Tire's pressure ?

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Tire's pressure ?

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Tire's pressure ? - 1/30/2008 1:11:15 AM

aldous

Posts: 128
Joined: 1/5/2008
Status: offline

Hi ,

doubts about tires' pressure

bought these goodyear eagle GT+4 255/60/15 . OK , there's better stuff on the market, but the availability of tires with white letters here is quite difficult ( and price was fair for my tires)

can't find any spec about correct pressure ( nothing written on the tire itself and nothing on the Goodyear website). So I'm referring to my car's specs on the door. But I suppose that I'm making mistakes with the pressure choice.
Help please

Aldo

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Aldo from south Italy

1979 L82 ,4 speed, edelbrock performer rpm intake, edelbrock 600cfm carb,double hump 64cc heads 2.02/1.6 valves, Hedman Hedders dual headers, Flowmaster 40 series, Goodyear Eagle GT+4 255/60/15 , 4 Bilstein HD shocks

Post #: 1

RE: Tire's pressure ? - 1/30/2008 6:06:26 AM

C3 Starship

Posts: 4749
Joined: 7/25/2006
Status: offline

32 or 34 psi is pretty much a standard pressure.

_____________________________

1980 L-82 Fastback (forward too)
Mono composite front and rear.
Full adjust ride height and
response.
400+ hp, 454, M-22, 3.07

http://i121.photobucket.com/albums/o225/C3Starship/Patch.jpg

2007 H. D. Sportster, XL 883 EFI

(in reply to aldous)

Post #: 2

RE: Tire's pressure ? - 1/30/2008 10:15:28 AM

Texas Jim

Posts: 441
Joined: 12/15/2005
Status: offline

Aldo,
I usually keep my tires at 35 psi which is the max pressure on most of our size tires and is also listed on the placard on our driver side door.
When I had the Firehawks on my 'Vette, I would run 30 to 32 psi in them, unless I was going for a long trip on the highway, as those tires rode very hard, something I suppose should be expected from some performance tires. The lower pressure didn't cause any premature or abnormal wear, but I got just alittle smoother ride. With the "Good Year Integritys" I have now, a middle of the road touring tire that performs just fine for the kind of driving I do, my 'Vette rides VERY smooth running them at 35 psi. and creates no new rattles in the process.
In the GM manual for my '81 'Vette, they mention that for driving at 75 to 85 mph you should increase the tire pressure by 4 psi if that 4 psi doesn't cause you to over-inflate the tire, max being 35 psi.. So it sounds like 31 psi. is OK according to the manual.
Personally, I like to beable to run my tires at max pressure as they're ready to be pushed to the limit and at which time I'll get the most out of them.  Especially with the 'Vette, why not? If you have tires that ride alittle hard, I don't feel that it's bad to run them alittle soft as long as it's not to the point where you'll get abnormal or premature wear, which from underinflation would be excessive wear at the outer edges of the tire. (Over inflation would cause excessive wear in the center of the tire. Although for you "foot-stompin' 'Vette owners, the excessive wear in the center of your tires, only on the rear, is from opening the secondaries every time you take off from a dead stop. LOL)
I called "Shine Brothers" today which is a local Good Year dealer who does good front end work. I've gotten afew alignments there and (I watched the guy and the car drove perfectly afterward) they did a good job. The guy told me that 31 or 32 psi. wouldn't hurt that Eagle plus4 you have, Aldo, and that 35 was the appropriate max psi. for it.
One thing that is very important is to make darn sure that you have a good quality gauge and that it's "ACCURATE." I have afew gauges and even acouple of the good ones vary a pound or two in either direction. A friend of mine who used to have a Matco Tool business checks my torque wrench and my best tire gauge for me every now and then and I keep them both in a padded metal box. I've seen tire gauges that are four to six pounds off right off the shelf. The kind at the check out counter in a big bucket at your local ie; Auto Zone are like "pot luck." You can get a good one or one that's way off.
I've also been told by more than one reputable tire person that using that tire shine or tire dressing will dry your tires out prematurely. Supposedly, it's not harmful if you use it in moderation, like anything else.
As I said in another post, I also found the selection of lettered tires for our 'Vettes is going away due to all the bigger rims and low profile tires that are made now days. If we want to stay with our stock size rims, we'll just have to settle for what's available.
I hope I helped you alittle, Aldo. I know that you and DeeVee will be taking your new treads to the limit. Just becareful and keep you 'Vettes "rece-worthy" in the process.

