- 1 - Date: 11/2006 Information concerning 'RSC': BMW Group Runflat tyres Discontinuation of spare wheel RSC In recent years after starting with the BMW Z8 we have come a long way to making the 5th wheel on BMW vehicles superfluous. The 5 Series (E60) features the new runflat tyre technology for all optional extra () and optional equipment and accessories (SZ) tyre sizes, i.e. 17", 18" and 19". The standard recess for the emergency wheel is available as additional load space. The Z4, 6 Series Coupé and Convertible are exclusively equipped with runflat tyres, rendering it possible to dispense with the spare wheel and its recess. By consistently developing this strategy, the 1 Series (E87) is the first BMW highvolume model to feature RSC technology from the standard tyres through to optional equipment (no spare wheel recess). This strategy continues with the re-issue of the 3 Series (E90) in all variants. The further-improved 3rd generation of runflat tyres optimally matched to the 1 and 3 Series represents a quantum leap in terms of driving dynamics, agility and tyre safety and now largely satisfies the most demanding rolling comfort requirements of Saloons. With the new X5 (E70) an V vehicle will start with the runflat innovation, universally in all tyres and tyre sizes. The 4th RSC generation tyres - further improved in terms of comfort performance - satisfies all the requirements and specifications of the designers for this vehicle class as well and set particular standards in agility and driving dynamics. The MINI from the start features a mobility concept that is unprecedented in its class. And this has been consistently developed further on its successor, the R56. Thus, the runflat tyres of the R56 feature in 16", 17" and special accessory 18" (predominantly optional extras and special accessories) all the advances in development of BMW tyres (4th generation), which is expressed here in particular in the form of improved comfort while retaining the handling characteristics typical of MINI. The Rolls-Royce has as standard the so-called 'PAX ' as well as a wheel/tyre system with limp-home properties, but geared towards the support ring. The 21'' optional extra tyres of the RR01, however, already feature RSC technology. 1. description RSC = Runflat--Component is a wheel/tyre system with emergency running characteristics consisting of - Self-supporting tyre RSC - Extended Hump rim EH2 or EH2+ and - Runflat indicator RPA (in U RDC).
- 2 - Date: 11/2006 Since 10/2001, the letters 'RSC' have been displayed in a 20 mm circle on both side walls of all BMW runflat tyres, making these new types of tyres easily and clearly identifiable. The tyres, optimally matched to the chassis of BMW Group vehicles, can be additionally identified by the BMW (MINI or Rolls-Royce) tyre identification marking ( ) following the sales designation of the respective tyre. For example: 205/55 R 16 91V Continental Premium Contact SSR The principle of the "self-supporting tyre" is based on reinforced side walls with additional flexible rubber springs made from temperature-resistant rubber mixtures that prevent the tyre from collapsing over a certain distance when in a deflated condition thus enabling the driver to continue his journey in the event of tyre failure. tyre deflated RPA or RDC Self-supporting tyre deflated In the event of tyre failure indicated on the display/screen in the instrument cluster on 'High' and by a warning lamp in 'Low' instrument clusters depending on the load status, it is possible to continue driving with the defective tyre at reduced top speed (max. 80 km/h) and the driving style adapted accordingly to suit the situation. With this system it is generally possible to safely reach a service station without having to stop and without having to change a wheel. Added to this a substantial gain in active safety is ensured in the event of sudden, total pressure loss (blow-out) while driving straight ahead and above all while cornering. In contrast to standard tyres, RSC tyres do not detach from the (EH2) rim in such cases and maintain their lateral support. The driver is therefore able to control the vehicle also in the case of a high-speed blow-out in a curve while driving on the motorway for instance, whereas with standard tyres the loss of control is unavoidable even for the most experienced driver.
2. features - 3 - Date: 11/2006 Road safety and handling characteristics conform to the renowned, high BMW standards (see BMW tyre marking ). Compared to standard tyres, the system offers advantages in all aspects of vehicle dynamics. Additional, active safety by largely maintaining the lateral support in the event of sudden, total pressure loss (blow-out). Journey can be continued in the event of tyre failure involving virtually all types of damage, including side wall damage = increased safety and comfort. Flat-rolling target values under above-specified conditions, 3rd/4th generation comfort-optimised: 1st generation Further generations Load up to 1 person: > 500 km > 200 km Average load*: 250 km approx. 150 km (* Roadster: 2 persons, 4/5-seater: 3 to 4 persons) Full load (Saloons): approx. 50 km approx. 50 km This remaining distance applies to the tyre when completely deflated (0 bar) a condition that very rarely occurs in practical applications! Considerably greater emergency running distances can be achieved even at a low residual pressure of, for example, approx. 0.5 bar, particularly on the non-driven axle. RPA already triggers a warning at tyre pressures > 1.5 bar! In tests and depending on the size of defect, runflat tyres of all generations achieved distances of approx. 1000 km (slow pressure loss corresponding to approx. 80 % of all real cases) were achieved as from the RPA warning! Reliable fit of the tyre on the extended hump rim down to 0 bar. This cannot be guaranteed when using standard (H2) rims. Control systems (ABS/ASC/DSC) remain functional in the event of tyre failure. Tyres and wheels fully compatible with existing wheel/tyre systems, i.e. a "standard tyre" can also be mounted if necessary. On account of their stiffer side walls (necessary for technical reasons), the 1st generation runflat tyres with the development aim of covering 'the longest possible flat rolling distance' are comparable to extremely sporty low-profile tyres. Due to physical aspects, the 1st generation tyres did not achieve today's very high comfort properties on very uneven road surfaces, cross expansion joints, tar accumulations or similar. The 2nd through to currently 4th generation tyres which were modified in terms of rolling distance give a considerable more comfortable ride under
