Topic: smoother ride?
in Forum: C3 Engines, Driveline and Handling
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Former Member
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BRADENTON, FL - USA
Joined: 8/4/2002
Posts: 669
Vette(s): 1972 convertible 350 auto trans, delux int, air, ps, pb, t/t wheel, pw, 79,000 org miles Rare one year only color
i have heard that the fiberglass rear leaf spring will make a smoother ride. i have lowered my tire pressure to help with the ride i was running 32 psi but have lowered to 28 and it helps. i also installed delco gas shocks at all four corners. i plan on lowering the tire pressure to 26 to see if it gets any better.
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Hi Don,
Remember everything has a trade off. Softer ride means that you will lose some of the tight feeling that performance suspension has ("performance" is used loosely when looking at 30 year old technology). Cornering may also suffer and you may notice more body roll. Suspension that becomes excessively soft can lead to unpredictible handling (bouncing/swerving) especially in emergency situations. You certainly want to avoid over-softening the ride although the corvette ride can certainly stand some softening without a substantial loss in performance. I suggest looking at a fiberglass rear spring (330lb maybe) with a set of touring springs up front. Cost is not a good measure. The most expensive suspension systems tend to be very hard with performance in mind. Also, I agree with Gary that lowering the tire pressure does seem to help. Also consider your tires, the ride quality from one tire to another varies greatly with the same performance/ride tradeoffs. Bear in mind too that rubber hardens with age, if your tires are more than a few years old its very likely that they are your culprit. After all, how hard can 30 year old suspension still be?
Gary- I have found that 26lbs (I run 29lbs)is too low, it makes the car hard to steer at slow speeds and it feels sluggish. Any idea what the factory recommended pressure is for the later C3's? All the info I have is for bias tires.
PS: I'm hoping for more discussion on "69 rear spring rates"
|UPDATED|3/16/2003 11:35:53 PM|/UPDATED|
Remember everything has a trade off. Softer ride means that you will lose some of the tight feeling that performance suspension has ("performance" is used loosely when looking at 30 year old technology). Cornering may also suffer and you may notice more body roll. Suspension that becomes excessively soft can lead to unpredictible handling (bouncing/swerving) especially in emergency situations. You certainly want to avoid over-softening the ride although the corvette ride can certainly stand some softening without a substantial loss in performance. I suggest looking at a fiberglass rear spring (330lb maybe) with a set of touring springs up front. Cost is not a good measure. The most expensive suspension systems tend to be very hard with performance in mind. Also, I agree with Gary that lowering the tire pressure does seem to help. Also consider your tires, the ride quality from one tire to another varies greatly with the same performance/ride tradeoffs. Bear in mind too that rubber hardens with age, if your tires are more than a few years old its very likely that they are your culprit. After all, how hard can 30 year old suspension still be?
Gary- I have found that 26lbs (I run 29lbs)is too low, it makes the car hard to steer at slow speeds and it feels sluggish. Any idea what the factory recommended pressure is for the later C3's? All the info I have is for bias tires.

PS: I'm hoping for more discussion on "69 rear spring rates"
|UPDATED|3/16/2003 11:35:53 PM|/UPDATED|
'69 350/350 conv.
I currently am running the fiberglas rear leaf and it produces a very smooth ride...albeit a little more bouncy,but without sacrificing handling.I,personally,would endorse the fiberglas rear spring.
My problem seems to be in the front.Please refer to my post.
My problem seems to be in the front.Please refer to my post.
Bute
70 Convertible
Former Member
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BRADENTON, FL - USA
Joined: 8/4/2002
Posts: 669
Vette(s): 1972 convertible 350 auto trans, delux int, air, ps, pb, t/t wheel, pw, 79,000 org miles Rare one year only color
i think you would have a hard time finding softer springs for the front. higher profile 70 series tires would also help with more sidewall flex
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From my Haynes manual, tire pressures are listed as the following.
68 - 72 : 24 psi front / 24 psi rear
73 - 75 : 20 psi front / 20 psi rear
76 - on : 20 psi front / 26 psi rear
I looked in my 73 owners manual and they list 20 psi front & rear just like the Haynes manual.
For me, I like the stiffer ride and run 28 psi all around.
68 - 72 : 24 psi front / 24 psi rear
73 - 75 : 20 psi front / 20 psi rear
76 - on : 20 psi front / 26 psi rear
I looked in my 73 owners manual and they list 20 psi front & rear just like the Haynes manual.
For me, I like the stiffer ride and run 28 psi all around.
Former Member
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DOWNINGTOWN, PA - USA
Joined: 11/24/2001
Posts: 962
Vette(s): 1969 Monza Red Black Conv / Black Vinal hardtop
454/480 Tremec 5 Speed 308 Posi.Black Leather Interior, PS, PW, Air cond., tilt/tele,AM/FM Cass.-5 Pack CD, Hurst Shifter, side pipes
2004 Yellow convertible with black top and black interior
Are those numbers for the stock tires? Wouldn't pressures in radials be slightly different?
My 76 door plate says 20/26 psi also but I wonder if that was for bias ply tires. That just seems too low. Why the difference between the front and back? Anyone know? 

Former Member
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BRADENTON, FL - USA
Joined: 8/4/2002
Posts: 669
Vette(s): 1972 convertible 350 auto trans, delux int, air, ps, pb, t/t wheel, pw, 79,000 org miles Rare one year only color
the original tires for a 76 are GR70-15 this is a radial tire. so those pressures should be correct for your current tires. radial tires were installed from 1973 and later C3's
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I agree with JK, 20/26 seems way too low!!
Anybody out there with a '79 or newer beast that can share factory specs??

Anybody out there with a '79 or newer beast that can share factory specs??

'69 350/350 conv.
in Forum: C3 Engines, Driveline and Handling
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