The 1924 Isle of Man Tourist Trophy saw the introduction of the Ultra-Lightweight class for motorcycles of 175 cc capacity that was run only twice, in 1924 and 1925. This was the second year of the Sidecar race that would also be dropped after 1925.

The Ultra-Lightweight TT began with a massed-start for competitors rather than pairs as with the normal time-trial format of the TT races. The winner of the first Ultra-Lightweight TT was Jock Porter riding a New Gerrard at an average speed of 51.21 mph (82.41 km/h).

The Junior TT race was won by Ken Twemlow on a New Imperial at an average speed of 55.67 mph (89.59 km/h). In the same Junior race, Jimmie Simpson set a new lap record of 35 minutes and 5 seconds at an average speed of 64.54 mph (103.87 km/h) on an AJS – the first average lap-speed over 60 mph. The Lightweight and Senior TT races were run in conjunction, and Eddie Twemlow (brother to Ken Twemlow) riding a New Imperial won the six-lap race in 4 hours, 5 minutes and 3 seconds, an average speed of 55.44 mph (89.22 km/h).

The Senior TT, like the Junior race, was also run at a record breaking pace and was the first with a race-average speed over 60 mph (97 km/h). The six-lap race was won by Alec Bennett riding a Norton in 3 hours, 40 minutes and 24. 6 seconds, with an average speed of 61.64 mph (99.20 km/h).

Rank	Rider	Team	Speed	Time	Laps
1	Alec Bennett	Norton	3.40.24.6	61.64 mph (99.20 km/h)	6
2	Harry Langman	Scott	3.41.54.2	61.23	6
3	Freddie Dixon	Douglas	3.45.46.4	60.17	6
9	J A Stuart	Norton	3.59.05.0		6

6 laps (226.38 miles) – Mountain Course.

Rank	Rider	Team	Speed	Time
1	Kenneth Twemlow	New Imperial	56.68 mph	4:04.49.0
2	S. Ollerhead	DOT	54.91 mph	4:07.26.2
3	I. H. R. Scott	AJS	54.55 mph	4:09.01.6
4	Cecil Ashby	Montgomery	53.39 mph	4:14.27.4
5	Harold J. Willis	Montgomery	52.80 mph	4:17.18.8
6	J. L. E. Emerson	DOT		4:20.39.8
7	F. Simpson Jnr	Excelsior		4:28.55.2
8	L. Nicholson	OEC-Blackburne		4:31.38.0
9	F. R. Marston	AJS		4:31.39.0
10	J. W. Shaw	Zenith		4:43.48.4

6 laps (226.38 miles) – Mountain Course.

Rank	Rider	Team	Speed	Time
1	Edwin Twemlow	New Imperial	55.44 mph	4:05.03.0
2	H. F. Brocklebank	Cotton	52.85 mph	4:17.05.0
3	J. Cooke	DOT	52.54 mph	4:18.03.0
4	L. J. Cridland	JES	51.84 mph	4:22.03.0
5	P. Pike	Levis	51.16 mph	4:25.31.0
6	H. F. Harris	New Imperial	50.50 mph	4:29.01.0
7	F. Simpson Jnr	Excelsior		4:32.50.0
8	C. G. S. Cleare	OK-Supreme		4:38.50.0
9	C. W. Johnston	Cotton		4:40.23.0
10	Geoff S.Davison	Levis		4:52.40.0

It was held on Wednesday, June 25, 1924, over a distance of 113  miles and 380 yards, 3 laps of 37.75 miles each. The machines were limited of cylinder capacity not exceeding 175cc. All seventeen riders started the race simultaneously, only twenty yards separating the last numbered man from the first. Eleven riders finished.^[1]

The 13th International Isle of Man Tourist Trophy

Pos # Rider Bike Ultra Lightweight TT race classification Laps Time Speed Prizes & Remarks 1 1 Jock Porter 174cc New Gerrard 3 2:12:40.40 51.20 mph 1st Prize - Winner of Ultra Lightweight Tourist Trophy, £20. 2 15 Freddie Morgan 175cc Cotton 3 2:17:11.40 49.51 mph 2nd Prize - £10. 3 10 Chris Stead 175cc Cotton 3 2:17:39.80 49.34 mph 3rd Prize - £5. 4 2 Geoff Davison 173cc Levis 3 2:23:00.40 47.49 mph Silver replica. 5 11 Harry Brockbank 175cc Cotton 3 2:26:59.00 46.21 mph 6 6 Tommy Meeten 173cc Francis-Barnett 3 2:44:43.00 41.24 mph 7 13 B.B. Smith 173cc Wee Macgregor 3 2:51:59.00 39.50 mph 8 8 Jimmy Oates 173cc Powell 3 2:54:32.00 38.92 mph 9 3 Alec Bennett 175cc Diamond 3 2:57:09.00 38.35 mph 10 4 Dan Young 173cc Wee Macgregor 3 3:07:07.00 36.30 mph 11 5 Doug Prentice Mackenzie 3 3:10:10.00 35.72 mph DNS 17 Percy Dallison 170cc Omega-Norman Was unable to start and Gus Kuhn took over his entry. Fastest lap: Jock Porter, 43min. 2sec. 52.61 mph[2]

It was held on Wednesday, June 25, 1924, at 2:00pm over a distance of 150  miles and 1,680 yards, 4 laps of 37.75 miles each. Sidecar TT machines were limited of cylinder capacity not exceeding 600cc. Out of 10 entries, nine started the race at one minute intervals and only five finished.^[3]

The 13th International Isle of Man Tourist Trophy

Pos # Driver Passenger Bike Sidecar TT race classification Laps Time Speed Prizes & Remarks 1 6 George Tucker Walter Moore 588cc Norton 4 2:56:34.20 51.31 mph 1st Prize - Winner of Sidecar Tourist Trophy, £20. 2 2 Harry Reed Joe Hooson 349cc DOT-Bradshaw 4 3:26:46.40 43.80 mph Silver replica for the driver and bronze replica for the passenger. Reed drove last two laps with broken forks. 3 10 Almond Tinkler N.R. Tinkler 349cc Matador 4 3:33:08.40 42.49 mph Silver replica for the driver and bronze replica for the passenger 4 9 J.W. Taylor R.J. Lilley 350cc New Scale 4 3:35:40.00 41.99 mph Silver replica for the driver and bronze replica for the passenger 5 3 George Grinton Tony Mahon 588cc Norton 4 3:36:27.00 41.83 mph Grinton's throttle wire broke on lap 1 and he rode the race holding it in his hand, which at the end was cut and bleeding.[4] DNF 4 Bert Taylor C.R. Hirst 590cc OEC-Blackburne 3 Retired on last lap at Ballaugh with engine trouble. DNF 8 S.E. Longman Arthur Kinrade 600cc Coventry-Victor Super-Six 2 Retired on lap 3 at Gooseneck with engine trouble. DNF 1 Freddie Dixon Walter Denny 596cc Douglas 2 Retired on lap 3 while leading the race at Kirkmichael with engine trouble. DNF 7 Alfie Alexander S. Ford 596cc Douglas 2 Retired on lap 3 while running third, due broken sidecar stay, pushing the machine in from Governor's Bridge to Start. DNS 5 Freddie Hatton 596cc New Hudson Fastest lap: Freddie Dixon, 43min. 32sec. 53.23 mph[5]

• Detailed race results
• Mountain Course map