Manuals and Catalogues
General Small Horsepower
Rolls-Royce 1925-39 Manual, J. H. Haynes & Co. LTD
Small Horsepower Owners Guide, by Steve Sherriff, 2nd edition, 2022
Small Horsepower Brake Systems, R. Haynes/RREC, 1983
Small Horsepower Engines, R. Haynes & M.A. Grigsby/RREC, 1977
Twenty Specific
RREC 20HP Register: comprehensive source for 20HP manuals and parts lists
Catalogue of Parts 20 H.P. Chassis, February 1924
Supplement to Catalogue of Parts for 20 H.P. Chassis, January 1928
Instructions for the Care & Running of the 20HP Rolls-Royce Car, December 1922
Instructions for the Care & Running of the 20HP Rolls-Royce Car, No. 7, March 1928
Instructions for the Care & Running of the 20HP Rolls-Royce Car, November 1925, April 1927, and No. 7
For chassis series:
GPK, GSK, GCK, GOK, GZK, GUK, GYK, GMJ, GHJ, GAJ, GRJ, GUJ, GZL, GYL, GWL, GBM, GKM, GTM, GFN, GLN, GEN, GVO, GXO.
Handbook for the 20 H.P. Rolls-Royce Car, Condensed edition 1929, Combines April 1924, November 1925, April 1927, No. 7, & No. 8 editions
20/25 Specific
Judging Manual, Early Small Horsepower, Class 106 (applicable to the Twenty and 20/25), Lee Hacker, 1990
Handbook of the 20/25 H.P. Rolls-Royce Car, Numbers XII and XIV, August 1938
25/30 Specific
Handbook for 25-30 Rolls-Royce, Number XVII, Chapter 1.
Chassis Series: GUL, GRM, GAN, GRO, GRP, GAR, GYL, GXM, GWN, GHO, GMP, GGR, GHL, GGM, GUN, GMO, GLP, GZR
Chapter I
Chapter 2
Chapters 3-5
Chapters 6-7
Wraith Specific
Guide to the Late Small Horsepower Car, Class 107 (applicable to the 25/30 and Wraith), Lee Hacker, 1995
Handbook of the 25/30 Rolls-Royce Car (“Wraith”), Number XIX, January 1962 reprint
There are differences between the Handbook of the 25/30 (without "Wraith") and the Handbook of the 25/30 "Wraith" Number XIX manuals. Handbook XIX is valid for the later series Wraith (C-series) #WHC1 to #WKC25 (1939). The first series of the Wraith model needed handbook XVIII and the 25/30 needed handbook XVII. So, there is only one handbook for 25/30 and two different handbooks for Wraith.