<Tr> <Th> Class </Th> <Td> Standard, Sport bike (TVS Apache RR 310) </Td> </Tr> <Tr> <Th> Engine </Th> <Td> 150 cm3, 159.7 cm3, 177.4 cm3, 197.75 cm3, 312.2 cm3, Single Cylinder, SI, 4 - stroke, 2 valves, 4 valves, Air - cooled, Oil - cooled, Liquid Cooled </Td> </Tr> <P> The TVS Apache is a brand of motorcycle made by TVS Motors since 2006 . In 2008 the company claimed that more than 2.5 million Apaches were on the road. Currently the company sells five variants of the TVS Apache . The differences between each variant being the engine displacement, the options on offer and performance characteristics . The abbreviation' RTR' in the names of the motorcycles refer to' Racing Throttle Response' . </P> <P> TVS which partnered with Suzuki for 19 years had brought out several two - stroke motorcycles in India . When the emission norms in the country changed, a need for more fuel efficient and less polluting four - stroke motorcycles suddenly came into being . However Suzuki at the time was globally known to produce two - stroke motorcycles and did not have strong R&D in the four - stroke department . All this led to the late introduction of the TVS - Suzuki Fiero in 2000 which was specifically developed for the Indian market . </P>

What is the full form of rtr in apache