Dually Tire Size Question

[HomerDog]

I just put 2 Michelan 245/75/16 on my front and I would like to put the same on the rear. The stock tire is 215/85/16. I asked the guy at the tire store and he said it "should" work but it would be close (the spacing). Any comments will be appreciated before I order them, as I don't know much about tires... .

 

[D White]

I'm not sure about the spacing, but the 3500's now come stock with 235/85/16. Don't know for sure how much difference there is in size.

 

[jqram35]

235/85r16's are supposed to work on those trucks, but 245/75's are a bit wider I think you will be pushing your luck. You could put 235 on I think they are the same height as the 245's and they will fit. You just won't be able to rotate.

 

[dcochran]

I believe the offset on the rims is greater (from 2K on) in order to accomodate the 235 tires. Be carefull because if you go ahead with the install and those tires start to "rub" during the driving experience - you'll be in big trouble.

 

[MUDDY]

Originally posted by jqram35

235/85r16's are supposed to work on those trucks, but 245/75's are a bit wider I think you will be pushing your luck. You could put 235 on I think they are the same height as the 245's and they will fit.

negative. not the same height. 235, 31 7/8 inch tall.



245, 30. 5 inch tall. play heck with t-case on 4x4. and diffs too.



just go all 235/85 16. imo.



a friend with a 96 w-3500 went with 235 with no rubbing.

 

[Koa Man]

Largest tire I was able to put on my truck was 235/85X16. No problems with tires rubbing, even with heavy loads. I keep the tires inflated to max. pressure.

 

[jsimpson]

I've got 235's on my 89 with no problem and I just bought a 94 with 245's which has no problems for over 50,000 miles, but once I load my Lance on it, I'll be looking for tire-to-tire contact.

 

[Extreme1]

I would stick with 215-85. I have 235-85. Yes, they will work IF you drive around at max tire pressure. But if you get tired of the spine numbing action of the rear suspension and the ABS tripping when stopping on mildly rough roads, you can't drop the tire pressure without problems.



If you look at the tire inflation guide (packaged with your owners manual) it will tell you that you can run at 40 psi on the rear tires. Due to rubbing (I run empty most of the time), I can't go below 70 psi. 65psi will rub on bumps and dips, 70 psi only rubs on bigger bumps.



The tire manufacturer will tell you that NO rub is acceptable. This is true to a point. My old tires NEVER rubbed. Take a look at the sidewall clearance on a fully loaded semi trailer sometime, lots of space.



I also noticed a milage decrease (spedo corrected) with the larger rubber. A 4. 10 axle ratio would probably minimize that. I'll be buying 215-85 next time.

 

[FAllen]

Tire size

Homerdog



The Michelin guide that I have says you need a 6-1/2 inch rim for the 235 tire.



I beleive the 3500's have a 6 inch rim ??

 

[backroad]

Yes & maybe not.....

My 1990 W350 ran through 2 complete sets of the 245/75-16's with no trouble whatsoever. Yes they are close and yes the truck did haul some very heavy loads. (35,000 lbs. gross with gooseneck on many occassions).



Now for the kicker. My 1987 FORD 4X4 Crewcab DUALLY has, for the last 30,000 miles, been running a Dunlop 255/85-16 on ALL positions. The tires, from day one, touch on the bottom sidewall. I ended up puting 2 quarter inch spacers between the duall wheels. I also had to install longer wheel studs on the rear to get a full lug of threads. Would I do it again? Probably not. I am planning on going back to the 235/85-16's on aluminum wheels. I decided that a smoother ride with less vibrations is more important than the MACHO larger tires, even on the 4X4.



Hope this helps a little. It is a no-no to have the dually tires touching but... ...



The touching is a problem because it builds friction between the 2 tires and the friction builds heat and the heat causes tire failure. I have checked my tires regularly while towing heavy loads for heat build up, but have not had any problems "so far". (Cross my fingers for continued good fortune).....



Dennis Webster

Backroad... ... ... .

