| Description | Date | Identifier | |
| Letter to The Dunlop Rubber Co. regarding inconsistencies in tyre dimensions and weight. | 31th Aug 1928 | Box 58 \ 1 Scan058 | |
| Letter to The Dunlop Rubber Co. regarding inconsistencies in tyre dimensions and weight. | 31th Aug 1928 | Box 58 \ 1 Scan059 | |
| Specification table comparing two types of Dunlop wheels and tyres. | 31th Aug 1928 | Box 58 \ 1 Scan060 | |
| Various tyre types and dimensions for the 20 HP chassis, and the implications of standardizing certain options. | 31th Aug 1928 | Box 58 \ 1 Scan061 | |
| Comparison table of various 20 HP Dunlop wheels and tyres with their dimensions and weights. | 7th Sep 1923 | Box 58 \ 1 Scan062 | |
| 20 HP car, focusing on the need for balloon tyres and criticism of the Barkerlite demonstration body. | 7th Sep 1923 | Box 58 \ 1 Scan063 | |
| Introduction of 20' wheels and low-pressure tyres for the 'N' Series chassis, including cost analysis. | 18th Sep 1928 | Box 58 \ 1 Scan064 | |
| The standardization and introduction of 20 HP balloon tyres with silent tread. | 8th Sep 1928 | Box 58 \ 1 Scan065 | |
| Letter to The Dunlop Rubber Co. Ltd. proposing a meeting to discuss tyres, rubber engine mounts, and aero-engine rubber joints. | 22th Sep 1928 | Box 58 \ 1 Scan066 | |
| Visit to the Dunlop Rubber Co. to discuss the development of 'Fort' and 'Super' model tyres. | 1st Sep 1928 | Box 58 \ 1 Scan067 | |
| Tyre shimmy, dimensions, rubber engine feet, and rubber cylinder joints. | 26th Sep 1928 | Box 58 \ 1 Scan068 | |
| Blueprint showing the inflated and deflected shapes of four different 32x600 Dunlop tires under standard load and pressure. | 26th Sep 1928 | Box 58 \ 1 Scan069 | |
| Letter from Dunlop Rubber Co. regarding the supply and production of Silent tread tyres for 19' rims. | 4th Oct 1928 | Box 58 \ 1 Scan070 | |
| Letter from Dunlop Rubber Co. Ltd. concerning the delivery timeline for a tyre. | 4th Oct 1928 | Box 58 \ 1 Scan071 | |
| Letter to The Dunlop Rubber Co. requesting 'silent tread' tyres, highlighting Mr. Royce's desire to receive them quickly. | 5th Oct 1928 | Box 58 \ 1 Scan072 | |
| Selection of quiet and flexible car tyres for various models, including Dunlop silent tyres. | 6th Oct 1928 | Box 58 \ 1 Scan073 | |
| Letter to Dunlop Rubber Co. regarding the production and testing of silent tread tyres for 19 and 20 inch rims. | 16th Oct 1928 | Box 58 \ 1 Scan074 | |
| Introduction and performance of new silent tread tyres for cars. | 9th Oct 1928 | Box 58 \ 1 Scan075 | |
| Letter from Dunlop Rubber Co., Ltd. regarding the availability of silent tread tyres. | 19th Oct 1928 | Box 58 \ 1 Scan076 | |
| Standardisation of 20' rims and 6' tyres for the 20 HP model. | 24th Jul 1928 | Box 58 \ 1 Scan077 | |
| The fitting of a new part to a chassis, including costs and testing date. | 3rd Nov 1928 | Box 58 \ 1 Scan078 | |
| Delay in the delivery of silent tread tyres from Dunlops due to faulty moulds. | 24th Nov 1928 | Box 58 \ 1 Scan079 | |
| Order for a set of 6 silent tread tyres with tubes. | 5th Dec 1928 | Box 58 \ 1 Scan080 | |
| Requesting to check availability and order six silent tread tyres from Dunlop for Mr. Royce's car. | 25th Mar 1929 | Box 58 \ 1 Scan081 | |
