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Rally Suspension Advice

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  • Rally Suspension Advice

    Hello to everybody !!!
    Please help me with your advice for choosing the right suspension for my Astra Rally Car, it has an C20XE redtop engine, F20 gearbox with TranX LSD and 5.18 final drive.
    I want to drive the car on both tarmac and gravell rallies, I will use Bilstein Motorsport dampers, Cup version for front 34-001462 (250/80) and for rear 24-000925 (160/50).
    I don't know what springs should I use for the rear of the car, what lenght and what rate ( for tarmac and gravell )?
    For the front I thought for tarmac the spring will be fine 8inch lenght, 2.5inch internal diameter and rate 300lbs and for gravell 10.5inch lenght, 2.5inch internal diameter and rate 225lbs. Are this OK for the front?
    Please tell me what is the proper height of an Astra for tarmac and gravell rallies.
    Thank you very much in advance and best regards !!!

  • #2
    Already discussed by PM but will post my views here for others to see...

    The "Cup" Bilstein dampers are a good starting point, but they lack a lot of travel for gravel events. Its worth looking at the 40mm Bilstein "inverted" front struts as they are much stronger for gravel.

    In terms of spring rates, 300lb tarmac and 225lb gravel will be fine with those dampers. Do you have coilover converted front struts?

    For the rears it is more tricky. I used to use Eibach Astra F GSI rear Pro Springs for tarmac which are quite stiff but not too much. Gravel rear springs are more difficult and expensive. I have had a set of Progressive Gravel springs made up but theyre ?200 a pair.

    For info on the inverted struts See

    Astra F / Mk3 type here but the Astra Mk2 / Kadette type are the same.. The strut is modified with a thicker wall and bronze bushes and the damper fits in it upside down as such.

    My rallying with mk2 adventures...


    • #3
      Thanks a lot Paul once again !!!