 

[QRTRHRS]

9. 4" sidewall width is supposed to be the max. Not long ago, someone posted that they had 7. 50/16's. Don't know about the effect on the ABS though.



Re: going from 235's down to the 215's. They sure look "weeny". The other thing I notice is more wear. Might be my imagination or could be from more BOMBing.

 

[MCummings]

Well, I've been watching this thread, and just thought I'd chime in. .



I have Michelin LTx A/T 245/75/16's all around on my 2wd 3500.

Haven't checked the pressures lately but look like they still have "good pressure". (I guess I'll check 'em tomorow and report back on pressure)



The rear tires have a "finger width" seperation between the two tires, and do not rub on the bottom. These tires have been on since about 30K and the truck odo reads 78K right now, most of these miles, except the last 2-3K have been towing a heavy gooseneck 19KLbs+



If they rub, they haven't rubbed enough to cause anytype of tire failure, as we tow at 70MPH on the open highway. We tow alot slower in heavy traffic situations.



Anyway, I'll report back tomorow or the next day to tell you what I can see after the 40,000 mile evaluation period I've had with these tires.



MerrickNJr



P. S. Anybody going tothe Kerrville, 2001 Texas Rally will be able to see these 245/75 tires on my truck, if they would like to see the fit.

 

[QRTRHRS]

MerrickNJr,



Do you know what your tongue weight is with that 19k trailer? Also, do you have ABS? Any problems there?

 

[SOOT]

tires

I have 235/75/16 on my truck with no tire rub. but would not go any wider.

 

[gitchesum]

OK fellas, gonna let you in on a little secret



I'm running 7. 50 X 16 size tires.



You might have to look for them but they are out there. They are as tall as a 235, but only as wide as a 215. I run mine at 55psi on a regular basis. I can almost stick my whole hand sideways between the tires. The ones I have are only D range though. Not sure if they make a load E range.

 

[MCummings]

Originally posted by QRTRHRS

MerrickNJr,



Do you know what your tongue weight is with that 19k trailer? Also, do you have ABS? Any problems there?

No problems with the ABS. I had a 2000 Chevy, 2500 with an auto that I put 285/75/16's on, (which BTW will rub when you turn nearly all the way), I had no ABS problems on that truck, and, our old Navigator had 255/70/16's and it didn't have ABS probs either. THese trucks had the same size tires all around, and we didn't ever drive in snow, so I guess I can'ttell you how they work in neccassary ABS conditions.



In all reality I do not know the Tongue weight of the trailer, all I remember is the D. P. S. Officer that pulled us over and wieghed us had the trailer weigh in close to 19,000pounds. We calculated that when we load it up, (1,000gallons of water) plus a few hundred gallons of other liquids, as Diesel, Oil, Gear lube, Hydraulic fluid... that the weight was pushing 30,000pounds.



The trailer pulled very well, and didn't sit the truck down too bad. The overloads on the Dodge wouldn't barely touch when towing empty, and kinda press good on the little pads when full.





I looked closely at the tires last evening and there is just literally a fingers width between the top of the tires,(1/2") and at the bottom I would assume about a 1/4" looking hard at the sidewalls i can see they are slightly glazed from a small amount of touching, but the are not worn at all. The two tires rub on the sidewall lettering and the lettering looks as new as day one, except a little glazed/or clean, definatley not worn.



We pulled our trailer out in 100*-115* temperatures and have never had a tire failure with Michelins.



On a side note, we usually didn't pull for more than a constant 2-3 hours at 70MPH



Soon as I get the pictures developed, I'll post 'em up.





MerrickNJr

 

[QRTRHRS]

MerrickNJr



With those kind of temps, I would think if you were to overheat the tires, it would not take no 2-3 hours. Like you say, Michelin makes a good tire.



So, what did the D. P. S. Officer have to say about that gross?

 

[MCummings]

lol, he said,, to park the truck, and get a CDL.



so, we bought a new truck, and a new smaller, lighter trailer.



Me and my Dad got class A CDL without airbrakes.



this truck/trailer combo should be about 2-4K lighter





MerrickNJr