Oversize tires

[ejazz]

I am thinking of putting 285/75/16's on my '98 1500 4x4. It now has the 265/75/16's. Has anyone done this and did it have any negative effects on the shift points, overdrive, or anything else. I know it will affect the speedometer. Some of my buddies made the change on there Chevy's with bad results.
Thanks

[440Duster]

I don't know if this will help or not but i have a ramcharger with 33 by 12.50's on it and the shift points and overdrive work just fine. and if i'm not mistaken but a 285 tire is around 10 inches wide and about 27 inches tall but i'm no expert but it dousn't seem like it should have a problem at all. unfortunately that is all the advice i can give you but i hope you have good luck with it.

[scoutinkeith]

I have 265/75R16 on my truck now, and have also been thinking of changing to 285/75/R16 as well.
I went here http://www.dakota-truck.net/TIRECALC/tirecalc.html
and put in the tire sizes, and it says that the 265/75r16 is roughly 32"x10.43"x16 , and the 285/75r16 is roughly 33"x11.22"x16. these are just rough demensions, as actuail size will varry by manufacturer.
also, with the larger 285's, the spedo will read low by about 3.6%

sense the 285's are only about 1" taller, it shouldn't effect the shift points, but if it dose, if you have a programmer, or take it to the dealership, the computer can be adjusted for the new tire size, wich would correct any effects on the shift points.

[fredjacksonsan]

Also check out:

http://www.1010tires.com/TireSizeCalculator.asp

for more tire size calculations.

[HemiGottaLuvIt]

I'm running 285/70r16's on my 98. The tire calculators are great and give you good ballparks to play with. Like scoutinkeith says reality isn't always getting the memo about what the calculator says. My tires actual height 30 1/2".

I've noticed to issue with shift points as this tire isn't too much larger than stock.

Consider paying more attention to your steering clearance. The larger meats may rub when you make turns lock-to-lock.