The Miami Cycle Company typically produced six different Racycle models each year. The information I have suggests that the company denoted models with letters (for example Model P for the Pacemaker in 1898 and Model R for light road racer in 1899) before switching to numbers in 1900.
The Pacemaker was the top-of-the-line model from its introduction, which I believe to have been in 1898. The Pacemaker is instantly recognizable by its gigantic 40-tooth (1-inch pitch) front sprocket. A variety of rear sprocket sizes was offered, but the standard gearing was quite tall. (I intend to investigate Racycle efficiency claims and engineering in future posts.) Second in line in the catalogues was usually the Racycle racer, at least until about 1913.
In the product hierarchy, the Pacemaker and racer were followed by variants that all carried a 30-tooth (1-inch pitch) front sprocket and had apparently identical frame geometry. These other Racycles—that is, the other four models that were neither Pacemakers nor racers—were differentiated mainly on the basis of their equipment, such as hubs, handlebars, and saddle.
However, sometimes there were fairly significant differences among them. For instance, in 1904 an improved crank hanger was introduced, one that the catalogue noted was not available on the three lower-ranked Racycle models. Although the next year’s catalog announced that the company had decided to include the improved crank hanger across a broader range of models, it remained unavailable on the least-expensive model. Similarly, when the Pacemaker crank sets were forged from vanadium-steel alloy in 1908, the material was offered as an option in only the next two lower-priced models (the racer and the Racycle roadster). Vanadium-steel cranks were not available in the women’s model or the two least-expensive Racycles.
I have very little information about 19th century Racycles, so this next bit pertains only to those constructed in 1900 and later. Some Racycles had a model-number badge affixed to the head tube above the head badge, but it seems that others did not. The model numbers contained either two or three digits. The last digit denoted the position in the model hierarchy, with 0 (zero) the highest (the Pacemaker) and 5 the last in line. From my review of several catalogues, it appears that the preceding one or two digits of the model number denoted the year of manufacture—not the calendar year but the number of years since production commenced in 1896. Thus, the 1900 models (built in the fifth year of production) were numbered 50 through 55, the 1905 models were numbered 100 through 105, the 1910 models were 150 through 155, etc.
If you have information about Racycle model numbering prior to 1900, or can shed light on whether Pacemakers carried model number badges above the head badge, please feel free to share.