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      12-19-2012, 04:00 PM   #35
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Drives: 2015 Alpina B6; 430i; X5 40e
Join Date: Jul 2010
Location: Orange County, CA

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BMW's official documentation sure is confusing!

E82 Complete Vehicle Manual reads:
Quote:
The following steering systems are fitted in E82 vehicles:
• Conventional rack-and-pinion steering with Servotronic assist hydraulic pump
(vane cell pump) this is the standard steering for all 128i and 135i vehicles.
• Active Steering with hydraulic pump and ECO valve is available as an option.
Active Steering in the E82 features the following optimization measures carried over
from the E70 or E6x LCI:
• Modified planetary gearing
• New control module
• Absence of the cumulative steering-angle sensor on the rack.
Note: The new procedure for initializing the Active Steering (as in the E70) now
also applies to the E82. (because of the absence of the cumulative steering-
angle sensor).
There will be no electrical steering lock (ELV) in the US variant of the E82. This applies to
vehicles with automatic transmission and to vehicles with manual transmission.
While the E82 M Complete Vehicle Manual reads:
Quote:
2.1.8. Standard/optional equipment
Standard equipment compared with 135i

• Servotronic

4.4.2. Steering
The hydraulically assisted rack-and-pinion steering has been carried over unchanged from the BMW
E9x M3. With an average overall ratio for the variable gearing of 12.5:1 it is direct as a sports model
(16:1 on 135i). The power assistance is controlled by the Junction Box control unit via the Servotronic
valve according to a set sports characteristic. Active steering is not offered.
Quote:
Originally Posted by John_01 View Post
The word 'servotronic' is confusing, because it was used for an advanced hydraulic power steering system since about 10 years ago or more.
I can only conclude that "Servotronic assist hydraulic pump" is BMW's standard hydraulic steering like on the x28i and not the servotronic option that is standard on the x35i (nonadjustable) and 1M (adjustable).

According to RealOEM non of the US non-M E8x 1-series or E9x have servotronic standard (there is a retrofit). I'm not sure how to quantify my preference for the 128i steering over 335i other than vehicle size. Or perhaps there is a different steering ratio between the E8x 1 and E9x 3 series.
Appreciate 0