| Supply and design status of Dunlop 'Fort' Silent Tread Tyres for the 20-HP model. | 28th Mar 1929 | Box 58 \ 1 Scan082 | |
| Letter to W.A. Robotham concerning a customer's objection to the silent type of tyre. | 1st May 1929 | Box 58 \ 1 Scan083 | |
| Page two of a letter from W. Bond, Development Manager, to W.A. Robotham, Esq. | 23th Apr 1929 | Box 58 \ 1 Scan084 | |
| Customer's objections regarding the original equipment 'Silent Tyres' fitted to their 20 HP car. | 23th Apr 1929 | Box 58 \ 1 Scan085 | |
| Investigation into incorrect tyre pressures caused by a faulty gauge and the resulting performance issues. | 23th Apr 1929 | Box 58 \ 1 Scan086 | |
| Recommendation for a tyre pressure experiment for a customer's vehicle. | 5th May 1929 | Box 58 \ 1 Scan087 | |
| The limitations of the gear ratio for the 20 HP vehicle based on tyre size and engine performance. | 5th May 1929 | Box 58 \ 1 Scan088 | |
| Recommendation regarding rear tyre pressures for the 20 HP model. | 2nd Sep 1929 | Box 58 \ 1 Scan089 | |
| Dunlop's difficulty in meeting the out-of-balance limit for 20 HP tyres and proposed solutions. | 19th Dec 1929 | Box 58 \ 1 Scan090 | |
| Number and size of balance weight washers for 20 HP Chassis tyres. | 19th Dec 1929 | Box 58 \ 1 Scan091 | |
| Customer objections to 'India' tyres and strategies for accommodating alternative tyre fittings. | 1st Jan 1930 | Box 58 \ 1 Scan092 | |
| Letter to Dunlop Rubber Co. Ltd. clarifying tyre specifications used for power consumption tests. | 14th Feb 1930 | Box 58 \ 1 Scan093 | |
| The out-of-balance allowance for 6' tyres on 19' rims for the 20 HP chassis. | 14th Feb 1930 | Box 58 \ 1 Scan094 | |
| Letter to the Dunlop Rubber Co. Ltd. authorising the supply of tyres with a specific out-of-balance limit. | 14th Feb 1930 | Box 58 \ 1 Scan095 | |
| Remedy for out of balance 6' tyres for 19' rims on a 20 HP Chassis. | 18th Feb 1930 | Box 58 \ 1 Scan096 | |
| 7' x 19' U.S. Royal Tyre, comparing its dimensions and weight with standard Dunlop tyres. | 8th May 1930 | Box 58 \ 1 Scan097 | |
| Comparative table of specifications for four different types of tyres. | 20th Feb 1924 | Box 58 \ 1 Scan098 | |
| Correcting the wheel revolutions per mile figure for a specific Dunlop tyre. | 15th May 1930 | Box 58 \ 1 Scan099 | |
| The recommended tyre pressures for Phantom II and 20 HP models. | 20th May 1930 | Box 58 \ 1 Scan100 | |
| Encouraging results of testing a new experimental silent tread Dunlop tyre. | 1st Aug 1930 | Box 58 \ 1 Scan101 | |
| The wear and tear of experimental silent type tyres after 4,700 miles of use. | 4th Oct 1930 | Box 58 \ 1 Scan102 | |
| Letter to Dunlop Rubber Co. confirming the decision to make the modified Silent Tread tyre the standard equipment for their cars. | 7th Oct 1930 | Box 58 \ 1 Scan103 | |
| Test report on modified Dunlop Silent Tread Tyres, focusing on road adhesion and noise characteristics. | 7th Oct 1930 | Box 58 \ 1 Scan104 | |
| Tyre modification and testing, noting improved road adhesion and wear compared to the standard silent tread. | 7th Oct 1930 | Box 58 \ 1 Scan105 | |
| Returning a signed standardisation sheet for a tyre tread pattern modification. | 9th Oct 1930 | Box 58 \ 1 Scan106 | |
| Standardisation document for a modification to the tyre tread pattern to improve road grip. | 7th Oct 1930 | Box 58 \ 1 Scan107 | |
