AvRog

How do I know if it's time for a new leaf spring?

MelWff

the ends of the spring are bowed up
the rear of the car looks like it is sagging
the half shafts are no longer roughly parralell to the ground, the outer ends are higher than the inner ends.

AvRog

Thanks!

TheSkunkWorks

If you happen to be in the market for a new rear spring anyway, it may be worth noting that you can increase anti-roll stiffness out back (thus moving balance away from the understeer end) with a higher spring rate without the penalty of increased weight transfer that comes with adding rear bar; the penalty being that higher weight transfer across a given axle equals reduced grip at that axle. This, of course, assumes a higher spring rate is tolerable/practical for the roads on which you usually drive, but IMHO every would-be BB C3 chassis tuner should understand that it is possible to sort out handling without a rear bar. Just some food for thought.


TSW

Alan 71

Hi AR,
Here are 2 quotes from the Eaton Spring site:

"The 9 leaf spring which the 1st 6 leaves are curved and the shortest 3 leaves are straight is a 2 stage or variable rate spring. It's rate starts at 140lbs and increases to 196lbs when all the leaves are touching".

"All 9 leaf and 7 leaf springs are designed to have a 3/8" reverse arch when at their design load."

Regards,
Alan

AvRog

I find my car to be very sloppy. Lots of roll. Shocks are stock but not OEM. The ride I find very smooth as for as bumps are concerned. I would like less roll, this would require higher rate shocks?

Alan 71

Hi AR,
Yes the shock absorbers help control 'roll'.
Do you just need new shock absorbers or do you need higher rated shock absorbers?
What type of driving do you do?
Regards,
Alan

MelWff

wouldnt roll be the sway bars?

TheSkunkWorks

Both bars and springs contribute to anti-roll, but by different means. Springs resist roll by their effective rate at the respective wheels, while bars increase weight transfer directly from the inside wheel to the outer one. Thus, it is possible for springs to provide up to and including 100% of whatever may be the amount of anti-roll necessary, so long as the required spring rate to do so is practical. However, as bars do nothing to support the chassis' sprung weight (nor do they contribute to anti-squat or anti-dive), they only provide anti-roll in addition to whatever amount is inherent to the relative spring. Although very often required to properly sort a chassis, IMHO bars are best considered as a supplemental crutch rather than being the tuning tool of first resort, especially out back.

Shocks, on the other hand, only control how quickly weight transfers, which in the case of firmer ones may seem to limit roll if the event causing weight transfer takes less time than required by the shocks for weight to fully transfer. Thus, a car that takes a "set" more slowly than a particular turn lasts won't have enough time to roll to its full extent before the corner is over.

Hope that helps.



.

AvRog

Not a radical driver, just like to remove the slop. For now I think it's back on with the factory rear bar. See how that feels as a stock chassis. Later perhaps better shocks.

Thanks, Rog.