# Four Inch Course > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Four_Inch_Course > Markdown URL: https://mediated.wiki/source/Four_Inch_Course.md > Source: https://en.wikipedia.org/wiki/Four_Inch_Course > Source revision: 1315087324 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Isle of Man road-racing circuit Four-Inch Course Location Douglas, Isle of Man Major events RAC Tourist Trophy Length 37.52 mi (60.39 km) Turns 219 Race lap record 1 hour 32 mins, 32.2 sec (57.70 mph) (Major Henry Segrave, Sunbeam, 1922) The **Four Inch Course** was a [road-racing](/source/Road_racing) circuit first used for the [1908 Tourist Trophy Race](https://en.wikipedia.org/w/index.php?title=1908_Isle_of_Man_Tourist_Trophy_(automobiles)&action=edit&redlink=1) for cars,[1] held on public roads closed for racing by an Act of [Tynwald](/source/Tynwald) (the parliament of the Isle of Man). The name of the course derives from the regulations for the 1908 Tourist Trophy adopted by the [Royal Automobile Club](/source/Royal_Automobile_Club), which limited the competitors' engines to a cylinder-diameter of four inches. The Four-Inch Course was adopted by the Auto-Cycle Club for the [1911 Isle of Man TT](/source/1911_Isle_of_Man_TT) Races. The Four-Inch Course was subsequently known as the [Snaefell Mountain Course](/source/Snaefell_Mountain_Course) or Mountain Course when used for motor-cycle racing. ## Four Inch Course The new course length was 37.5 miles (60.4 km), based on the 'Short' [Highroads Course](/source/Highroads_Course) with the omission of the *Sandygate Loop* and the *Peel Loop*. The start-line was moved from the road junction of the [A2](/source/A2_road_(Isle_of_Man)) Quarterbridge Road/Alexander Drive to [Hillberry Corner](/source/Hillberry_Corner) on the A18 Mountain Road. William Watson, winner of the 1908 Tourist Trophy at the Four Inch Course The Four Inch Course was based on a number of public roads closed for the duration of racing, including: - The primary [A18](/source/A18_road_(Isle_of_Man)) Snaefell Mountain Road from the start-line at Hillberry Corner to the junction with the primary [A21](https://en.wikipedia.org/w/index.php?title=A21_road_(Isle_of_Man)&action=edit&redlink=1) *Johnny Watterson's Lane* and the tertiary C10 *Scholag Road* at [Cronk-ny-Mona](/source/Cronk-ny-Mona) in the town of [Douglas](/source/Douglas%2C_Isle_of_Man). - The primary [A21](https://en.wikipedia.org/w/index.php?title=A21_road_(Isle_of_Man)&action=edit&redlink=1) *Johnny Watterson's Lane* from Cronk-ny-Mona to the junction with the [A22](/source/A22_road_(Isle_of_Man)) Ballanard Road. - The A22 Ballanard Road in an easterly direction to the road junction at [St Ninian's Crossroads](/source/St_Ninian's_Crossroads), the A2 [Bray Hill](/source/Bray_Hill) and the A2 [Quarterbridge Road](/source/Quarterbridge_Road) in Douglas to [Quarter Bridge](/source/Quarterbridge%2C_Isle_of_Man). - The [A1](/source/A1_road_(Isle_of_Man)) [Douglas](/source/Douglas%2C_Isle_of_Man) to [Peel](/source/Peel%2C_Isle_of_Man) road from Quarter Bridge to [Ballacraine](/source/Ballacraine) at the junction with the [A3](/source/A3_road_(Isle_of_Man)) [Castletown](/source/Castletown%2C_Isle_of_Man) to [Ramsey](/source/Ramsey%2C_Isle_of_Man) road. - The A3 Castletown to Ramsey road from Ballacraine to [Parliament Square, Ramsey](/source/Parliament_Square%2C_Ramsey). - The A9 Albert Road in Ramsey, including two small sections of private road with