Most ships measured speed on a Time Distort scale. The London left Earth at TD-5. Keera in Duel estimated Liberator's arrival speed at the unnamed planet as TD-6. The ship in which Servalan travelled to Exbar had a safety maximum of TD-9, but an emergency maximum of TD-10. Servalan ordered her cruiser to depart from Obsidian at TD-10.
The Liberator used a different scale, of multiples of an unspecified standard. Blake instructed Zen to plot a course to Cygnus Alpha at "standard speed" and the journey was completed in what appeared to be a very short space of time. Later journeys were made at SB-2, SB-3 etc but later SB-6 became the norm for long distance travel. SB-10 was frequently used to escape from places on departure, and Blake's attack run on Servalan's HQ in Trial was made at this speed. Maximum speed appeared to be SB-12: Zen identified the landing module from Kairos fitted with the Sopron analogue as capable of SB-12.203, presumably marginally faster than Liberator. Blake completed the journey to Star One at SB-12. The sister ship despatched by the System in Redemption was stated by Zen to be approaching at SB-14.
In Duel the Liberator tried to ram Travis at an implied speed of SB-2, and Keera stated this to be TD-3. This suggests a SB:TD ratio of 1.5:1. In Hostage the Liberator accelerated to SB-10 and then SB-12 when first attacked. On the second attack speed was again increased to SB-10 on Blake's order. The command ship's mutoid pilot determined Liberator's speed as TD-20 soon after. This suggests a 2:1 ratio, unless Blake accelerated again to SB-12, a ratio of 1.7:1 and closer to the value suggested in Duel.
In Breakdown Blake states that Standard by 20 will cause the crew to lose control of the Liberator.
In Project Avalon Terloc told Travis that the Liberator had entered the planet's system and was expected to rendezvous with Avalon within 50 hours. This is rather a long time for a ship that could easily travel between stars and might refer to intra-system travel at sublight speeds (as a basic comparison, to travel the distance from Pluto's mean orbital distance from the Sun to Earth's mean orbit - about 5.7 billion kilometres - in 50 hours would require travelling at a speed of about 0.1c).
Some confusion over speed arises in Stardrive: Scorpio approaches an asteroid at a converging speed of SB-1, and the photonic drive-fitted space chopper seen near the Altern system was said by Orac to have a speed of SB-12.6, but further references by Atlan were to TD-12 and, in the case of the Mark II drive, TD-15. Fitted with the photonic drive, Scorpio fled from Bucol-2 at a speed estimated at TD-12. This is somewhere between SB-6 and SB-8, making Scorpio at least as fast as Liberator's standard cruising speed.
Speeds were usually given as whole integers, but some fractional speed values include speed increasing to SB-8.65 in The Web, and Jenna pulling away from XK-72 at SB-0.01.
TD and SB speeds appear to refer to faster-than-light velocities, but were also cited to when manoeuvring around planets, something that might conceivably be better done at sublight speeds.
See also HYPERDRIVE, PHOTONIC DRIVE, TIME DISTORT, INTERGALACTIC DRIVE.