Jim Lane

Has anyone ever had any experience Bridgestone tires riding rougher as they get more miles on them?

I have a set of 6 Bridgestone LT21585R16 tires on my D-350 and I do not think it is my imagination but I think these tires are getting harder and rougher riding the longer I have them, the balance is fine @50PSI (down from 70PSI Tucker Tire aired them with) but it feels like they have about 100 pounds of air in them or I filled them with water.
It is not the usual 1st. gen harsh ride, even with air rides and a reduced spring pack if you hit a rough spot on the road it will cause the truck to shudder.
It has really just started doing this in the last 6 months, like I said the tires are balanced, new gas shocks, alignment is good, no loose suspension cab or body mounts I can find.
Anyone have any ideas?
Before I bought these I tried a set of some Firestone “E” tires and they were terrible, it almost got me sick driving down the street, the truck would swish and squirm while driving straight, I didn’t even want to turn.
You guys find going to a passenger car tread pattern rides smoother but how much does this reduce the GVW?
Jim

BearKiller

Many will flame me off of my stump for stating this; but, here goes.

It is a bad mistake to attempt to adjust ride quality by lowering tire air pressures.

The absolute best pressure to run in a tire, especially failure-prone radial tires, is the maximum stamped on the sidewall, and then some in my case.

If a vehicle then rides/drives peculiarly, there is probably something(s) worn out that just hasn't been found yet.

To improve the ride of a 4x4, replace the negative-arch springs with a set of positive arch and you will think it is a Cadillac.

Every day, we replace a set of P-rated tires that someone, usually a car-dealer, has installed on a 3/4 or 1-ton truck, in an attempt to save money.

In every case, the owner is complaining of the truck squirming around, following ruts, and laying over in curves.

Put him on a set of LR-Es and 80PSI and problem solved.

I will also say this:

You have named the two worst tire brands that I have ever dealt with, except General, and they don't count.

Firestone truck tires will fly apart, taking mirrors, lights, fenders, and fuel-lines with them.

Many is the Firestone that has completely shed it's tread, leaving only the casing.

In their defense, nobody makes a better BIAS tire than Firestone.

Their farm and mining/logging tires are second to none; they just can't make a radial.

wannadiesel

Not gonna flame but I have a question:

How about lowering pressure to adjust the wear pattern? I'm down to 45 psi on the rear duals and they still are wearing the center. Fronts are at max so the outer edges don't wear off.

The Suburban in my sig calls for E rated 245/70-16's, the door sticker wants 45 psi in front and 55 out back. I tried it that way for a while but the fronts were getting the edges chewed and the rears were getting worn in the center. I'm now at 45 out back and 65 in front - contact patch is good but the steering is real light.

BearKiller

Yes, you can flatten/even-out tread-to-ground contact by adjusting air-pressures; but, you will also sacrifice proper handling characteristics, and the tires probably won't last any longer, anyway.

With the advent of soft-squishy sidewall radial tires, everything we knew about tires for generations went out the window.

Tread depth can no longer be counted on as an indication of tire safety.

The tread of a radial tire will far outlive the integrity of the casing.

You can no longer depend on a tire that has so many 32s of tread, to be good until that tread becomes close to slick; the casing will fail, if the age/abuse catches up with it, regardless of tread-depth.

Five years is stretching it on the life of a radial casing in my climate.

I really haven't answered either of you guy's questions, have I.



Are you certain on that size/rating??

I have yet to see a 245-70-16 in Load Range E; although, we have dozens of P-245-70-16s on hand.

245-75-16 LR-E are plentiful and popular.

ronnie

I have to agree with wannadiesel, it is reasonable and proper to adjust tire pressure for good wear. The maximum on the tire is just that, the maximum allowable. I have 50 in the duals, and the max in front. Mostly pulling a trailer with mine so full pressure in the rear is not needed for the wieght.

Did the ride roughen after the new shocks? Some are quite stiff, my old (47)Dodge I tryed air shocks, and was pleased with them. I keep the pressure low unless hauling. This gave me a better ride.

LOGAN

if it was my choice i would run bias tires on all my vehicles, i ran a set of 30 year old bias ply mud tires 33x12.50x16.5 on my v10 with 33x12.50x16.5 radial BFG at's on the front, the bias tires wore less and rode better than the BFG's did and they was 30 years old, anyone know where i can buy 16 inch directional bias truck tires??? cause i will put them on my dodge. only problem they get warm on the freeway.

BearKiller

If half the time and technology that has been wasted on radial tire development had been invested in improving the BIAS tire, you would seldom hear of a death caused by tire failure.

Myself, I prefer BIAS for the same reasons that you just mentioned.






Look on the rear of my F-350.

Good old BIAS 7.50-16 LR-E POWER-KINGs, with directional tread and pin-holed for #17 ice-studs if so desired.

I guess I had better be ordering me up another set, just in case they get scarce.

wannadiesel

You're right, they are 75 series.

Micaiahfied

dave, i had a friend that had a diesel suburban a few years back and tires wear was one of the main reasons he got rid of it, or so he said. he could not get anything to wear correctly on it and continued to get buldges in the sidewalls. all of this is before i've been educated on many of these subjects but i know it was a similar vehicle to yours and had the same problems.