the northerly junction of the primary [A18](/source/A18_road_(Isle_of_Man)) Snaefell Mountain Road. - The A18 Mountain Road to the finish-line at Hillberry Corner. The Four Inch Course was adopted by the Auto-Cycle Club for the [1911 Isle of Man TT](/source/1911_Isle_of_Man_TT) Races and the start-line was moved to a level section of the [Quarterbridge Road](/source/Quarterbridge_Road) between Selborne Drive and the 1st Milestone/Alexander Drive, becoming known as the Snaefell Mountain Course when used for motorcycle racing.[2] From the [1920 Isle of Man TT](/source/1920_Isle_of_Man_TT) races, changes were made to the Snaefell Mountain Course and competitors turned left at [Cronk-ny-Mona](/source/Cronk-ny-Mona) following the primary A18 Bemahague Road to [Governor's Bridge](/source/Governor's_Bridge_(Isle_of_Man)), then to a new start/finish line on Glencrutchery Road which lengthened the course from the pre-[World War I](/source/World_War_I) length of 37.50 miles (60.35 km) to 37.75 miles (60.75 km). More changes to the course followed for the [1923 Isle of Man TT](/source/1923_Isle_of_Man_TT) races with the adoption of two small sections of private road between [Parliament Square](/source/Parliament_Square%2C_Ramsey) and [May Hill](/source/List_of_named_corners_of_the_Snaefell_Mountain_Course#Queen's_Pier_Road_and_May_Hill) in Ramsey. The Snaefell Mountain Course had previously negotiated the [A2](/source/A2_road_(Isle_of_Man)) Albert Road and Tower Road in Ramsey which differed from the original Four-Inch circuit which had incorporated these sections of private road and the new Mountain Course length increased to 37.739 miles (60.74 km). The official course distance for the Snaefell Mountain Course was amended for the [1938 Isle of Man TTraces](/source/1938_Isle_of_Man_TT) to 37.73 miles (60.72 km) which is the current Snaefell Mountain Course length.[3] ## See also - [Snaefell Mountain Course](/source/Snaefell_Mountain_Course) - [Clypse Course](/source/Clypse_Course) - [Billown Circuit](/source/Billown_Circuit) - [RAC Tourist Trophy](/source/RAC_Tourist_Trophy) - [Isle of Man TT](/source/Isle_of_Man_TT) - [Manx Grand Prix](/source/Manx_Grand_Prix) ## Sources 1. **[^](#cite_ref-1)** *TT Pioneers – Early Car Racing in the Isle of Man* pp.103–104 Robert Kelly, Mercury Asset Management (1996) (1st Edition) The Manx Experience, The Alden Press ISBN No 1 873120 61 3 1. **[^](#cite_ref-2)** *The Tourist Trophy in Old Photographs Collected by Bill Snelling.* Bill Snelling page 14 Sutton Publishing [ISBN](/source/ISBN_(identifier)) [1-84015-059-9](https://en.wikipedia.org/wiki/Special:BookSources/1-84015-059-9) 1. **[^](#cite_ref-3)** *Official TT Guide 1992* page 45 edited by Norrie White Isle of Man Department of Tourism (1992) Mannin Media Ltd ## External links v t e Isle of Man racing circuits Andreas Airfield Billown Circuit Clypse Course Four Inch Course Highroads Course Isle of Man TT Mountain Course Jurby Airfield Jurby South Circuit Mannin Beg/Mannin Moar Course St John's Short Course Willaston Circuit [54°10′18″N 4°29′31″W / 54.17167°N 4.49194°W / 54.17167; -4.49194](https://geohack.toolforge.org/geohack.php?pagename=Four_Inch_Course¶ms=54_10_18_N_4_29_31_W_region:IM_type:landmark) --- Adapted from the Wikipedia article [Four Inch Course](https://en.wikipedia.org/wiki/Four_Inch_Course) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Four_Inch_Course?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.