285's or 235's ?

[Gone Huntin']

I need tires for my truck. It currently has 285/75/16 Mastercraft Courser M/T's on it that wore out in about 20k miles. I'm gonna be towing 8-9k pounds with it on the interstate a few times a year. I have an E4OD and 3.55's. Should I go down to a 235/85/16 or will I be ok with the 285's towing that weight?

 

[towcat]

with the 235's, you won't have as much sidewall walk as you would with the285's

 

[FordGuy100]

You can get 285's with an E rating which should be good enough for those weights.

 

[ktpauley]

285s are 33" tall and 235s are 31" tall. 265s and 235s are the same size. Keith

 

[RedTruck]

I think what Calvin is saying is with the 235's the sidewalls flex less and makes the load seem more stable. I have 235's 10 plys (load E) 3.55 gears and the 4 speed. I've done a fair amount of pulling with no problems.

Paul

 

[1350]

try 255/85/16 i have cooper st good tread and are true 33" and little wider than 235

 

[Gone Huntin']

Well, the gearing is what I'm concerned with. I'm wondering how well it'll tow with a 33" tall tire compared to a 31.7" (235) tire. I've towed my 20' gooseneck car trailer empty with it on the 285's and it would drop speed to 55mph on the hills.

 

[towcat]

imho, anything adding height will make a 3.55 work more.

 

[93turbo_animal]

imho, anything adding height will make a 3.55 work more.

agreed if its slowing down enough now to bother you then it will only be worse with anything taller

 

[82F100SWB]

On my truck, the difference between the 235's and 305's was pretty much negligible other than having to run a little faster to keep the RPM in the sweet spot. Without a turbo though, you may notice more of a difference.

 

[ghunt]

You can get 285's with an E rating which should be good enough for those weights.

FYI, a D-rated 285/75R16 will carry the same load (or sometimes more) as an E-rated 235/85R16.

 

[Cat_Rebel]

Ghunt has that right, don't go by the letter as much as just looking at the number. I have 265s on one truck & 235s on the other. I won't get anmother set of 235s unless it's for a dually, I just don't like the way they handle & doesn't seem as stable. My next set will be 285s just because I like the extra ground clearence off road but there is nothing wrong with a 265/75-16r. Lots of options out there for that size.

 

[Cheaper Jeeper]

I have four 235/85/16 Michelins on my duallies and a pair of 265/75/16 on the front. I'd have put 265/75/16 on the duallies too - but they would be too wide without adding a spacer.

Looks good and tows just fine.

 

[LCAM-01XA]

I have four 235/85/16 Michelins on my duallies and a pair of 265/75/16 on the front.

That's exactly what I'll be doing to mine soon, front is a bit marshmallow-ish with the e-rated 235s. How much spacer would be needed for 265s or 285s in the rear?

 

[Cheaper Jeeper]

That's exactly what I'll be doing to mine soon, front is a bit marshmallow-ish with the e-rated 235s. How much spacer would be needed for 265s or 285s in the rear?

Well, look at it this way...

You probably want to maintain the same amount of gap between the tires as you have with the (stock size) 235's right? As the tires get wider, 1/2 of the additional width sticks out past the wheel on each side, right? And that is true for BOTH of the duals. SO, the spacer needs to be equal to the additional width of the tires.

For example: 265's are 30mm wider than 235's, and 15mm of that additional width sticks out towards the inside and 15mm sticks out towards the outside of EACH rim. So with two of them side by side, to maintain the same gap between the sidewalls, you'd have to put a 30mm spacer between the two wheels. That's a spacer just under 1.2" wide...

285's would require a 50mm spacer - just a hair under 2". You probably don't have to maintain quite as much space between the duallies as what you have with the stock 235's, especially since putting them on the stock wheels is going to pull the sidewalls in a bit, but you probably can't reduce it by more than about 1/2" or so without risking the sidewalls rubbing against each other and causing a heat-related blowout.

Also, keep in mind that the lugbolts are only about an inch to inch and a quarter longer than they need to be to go all the way through the standard lugnuts. You might be able to get a pair of 285's on there with about a 1.5" spacer, but the gap would be pretty much at a minimum, and the lugbolts would just BARELY be long enough. So, I think that for practical purposes 265's are about the limit.