| Comparison of Dunlop and India tyres for 40/50 & 20 HP cars, focusing on tread, non-skid properties, and comfort. | 5th Feb 1931 | Box 58 \ 1 Scan108 | |
| Confirming a telephone conversation regarding modifications to frame width, axle design, and tyre specifications for 'Japan III'. | 19th Oct 1931 | Box 58 \ 1 Scan109 | |
| Tyre sizes, including the actual and nominal sizes for chassis prints. | 20th Oct 1931 | Box 58 \ 1 Scan110 | |
| Consequences of a tyre change on vehicle height and proposing trials with different rim sizes. | 20th Oct 1931 | Box 58 \ 1 Scan111 | |
| Tyre and wheel specifications for a 25 HP car, including effects on gear ratios. | 23th Oct 1931 | Box 58 \ 1 Scan112 | |
| Tyre and wheel dimensions for the 25HP model, noting discrepancies and planning for new wheel tests. | 26th Oct 1931 | Box 58 \ 1 Scan113 | |
| Questioning the recommended tyre pressures for various chassis, comparing them to lower pressures for better comfort. | 27th Jun 1932 | Box 58 \ 1 Scan114 | |
| Secret memorandum regarding the temporary unavailability of the 20 HP 'India' demonstration car. | 24th Jul 1925 | Box 58 \ 1 Scan115 | |
| Unsatisfactory slipper drive on a New 20 HP Trials Saloon Chassis, GYK-10. | 26th Nov 1926 | Box 58 \ 1 Scan116 | |
| Faults and the inconsistent working of the slipper wheel on the 20 HP Trials Saloon, chassis GYK-10. | 29th Nov 1926 | Box 58 \ 1 Scan117 | |
| The 20-HP Trials Saloon, chassis GYK-10, in reply to a previous memo. | 30th Nov 1926 | Box 58 \ 1 Scan118 | |
| Need for frequent attention to old mechanical friction type dampers due to variations in loading. | 12th Dec 1926 | Box 58 \ 1 Scan119 | |
| Engine thump on a 20 HP Landaulet trials car (GSK-35) before the Scottish Motor Show. | 6th Dec 1926 | Box 58 \ 1 Scan120 | |
| Arrangements for a road trial of the GSK-35 20-HP Trials Landaulette. | 9th Dec 1926 | Box 58 \ 1 Scan121 | |
| Arranging for a 20 HP Trials Landaulet to be inspected in Derby. | 10th Dec 1926 | Box 58 \ 1 Scan122 | |
| Instructions for modifications and engine work on a 20 HP Landaulet, chassis GSK-35, following the Scottish Motor Show. | 22th Dec 1926 | Box 58 \ 1 Scan123 | |
| Disposal of a demonstration car, a 29-HP Landaulet, due to an undesirable engine feature. | 24th Dec 1926 | Box 58 \ 1 Scan124 | |
| Summary of an investigation where no cause for a reported trouble was found. | 30th Dec 1926 | Box 58 \ 1 Scan125 | |
| Modifications and issues with a 20-HP Landaulet, chassis GSK-35. | 30th Dec 1926 | Box 58 \ 1 Scan126 | |
| Plan for the 20 HP Trials Landaulet, GSK-35. | 1st Jan 1927 | Box 58 \ 1 Scan127 | |
| Standardisation of the cross steering tube on the 20-HP Trials Landaulet, chassis GSK-35. | 1st Jan 1927 | Box 58 \ 1 Scan128 | |
| Engine roughness and vibration issues on a GAJ-53 Barkerlite Limousine. | 7th Dec 1927 | Box 58 \ 1 Scan129 | |
| Swapping of an engine between two 20 HP trials cars for testing and improvement purposes. | 13th Jan 1928 | Box 58 \ 1 Scan130 | |
| Expressing disappointment with the rough performance of an Open Touring car following an engine swap. | 19th Jan 1928 | Box 58 \ 1 Scan131 | |
| The engine changeover between 20-HP trials cars GHJ-81 and GAJ-53. | 20th Jan 1928 | Box 58 \ 1 Scan132 | |
