1988 Dodge B250 Tire rating

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Hi, I have a 1988 Dodge B250 Hightop conversion van. This van has a queen bed, solar panel, lithium battery and a lot of camping gear. Last year, discount tire sold me new tires and put 235/75r15 Cooper Discoverer AT3 4s 109T XL Load tires on my van. Upon reading today, I realize that these are only 4ply tires. I am googling but it appears these are actually the best tires made in my size. Does anyone have a tire that is Load E and 10 ply in this size? How dangerous is my current tire?
 
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First check for a vehicle tire placard. It's usually located on the driver's doorframe, but sometimes its in the glove box, or the fuel filler door. That will tell you the original tire size and inflation pressure.

According to Tire Guides, a 1988 Dodge B250 Wagon used P235/75R15 SL or P255/70R15 SL - both at 35 psi - although there is a listing for a Dodge B250 Maxi with P235/75R15 XL at 41 psi.

Either way, that lines up. That's exactly what Dodge originally specified.

Now about the 4 plies: I'll bet it's 2 plies of polyester and 2 plies of steel. But that doesn't tell you is how strong each of those are - and some polyester and some steel are plenty strong. Even a Load Range E (80 psi) typically use a 2+2 construction.

And No!, an LT235/75R15 only comes in a Load Range C and it's basically the same construction as the XL.
 

petes67bird

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First check for a vehicle tire placard. It's usually located on the driver's doorframe, but sometimes its in the glove box, or the fuel filler door. That will tell you the original tire size and inflation pressure.

According to Tire Guides, a 1988 Dodge B250 Wagon used P235/75R15 SL or P255/70R15 SL - both at 35 psi - although there is a listing for a Dodge B250 Maxi with P235/75R15 XL at 41 psi.

Either way, that lines up. That's exactly what Dodge originally specified.

Now about the 4 plies: I'll bet it's 2 plies of polyester and 2 plies of steel. But that doesn't tell you is how strong each of those are - and some polyester and some steel are plenty strong. Even a Load Range E (80 psi) typically use a 2+2 construction.

And No!, an LT235/75R15 only comes in a Load Range C and it's basically the same construction as the XL.
Should I return my Cooper for these? I called Discount Tire and they recommended this tire if I wasnt comfortable with the Coopers. My placard is long gone after almost 34 years.

 
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Your tires have a load rating of 109 which is 1030 kilograms or 2271 pounds, so if the rear weight is under 4000 pounds, I'd call it good.
 
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I have Cooper 235/75/15XL and they are rated for a maximum load of 2400 lbs at 41 psi. Multiply that by four. I doubt you are anywhere near that weight with your van. I wouldn't worry.
 

petes67bird

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I have Cooper 235/75/15XL and they are rated for a maximum load of 2400 lbs at 41 psi. Multiply that by four. I doubt you are anywhere near that weight with your van. I wouldn't worry.
Its the sidewall rating and the mushiness of the tire. My concern is that when wind is 10+mph, its difficult to keep it in its lane. From what I was reading elsewhere, this is due to a soft sidewall. My suspension, shocks and steering box is all brand new and completely rebuilt. According to Cooper, that rating is when on a passenger vehicle. If on a truck, they state you must reduce by 12% and after that an additional 1% which brings it right around to a normal load passenger tire of 1984 lbs per tire.
 

petes67bird

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Your tires have a load rating of 109 which is 1030 kilograms or 2271 pounds, so if the rear weight is under 4000 pounds, I'd call it good.
Its the sidewall rating and the mushiness of the tire. My concern is that when wind is 10+mph, its difficult to keep it in its lane. From what I was reading elsewhere, this is due to a soft sidewall. My suspension, shocks and steering box are all brand new and completely rebuilt. According to Cooper, that rating is when on a passenger vehicle. If on a truck, they state you must reduce by 12% and after that an additional 1% which brings it right around to a normal load passenger tire of 1984 lbs per tire.
 
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I would say to add some PSI to the tire to see if that helps. I have to be honest, I'm incredibly picky with tires. If you aren't happy with them now, I would say to get something else because it's likely not going to improve. Especially if Discount Tire is willing to swap them out. What tires did you have before these ones?
 

petes67bird

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I would say to add some PSI to the tire to see if that helps. I have to be honest, I'm incredibly picky with tires. If you aren't happy with them now, I would say to get something else because it's likely not going to improve. Especially if Discount Tire is willing to swap them out. What tires did you have before these ones?
They were some cheap Cooper passenger tires I never heard of before that were from Walmart. They were about 14 years old because I bought the van after it sat 8 years from the original owner who was 92.

Update: just remembered the tires.... Cooper Starfire Solarus
 
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32 year old springs.

I have essentially same vehicle.
Lt 30x9.5x15 cooper at3 44psi rear, 42 front, 50 max.
Speedo is now.dead.nuts accurate..was nearly 4mph fast at 60 with 235 75 15.

Firestone ride rite airbags on [email protected]~20 psi
Moog 7272.coils up front. Thicker than stock tired 7270.
Kyb gas a just all 4 corners.
Redhead steering gear.

Handles quite well for a topheavy brick with wheels.
Airbags made biggest difference on highway in cross.winds.or getting.pushed sideways by bigrigs.
Then kybs. Then thicker coils..springs up front.
Big rigs passing and strong crosswinds are much less problematic now.