- 4 - Date: 11/2006 normal operating conditions. Particularly as from the E90, the difference compared to 'standard tyres' is now only very slight, i.e. scarcely perceivable by the average customer. 3. RPA description The RPA (Run Flat Indicator) is a so-called flat-rolling indicator, i.e. a tyre pressure monitoring system with slightly coarser warning threshold than RDC, sufficient for reliable indication of a defective tyre with a large, abnormal drop in inflation pressure (>30 %). 1 2 Wheel Speed Pulses ABS, ASC, DSC 3 4 button RPA Deflation Warning Functional principle: When a loss of air pressure occurs, the rolling radius of the tyre and therefore its circumference is reduced, consequently increasing the rotational speed of the wheel. The RPA measures the wheel speeds with the aid of the sensors of the 4-channel ABS system, compares the diagonally opposed wheels and the average temperature and is therefore capable of detecting a loss in air pressure. After a short driving period of generally 1-3 minutes, the RPA correspondingly informs the driver as from a speed of 15 km/h. In Europe, RPA was installed as standard for the first time on the BMW M5 (E39) models and on the 7 Series protection line. As from MY 2000 it has been a standard feature on the Z8 and phased in on the 7 Series and 3 Series equipped with the runflat tyre. From the very beginning, the MINI has featured an RPA as standard both for normal as well as runflat tyres. This is a unique feature in this vehicle class. As from MY 2004 all new model series will be equipped with RPA as standard. All subsequent BMW Group models will feature RPA as standard. With the introduction of these safety features as standard, the BMW Group maintains its leading position in international comparison.
- 5 - Date: 11/2006 4. Pilot applications and volume production launch at BMW The pilot applications of the 1st generation of RSC tyres ran on the 7 Series (E38) and on the Z8. All other applications US 3 Series (E46), MINI, 7 Series (E65) already involve tyres as from the 2nd 'soft' generation. An overview of the current range is provided below: 5. RDC / RPA / Runflat tyres / spare wheel / MMS ex-factory range Model Series E-Series RDC RPA Runflat tyre Spare wheel MMS Tyre pressure control Run Flat Indicator M / MINI Mobility 1 Series E87 3 Series E46 (up to 08/2003) (as from 09/2003) (US only) Emergency wheel as standard full-size spare wheel as E46 M3 E90/E91/E92 5 Series E39 E39 Protection E39 M5 E60 M5 E60/E61 Emergency wheel* 6 Series E63 M6 E63/E64 7 Series E65/E66 (up to 09/2003) (as from 12/2003) E67 (PAX) E68
- 6 - Date: 11/2006 Z E52 E85/E86 X E53 (up to 04/2004) (as from 04/2004) Winter and all-season E70 Emergency wheel as standard full-size spare wheel as E83 Emergency wheel MINI R50 Emergency wheel as R53 R56 MINI Mobility Rolls Royce RR01 = Not offered * Emergency wheel as possible with RSC. On account of statutory provisions all new vehicles in the U will be fitted with RDC instead of RPA as standard from 09/2008 at the latest. 6. Tyre manufacturers, tyre designations => 'Identifier' All BMW tyre suppliers (Bridgestone, Continental, Dunlop, Goodyear, Michelin and Pirelli) are now well established manufacturers in RSC technology. Bridgestone, Goodyear and Dunlop have been the driving force behind this development. Since there was previously no "standardised" letter in the tyre designation for runflat tyres, together with the tyre manufacturers, BMW has agreed upon a uniform, standardised 'identifier': RSC The letters RSC in the approx. 20 mm circle stand for Runflat--Component. This symbol is permanently displayed in the rubber on both side walls of all BMW runflat tyres, thus enabling our customers to easily find the right 'BMW runflat' tyre whenever replacements are necessary. Reference is also made to the RSC logo in the Owner's Handbook and Service Information. In future runflat tyres will use a new standard designation "RF" instead of "R" for conventional radial tyres, example: 205/55 RF 16 91 V. However, the RSC symbol will remain on the tyres for a transitional period. In addition to these standardised designations, each manufacturer will continue to use its own product identifications:
- 7 - Date: 11/2006 Bridgestone "RFT" Run Flat Technology Continental "SSR" Self-Supporting Tyres Dunlop RunOnFlat Dunlop "DSST" Dunlop Self Supporting Technology (up to 2005) Goodyear RunOnFlat Goodyear: "EMT" Extended Mobility Technology (up to 2005) Michelin: "ZP" Zero Pressure Pirelli: eufori@ The complete designation of an RSC tyre is therefore currently: 205/55 R 16 91V Continental Premium Contact SSR 7. The Michelin PAX system The Michelin "PAX system" is an alternative extended mobility tyre concept based on a support ring with a completely different rim and wheel design that is not compatible with the wheel/tyre systems used to date (winter tyres!). Prominent features of this new system include the very safe tyre and wheel locking system which is also responsible for the 'different' appearance of the PAX system, and a slightly larger package space for the brakes. This system has considerable weight disadvantages compared to RSC tyres, however, it allows for higher axle loads due to the generally higher load bearing capacity. The PAX system is therefore currently used on the RR01 and on the E67. The 21'' optional extra wheels of the RR01, however, already feature RSC technology.