| The trials of a Barkerlite car, detailing issues with body resonance and experimental alterations to mitigate them. | 9th Feb 1928 | Box 58 \ 1 Scan133 | |
| Letter regarding the return of a car with experimental parts and the process to restore it to standard condition. | 13th Feb 1928 | Box 58 \ 1 Scan134 | |
| Telegram received by telephone asking when bakelite will arrive in London for the Experimental Department. | 13th Feb 1928 | Box 58 \ 1 Scan135 | |
| Front axle oscillation, or 'axle rocking', observed during the London's Continental trials of chassis G.X.L.-60. | 2nd Mar 1926 | Box 58 \ 1 Scan136 | |
| Requesting the preparation of a 20 HP chassis for a 10,000-mile trial car. | 22th Mar 1926 | Box 58 \ 1 Scan137 | |
| Inquiry about the progress of a 20 HP trial chassis and the concealment of any noticeable experimental parts from coachbuilders. | 13th Apr 1926 | Box 58 \ 1 Scan138 | |
| Preparation of a 20 HP car for a 10,000-mile sales test. | 4th Apr 1926 | Box 58 \ 1 Scan139 | |
| Allocation of chassis No. 1644 for a 20 HP car ten-thousand-mile sales test and dispatch to Hooper's Works. | 20th Apr 1926 | Box 58 \ 1 Scan140 | |
| Arrangement for fitting a louvered bonnet to chassis no. 1644 for a 10,000-mile test. | 21th Apr 1926 | Box 58 \ 1 Scan141 | |
| Requesting the chassis number and proposed programme for the 20 HP 10,000 miles test car. | 20th May 1926 | Box 58 \ 1 Scan142 | |
| The fitting of experimental parts to chassis no. 1644. | 9th May 1926 | Box 58 \ 1 Scan143 | |
| The completion of a new 20-HP engine with modified parts for a 10,000-mile test. | 2nd Jun 1926 | Box 58 \ 1 Scan144 | |
| Modifications to the steering column and pedals on a 20 HP experimental car. | 21th Jun 1926 | Box 58 \ 1 Scan145 | |
| Clarifying the specifications for a 20 HP car test, regarding its 'India' build features like the louvered bonnet and springs. | 22th Jun 1926 | Box 58 \ 1 Scan146 | |
| Confirming an altered coachbuilder's drawing for a 20 HP car has been passed to Messrs. Hooper. | 25th Jun 1926 | Box 58 \ 1 Scan147 | |
| Chassis inspection at Hooper's for a 20 HP car regarding altered pedals and steering column. | 2nd Jul 1926 | Box 58 \ 1 Scan148 | |
| Policy discussion on not sending experimental cars with new features to London coachbuilders. | 6th Jul 1926 | Box 58 \ 1 Scan149 | |
| Correspondence regarding alterations to seating dimensions and a custom cushion for 20 HP Chassis No. 1644. | 7th Jul 1926 | Box 58 \ 1 Scan150 | |
| Bodywork, seating, and consultation for 20 HP Chassis No. 1644. | 8th Jul 1926 | Box 58 \ 1 Scan151 | |
| Confirming the fitting of an adjustable front seat to Experimental Car No. 1644. | 9th Jul 1926 | Box 58 \ 1 Scan152 | |
| The unsuitability of a standard Hooper Saloon body for a 10,000-mile test on a Goshawk chassis. | 14th Jul 1926 | Box 58 \ 1 Scan153 | |
| New features and modifications for the 20 HP. chassis 1644. | 16th Jul 1926 | Box 58 \ 1 Scan154 | |
| Sale and body fitting for a 20 HP chassis, number 1644. | 22th Jul 1926 | Box 58 \ 1 Scan155 | |
| Engine modifications for chassis 1644 and the agreement to sell it. | 23th Jul 1926 | Box 58 \ 1 Scan156 | |
| Letter arranging the collection of a 9G.111 car and the return of a 20 HP Weymann trials car. | 10th Jul 1928 | Box 58 \ 1 Scan157 | |
| | | | |
