for anyone interested:BISHOP RACK AND PINION GEAR SETSBishop Active Rack
some comment's thoughts on the topic of VR racks in racing. It's probably a lot more common then Mat's likes to think.
Variable ratio steering development for Formula 1
The use of variable ratio (VR) steering racks is common in passenger cars. This gives the ability to tune the steering effort and yaw response of the vehicle. Bishop VR steering racks are becoming more popular in Formula 1 (F1) cars. The effects of aerodynamic download in high-speed (200 plus km/hour) and low-speed (100 km/hour) corners in an F1 car are outlined. The steering rack load is significantly higher near the straight-ahead steering wheel position than at lock for an F1 car, the opposite for a standard road car where rack loads are lower on-centre than at lock. VR allows the overall steering ratio to be increased locally on-centre to reduce the steering torque in this region. VR technology also allows F1 engineers to tune the yaw response of the car to reduce the load on the driver. The application of VR steering racks in F1 cars is discussed in relation to revised racing regulations.
Bishop Steering Technology’s variable ratio rack-and-pinion steering, new to the 92nd Indianapolis 500, received the 42nd annual BorgWarner Louis Schwitzer Award on May 16 at the Indianapolis Motor Speedway.
The variable ratio rack-and-pinion steering technology developed by Bishop offers a number of driver performance benefits, including reduced fatigue through improved ease in steering, more efficient pit entry and exit, and improved maneuverability for hazard avoidance.
Engineers Andrew Heathershaw, Soungjin Wou and Nick Belonogoff of Bishop Steering Technology and Andrea Toso from Dallara Automobili were honored for their work in the development and implementation of this technology for the IndyCar Series. Bishop’s North American facility is based in Indianapolis, while vehicle dynamics work on the system was performed in Sydney, Australia.
"This is another great tool to tune the cars," Wou said. "It’s very exciting."
The variable ratio rack-and-pinion steering system combines a range of steering rack teeth into one compact, efficient system that is manufactured with a high-tech machining process that creates gear tolerances of 1 to 2 microns. In the past, teams had to select one steering-rack tooth size for an event.
"With a variable rack, when drivers go into a high-speed corner, it’s a six-tooth rack," said Andretti Green Racing General Manager Kyle Moyer. "When they go through a chicane, it’s a 10-tooth rack. This system covers all of our bases."
Development of the variable ratio rack-and-pinion steering system for the IndyCar Series started in 2007 with Panther Racing, and Andretti Green Racing also joined in development with Panther and the Indy Racing League last year. The technology became available to all IndyCar Series teams this season.
Variable ratio rack-and-pinion steering is ideal for the road course events in the IndyCar Series, but Moyer said 2004 series champion Tony Kanaan uses it at all races, including the 92nd Indianapolis 500.
"He will drive it everywhere he goes," Moyer said of Kanaan. "He loves it."
And no I do not work for Bishop
, but their stuff, especially the machining of the rack&pinions, is probably the most common "off the shelf" components for motorsport applications.
Some teams, take only their rack&pinions and then build their own housings and the rest of the complete system.