Author Topic: 1969 Rear Spring Rates?  (Read 1359 times)

olympic69

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1969 Rear Spring Rates?
« on: January 20, 2010, 03:09:18 PM »
I may have this all wrong- but in looking at spring rates (rear) the Z28 shows a rate of 103, while other base models have up to 126 Lbs, while the 427 CI option shows a 4 leaf 126 Lb spring. I used the MOOG 6308 in my Z28 as a replacement, and additionally Mr. Pozzi recommends 125-150 rear rates- so why did GM choose to use such a "light" spring on the "HD" model(s), which would seem to make the car prone to oversteer?
Rob
Olympic Gold X33

"Its all crazy..."

JohnZ

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Re: 1969 Rear Spring Rates?
« Reply #1 on: January 20, 2010, 09:41:04 PM »
why did GM choose to use such a "light" spring on the "HD" model(s), which would seem to make the car prone to oversteer?

It's the other way around - lower rear spring rate reduces rear roll stiffness, which reduces the tendency for oversteer.
'69 Z/28
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olympic69

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Re: 1969 Rear Spring Rates?
« Reply #2 on: January 20, 2010, 10:15:00 PM »
Thanks- I appreciate the response from a reliable source!

BlackoutSteve

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Re: 1969 Rear Spring Rates?
« Reply #3 on: January 24, 2010, 02:03:08 AM »
I always thought monos were ~145in/lbs.. 4 & 5 leaves are naturally a heavier rate.
Restoring my RHD 69 Jane in Melbourne, Australia.
http://www.usmuscle.com.au/Forum/showthread.php?t=2840