Mechanical power transmission: Technology advances
Toothed belts, smarter gears and plugging compressed-air leaks
What this tab covers The newest technologies in service or close to adoption, what each improves, and how the main options compare.Mechanical transmission is mature; the advances are incremental efficiency gains (toothed belts, better gears, recovering exhaust air and smarter hydraulics) and new ropeway designs for city transport.
Latest advances
Synchronous (toothed) belts in service · 2012Belts with teeth that engage pulley grooves instead of relying on friction.1
Improves: About 98% efficiency with no slip; a 100 hp fan saves about 16,130 kWh a year against a 95% V-belt.
Optimised helical gear geometry research · 2021Choosing gear ratio, tooth count and helix angle to cut friction.6
Improves: Modelled drive efficiency ranged from about 93.9% to 97.5% depending on design.
Higher-efficiency fluid power research · 2012Best-practice and research programmes for pumps, valves and controls.2
Improves: Could raise average US fluid power efficiency from 22% to 27% near term and 37% long term.
Pneumatic exhaust recovery research · 2012Reusing the energy in exhausted compressed air.2
Improves: Raised pneumatic efficiency by 14 to 23% in a cited study.
Compressed-air leak programmes in service · 2026Updated Compressed Air Challenge guidance on finding and fixing leaks.3
Improves: Brings leakage from about 20% towards under 10% of output.
New ropeway systems in service · 2025-2026Doppelmayr's 2025/26 projects included an urban ropeway in Paris, and its revenue rose 9.1% to about EUR 1.3 billion; HTI Group (Leitner, Poma) grew turnover 15.8% in 2025.916
Improves: Extends rope transport into cities.
Comparing the options
| Option | Efficiency | Cost | Capacity or distance | Maturity |
|---|---|---|---|---|
| Shafts and gears6 | 98 to 99% per mesh at best | Not quantified here | Metres; up to megawatts | mature |
| Belts1 | About 95% (V-belt) to 98% (synchronous) | Minimal premium for synchronous belts in new installations | Metres; small to medium power | mature |
| Ropeways (ropes and cables)7 | Not quantified here | US$10 million to 25 million per km (Latin American urban systems) | Average urban line 2.7 km; 1,000 to 2,000 passengers per hour each way | mature |
| Hydraulic network24 | About 21% (mobile) to 50% (industrial) end to end | Not quantified here | Factory scale today; city scale historically (about 180 miles of mains in London) | mature |
| Compressed-air network25 | 12 to 17% end to end | Useful energy about 6 to 8 times the price of the electricity used (calculated) | Factory scale today; about 1,000 km in historic Paris | mature |
Over short distances, shafts, gears and belts are hard to beat, and they sit inside almost every motor-driven machine. Over longer distances, electricity wins easily because wires lose only a few percent while fluid systems lose most of their energy. Hydraulics remain where huge forces are needed in a small space (excavators, presses), pneumatics where cheap, safe, simple tools matter more than efficiency, and ropeways where steep terrain or crowded streets make roads or rail hard to build.
Sources
- Replace V-belts with notched or synchronous belt drives (Motor Systems Tip Sheet #5) US Department of Energy, Advanced Manufacturing Office, 2012
- Estimating the Impact (Energy, Emissions and Economics) of the U.S. Fluid Power Industry (ORNL/TM-2011/14), Love, Lanke and Alles Oak Ridge National Laboratory, 2012
- Compressed Air System Leaks (Improving Compressed Air System Performance, Fact Sheet #7, Rev. 1) Compressed Air Challenge, 2026
- London Hydraulic Power Company Science Museum Group Collection, 2025
- Victor Popp et l'horlogerie pneumatique à Paris Ville de Paris, 2024
- Using the Box-Behnken response surface method to study parametric influence to improve the efficiency of helical gears (Machines 9(11), 264) MDPI, 2021
- Innovation in the air: using cable cars for urban transport World Bank (Transport blog), 2017
- Doppelmayr: Umsatz wuchs 2025/26 auf 1,3 Mrd. Euro APA (Austria Presse Agentur) via news.at, 2026
- HTI Group: a year of results and investments Leitwind (HTI Group), 2026