Everything you wanted to know about Damper Knobs but were too afraid to ask.

Like most manufacturers Ariel changed the design of parts from time to time for either technical or aesthetic reasons. Usually the new part was given a new number, even if the two parts were interchangeable or one superseded or replaced the earlier part, so that everyone involved could be sure that they were talking about the same part. Sometimes the part was changed but the number was not and rivet counters love spotting these undocumented changes.

Between 1938 and 1958 the steering damper knob exists in no fewer than six variants, made up of three tops and two bottoms, but all using the same number. All are made in Bakelite with a steel insert cast in to the base for screwing to the damper rod and are used with a spring to slow down the rate at which they unwind. After many years of being confused about these I have come to the conclusion that both styles throughout 1938-58. The evidence is that both styles are seen on machines from all the years and the fact that both styles were made each of the three types of bases. It may be that not enough of the new style could be made to keep up with production and that the old mould was modified to boost quantities.

	4901-26 Original Part No. D9/16 drawing available Years 1926-29 Models A-G No retaining screw or spring Nickel plated steel
	4901-29 Original Part No. D9/190 Years 1929-31 Models – Colts No retaining screw or spring Nickel or chrome plated steel
	4901-30 Original Part No. D9/189 Years 1930-31 Models A-G/V With groove for retaining screw
	4901-31 Original Part No. D10/20 drawing available Years 1931-32 Models S/4F Bakelite, 8 points, with groove for retaining screw
	4901-32 Original Part No. D10/30C Years 1932 Models V Steel, with groove for retaining screw
Taller version of 4901-32	4901-32 Original Part No. D10/32C Years 1932 Models Colts Steel, with groove for retaining screw
As 4901-31 but without groove for screw	4901-33 Original Part No. D10/85 Years 1933 Models All Bakelite, 8 points, without groove for retaining screw
	4901-34 Original Part No. D10/110 drawing available Years 1934-37 Models All Bakelite, 72 serrations, “ARIEL Selly Oak Birmingham” No lip on underside of the top, no serrations on base and hexagonal insert
	4901-46 Original Part No. ? Years 1938-58 Models All Bakelite, 72 serrations, “ARIEL Selly Oak Birmingham”, as 4901-34 but with lip on underside, different insert, initially with serrations, three alternative bases. We made up the part number for this one.
	4901-51 Part No. D10/141 Years 1938-58 Models All Bakelite, 72 serrations, “ARIEL” in central totem, three alternative bases. We made up the part number for this one.
	4901-46 / 51 styles Years 1938-46 Models – girder forks The steel insert protrudes by 1/32”, a spring that was the same as the one on the primary chaincase oiler, was placed inside the steel insert to press on the end of the rod. The steel insert had serrations to engage with matching serrations on the plug (4902-35) in the steering stem.
	4901-46 / 51 styles Years 1946-51 Models – telescopic forks Groove is for 4929-47 spring, insert has serrations for use with steering column plug 4834-47/H41-46.
	4901-46 / 51 styles Years 1952-58 Models – telescopic forks Groove is for 4929-47 spring, insert does not have serrations for use with plain steering column plug 4834-52. Photo shows later style B with wider lip on underside

D10/141 is sometimes listed with a ‘C’ suffix that normally indicates ‘complete’