De 1910 à 1915, la Cadillac Model 30 à quatre cylindres a été le pilier de la compagnie
   Ce successeur du modèle K, le model 30, fut la première voiture avec un générateur, une batterie, des lumières électriques et un démarreur. Cette innovation fit à nouveau remporter àCadillac le Dewar Trophy de 1912.Un trophée qu’aucune firme automobile n’a jamais remporté deux fois consécutives. Le RoyalAutomobile Club proclama cette année là : Cadillac « The Standard of the World », un sloganque la marque utilisera pendant des années.
   Pendant ce temps, d'autres manufacturiers que l'on pourrait qualifier de haut de gamme ont commencé à adopter des moteurs à six cylindres en ligne plus puissants et plus doux. Les ventes de Cadillac ont dégringolé devant cette compétition de plus en plus féroce. La pression s'est intensifiée.

   CADILLAC - MODEL "THIRTY" - FOUR: After an inauspicious trial in the luxury car field, and recognizing the disappearing market for the single cylinder cars which made their reputation, Cadillac settled down with a design which had originated in 1906 (the 1907-1908 Model G). With in-house mass production of a single line, Cadillac was able to offer a high quality automobile at a moderate price: $1400 for the Model "Thirty" as compared to $2000 for the Model G.
   Cadillac offered three models: 2-door Touring 5-passenger; 2-door Demi-Tonneau 4-passenger; and Roadster 3-passenger. The "Thirty" differed from the Model G as follows:
   Bodies: No closed bodies offered. Detachable tonneau once again available. Steel doors and cowl on Roadster and Demi-tonneau. Flaring, twisted front fenders replaced bky flat fenders with filler between fender and frame. Full running boards and running board dust shields on all bodies. No louvers in hood. Bodies finished (painted) by Cadillac
   Chassis: 3/4 plaatform rear spring system. Single dropped frame. Wheelbase lengthened to 106 in. In mid-year, brake drum diameter was increased to 12 in.
   Drive line: transmission refined and mounted at three points to frame cross members rather than at four points to frame side rails. Universal joint housed in ball joint at rear of transmission. Rear axle with bevel gear differential made by American Ball Bearing
   Engine: Drive for water pump (gear type) and oiler changed from external belt to internal gears. Gear driven accessory shaft allows for optional magneto. Speed governor no longer used.
   I.D. Data: Serial numbers on plate on rear of body or on dash (with engine no.). Engine numbers were stamped on top surface of crankcase -- in front of and to the left of number one (front) cylinder. Starting: 32002. Ending 37904.
   ENGINE: Vertical in-line, L-head. Four cylinder. Individual cast iron cylinder, copper water jacket. Bore & stroke: 4 x 4.5". Displacement: 226.2 cubic inches. Brake horsepower: 30 A.L.A.M.; 25.6 Advertised H.P. Five main bearings; Mechanical push rod roller cam followers. Float feed carburetor made by Cadillac.
   CHASSIS: W.B.: 106 in. Frt/Rear Tread: 56 in. (61 opt.) Tires: 32 x 3-1/2.
   TECHNICAL: Selective sliding gear transmission. Speeds: 3 Forward/1 Reverse. Right hand drive, controls to right. Leather faced cone clutch. Shaft drive. Plain live rear axle, bevel drive; bevel gear differential. Overall ratio: Touring and Demi-Tonneau = 3.5:1; Roadster=3:1. Mechanical brakes on two wheels - service/foot/contracting - emergency/lever/expanding. Wood artillery wheels, 10 & 12 spoke, quick detachable rims. Wheel rim size: 25 in. Optional: Final drive ratio: 3:1, 3.5:1, 4:1
   OPTIONS: Seat covers ($45-75). "Rubber," mohair, or leather tops ($55-125). Bosch, Dow, Eisenbann, or Splitdorf magnetos ($100-126) Rushmore style B headlamps with Rushmore No. 1 generator ($46.50). With Prest-o-lite style B tank ($59.50). Mezger windshield ($50). Gabriel horns, style 1, 2, 3, 4 ($15-35). Stewart & Clark speedometer ($15-40).
   HISTORICAL: Introduced December 1908. Calendar year sales and production: 5903. Model year sales and production: same. The president/general manager of Cadillac was Henry Leland. On July 29, 1909, Cadillac Motor Car Co. became a wholly owned subsidiary of General Motors Co., and Henry Leland became president and general manager of Cadillac Motor Car Co.
   HISTORICAL: Introduced November, 1909. Innovations: Delco ignition system. Model year sales: 8008. Model year production: 8008. President & General Manager of Cadillac was Henry Leland.
   Note: In the early days of automobiling in America, open cars and poor travel conditions precluded winter motoring. Manufacturers displayed samples at the winter auto shows and took orders for spring and summer delivery. Cadillac's model year coincided with the calendar year and the year's production was presold.
   In 1910, Cadillac got more heavily into closed cars and had a solid reputation for quality and value. With a ready demand for their full factory capacity, they introduced the 1911 models in late summer of 1910 and had delivered a significant percentage of the 1911 model production by the start of the calendar year. Cadillac was now producing below demand and customers were willing to accept delivery at any time or wait as long as necessary for delivery.