tire pressure
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Joined: May 2014
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From: Washington nj
tire pressure
Question about tire pressure. Should tire pressure be the same on all four tires? Reason I ask they are all at pretty much 30#, but front passenger side seems way low. They are new tires, 255/45/18 all around with new rims. Bought them both from tire rack, where they mounted , balanced, and set tire pressure based on specific vehicle and factory specs which they came up with 30# for wear and performance. They all look good except passenger front. Rolled the car maybe a bubble, still looked the same. Inflated to 40# maybe a little more to get it looking the same as others. It is a a/c car but new sanden type compressor. Is there that much more weight on that front side or does something sound off? Oh its a 350 sb al. heads. Also cut the new front spring, driver side to lower it a bit, but didn't need to cut the passenger side. So was thinking a difference in weight, but dont know.
Thanks for the help.
Brent
Thanks for the help.
Brent
Drifting
Joined: Jun 2005
Posts: 1,950
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From: Chino Hills CA
Question about tire pressure. Should tire pressure be the same on all four tires? Reason I ask they are all at pretty much 30#, but front passenger side seems way low. They are new tires, 255/45/18 all around with new rims. Bought them both from tire rack, where they mounted , balanced, and set tire pressure based on specific vehicle and factory specs which they came up with 30# for wear and performance. They all look good except passenger front. Rolled the car maybe a bubble, still looked the same. Inflated to 40# maybe a little more to get it looking the same as others. It is a a/c car but new sanden type compressor. Is there that much more weight on that front side or does something sound off? Oh its a 350 sb al. heads. Also cut the new front spring, driver side to lower it a bit, but didn't need to cut the passenger side. So was thinking a difference in weight, but dont know.
Thanks for the help.
Brent
Thanks for the help.
Brent
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The door tag on my 1978 shows 28 lbs for the front and 32 lbs for the rear under "max load" with stock size tires. If a person has changed the size of tires or wheels from stock, it's a SWAG as to what the pressure should be. 
Thread Starter
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Joined: May 2014
Posts: 81
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From: Washington nj
Many vehicles that have front or rear weight bias run different pressures front an rear. C3's have almost a 50-50 weight distribution, so pressures should all be equal with sa,e size tires all around. I don't think the AC would have an effect. The fact that you cut the left spring and the right is still low, makes met think there's something else going on. I would have suggested swapping right and left springs before you had cut them. I might still remove them and compare the lengths. At the same time I would inspect the a arms and bushings. If all is well, try adding a spacer to the right spring or maybe replacing it. There may be a fatigue issue.
Drifting
Joined: Jun 2005
Posts: 1,950
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From: Chino Hills CA
They are brand new springs. Moogs shorter than stock but I guess spring rate was changed to compensate for length. Also they where for a sb with Ac or a bb car. I started shortening the driver side cause that was the highest. Removed a half a cool first, not enough so did another half. A little to much so added a rubber spacer to the bottom. Both times cutting that spring it affected also the passenger side lowering it to just not as much. That's why I never shortened that side. Also had the a arms out upper and lower changed the bushings to poly and didn't fully tighten till the car was back on the ground also rocked it up and down to kind of set them before tightening. Also all new tie rods and ball joints just seems odd?
