Wider Tyres - AHK - CSi

    In another thread, I mentioned that I had seen something about Alpina 5.7s having their AHK modified because of wider tyres rubbing - but couldn't remember where I'd seen it ...


    Its on here !! (not good with links, so..)
    ClubE31 Content - General - Alpina - B12 5.7


    Says
    NOTE:
    According to Stephen Spears (anybody know him ?)
    "Because of the huge increase in the tire size (285/35 on 18s - my note) on the B12, Alpina was forced to modify the rear steering system to restrict directional changes.
    This was due to tire rub happening when steering around hard corners".


    As I mentioned earlier, I have 285/35/18 on my CSi and have not experienced any tyre rubbing on mine. And I have done some "steering around hard corners" but guess it depends on how severe.
    Eg, Ive not done any slaloms or track hairpins.


    I wonder what "modifications" they did ?
    Disable it perhaps !? or just restrict the max camber ?


    Something for the CSi guys .....

    Wider Tyres - AHK -CSi


    I have the Alpina rims and tyres on mine, there with no rubbing whatsoever. Even when pushing it a bit hard on fun days out :twisted:


    I read somewhere they switched it off completely.

    Had One For A While Now Really !

    '96 BMW 850CSi
    '11 MV Agusta Brutale 1090rr
    '89 Ducati Indiana 750
    '83 Suzuki GR650


    I have 295/35 x 18 on my CSi and have no rubbing issues and I HAVE done slalom and circuit driving. As the AHK steers the rear wheels and does not change camber/castor, I assume the Alpina was rubbing on the leading or trailing edges of the inner arch liner. I would suggest this was more a rim width and offset problem than a tyre width problem but to disable the AHK is sacriledge! Thats a major feature of the CSi to remove in the interest of fitting the Alpina wheels.

    8Tech,
    I was also thinking of offset on the original Alpina wheels being perhaps the reason ....


    Of course you are right on it being a steering issue with AHK rather than camber (silly me).
    Just got it into my head from picturing that old photo of the AHK system on the test bench. Always looks like a camber change somehow to me ...


    Agree on it being sacrilege to disable AHK (if thats what they did)

    Re: Wider Tyres - AHK -CSi


    Zitat von Got-One-At-Last!

    I have the Alpina rims and tyres on mine, there with no rubbing whatsoever. Even when pushing it a bit hard on fun days out :twisted:


    I read somewhere they switched it off completely.


    GOAL I do like those rims - forgive my ignorance but what sizes are they? Are they specific the the E31 Alpina?

    There were some very early Alpina 5.7 which were based on the 850i and hence did not have AHK nor some other enhancements. The 5.7 that were based on the CSi reportedly had the amount of AHK steering angle reduced (but not disabled) to permit use of the wider tyres. Remember also that the 5.7 is 10mm lower than the CSi I think however, that the CSI may also have a reduced AHK angle compared to the later 850i, which were fitted with AHK. The CSi also had a slightly reduced-ratio steering box and an ///M version of the servotronic assistance.


    The 18" Alpina deep-dish wheels are still available new for sale on certain websites and so one can check the offsets to see if this may also be a factor compared to, say, the M-parallels, which were officially offered on eth CSi.

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