I've bought myself a new 37 ft 5th wheel (4 slides) and I'm wondering about the size of my tires currently mounted on the truck.

The truck came stock with the 245 75R'sX16 and currently I have 265 70R X 17's so they are taller.

Question should I put the OEM's back on for the summer while towing the 5 wheel ?

Little concerned about the gear ratio difference towing in a hilly terrain but also wondering if it will put the truck in the right range for towing when not in the hills ?

Any comments ?

I've always had the OEM's on during the summer but before swapping out I thought I would ask if leaving the 265's on would be an issue ?

What is the weight of your 5th wheel? What is the pin weight?

Which tire has the most load rating? That would be my first deciding factor. You don't want to have a blowout carrying something that large.

I WAS in the same situation except I wanted to go up to 265's. Talked to several tire shops (not the big name one, local type) and explained what I wanted. They ALL said due to the high weight etc of the tow load stay with stock size.

The 265s are a bit too wide for the rim and could be a problem with the tire not staying 'flat to the road'. Going to 70 series it would be too squirrelly because of the taller sidewall.

Bill

If going up in tire size, go up in wheel size also. I use 265's to tow and they work excellent on my LBZ. I don't notice any power difference while towing my 5th, whatsoever. And I pull heavy, mines always loaded with water, supplies, quads, or my suzuki samurai. The larger tires ride smoother, and the mileage is exactly the same(9mpg towing). If you are looking for a larger wheel, take a look at a used set of hummer
h2 wheels(look in my sig). These can be had for next to nothing, and the stock center caps fit. Hope this helps.

I am running 285's and my trailer weighs well over 20k. You will have no problem with 265's.

Shoot- if you are really concerned then hook up the trailer and go for a ride. If you notice a difference (you won't) then switch back to the stock size.

Thanks for the reply's, I guess I wasn't clear in the first post.

I have my OEM tires and rims which are 245 75R 16's (hate the OEM tires but they ain't worn out just yet).

But I also have a and currently run a set of Bridgestone 265 70R 17's which I have mounted on separate 17 inch aluminum rims.

Both sets of tires are E load rating and I'm not worried about the load, pin weight or anything. I've towed trailers for years and know the risks of having low load ratings.

I had a 34 ft fifth wheel previously and always ran the 245's however since then I purchased the 265's and want to know if there would be an issue leaving them on while towing.

My concern is/was the change in gear ratio which I was afraid may cause a lack of power and lugging. Trailer weighs in around 16k ....

Not sure who gets 9 mpg towing, that sucks. I get around 13 - 17 with the 34ft trailer with the 245's.

IMO there is a noticeable difference in get up and go between the OEM donuts and LT265/75R16 tires when pulling my 14K fifth wheel. I am in the Seattle area so it is not flat going anywhere local or long distance... It still does the job. Is it enough difference to change back -no.

Thanks for the reply's, I guess I wasn't clear in the first post.

I have my OEM tires and rims which are 245 75R 16's (hate the OEM tires but they ain't worn out just yet).

But I also have a and currently run a set of Bridgestone 265 70R 17's which I have mounted on separate 17 inch aluminum rims.

Both sets of tires are E load rating and I'm not worried about the load, pin weight or anything. I've towed trailers for years and know the risks of having low load ratings.

I had a 34 ft fifth wheel previously and always ran the 245's however since then I purchased the 265's and want to know if there would be an issue leaving them on while towing.

My concern is/was the change in gear ratio which I was afraid may cause a lack of power and lugging. Trailer weighs in around 16k ....

Not sure who gets 9 mpg towing, that sucks. I get around 13 - 17 with the 34ft trailer with the 245's.

If you are getting that kind of mileage with a 16k # trailer you should switch back. Those are magic tires!:D

If you are getting that kind of mileage with a 16k # trailer you should switch back. Those are magic tires!:D

:exactly:

That's what she gets for mpg driving 55 - 60 mph, we don't have interstates up here in Canada where you can drive 70mph.

I did get 12.5 average all the way to Florida and back driving 70 - 75 mph and it was winter fuel in Ontario and the upper northern states...

I've found Driving habits have more to do with mpg than anything else maybe a good reason for the decent mileage numbers.

I average 21 - 24 iin summer when not towing.

When I first got the truck (bought off lease return) it got fairly lousy mileage but about 3 months after getting it I heard it start one night around mid-night by itself. Discovered that the remote starter had been programed to start every 4 hrs and run for a half hour.

Reprogrammed it and the mileage went way up.........LOL

Who would have guessed that was the issue....

Anyhow sounds like it is worth giving it a try with the larger tires and seeing what she does. If it don't work its only an hours work to swap out to the OEM's.

thx

Just wanted to put in my two cents worth about tire sizes. I had a 2004 CCSB gasser with 245 tires (stocks). When I towed my 33' trailer with that truck I experienced quite a problem with being blown around by semi's as they passed me or I passed them. I now own a 2004 CCSB diesel with 265 tires. Same body, same trailer, same hitch set up, same pickup cap. This truck towes completly different, the semi's or other RV's that pass me or vice versa do not push this truck around. The truck has plenty of rpm range with these tires -tows at 70 MPH good. There are only two things I can attribute the difference to, the tire size, and maybe the weight difference between the diesel and the 6.0L I load the back of the pickup the same and I load the trailer the same. I personnally think the difference is the tires. By the way towing very gently using cruise control religiously I only get 11MPG towing at 70. The trailer has a big flat front on it that just pushes air.

ill chime in on tires here..

my last camping trip of the season last year i was still in my crew F350 at the time.. 37 inch tires , 20 inch wheels.. i went back to the 265s i had on my stocker rims just prior to the trip.. asside from the power gain by switching to smaller tires.. i noticed no change in towing . Furthermore, the smaller 265s actualy rode smoother due to larger side wall..

the BIG BIG BIG thing you need to worry about when choosing tires , is the load rating. you could go through the hassle of swapping back to your smaller tires to find out the load rating is sub par for what your trying to do.. figure out how much weight will be on that rear axle and go from there i guess..

load rating is everything.


