Saturday 3 December 2011

Changes in 2012 Blue Book

As a former business colleague once said "I remain confused but after this clarification my confusion is at a higher level". Now I think I know what this was meant to say but I am not sure if this says it.

Red is new. Strikeout is removed from old.

9.4. Vehicles may not be fitted with torque biasing
differentials in full and free operation between the
driving wheels (It is not Permitted to fit any form of
differential that was originally offered by its
manufacturer as torque biasing, whether fitted in
modified form or not) unless:
9.4.1. A differential was not fitted by the manufacturer
9.4.2. The vehicle is restricted to running in a
nominated Class.
9.4.3 It is not Permitted to fit any form of
differential that was originally offered by its
manufacturer as torque biasing, whether fitted in
modified form or not

10.12.4. Cars in Class 1 may fit replacement
differentials, crown wheels and pinions provided the
differential action remains free operating


6 comments:

  1. I guess it means that if you a torque biasing differential which is modified so it doesn't provide torque biasing action but runs freely you still can't use it - pity as it could have allow you to have the strength of a 4 star system without the torque biasing bit. Strange as you could build a a 4 star system from scratch and be ok as I read it !

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  2. Michael were you really reading the RAC Blue book at 7.30 am upon a Saturday morning ? If you try it a 11.30 pm after a few glasses of Red wine it will be all as clear as day or not !

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  3. ACTC have been involved in this. You may find that one or two specialist manufacturers will offer a 'strong' diff which is basically a torque biasing without the bits, but it will be given a new name and specification and thus should be OK for use.
    Stuart Harrold

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  4. In a nutshell, Class 1 may use a four star diff of any sort so long as it is free. For Classes 2-8 there is no change to the current rules. This has been done to allow Class1 access to a range of strong diffs from manufacturers who base their free four star diffs on their LSD offerings. We (ACTC) wanted the rule to work for all classes but even after much debate could not agree a wording with the MSA. So rather than make the FWD guys wait another breakage filled year we have come up with this compromise.

    Yet another example of all the work that goes on in the background of which most of you are blissfully unaware.

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  5. It's good that the ACTC is making sense of this !
    Apart from Class 1 is it permissible to use 4 star transit diffs/parts in other classes (not that they would fit in my TR 7 anyway!) - as I read it it's only the axle casing which cannot be changed/modified. All the new regs only seem to imply is that you cannot modify an original LSD to to run in free mode.

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