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AC Bingel
11-16-2003, 21:24
I own a 99 2500 Suburban. I am about to replace the 245/75/16's that came on it. I was thinking about going to 265 or 285's. I was told by one tire dealer that the 285's would not fit. Is there any difference in handleing or performance if I go to a larger size tire or should I stay with the stock size?
fogg65td
11-17-2003, 06:28
both the 285/75 and the 265/75 should fit without any problems. I ran 265/75 on 16x8 wheels with a slight positive offset and had no problems and now have 305/70 and only tweaked the t-bars a little more and trimmed the fender and bumper slightly. I have had my t-bars cranked a little before just to make the truck level, i think it was only 2 turns and raised the truck like and inch or so. But the bottom line is both should fit without a problem.
richard7
11-17-2003, 08:03
If you have OEM style 6.5 in. wide wheels, 245 is the widest recommended tires for them. I know people are putting 265 on them and they report having no problem. Maybe 285 is a little too much...
Phil Holmen
11-17-2003, 09:21
I am running 285's on stock wheels and have no problems ... wear is even truck rides nice... steers well..I have 2.5 inch blocks in the rear and turned the bars up to level the truck...
James Schaack
11-17-2003, 21:53
i'm running BFG Mud Terrains in a 265 on stock wheels w/ out any suspension modifications and i have no problems. i was curious what others have seen as far as fuel mileage after an increase in tire diameter. i have a 4:10 rear in my truck so i was hoping the taller tire would give me a little better fuel mileage. well, in fact the taller tires decreased my mileage by roughly 1.5mpg!!!! am i missing something here. is it possibly because of the more aggressive tread? just curious if anyone has any comments.

james
fogg65td
11-18-2003, 11:08
A guess for why you are loosing milage is with the bigger tires you are actually goin further than your odometer says. I noticed the same thing when i swiched tires but when i corrected my speedometer my mileage was back closer to what it was before. Just a obeservation that many people don't take into account.
James Schaack
11-18-2003, 15:14
fogg65td,

that is a very good point. i knew the final drive ratio would change but totally disregarded the fact that the speedometer would be off (some days i'm a little off myself, whew!) how can a guy go about correcting the speedometer?? thanks for the help!
fogg65td
11-19-2003, 06:09
James,

when the tires changed to a larger diameter the circumfrence also changed to a larger diameter changing both the speedometer and odometer as well as the final drive ratio since the spedometer/odometer takes its measurememnts at the transmission. Now with an increase in tire circumference you are going further per revolution of the tire. this causes the change in the spedometer, odometer and drive ratio. hope this all makes sense. I dont know how to change the the spedometer on the older trucks but on mine it was through the computer. Heres a link that might help you understand http://www.off-road.com/chevy/calc.html
And someone please correct me if i am wrong
James Schaack
11-19-2003, 08:24
fogg,

makes perfect sense. thanks for the website and the help!

james
G B Sisson
11-20-2003, 00:10
Hi I just posted a formula relating to tire dia on scooby's thread 'shuts off after 20 minutes' that is actually more pertinent here. Gary