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Thread: TPMS - New rims & snow tires.
10-13-2009 07:28 AM #1
TPMS - New rims & snow tires.
I am planning on installing new snow tires and rims on my wifes 2009 328i for the upcoming season.
Since it is a 2009 car it comes with TPMS which monitors the pressure in each wheel via a rim mounted sensor. Question is, if I install new rims and snow tires without sensors will the system:
a) provide a continuous error all winter or
b) be smart enough to know that there are no sensors and ignore any error message.
It all comes down to cost. the incremental cost of adding new sensors to the new rims is +$200.
10-13-2009 09:00 AM #2
- chesapeake, VA, United StatesMember No: 59049
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I think you cannot get by without errors
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2008 335i Coupe Alpine PP SP CP Saddle Heated Seats Comfort Access Sirius iPod
10-13-2009 10:07 AM #3
- , , United StatesMember No: 99782
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10-13-2009 02:23 PM #4
Re: Had trouble last week resetting pressure monitor...
The manual is poor on this, took me two days to finally get mine to reset. My manula has a bad graphic symbol for the first step, then it has duplicate steps, which are required but not clear.
As far as running without, expect errors. And, the warning overrides the small display, always showing the waring symbol.
10-13-2009 06:24 PM #5
10-14-2009 08:36 AM #6
10-14-2009 10:58 PM #7
10-22-2009 10:15 AM #8
10-22-2009 10:39 AM #9
10-25-2009 06:07 PM #10
10-26-2009 08:28 AM #11
Most do, but that's not the definition.....
By definition, indirect TPMS uses ABS and other rotational sensors to measure the difference in the rate of revolution of the wheels, based on the principal that a deflated tire would have a smaller circumference. Direct TPMS uses a sensor in each wheel which usually transmits pressure and temperature data to a receiver in the car. Unfortunately, BMW chooses to not display the data. My 2007 Cadillac CTS-V did and I miss the little graphical display of the tire pressures. My 2009 has a sensor in each wheel, but it's frustrating that there is no way to get the numerical data from the sensors. They are manufactured by Beru.
Here is a lengthier explanation:
Indirect TPMS do not use physical pressure sensors. Indirect TPMS measure the "apparent" air pressure, by monitoring individual wheel rotational speeds, and other signals available outside the tire itself. Most indirect TPMS use the fact that an under-inflated tire has a slightly smaller diameter than a correctly inflated tire and therefore has to rotate at a higher angular velocity to cover the same distance as a correctly inflated tire. Newer developments of indirect TPMS can also detect simultaneous under-inflation in up to all four tires using vibration analysis of individual wheels or analysis of load shift effects during acceleration and/or cornering, which can be realized in software using advanced signal processing techniques. However, the vibration analysis technique requires the use of additional suspension sensors which result in increased complexity and cost of the overall system as long as vertical chassis movements are concerned. That is why most current advanced indirect systems use the spectral content of the wheel speed sensor signals so no additional sensors are needed and the computations can also be carried out by usual processors for example in usual ABS or ESC control units.
Indirect TPMS are realized in software in combination with wheel-speed sensors for anti-lock braking systems, and electronic stability control systems. A disadvantage of indirect TPMS is that the driver must calibrate the system by pushing a reset button on the dashboard or through the on-board computer and if this is performed when any tire is in an under inflated condition then the system will not report correctly.
Direct-sensor TPMSes employ physical pressure sensors inside each tire and a means of processing and sending that information from inside the tire to the vehicle's instrument cluster. These systems can identify simultaneous under-inflation in all four tires in any combination.
Direct-sensor TPMS are specifically designed to cope with ambient and road-to-tire friction-based temperature changes, both of which heat up the tire, and increasing its pressure. The alarm-activation threshold pressures are usually set according to the manufacturers recommended "cold placard inflation pressures".
In order to transfer data from a rotating wheel, a direct-sensor system may use a radio-frequency (RF) communication channel or an electromagnetic coupling means to overcome the tire/chassis rotational boundary.
BERU tire pressure control system TSS fitted as standard in all BMW models for export to the US
BMW has chosen the BERU Tire Safety System (TSS) for its export vehicles for the American market. Directly recording tire pressure control systems are effectively mandatory in the USA.
(Ludwigsburg, November 27, 2006) The BERU Tire Safety System (TSS) ensures safety and comfort as standard in all BMW vehicles for export to the US. The German premium car manufacturer is fitting all models destined for the American automobile market with the directly recording BERU system.
According to regulations issued by the US highway safety authority NHTSA, all cars approved in the USA from model year 2006 onwards must be fitted with a tire pressure control system. The law states among other things that such systems must have the technical capability to monitor the pressure in all four tires simultaneously and independently. Only a directly recording tire pressure control system such as the BERU TSS can effectively satisfy these requirements.
BMW is fitting its US export models with a second-generation BERU TSS system with trigger transmitter. It monitors the tire pressure when the vehicle is both stationary and on the move and alerts the driver if the pressure is down by just 0.2 bar (2,901 psi). It also warns of a gradual or sudden loss of pressure. In addition it supplies a position identification for the wheel electronics units and hence for the individual tires. All BERU TSS wheel electronics units are designed to withstand even extreme environmental conditions.
Greater safety and comfort, lower fuel consumption
Anyone buying a new car who cares about safety, economy and comfort should opt for the Tire Safety System from BERU. For example, experts reckon that if the tire pressure is down by just 0.6 bar, a vehicle uses around four percent more fuel. What's more, if the tire pressure is down by 0.2 bar (2,901 psi) for any length of time, tire wear increases too. As a result, the service life of tires is shortened by around ten percent and by about 50 percent if the pressure drops by 0.6 bar (8,703 psi).
Other advantages of the BERU Tire Safety System:
Greater convenience thanks to the avoidance of tedious routine tire pressure checks at the filling station. The air pressure is only adjusted when really necessary.
Greater protection against potential tire damage or blow-outs thanks to continuous, automatic monitoring of the tire pressure when the vehicle is stationary and on the move.
2009 E90 335i
2002 E46 M3 - sold 2006
10-30-2009 06:59 PM #12
10-30-2009 08:43 PM #13
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