Why were 215/85 R16's originally used

[JDMills]

curious as to why the factory would use a 215/85 R16 on the dual wheeled trucks as they came from the factory. Is it economics? has to be, but there is so much more options available in the 235 size. Also around here the 215 size tire is more expensive.

Jason

 

[paccool]

Jason,



I don't have a dually but remember some of the guys saying there was a potential problem with the tires rubbing together if you went up in size very much. I know some are running the 235's without problems so it may be a difference in how the tires are manufactured. I'm sure there will be someone respond with better info.



Stan

 

[DKarvwnaris]

Jason,



I don't have a dually but remember some of the guys saying there was a potential problem with the tires rubbing together if you went up in size very much. I know some are running the 235's without problems so it may be a difference in how the tires are manufactured. I'm sure there will be someone respond with better info.



Stan

The larger the diameter of a tire, the more flex it will allow under load. Why they would prefer a 215 over a 235 would seem minimal at best regarding this issue. As for tires rubbing one another, the width of the hub and the rim offsets will adjust for tire width on a duall, ( Just keep in mind the larger the sidewall diameter, the more the sidewalls will squat under load at the base of the tire. 215's are less apt to touch under load due to this as mentioned above).

Other than that and Daimler Benz's tight fisted expense reduction on overall vehicle costs, I couldn't imagine much else being a reason to worry about it.

If you install bigger tires, set the air pressure to about 15 to 20 psi and see if they touch with an no load on the truck. This will give you an idea of the amount of sidewall bulge under load. (reinflate again before driving)

I have run 235's, 245's, and 265's on all my dually's without spacers. None have touched, (Newest dually I owned was a 95 dodge, can't speak for newer models).

 

[JDMills]

My truck has 235's on it, and the sidewalls touched one day when I had a load of wood on it, bumped up the pressure to around 70 psi and solved that. .



May be there is no good reason?

 

[DKarvwnaris]

My truck has 235's on it, and the sidewalls touched one day when I had a load of wood on it, bumped up the pressure to around 70 psi and solved that. .



May be there is no good reason?

The fact you had to reinflate the tires to keep them from touching is reason enough.

Look at the typical car owner who doesn't even bother to check their oil every other tank of fuel, few only bother to check their tire pressure unless the tire is flat. This is the "idiot factor" that Manufacturers have to take into consideration when equipping most consumer goods, vehicles included.

I agree with yout in principle, but I also know from previous days as a service writer how stupid the dealers have to consider most customers are.

 

[mysteryman]

get the correct rims

I thought I would add that all the 1st gen dual trucks came with 215 tires.

The main reason was because it was hard to balance the 235's when used as duals due to the rims not liking to center vary well on the hub. This was due to the flat faced lug nuts and coined stud holes in the wheel. There is a TSB on the centering problem that fixes the problem. Jujst follow the directions.

Another thing I would like to add is that you CAN NOT use 235's on the stock dual wheels!!!! they will rub when loaded and blow out on the highway. Kelsey does make a coined stock steel wheel just for the 235 tire to be used on the dually Dodge trucks. they are 100. 00 each wholesale. Some of the first gen

"cab & chassis" (not pickups) trucks did come with them when special ordered by fleets. These wheels looked exactly like ones that came with the pickups but had a . 700" different ofset.



I myself prefer the 235-85 10ply tire . It used to be called a 7. 50 x 16 in years past. I hope this helps

curious as to why the factory would use a 215/85 R16 on the dual wheeled trucks as they came from the factory. Is it economics? has to be, but there is so much more options available in the 235 size. Also around here the 215 size tire is more expensive.

Jason

 

[tugboatphil]

I run 235 85 because it was what was on there when I bought it. I've had the bed loaded down plenty, and even had the wife follow one time to check the duals. Never had any problems. I also run about 70 psi all the time, as I never know when I'm going to "find" something along the road.



My step-dad has a 97 3500 and the stock tires look like go-cart tires on it. My data sticker on the door frame says 215 85, but I doubt I'll ever run those.

 

[DKasper]

I put Toyo M-55 235/85's on my W350 last year. I love the tires, but have experienced some quirks.

To get them to wear properly when running empty I have to run them at about 15-20 pounds in the back, I use about 60 pounds in the front. These are pretty stiff tires. I haven't had any trouble with rubbing, but they are close enough that I have to increase pressure when I'm towing or hauling wood.



I also have to rotate religiously to get good wear -- mostly due to the light load in the back -- I run unloaded a lot.



Also, be aware the change in size will affect your accelleration ability -- not quite as quick.

 

[DKarvwnaris]

I also have to rotate religiously to get good wear -- mostly due to the light load in the back -- I run unloaded a lot.



Also, be aware the change in size will affect your accelleration ability -- not quite as quick.

Most of the guys driving dually's around here as their daily drivers are living in trailer houses with their bald tires holding the roofs down. Why bother rotating, its cheaper than shingles. :-laf



While you may loose slight acceleration abilities, the lower rpm's in high gear is worth it to me. You can always start out in a lower gear or accelerate in a lower gear, but without bigger tires, its harder to get the RPM's lower when you're already in 5th gear at 70 mph without investing in an overdrive unit.

 

[KWeber]

you CAN NOT use 235's on the stock dual wheels!!!! they will rub when loaded and blow out on the highway.

I disagree.

My W350 has spent it's life a service truck. It was equipped with a steel deck, welder, torches, tools, compresser... etc.

I only recently purchaced it as a cab and chassis, but I know the previous owner well, being that he's my father.

It has had 235's for 95% of it's life. A size related tire failure has never occured.

 

[tugboatphil]

with their bald tires holding the roofs down.

Hey! Us bald guys would prefer that you said "tread challenged. " :-laf