Tire Pressure

[Wgesnerjr]

Hi all,
I did want to ask if anyone knows what was the original factory tire pressure was on the sticker on the door? It was long gone by the time I took ownership. An internet search says its 35 psi front and rear, but I didn't want to just assume the Google was right.

Vehicle info: 1985 Custom Deluxe, Single Cab, Long Bed, Single rear wheel. Originally is was a 305 4BBL. 700R4, 2.73 non-posi rearend, 205/75R 15 tires on 15x7 rally rims. Post Resto it is a 5.3 LS, 4L60-E, 15x10 wheels and 295/50R15 tires all around. Still has the 2.73 rear.

My goal with the new tire and rim combo; I wanted to start at the factory setting and adjust from there.

Thanks for any help.
Jay

[LT7A]

My truck is fairly similar, so if I find the factory pressure sticker, I will let you know. But I'll go out on a limb and say that starting at 35 is probably going to get you closest. I usually run 28 outback and 32 up front because of the difference in the weight that they carry. And those 295s will probably have to be a little lower pressure in order to lay flat and have full contact patch. If you have somewhere dusty you can go, or drive across a smooth concrete slab, you can either see where the dust is sticking to the tire or where the tire has lifted dust off of the slab and tell whether or not you are making full contact. That's what I watched in order to get to the 28/32. But that was with 285s.

[geezer#99]

There’s a tire sticker on here that shows 32 lb cold but for a 235 tire. A 205 tire likely would be the same.
I’d start yours at 28.



https://www.txclsx.com/index.php/pro...chevy-c10-swb/

[Wgesnerjr]

Thanks for the replies.

With the original steering box I had run the pressure down to 32 just to keep the truck from wandering all over the road. The box had a HUGE deadspot in the middle.

With the new Borgeson steering box, the deadspot is gone and the wandering is so longer an issue. I aired up to 35 all around with no noticeable difference.

Funny the sticker in the photo calls for 35 out back and 32 up front. Again, different size tires then I have.

I am off work next week and will look for a dusty place or bring some flour to test.

[Pontiac1976]

32-35PSI as the stick had said 205-215-225-235 x75-15" Tires have a set pressure on the side wall to weight of the truck tire side wall thickness heat of the day changes the and options and stuff in the truck persons load. So even two truck's with the same set up motor can be different tire but the same size tires.
Very smart as said by LT7A :

My truck is fairly similar, so if I find the factory pressure sticker, I will let you know. But I'll go out on a limb and say that starting at 35 is probably going to get you closest. I usually run 28 outback and 32 up front because of the difference in the weight that they carry. And those 295s will probably have to be a little lower pressure in order to lay flat and have full contact patch. If you have somewhere dusty you can go, or drive across a smooth concrete slab, you can either see where the dust is sticking to the tire or where the tire has lifted dust off of the slab and tell whether or not you are making full contact. That's what I watched in order to get to the 28/32. But that was with 285s.

This one of the best ways to find out I use that at the drag track cars. Heat direct sun of the day can see a tire gain 1-2.5 PSI Average but can be higher just by one side to the other side. So you have to Play PSI a little 4-Season and Morning, Midday, Night for your Truck/Car to get the best tread wear traction.

But the next time your in a tire shop or online tire shopping check the tire info the same size's from 4 manufacture and see the height will be mostly close all will be different but all the same size stamping.

[LT7A]

I'm glad that steering box is working out well for you. I'll be curious to hear what you figure out for good pressures. How about a picture of the truck with those 295s all over the place, sounds cool.

[kipps]

The original tire pressure sticker is meaningless with your drastically different tire size. Ignore the sticker entirely.

Your goal for tire inflation is to get a completely flat tire-to-road contact patch. If it's overinflated, more weight and wear will be occurring in the middle of the tire. If it's underinflated, more weight and wear will be seen on the outside edges of the tire.

Make a chalk mark across the tread of the tire, and go for a short drive. The chalk mark should wear away uniformly.

[geezer#99]

Better than chalk, get a depth gauge.
Like this.


https://www.grainger.com/product/TRU...th-Gauge-1MZF7

[kipps]

Originally Posted by geezer#99

Better than chalk, get a depth gauge.
Like this.


https://www.grainger.com/product/TRU...th-Gauge-1MZF7

The reason for chalk is to apply something that will wear away within a mile or so.

You don't want to run improper pressure long enough to actually get a measurable difference between the inner and outer tread.

[hooverfish]

My orig tire sticker says 35 for front and rear.
84 Custom Deluxe, short bed, 6 cyl automatic, 273 rear, orig tires were 195's.

[Pontiac1976]

Normally the short drive IE: flower, water, lite damp sand dust, then 4-5 feet and stop get out look at the tire tread patch on a clean paved section, then you re do as many time as needed to try get the best tread pattern ( or drag race you do a rolling hard launch 4-5 feet drop PSI or add PSI count the lines, I bars, N bars, or flat patch, what your tire has across it. Then count the three bars in the middle then your tire has 9 bars then too high PSI and only riding on the center of the tire.
That way you need go some place out of the way, some help wet the tread of the tire not the soak the tire.