I run 285-75-16 BFG KM2s (10 ply) with zero issues so far. pulling a 32' GN with a heavy rig on it (5500# rig). that same setup will soon have a slide-in camper on it and I don't anticipate any issues there as well.

total weight should be no more than 12K

I ran 355/65/18's on my old Chev 2500 6.0L. I've both towed and had a slide in camper in it a lot, and it was the best ride I've ever towed with by far. I contribute most of this to the wide footprint which made it very stable at all speeds. As long as you have the rim width and the tires are rated properly, I say the wider the better as far as towing goes. Now I cant say much for mileage because they were massive tires, but they towed extremely well. Skinny tires seem to "float" much more IMO.

My current dmax has 285's and although I don't feel as "planted" or wide stanced as my old truck, they still tow very well with no problems. Plus the power difference makes me forget about tires :).

The right tires for your application is the key!

out here in CA...huge lifted trucks rockin 35 in and bigger tires, without regearing, pull bigger 5th wheel toy haulers that weigh much more than your 5ver.

you should not have a problem

I'm going to run the 265's 70R X 17 inch for a trip or two and check em out sounds like there will be no issues at all and actually with the added tread width it might actually ride better.

With the gasser I used to have tire diameter ment everything when pulling !

Thx everyone for the input.

I'm going to run the 265's 70R X 17 inch for a trip or two and check em out sounds like there will be no issues at all and actually with the added tread width it might actually ride better.

With the gasser I used to have tire diameter ment everything when pulling !

Thx everyone for the input.

Just FYI 265 70/17 is available as a stock tire size on LMM trucks, the LML's are gonna have even bigger options stock.

I have the 265 70/17 load E as stock, I've had no tire issues whatsoever.

I WAS in the same situation except I wanted to go up to 265's. Talked to several tire shops (not the big name one, local type) and explained what I wanted. They ALL said due to the high weight etc of the tow load stay with stock size.

The 265s are a bit too wide for the rim and could be a problem with the tire not staying 'flat to the road'. Going to 70 series it would be too squirrelly because of the taller sidewall.

Bill


Bill, you are incorrect on a couple minor points.

70 series is shorter sidewall than 75 series -- not taller.

265's (as in LT265/75/16) will fit on the factory rim and are within the recommended rim width range. However, he has separate rims for his 17 inch tires. So, there was no need to go there.

Many (if not all) larger LT tires have greater load capacity than the stock pizza cutters. Only bargain bottom "8 ply rated" tires will be less. Larger "P" series tires will have much lower load capacity. Maybe you were thinking about a P series tire?

:exactly:

Who in the hell gets 13-17 towing 16k............They must be majic tires;)
Do you hand calculate mileage....or Do you belive the monkey in the DIC crunching the numbers...........My DIC is of 4-6 mpg been that way since day 1.
Oh and you will be just fine with 265s as long as they are E-rated.

I'd like to get 13 to 17 with my 5er. I get more like 12-14, with a lot more 12.0-12.5, and I get about 18-19 empty.

I'm jealous.

Pretty much the average mpg towing the other 5'er being as this one has the same front end as the other one and is virtually the same other than a little longer at 37ft instead of 35 and a little heavier due to the length and the options...

Have got worse in a strong head wind but nothing grossly near what I got with the gasser !

It's stock and hasn't been played with and I'm pretty easy on equipment as I got all my ramrodding out of me in my drag racing days........LOL

As I said we ain't driving on 4 lane or greater Interstates at 70mph either...

Speed limits 50mph on most of the roads so we drive 58 mph...

Should mention I run Sunoco Gold fuel, whether it makes a big difference I don't know but I've been told it has a higher octane rating ???

I upgraded to the LMM 17" wheels and tires on my 2006 and noticed NO difference in towing a 36' toyhauler 5th wheel. After two of my fifth wheel tires blew within 100 miles of each other and the other two barely made it home, I replaced the trailer tires with my old 245/75-16 truck tires. An upgrade all around!

Bill, you are incorrect on a couple minor points.

70 series is shorter sidewall than 75 series -- not taller.

265's (as in LT265/75/16) will fit on the factory rim and are within the recommended rim width range. However, he has separate rims for his 17 inch tires. So, there was no need to go there.

Many (if not all) larger LT tires have greater load capacity than the stock pizza cutters. Only bargain bottom "8 ply rated" tires will be less. Larger "P" series tires will have much lower load capacity. Maybe you were thinking about a P series tire?

Opps, that's what I get for typing early in the morning...you are correct.

Damn, didn't see the 17incher...as Roseannadanna says, "Never mind."

Bill