knight, Hughes Triumph] {{Webarchive|url=https://web.archive.org/web/20160304035602/http://www.manxgrandprix.org/Mountain-Course-Database/Events/Races.aspx?meet_code=MGP64&race_seq=3 |date=4 March 2016 }}, Manx Grand Prix.Org official website, Retrieved 19 October 2015</ref><ref>[http://www.iomtt.com/TT-Database/competitors.aspx?ride_id=2459&filter=K Ray Knight, Competitor Profile], IoM TT.com official website, Retrieved 19 October 2015</ref> commented in early 1965 that the [[Auto-Cycle Union|ACU]] had refused a request from manufacturers to run a production TT race, which he thought was a missed opportunity, particularly considering the dwindling support for the 500&nbsp;cc race.<ref>Motor Cyclist Illustrated, January 1965, p.41 ''More Production racing''. Accessed 19 October 2015</ref>[[File:Start lightweight TT IMG 0018.jpg|thumb|200px|right|[[Ryan Farquhar]]'s 650&nbsp;cc [[Kawasaki Heavy Industries|Kawasaki]] at the start line of the 2012 Lightweight TT. He went on to win that year's race.]]A Production TT for roadster-based motorcycles having classes for maximum engine capacities of 250&nbsp;cc, 500&nbsp;cc and 750&nbsp;cc was introduced from [[1967 Isle of Man TT|1967]] until [[1976 Isle of Man TT|1976]] when the class was discontinued.

The Production TT was reintroduced for the 1984 races in three classes, reduced to two classes on safety grounds for the 1990 races. For the [[2005 Isle of Man TT|2005 races]] the Superstock class replaced the previous 1000&nbsp;cc and 600&nbsp;cc Production TT classes that had been part of the race schedule since 1989.

====Ultra-Lightweight TT====
{{main|Ultra-Lightweight TT}}

====Lightweight TT====
{{main|Lightweight TT}}

====TT Zero====
{{main|TT Zero}}

The TT Zero was a one lap race for electric bikes running from 2010 to 2019. It was announced that the race would take a two-year break after 2019, but it never came back on the schedule since.<ref>{{Cite web |date=2023-06-07 |title=Will TT Zero class ever return? |url=https://www.iomtoday.co.im/news/will-tt-zero-class-ever-return-619267 |access-date=2023-11-23 |website=Isle of Man}}</ref>