Jim Lane

No the ride has been getting worse months after I had installed the new shocks. I installed the new shocks back when I installed the air bags; I had a shock on the rear that was rattling because the outer shell had broken loose from the piston rod.
The truck rides like there is no flexing or cushion in the sidewall. The tread pattern is flat across the tire so the pressure is ok.
I have about 1000# in the back of my truck most of the time and about 20 PSI in my air bags, which seems to make no difference in the quality of the ride.
It feels like I have tires from a Bobcat on my truck

BearKiller

From everything my common sense tells me , the older a tire gets, the more broken-down the cords that hold things together get; so, as a tire gets older, the ride gets more mushy, the exact opposite of what you are experiencing.


I am going to go out on a limb and say that, possibly, your shocks are siezing inside, either from bad pistons, collapsing cylinder walls, sticking valves, or whatever.

This would effectively take the "give" out of your suspension, and produce the symptoms you are describing.

If they are decent shocks, they should have a lifetime warranty; I took back a set of old Monroe Magnums, that were probably twenty years old, no receipt or nothing, and the parts man gave me four new ones and wouldn't take my money.

This is a long shot; but, why not take the bottom ends of the shocks loose and see if they feel normal, maybe even take a test drive with the shocks loose??

I honestly don't think your problem is tire related.

Another option is to temporarily switch tires/wheels with someone, and see if the problem transfers to their vehicle and leaves yours.

Jim Lane

I thought I would disconnect the shocks and take it for a ride but I have not had the chance to do that yet. They are good shocks and I have no problem getting them replaced if they are not right.
I was trying to find a good oil shock but it looks like everyone thinks the gas charged is the way to go.
I always ran Koni's on anything performance of 4-Way's on my Suburban, they were designed for ambulances and rescue vehicles so they could cross intersections at a high speed and not bottom out.

I would like to swap tires with someone but 1st. gen Dodges out here in Southern California are rare, I can count the ones I have seen on one hand and still have fingers left over.

Tomorrow I am going to try and find a REAL suspension shop, I went to Bear Wheel and Frame, the people working there are real certified tattooed pierced idiots I get so frustrated when I talk to them.

This has to be something so simple I am overlooking it, the front springs are new, front end is rebuild both upper and lower ball joints, rear springs reworked, air bags, almost every part of my suspension is new, not because it was worn but just because this is me.
Thanks.
Jim

Totallyrad

In my opinion, I don't think the change in ride quality is a big mystery. When a tire is new, it has tread. The tread has grooves and slits in it that allow it too move water and provide additional traction. They also allow the rubber of the tread room to flex and absorb some of the deflection caused by bumps in the road. When a tire is worn, the tread is gone and the carcass of the tire has to absorb all the shock of any deflection. Without the tread there to help, it's going to ride rough.

I agree that tire life should not only be measured by the depth of tread but the age of the carcass. I've had semi tires that looked perfectly fine to cap but the recapper would not touch them because the carcass was 6 years old. He stated that they fail at a rate too high for him to accept the liability for. I can understand that.

I also adjust air pressure on my pickup and GN trailer to allow the tire to wear flat across the tread. This gives me the most mileage out of the tire. I run 80 in the fronts and 30 in the rears of the vehicle in my sig. My 93 2500 w/CTD ran 65 front and 55 rear. GN gets 75 in all four. This works for me, it may not for you. I can say that I have never had a tire fail on my pickup or trailer from inflation issues. I've had metal, nails, screws and even sharp rocks puncture them, but never had one separate or explode due to inflation issues.

I have had semi tires and semi trailer tires (17.5's) separate and explode. The cause for the 17,5's is due to the tight turns in cul-de-sacs. Those turns, especially when loaded, cause the belts to separate over time. As a measure of tire life, when the tread on these tires reaches 50% they are basically "may pops". I start looking to replace them at that point. Typically, with only a very, very, rare exception, the tires always show signs of separation in the tread. For those who will ask, the answer is NO, I'm not overloading the truck or the trailer. I've scaled with both machines and I'm well within the safe operating ranges of the truck, trailer and the tires.

One other note, on the semi and it's trailer, by law I have to run the tires at the pressure stated on the side of the tire or risk a fine if I'm stopped and inspected. I only gross about 62,000 and my weight distribution is good. On the pickup and GN, I can adjust the pressure for tread life.

KartRacer

I have to agree to Wanna. Setting your tires at the max as a rule is dumb. You set them at the max if you are loading them to the max. With most vehicles, the recommended pressures in the door jamb are a good start (not sure if these old trucks have that) for normal use. The "proper handling characteristics" were figured at the factory when they designed the suspension and tire combo. They design with a good compromise between wear and safety. You may be able to make it more desirable to your liking by playing with the pressure, but you will be sacrificing somewhere else.

I set my pressures by wear pattern, but if it causes a problem with the handling I compromise a bit. My fronts are up there a ways, but my rears would probably like about 20 psi unloaded. I obviously don't run them that low because of the stability and how often I hook up to a trailer. But, if I had them at 80 psi the center of the tread would be gone in a month unless I had 2k lbs in the back at all times.

-Steve

johnh

are you a tire manufacturer,designer or is this just your opinion?