Outer Limits 4x4 Board

i got a gq lwb with a 5l v8 in it currently running 33'' an 4.11 diff gears. im soon going to 35'' and want to no if the highway fuel useages would change much.
it does a 100k at 2450 rpm with 33''. the 35's would drop it down to about 2050 so its less rpm but more load on the motor. i no around town it would use more. what rpm would it do in 4th gear at a 100k with the 35's for when im towing heavy loads

Towing heavy loads should not change the overall gearing (ps your revs will be 33/35 x 2450 = 2300 rpm, not 2050)

My guess is it would be barely noticable, however if you have an automatic it may kick down more or lose the TC lock-up more often.

After correcting for speedo differences probably add anothe couple of percent to your fuel consumption.

i no towing wont change the gearing but when i tow big loads i use 4th gear not 5th (manual) 2350 would have to b 4th. a tire 2 inchs bigger would drop the rpm a lot more (in 5th) on the highway 100k

I dont think 35"s will drop RPM as much as you think.
the change in gearing will only be around 5% from 33" to 35" tyres

if it is doing 2400rpm at 100km/hr now, it will only drop to around 2250-2300rpm