Stock tired springs need help. They're too old and soft.
New. Leafsprings likely ride.more.pleasant for.rear passengers than airbags.
Not a factor.for me.
Rather adjust airbags for different loads carried.
 

petes67bird

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32 year old springs.

I have essentially same vehicle.
Lt 30x9.5x15 cooper at3 44psi rear, 42 front, 50 max.
Speedo is now.dead.nuts accurate..was nearly 4mph fast at 60 with 235 75 15.

Firestone ride rite airbags on [email protected]~20 psi
Moog 7272.coils up front. Thicker than stock tired 7270.
Kyb gas a just all 4 corners.
Redhead steering gear.

Handles quite well for a topheavy brick with wheels.
Airbags made biggest difference on highway in cross.winds.or getting.pushed sideways by bigrigs.
Then kybs. Then thicker coils..springs up front.
Big rigs passing and strong crosswinds are much less problematic now.

Stock tired springs need help. They're too old and soft.
New. Leafsprings likely ride.more.pleasant for.rear passengers than airbags.
Not a factor.for me.
Rather adjust airbags for different loads carried.
I have done tie rods, ball joints, upper control arms, blue top steering, brakes, tires, lines etc. I wanted to replace some squeaky worn out bushings this year, replace my oil pan, and help with the crosswind issue. I am trying to figure out what will make the biggest improvement from this list:

1. Changing tires from extra load to load e. My cooper's at3 are passenger not load e since they don't make them in 235-75-15
2. Replacing kyb gas a just with bilstein shocks
3. Adding rear sway bar
4. Adding helper leaf springs or replacing
5. Replacing front coil springs
 
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My van came with p235 75 15 xl.
First tires i bought were LT's...no.significant difference.

The soft wornout rear leafsprings made for scary handling. I went through two.cheapo.pairs of helper.springs. the type.which attach to bottom of rear portion of spring. The plastic.sliders.wear out.metal on metal grinding thereafter.
And removing them made handling s c a r y.

No rear sway bar fits if you have 35 gallon gas tank.
Airbags made biggest handling improvement. But weak gabriel shocks on rear axle were poor.match with airbags.

B250 come.with 7270 coil spring. B350 come with 7272.

I descended sierras.once. twisty turney smooth road big shoulders. No traffic.
4 wheel drifts around.some corners.
Hissing tires.
Laughing.
Complete confidence

Seek firmer springs first.
 

petes67bird

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My van came with p235 75 15 xl.
First tires i bought were LT's...no.significant difference.

The soft wornout rear leafsprings made for scary handling. I went through two.cheapo.pairs of helper.springs. the type.which attach to bottom of rear portion of spring. The plastic.sliders.wear out.metal on metal grinding thereafter.
And removing them made handling s c a r y.

No rear sway bar fits if you have 35 gallon gas tank.
Airbags made biggest handling improvement. But weak gabriel shocks on rear axle were poor.match with airbags.

B250 come.with 7270 coil spring. B350 come with 7272.

I descended sierras.once. twisty turney smooth road big shoulders. No traffic.
4 wheel drifts around.some corners.
Hissing tires.
Laughing.
Complete confidence

Seek firmer springs first.
Hellwig said this would fit....
 
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I've read the swy bar only fits the vans with 22 gallon tanks. Not 35.
This info is dated though.

Cant say what you should.do. Just what worked for me.

If kyb gas a justs are not too stiff for you then i dont think 7272 coil springs will be either.

I do know of one b250 owner that tried 7272 stiffer coil springs and went back to 7270.

I love my airbags. Adjustablity is highly desirable to me.
Have had them installed for 13 years last October.....

Good luck!
 

petes67bird

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Thank you very much for your help! So now I have a few things to consider moving forward. I think I am going to switch the tires to be on the safe side and just run them at a lower PSI. This will give my sidewall strength since I will be taking this van on dirt roads, to the Badlands in Dakota camping and other national/state parks.
 

petes67bird

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I also would like to clarify the weight of my camper conversion including passenger weight will be around 1200-1500lbs minimum that will be riding in the van full time. I will also be adding shiplap wood to the ceiling and walls next year, and a vinyl plank floor as well. Thats more additional weight. I have beefed up the shocks, and I am getting new heavy duty leaf and coil springs this spring.
 
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I didn't realize that we weren't talking about a van that had been "converted" back in 1988 - that we are talking about a van you are converting now. That certainly changes things.

First, you may want to consider abandoning the project. A B250 doesn't seem like a good candidate for adding the weight needed for a conversion.

Second, you are going to have troubles with tire load. Vehicles of this era had little margin for tire loading. That was one of the lessons from the Ford/Firestone situation in 2000.

Even going with a Load Range E presents a problem as the shocks and springs were designed for up to 41 psi, not 80 psi.

Neither Tire Rack nor Discount tire list the vehicle, so we don't know if there might be a 16" wheel available to try to get better options. Plus we don't know if a 16" will even fit in the fenderwells.

And I don't even want to mention that the rest of the vehicle was designed as a lighter duty van.

So let's explore some options:

Can you weigh the van? Especially corner by corner?

Do you know what the Payload was for this van?
 
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