***If anyone knows anything else about the tire pressures for that Good Year plus4 or anything that conflicts with what I was told by the local Good Year dealer here, please post it so we all "get it right."

DeeVee, Nice job on the rims. I like the black as it blends in with the car and with the exception of the white letters on the tires, the car has a really cool plain look, which I like in a car.

(in reply to C3 Starship)

Post #: 3

RE: Tire's pressure ? - 1/30/2008 11:53:58 PM

aldous

Posts: 128
Joined: 1/5/2008
Status: offline

Hi Texas Jim,

thanks so much. Now I'm running my tires less inflated than what you say. I will readjust the pressure. My pressure gauge is quite precise ( checked with a pro one).
Same pressure for front and rear tires? Or more on rear, like GM says?

I like the more comfort of " softer tires" ( I'm going also to replace the old oil shocks with gas Bilsteins which will make my ride "harder") but I want safety and performance when I decide to ride "strong". So I think I will set the pressure at an intermediate point : let's say 33-34 psi. What do you think?

I'm restoring my Corvette and my first thought is "safety" : I want to be sure that my car will remain stable in the turns and when riding a bit faster ( not very fast at all . I have dicovered that I have a 3.55:1 rear end gear ratio). So I'm going to replace :
-Front coil springs
-swaybar links and bushings
-rear spring links
-4 shocks ( all bilstein)
-power steering control valve ( I have a play on the steering wheel in the central position and it's "quite light" , not tight as I would like: I don't feel safe...)

my brakes seems really OK , instead. No leakage at calipers, pads seems OK. Brakes are strong and balanced.

referring to the old spark plugs matter...
Got a set of NGK UR4 and going to fit them on my engine ( replacing a set of 20 years old AC delco with lot of rust).
I want to file back the neg contact , but how? which tool do I need? It's not easy with a file ( I risk to "file" the pos contact too).
I was thinking that could be easier to move back the neg contact with tweezers , readjusting the gap to specs. please tell me about

thanks
Aldo

_____________________________

Aldo from south Italy

1979 L82 ,4 speed, edelbrock performer rpm intake, edelbrock 600cfm carb,double hump 64cc heads 2.02/1.6 valves, Hedman Hedders dual headers, Flowmaster 40 series, Goodyear Eagle GT+4 255/60/15 , 4 Bilstein HD shocks

(in reply to Texas Jim)

Post #: 4

RE: Tire's pressure ? - 1/31/2008 5:44:11 AM

C3 Starship

Posts: 4749
Joined: 7/25/2006
Status: offline

I gently pry the neg electrode upward, say about 1/8". ( I use my pocket knife blade to do that. I have a tool for that, but since I don't use it very often, I can't always find it.

) Now using a small flat file, round the end of the contact.

_____________________________

1980 L-82 Fastback (forward too)
Mono composite front and rear.
Full adjust ride height and
response.
400+ hp, 454, M-22, 3.07

http://i121.photobucket.com/albums/o225/C3Starship/Patch.jpg

2007 H. D. Sportster, XL 883 EFI

(in reply to aldous)

Post #: 5

RE: Tire's pressure ? - 1/31/2008 9:16:39 PM

73shark

Posts: 1089
Joined: 4/18/2006
Status: offline

quote:

ORIGINAL: aldous
-power steering control valve ( I have a play on the steering wheel in the central position and it's "quite light" , not tight as I would like: I don't feel safe...)

