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135i has rack & pinion/ 128i has electric steering

Discussion in 'E81/E82/E87/E88 (2004-present)' started by 330indy1, Mar 8, 2008.

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    330indy1

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    The recent issue of Bimmer has the details. Check it out!
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    330indy1

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    conflict in the magazines on this topic >>>

    there is a conflict in the magazines....

    Bimmer says the 128i gets the electric assist (not the 135i, which gets the hydraulic assist)
    European Car says the 135i (not the 128i) gets the electric steering.

    Which is it??

    I tend to believe Bimmer BTW...

    293215 guest

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    First look today - Albany,NY

    I just unwrapped the first I series in Albany with the guys at Keeler this afternoon. Didn't put down a deposit because I havn't decided on options and color yet.

    The only book they had (711 001 441 25 2 2007 VZ) says "Electric power steering with Servotronic power assist' for both 128i and 135i.

    Hope this helps

    Jim
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    330indy1

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    Really!

    That is really surprising given the preview articles on the 135i stating otherwise.....
    :confused:

    I wonder what early buyers will have to say about it, if they were under the impression it would be hydraulic assist....

    perhaps it's a non-issue.... :rolleyes:
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    johnh

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    There seems to be lots of conflicting information out there, some in BMW publications. The training manual for US cars says both the 128i and 135i have conventional rack and pinion steering with servotronic assist hydraulic pump.
    Of course there's the active steering option, which may be adding to the confusion.
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    330indy1

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    true, active steering adds to the confusion

    but 'servotronic' as i understand it is electrical assist steering with motors and gears, not hydraulic assist....

    wadsworl guest

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    no electric steering

    Stu at Motivemag posted the following answers from BMW on the 1addicts site:

    Quote:
    Originally Posted by stu@motivemag
    Sorry for the delay, but official responses from BMW:

    1. Is the new electronic LSD technology found on the 135i also on the 128i? One writer says as much, but not sure if that's the case.

    Yes, it is on all 1 Series, as well as all 3 Series. It is part of the DSC system which functions when DSC is fully switched off. Separately, the DSC on the 135i is tuned for performance driving, meaning that it cuts in later than the 128i would, as well as having sportier throttle settings.

    2. Is the aero undercar treatment of the 135i also found on the 128i?
    The aerodynamic components on the underside of both of the 1 Series vehicles are identical. However, the BMW M aerodynamic kit is only available on the 135i and standard.

    3. Is the 128i Sport package suspension the same as the 135i suspension?

    Yes, the 128i Sport package suspension is the same as the 135i suspension.

    4. Is the steering same on both 128i and 135i? Seen differing reports about electronic assist and lock-to-lock ratios.

    The steering is the same on both the 128i and 135i. However, Adaptive Steering, which automatically adjusts steering ratio based on vehicle speeds, is available as an option on both.

    The U.S. cars have hydraulic engine-speed sensitive power steering, similar to the 3 Series. No Electric Power Steering with Servotronic in the U.S.

    5. It appears the 135i comes with speedo, tach, fuel and oil temp gauges. What about the 128i?

    The gauges on the 1 Series and 3 Series are slightly different between the 28i and 35i. 28i has a current fuel consumption gauge in place of the oil temp. Current fuel consumption on the 35i can be seen as part of the board computer in between the tach and speedo.

    wadsworl guest

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    Servotronic

    Actually, Servotronic is just a speed-sensitive system used on Audis and BMWs to vary the boost in a hydraulic steering system. Here is a quote from the BMW web site:

    Servotronic.
    Effortless agility when parking, light-footed responsiveness and stability at higher speeds: Servotronic adjusts the amount of steering assistance to suit the current speed, enhancing driver comfort by lowering the effort needed to turn the steering wheel.

    The Servotronic control unit adjusts the amount of steering assistance to suit the speed of the vehicle. An electromagnetic valve accurately controls the amount of force applied by the steering hydraulics, enabling outstandingly precise steering that suits your current driving situation. Conventional power steering systems, by contrast, regulate the power steering in relation to the engine's RPM. The electromechanical steering system EPS uses an electric motor to achieve the same effect.
    Thanks to Servotronic, driving along narrow streets or parking becomes easier as it requires minimum effort to turn the steering wheel. The power assist progressively decreases when the vehicle speeds up, ensuring greater stability, improved precision and smoother vehicle behaviour.

    [The 128 and 135 both use hydraulic rack and pinion with Servotronic to vary the assist in relation to the speed of the vehicle rather than RPM.]
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    330indy1

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    QUOTE : "The electromechanical steering system EPS uses an electric motor to achieve the same effect"

    like I said, gears and motors....

    wadsworl guest

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    True enough

    The EPS system does have gears and electric motors, but that is a different system from the one on the 135 and 128. The several owners who have taken delivery of 135s all attest to the presence of hydraulic steering, as do recent full road tests by both Edmunds and Road&Track.

    wadsworl guest

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    True enough

    The EPS system does have gears and electric motors, but that is a different system from the one on the 135 and 128. The several owners who have taken delivery of 135s all attest to the presence of hydraulic steering, as do recent full road tests by both Edmunds and Road&Track. Electric Power Steering (EPS) is not synonymous with Servotronic, which is used to regulate the pressure felt at the steering wheel connected to a hydraulic rack and pinion. My Audi S4 Avant has hydraulic steering regulated by Servotronic. It is not an EPS or even (as on the 2002-2006 Mini) a hydraulic system with pressure supplied by an electric pump rather than by manifold pressure.
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    330indy1

