1924 Isle of Man TT
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).
Senior TT (500cc)
| 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 | |
Junior TT (350cc)
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 | .svg.png){kind=small} 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 |
Lightweight TT (250 cc)
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 |
Ultra-Lightweight TT (175 cc)
3 laps (113.00 miles) – Mountain Course.
| Rank | Rider | Team | Speed | Time |
|---|---|---|---|---|
| 1 | Jock Porter | New Gerrard | 51.93 mph | 4:21.37.0 |
| 2 | Bert le Vack | New Imperial | 51.14 mph | 4:26.19.0 |
| 3 | D. Hall | Rex-Acme | 49.53 mph | 4:34.20.0 |
| 4 | R. Gray | Rex-Acme | 49.31 mph | 4:35.29.0 |
| 5 | N. Black | Cedos | 49.25 mph | 4:35.36.0 |
| 6 | L. Horton | New Imperial | 49.15 mph | 4:36.29.0 |
| 7 | P. Pike | Levis | ||
| 8 | Wal Handley | OK-Supreme | ||
| 9 | Alec Bennett | Diamond | ||
| 10 | F. Simpson Jr | Excelsior |
Sidecar TT (500 cc)
| Rank | Rider | Team | Speed | Time | Laps |
|---|---|---|---|---|---|
| 1 | George H Tucker | Norton | 2.07.48 | 51.31 mph (82.58 km/h) | 3 |
| 2 | Harry Reed | DOT | 3.26.44.0 | 43.80 | 3 |
| 3 | A Tinkler | Matador | 3.33.08.0 | 42.49 | 3 |