245/75/16 E tires to 265/75/16 E tires

daamac wrote:
Is there any reason not to change from 245/75/16 E tires to 265/75/16 E tires? I'm considering doing so due to the increase in load capacity from 3042 pounds @80PSI for the 245 tire to 3415 pounds @80PSI for the 265 tire.

I realize that the speedometer will read about 4% slower with the 265 than with the 245 tire.

IMO you are in reality gaining nothing and it's going to cost you $$$ in just tire costs. Your current tires, assuming they are the OEM size already handle your GAWRs and you have whatever safety margin there is there already. Getting more "SAFETY MARGIN" which is all you are really doing is not something you can quantify anyway so IMHO this is a waste of time and effort.

One generic thing you can say is that it will most probably be a negative towing wise since it will effectively lower your drivetrain ratio in all gears (read rear gearing) and while you probably can't quantify it, it is as closer to a fact than this thought of gaining some "EXTRA SAFETY MARGIN" is.

Larry

If you have dual rear tires make sure you have enough room between them for the
wider size. You do not want the sidewalls to hit each other with wider tires.

bobx2 wrote:

daamac wrote:
Is there any reason not to change from 245/75/16 E tires to 265/75/16 E tires? I'm considering doing so due to the increase in load capacity from 3042 pounds @80PSI for the 245 tire to 3415 pounds @80PSI for the 265 tire.

I realize that the speedometer will read about 4% slower with the 265 than with the 245 tire.

No reason not to step up a size. I run the 265/16 on my '09 with no ill effects. The speedometer is off by about 1 mph when I'm going 65 mph. Nothing to worry about there either. The tires will cost a little more, but they will carry more, as well as look much better. Go for it.

X-3 I have run the 265's for apx 36K with out any problem. I run the rears at apx 70 psi when unloaded.......

It's only the back 6830 that matters. :)
The speedo/oddo is a different matter. On my Ben years GM dually and Sub I had to use a tuner that could set tire diameter to correct them. On my current truck my shop foreman corrected them by using the number of tire revolutions per mile with the FCA scan tool. A tuner could probably have worked as well.
Other systems are affected if the speedo/oddo are off. I would strongly suggest correcting them if tire sizes are changed.

My 2001 Ram came from the factory with the optional 265/75-16 E's. Love having 13,260# of tire rating on a TV with a GVWR of 8,800#, that is a safety margin!!!

Running 265's with no issues, even ran 285's for a while.

Jim...yes was am still a Boy Racer/GearHead/Wrench...till I die...

Am more outside the box than in...always...and never one to like being part
of any herd...

Understand that the majority or fat part of the curve are into weight ratings
for LT tires. On that, too many think their 'trucks' are 'cars' to boot these
days. Fashion more important than function/performance of the towing kind

With the wider rims...get less tire sidewall bend back. Almost none to speak of
and is exactly what I was engineering for

Did make a discovery (mistake) with Michelin LTX-MS LT265/75R16E's...they are
both too soft & too many sipes on the tread, but their carcass design/construction
is pretty good. So good that with these wider rims...the sidewall to tread transition
has it way stronger & stiffer than I guessed

The tires wore out the two outer tread ribs...even aired up to 80PSI.

Current Dueler Revo's of same size has a more compliant transition area for that
sidewall issue. They are wearing evenly at 80PSI on the same rims with the same
type of driving style. They provide much, much more traction than
either of the LTX-MS or LTX-AT

Most here would consider my setup 'harsh' with no ride quality at all. Okay with
me, as that is what I engineered my setup for.

My advice is for those or the common 'in the box' folks. Why recommend the tire
OEM's width range. Engineered for both a min level of performance...balanced with
ride quality


Lower aspect ratio along with the required wider rimes allows this type of
driving
aspectratio sidewallstiffness widerrim trackperformance torsionalrigitity


Along with the engineered 'less sidewall bend back' comes higher performance
of the kind I like (covet)...and yes, do that often in most all my vehicles...except
for the Odyssey. Why?...both love to and lets me know my vehicles

Reduced slip angle, quicker response from steering input to actual change of
direction, less transitions in a quick right/left/right/left type of maneuver


Again, most won't understand both the technical aspects, nor understand the
why on a truck....heck...even on their cars...

Grit dog wrote:
Thanks for all that Benk. Would think someone as knowledgeable as you would know 10" wide rims are too wide for 265 tires.......
To the OP, you'll be fine. More than likely the speedo is calibrated to larger tires anyway. Every work truck I've gotten with the little oe tires on steelies has read fast and going up a couple sizes got the speedo close to actual speed.

Ben ,as some of us were probably boy racers when we were younger. As some type of racer we played around with narrow and wide rims trying to get a particular performance from a tire on dirt or paved tracks. These vehicles had nothing to do with carrying weight.

Now when we move into the trucking world were more concerned with proper tire/wheel match for best load carrying performance and less stress on the tire.
A load carrying tire is happier when the rims width closely matches the tires tread width.
A 265/75-16 or 17 tire may have a tread width up to 8.2" wide. Some of GM OEM 16"-17" truck wheels are only 6.5" wide. Not the best idea for a load carrying tire. I've tried the LT265/75-16 E on 6.5" OEM wheels on a '92 chevy truck with terrible handling and wear issues.
Tire makers show a rim width range for a particular tire. One tire maker shows a 7"-9" wheel width recommendation for a tire with a 9" wide tread. A 7" wide wheel would not be a good idea for a tire with a 9" wide tread whan carrying heavy loads.
Just be aware of tire tread width/wheel width fitment when it comes to tires that carry heavy loads. Yes it matters.

Just an FYI, I run 265 Hankooks. Very strong tire, probably a little too aggressive as they make a bit of noise going down the road, but it makes much more sense to run something larger than the oem tire on a 2500 truck. As far as the speedo, at 55mph my gps is reading 51mph, so there is a substantial difference when I calculate my fuel mileage at fill ups.

Thanks for all that Benk. Would think someone as knowledgeable as you would know 10" wide rims are too wide for 265 tires.......
To the OP, you'll be fine. More than likely the speedo is calibrated to larger tires anyway. Every work truck I've gotten with the little oe tires on steelies has read fast and going up a couple sizes got the speedo close to actual speed.