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    thanks for the clarification

    sounds like you have done some digging....

    wadsworl guest

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    You're more than welcome

    Just the kind of digging a prospective buyer might have done. My 1351 (Sparkling Graphite Metallic, black leatherette, grey poplar trim, sport package) arrived Thursday. 330 miles into it, I can say it's far and away the best BMW I've owned since 1968: 2002, 2002tii, E30, E36. With the same performance as my one-time Porsche 996 (with appreciably better slalom times in R&T--66.5 mph vs 70.6 mph), the car is far more comfortable for long trips (not to mention that it's a steal at half the price). I prefer the 135 to the Cayman S as well. While the latter is of course more taut and nervous, the BMW is quicker up to over 100 mph, equal in R&T's slalom, and far more flexible. The Cayman S has a fairly narrow, peaky, torque band compared with the BMW's 300 pound-feet from 1400 to 5000. The power of the 135 astounds even at running-in speeds. The dreaded understeer noted in some test reports fails to appear at any rational speed on public roads. In fact, my 135 has less push than my 996 and only the tiniest bit more than the Caymans I have driven. Throttle steering is dead easy, even with the nannies on. Point to point through familiar twisties, it's quicker than my '05 Mini Cooper S, and that's without revving over 4K on the exit. Now that the tires are wearing in and I've begun really to adapt to the car, I find the steering feel to be excellent. If there's a little more muted communication with the surface than in the Porsches, that's more than made up for in the far more supple ride. THe 135 is what BMW does in spades: a car primarily for the road that embodies about 9/10 of the pure sports car but is more livable in real-world conditions, where surfaces are often less than ideal and a wide torque band is a great convenience in traffic. That's a trade-off I'm glad to live with, especially at the price. The 135 is a driver's car all the way. In the bare-bones configuration I have, it's well appointed rather than out-an-out luxurious; its switch gear is the best I've ever encountered, including that in our Audi S4 Avant, wonderfully tactile but positive, of a piece with the steering. Many years ago, Kar Ludvigsen, writing about the 2002tii, wondered if BMW had "sensation engineers." Of course they do. And, like the tasters at Glen Morangie, succeeding generations of BMW engineers work to keep the BMW taste alive and distinctive.:):):)

    atrhugo guest

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    Electric Steering?

    The rack assist is accomplished hydraulically, whether the hydraulic pump is powered via belt or electrics is another question. (And may be contributing to the confusion.)

    And wadsworl, where have I seen that post before? ; -)

    wadsworl guest

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    Hello, atrhugo

    Actually, that post appeared here first. Like you, I'm hanging out at both places. And I'll have to do a little more digging under the hood/bonnet to see how the pump is actuated. I don't think the BMW uses an electric motor à la Mini. I do know that the more I drive this car the more information I pick up through the steering wheel. The communication is more subtle than in the Mini, for example, but there's just as much information in the end. My fingertips are learning their way.
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    330indy1

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    Google Search for 135i and steering.

    "Where the other 1 Series Coupe variants have electric power steering, the 135i gets a conventional hydraulic system with engine-driven pump - not because it's intrinsically superior, BMW says, but simply for packaging reasons. The muscular 135i engine doesn't leave room for electric power steering."
    http://editorial.carsales.com.au/car-review/2897362.aspx

    "The 135i, like many new cars, has electric power steering. It also has more power assistance than old cars had, as it's heavier. These factors combine to make the steering feel a little unreal at times, especially when returning to the straight-ahead position, which brings on a viscous resistance. The 135i will never match the delicacy and transparency of the old M3 in its steering, but in isolation it's good enough and very accurate."
    http://www.independent.co.uk/life-style/motoring/road-tests/bmw-135i-coup-the-ultimate-fun-drive-from-bmw-780390.html

    "Speed-related steering assistance
    All models of the BMW 1 Series Coupé, except the 135i, have electric power steering (EPS) with integrated Servotronic for speed-related steering assistance. As a result, EPS offers even greater steering precision at high speeds and enhanced steering comfort at low speeds.
    New steering system reduces fuel consumption
    A further important point is that the new steering system reduces fuel consumption by using an electric motor - and not a conventional mechanical/hydraulic system - to boost the car's steering, with the electric motor operating only when the driver is actually turning the steering wheel.

    As an option, all models may be equipped with the world's only so-called active steering , which adjusts the steering transmission with optimum precision to the current speed of the car. This means that the driver is required to turn the steering wheel only slightly and with minimum effort when parking, while at higher speeds the steering transmission becomes less direct, improving the feeling of the steering and directional stability accordingly."
    http://www.cars4women.co.za/articles/253/1/We-review-the-much-anticipated-BMW-1-Series-Coupe/Page1.html

    "We are glad that for the driver's sake BMW did not switch to electrical (like Volkswagen) or electro-hydraulic steering (like Ford), because they never match the steering feel of a pure hydraulic system like the BMW's."
    http://www.autozine.org/html/BMW/1er.html

    >> I also downloaded the brochure that contains the diesel versions. The small engine models have EPS, but the 135i is the exception. Probably should have done that first! :)
    www.bmw.com/com/en/newvehicles/1series/coupe/2007/_shared/pdf/1series_coupe_catalogue.pdf?download=true

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