odin1954

I got a 96 with 310-70-16 tires 5'turbo back, S&B cold Air ,trans just upgraded and 410 gears 4x4 what should i be getin ? I think its only 12 to 14 hyway

TxDiesel007

Dont u mean 315 tires?

never heard of 310's anyways, again, what factors, extended cab? regular cab? does it have bumpers, headache racks, tool boxes? all of these factors add up. But to give u a ball park figure on mine, extended cab long box 4wd with a five speed, i get about 17-18 mpg city and about 21-22 highway driving the truck easily, nothing over 2K RPMS, at 85 mph my mileage drops to about 16-17 highway.... and i have 355 gearing.... I have seen some regular cab 4x4s with 355's get in the 18-20 mpg range in the city, and even more on the highway, now with 4.10s, with the tires will compensate and you will sort of have a 3.55 rear end, so u could be gettin about the same, if not a bit less if your truck is a regular cab, if its an extended, might be about the same as mine...

Rick

odin1954

Hey rick they are 315s sorry thanks for the info I'm new to diesel HP oh ya my truck is reg cab long bed tool box thanks Arnie

fschiola

Are you accounting for your odometer being off when you calculate your mileage? If you had 245's on as stock, your speedometer is reading 13.1% too slow , or when your speedo is reading 60 mph you are actually doing 67.8 mph.

fschiola

I'm sorry, I used the wrong tire size on my calculations on the above post.

The correct information is:

If your speedometer has been calibrated for 245/75 R 16 (30 x 9.65 x 16) tires, replacing them with 315/70 R 16's (35 x 12.40 x 16's) would result in the speedometer reading low by 8.67%.

Same as with the speedometer, if your odometer has been calibrated for 245/75 R 16 (30 x 9.65 x 16) tires, replacing them with 315/70 R 16's (33 x 12.40 x 16's) would result in the odometer reading low by 8.67%.

As far as gearing goes, if you have a 4.10 rear end and 245/75 R 16 tires (30 x 9.65 x 16), changing to 315/70 R 16's (33 x 12.40 x 16's) would be the same as if you kept your current wheels and tires but changed your rear end gears to 3.74's