CAC Training Run-Flat tires & TPMS Basics Noah Yanowitz, Service Engineering, December 9, 2008

Slide 2 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Run-flat wheel and tire types Self supporting tires- The Mercedes MOE (Mercedes Original Extended), is a self supporting tire (SST). Most run-flat tires on the road today are SST’s. The main advantage of SST’s is that they require no special wheel designs, mounting equipment or training to install. Simply put they are conventional tires with reinforced sidewalls capable of temporarily supporting the weight of the vehicle.

Slide 3 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Hutchinson Design The Hutchinson type run-flat tire is far less popular and reserved mainly for Military applications. The hutchinson design requires a specialized wheel design, mounting equipment and technician training. On the positive side the hutchinson design does offer a true pneumatic sidewall with superior ride qualities.

Slide 4 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Run-Flat Questions 1.If a tire gets a puncture, in a place where it can normally be repaired with a conventional tire, can it be repaired with a run-flat? Answer- Daimler policy is that tire repairs are not permitted on any tire, standard or run-flat. 2.If tire-fit is used to repair a puncture, can the tire-fit (foam) be removed and the tire repaired? (assume a puncture in the center of the tire, not a shredded tire) Answer- According to the manufacturer (Dunlop) the Tirefit can be cleaned from the tire and disposed of with the same precautions Which would apply to engine coolant. The tire could then be repaired to the individual tire manufacturers recommendations.

Slide 5 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Run-Flat Questions 3. What are some driving characteristics of run-flat tires in trucks (ML, GL, R)? Answer- Typically run-flat tires by nature of the stiffer sidewall give a firmer ride quality (typically described as feeling like a tire with an additional 10 PSI). However the MOE tire has different design criteria than industry standard run-flat tires. It is typical for run-flat tires to have a run-flat capacity of MPH, while a MOE tire is designed to go MPH. Mercedes engineers chose to exchange zero pressure durability in favor of a higher ride quality (the expected ride quality from a MOE tire is more like a tire with an additional 4PSI rather than 10PSI). Are mileage wear expectancies the same as conventional tires? Answer- For tires of the same design criteria (performance, all-season or touring), the wear characteristics should be similar. Remember that there are no mileage guarantees and that tire life is influenced by a variety of operating conditions such as temperature, load, inflation pressures, wheel alignment, road surface and driving style.

Slide 6 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Run-Flat Questions 5.With the use of tire-fit does it ruin the TPM sensor? Answer- The use of any tire sealant product is not advised on vehicles equipped with Tire Pressure Monitoring. Damage to the TPMS sensor may occur. 6.What is the availability of run-flat tires to our dealers? Answer- Run-flat tires are produced in far fewer numbers than conventional tires and currently we do not have much in the way of multiple choices for approved suppliers, so their availability may be a bit more difficult. 7.How far can a run-flat tire go without any air pressure? Answer- That depends upon variables such as temperature, vehicle load and speed. The MOE tire is designed to go 20 50MPH, however at lower speeds the tire life can be much greater.

Slide 7 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Run-Flat Questions 8.If the situation occurs, can a conventional tire (same size and load rating) be used on a vehicle if a run-flat is not available? Answer- It would not be advisable to do so, because the vehicle would not have balanced dynamics in all driving situations 9.Are there run-flat snow tires or just all season? Answer- Run-flat tires can be produced in all tire designs. Also the correct term is “Winter tire” because they are optimized for any driving condition when the temperature is below 45 degrees F, not just snowy conditions.

Slide 8 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Tire Pressure Monitoring TPMS has been an option in America since 2001 and is Federally required on all vehicles sold in America as of The expectation is that it is the drivers responsibility to maintain proper tire pressures placard values depend on load and speed recommended pressure values are close to minimum tire pressures

Slide 9 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Activation- Must have An accurate tire pressure gauge able to read pressures down to 1PSI increments A source of “dry” air- water or condensation in the tire can lead to system reliability issues Tire pressure MUST be set on cold tires to at least the placard minimum values Each vehicle differs in the activation process (due to different TPMS suppliers and vehicle control layouts) which can be found in the owners manual

Slide 10 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Warnings- Warnings which make reference to the tire pressure or to check tires are not system malfunctions, they are safety warnings. The tire does not have to be flat to trigger such a warning, just a few pounds too low in pressure is enough After such a warning a vehicle can simply have the pressure corrected in all 4 tires and the system reactivated- it is always wise to check for nails or other possible sources of leaks. Any warning related to “visit workshop” is a system malfunction and should be brought back to the dealer for investigation.

Slide 11 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt Extra- FYI’s The aluminum valve stems which are used with TPMS systems should not have steel or chrome caps installed- they will get seized together from corrosion. If the owner chooses to install a set of winter and/or aftermarket wheels/tires on their TPMS equipped vehicle, the alternate wheels must have the correct TPMS sensors installed in them or the system will not function. The dealer can not deactivate a TPMS system on a vehicle. It is a safety system and there as a federal requirement (MY 08 and later)

Slide 12 Title of Presentation, CorpoS, (9Pt.), Date071126_MB_PPT_Pres_Projector.ppt How it all works- Logic 25%