Larger Tires

[kennedycpa]

I have ordered a 2002 2500HD CC 4X4.  Can't wait until it comes in.  I would like to get bigger tires like I have seen in the pictures people have posted, but I will probably have to wait until the 245s wear out.  I was thinking about going with the 285/75s.  I was just wondering what effect does the oversized tires have on your gear ratio?  With stock wheels and tires it has a 4.10 gearing, would bigger tires, in effect change the ratio, since one turn of the axel would now cover more distance and what effect would it have on gas mileage.  Please tell me it would give you better mileage!!!!  Maybe if it improves the mileage enough my wife would let me get the new truck and tires.........I doubt it.  oh, and keep posting the pictures, I love 'em, and it makes me want mine even more.

[RyanbabZ71]

Yes it will lower your gear ratio

 

4.10 will go to appx 3.9?

 

I know my 3.73 is now basically a 3.6 with the larger tires

 

As for the better milage i doubt that.  In theory yea but not in reality

[CMNTMXR81]

Well your speedo will be roughly 7.7% slower with the 285's vs. the stock 245's.

 

As for mileage, I really can't say I noticed a discernable difference, but to be perfectly honest, I don't pay much attention to fuel economy.

 

BTW, I also have 4.10's

[kennedycpa]

They can correct the speedo difference due to oversize tires at the dealership, can't they?

[RyanbabZ71]

Not on 285s

[Shaners]

They can correct the speedo difference due to oversize tires at the dealership, can't they?

You can correct it with an aftermarket programmer like the HyperTech.

 

Your fuel milage will appear worse than it is due to the larger tires.  This is mainly because you will actually be traveling more miles than your odometer records.

 

Most of the time when people up thier tire size, fuel milage suffers even when they factor in the difference for the larger tires.  This may be due to the raised height of the truck, or the extra rolling resistance of the bigger tires.