Hard/Rough Ride & Tire(s) & Pressure

[55 Fargo]

Hi all, my 47 seems to run rough on the gravel roads, cracks in pavement bumps etc.

The car steers well, with the esception of some extra steering wheel play, no unusual tire wear either.

I jacked up the front end, the king pins seem okay, with minimal play, the tie rod ends are in good shape, I have decent colis up front, new shocks all the way around, and the leaf springs and shackles are in fair shape.

This morning checked the tire pressue again, the gauge I ws suing, I have about 5 of them, seemed off, and was hard to get a good seal for reading.

I pulled out my newest gauge, I was getting a reading of 35 to 36 lbs, on the other gauge I was showing 28 psi.

So I wlet air pressure out to 28 lbs, have not gone for a ride yet.

Would having my tires inflated to 35 plus make a hard ride?

These tires are also 10 yo, there Good Year, but a light suv tire P205 75 15s.

Have any of you expereinced this on your cars?..................thanx Fred

[Plymouthy Adams]

answer this..would a low inflated soccer ball bounce as much as one filled up...about the same effect..

[55 Fargo]

Just checked my Chrysler service manual, states 28 psi for tire pressure, not sure how this will relate to modern radial tires. Does anyone know if bias and radial tires require different inflation?

[55 Fargo]

answer this..would a low inflated soccer ball bounce as much as one filled up...about the same effect..

This one I should have known Tim, as there is about 4 soccer balls around this place, all with different inflation......LOL ps do the raidal tires require different inflation psi, than old bias type tires?

[Plymouthy Adams]

answer this..would a low inflated soccer ball bounce as much as one filled up...about the same effect..the truck tire also has a normally stiffer sidewall thus a tad harsher ride..but this should reflect that of the stock tire for the period in which the car was built..the soft sidewalls of todays modern cushion tire for mom and pops to get groceries are very forgiving as to road surfaces/conditions as felt in the steering wheel and the seat of your pant with the most adverse feel being sidewall flex in cornering.

[Young Ed]

Fred I run mine about 32. Rides nicely.

[greg g]

I run 32 all around on my coupw with the radials. I know I could use rear shocks but it still rides pretty well except over real big bumps. I don't run dirt roads in the Plymouth so can't comment on how that ride would be. I kow from my rally driving, the faster the smoother, cause you only hit the top of the bumps........

[BobT-47P15]

I guess it's 'cause I'm old - but I recall in them olden days we used to use 30 lbs.

On the majority of newer cars with radials -- 35.

You can drop down to less than 30 - say 25 or 28 - and get a little softer ride.

Of course, that may cause the tires to wear a bit more on the outer edges.

(Overinflation causes more center wear.)

Not sure how big an issue a little extra wear really is, since we don't

drive these cars regularly. My 2 cnts.

[40phil41]

FWIW, I have always used 32 psi on my '40 and '41. Never tried anything else. Ride is as per 40's cars!

How are your upper and lower control arm bushings?

Phil

[James_Douglas]

Modern radial tires should always be inflated to the recommended MAX pressure on the tire.

Also, if the tires are 10 years old, the should be replaced even if they have good tread. There is ample evidence that tires over 8 years old are failing around the US, particularly in hot regions.

There is a regulatory cat fight going on about setting a maximum tire life for all tires in the US. The industry is fighting it, but it is coming.

James

[claybill]

COKER TIRE CO. says...(taken from an interview with mr.coker in a magazine)..bias tires due to their bias/overlapping plies..have sidewalls that are hard and result in stiff cornering and a harder ride at 32 lbs, and often the FULL TIRE FOOT[PRINT is not level with road surface.( curves etc)

radials, with straight radial plies give a more pliable sidewall for better cornering and max footprint at all times. however...radials therefore cause a bit more strain on the steerng box due to more road/tire friction..so he recommends that radial tires ON OLDER CARS be inflated 35 to 45 lbs.

gravel roads..??..yer old car aint goin' to behave like a 4x4 with any tire pressure... basic suspension and chassis design is at work here.

bill

i have a mile of gravel road to go every day in my vibe AWD, and it skids if i dont watch it... H-m-mmmm...maybe those 50 mph hairpins are a bit much!!!

[55 Fargo]

Bill my other vehicles 2007 Torrent AWD is nice a nd smooth, so is my 2005 Dodge Caravan, the 1994 Ranger is a bit rougher, but the 47 was going over the same surfaces much harder.

Guys,

I reduced the inflation of my tires to 28 psi, much softer ride, still somewhat noisy,as there is no headliner, door panels, insulation uner carpet, so it's will sound more like a drum, for now........Thanx Fred

[BobT-47P15]

Fred, have you ever tried putting some foam rubber or other substance in the

bottoms of the doors as a temporary measure to dampen the sound of that

drum??

[aero3113]

My tires say 65 psi max cold. They are 700 X 15 radials. Should I run them at 65 psi or less?

[Don Coatney]

I dont believe it has been mentioned in this thread or if it was I missed it, but higher pressure in radial and bias tires makes for easier steering at low (or no) speed. I run my radials at around 34 PSIG. When the pressure has dropped below 30 PSIG there is a noticable increase in armstrong pressure required to turn the wheel when stopped. I personally would never return to bias tires simply for roadability.

[Don Coatney]

My tires say 65 psi max cold. They are 700 X 15 radials. Should I run them at 65 psi or less?

65 seems really high. Do your tires show increased wear in the center of the tread at this pressure or have you not driven enough miles to see any change?

[aero3113]

No, even at 65 psi there is still a little bulge at the bottom of the tire. They are new tires and seem to be wearing normal.

[Plymouthy Adams]

you can't fool me..that tire as pictured is not mounted...we know where the hot air is now...lol

[55 Fargo]

Update:

greased front end agan, this time king pins took the grease, and so did the upper control arm bushings.

The car steers better, handles nicer, and is taking the rough road easier, I also inflated tires to 30 psi.

Thanx all for the help and laughs....LOL