Sounds more like your steering gear box is loose and needs to be adjusted per the service manual. The control valve just controls which direction the assist goes.

_____________________________

So many toys, so little time

(in reply to aldous)

Post #: 6

RE: Tire's pressure ? - 1/31/2008 10:52:54 PM

aldous

Posts: 128
Joined: 1/5/2008
Status: offline

Hi 73Shark,

I have already checked the steering box and it seems that there's no play there ( but i'm possibly wrong). Anyway the control valve is leaking a lot of oil ( look at pic) so I'll replace it first, then I'll see what happens

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_____________________________

Aldo from south Italy

1979 L82 ,4 speed, edelbrock performer rpm intake, edelbrock 600cfm carb,double hump 64cc heads 2.02/1.6 valves, Hedman Hedders dual headers, Flowmaster 40 series, Goodyear Eagle GT+4 255/60/15 , 4 Bilstein HD shocks

(in reply to 73shark)

Post #: 7

RE: Tire's pressure ? - 2/1/2008 8:30:12 AM

Texas Jim

Posts: 441
Joined: 12/15/2005
Status: offline

Aldo,
Jack the car up, with both front wheels off the ground, and push and pull on the tires, left and right, top and bottom. Your play may be in the tie rod ends.
Per Spark Plugs: Cover the positive electrode with a small piece of sheet metal then use a file to file the negative electrode back to where it is half way across the positive electrode. The filed edge of the negative electrode cuts the circle of the positive electrode in half. Where I used to use a file, I now use a Dremel tool as it can cut the negative electrode back quickly, clean the burr from the cut edge and there's no need to use the piece of sheet metal to protect the positive electrode. After cutting the negative electrode back, check the gap and install them.
Back and front tires should be at the same psi.. And yes, Aldo, you should run youir tires at the max pressure, 35 psi.. With the roads being the way they are in your part of the world, your tires should be at max psi.
You're right. With a file, it's not the easiest job to cut the negative electrodes back. I did the job with a file for many years, but now I use a Dremel, as it's quicker and easier. Do not try to "move" the negative electrode.
If you're not sure how to cut these electrodes back, just send me your address and I'll buy some, file them back and send them to you, ready to go. Just let me know.

(in reply to aldous)

Post #: 8

RE: Tire's pressure ? - 2/1/2008 9:42:21 AM

aldous

Posts: 128
Joined: 1/5/2008
Status: offline

Thanks Texas Jim,

I have completed the spark plugs' job right now... look at pics : before and after. I have filed the neg electrode not exhactly to the mid of pos one , but enough in my opinion to have good performances. I can't wait to have the new sparks fitted on my Corvette . those I'm running now are more than old.
tomorrow morning I expect to replace spark plugs , check the compression ratio on at least 1-2 cylinders, go to my tires shop and set tires to proper pressure ( needless to say : my pressure gauge is not correct...)Ok , max pressure front and rear. I don't understand why GM says on my door's label less pressure on front tires in respect to rear...

power steering : I already lift the car at my mech to check everything underside. I checked also my rear end gear ratio by turning by hands the shaft and checking how many turns for 1 wheel turn. 3.55:1
My mech has checked the power steering and tie rod ends are OK. I have probably to check better the steering box , but it seems to me that no play is there. Instead I hear a strange vacuum noise from the control valve when I turn the steering wheel in the position where it has play ( with engine OFF). If I turn more the steering wheel , in the no play position , no noise anymore.

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(in reply to Texas Jim)

Post #: 9

RE: Tire's pressure ? - 2/2/2008 1:01:59 PM

Texas Jim

Posts: 441
Joined: 12/15/2005
Status: offline

Plug looks good, Aldo. You're right, they don't have to be perfect. The old guy who taught me that said that being pretty close was all it took. I would try to take the little burr off if possible.
With the power steering, when you turn the steering wheel as far as you can in one direction, it does make a hissing noise. If this is the noise that you're explaining.

(in reply to aldous)

Post #: 10