gear ratio questions

[beardeddummy]

I ve searched all I can find is general charts. But I want to know from experience what's the lowest gear ratio I can run on my 97 z71 with 285/75/16 tires and not kill highway mileage.

 

[98_k1500]

What gears do you currently have?

 

[98sierra4x4]

I have 3.73 with 265-75-R16 tires and its nice and still gets 14 mpg to 15


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[RichLo]

I've had 4.10s on 31's (winter) and 33s (summer) and it was AWSOME around town but even with the 33s it was screaming for mercy on the hwy. Forget about doing anything more than 75mph with the 31's.

 

[98sierra4x4]

I've had 4.10s on 31's (winter) and 33s (summer) and it was AWSOME around town but even with the 33s it was screaming for mercy on the hwy. Forget about doing anything more than 75mph with the 31's.

3.73 would be good probably


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[beardeddummy]

What gears do you currently have?

I have 3.42 s right now at 70mph in OD it's running 17-1800 rpm

 

[RichLo]

3.73's would be about it if you do much hwy driving. Like I said 4.10's are awsome around town, you can drive agressively and the truck never needs to go above 2000rpm before shifting. But on the interstate its screaming along at 2500-3000+ rpm and popping in and out of torque converter lockup. Hope this helps, I've been there.

 

[beardeddummy]

3.73's would be about it if you do much hwy driving. Like I said 4.10's are awsome around town, you can drive agressively and the truck never needs to go above 2000rpm before shifting. But on the interstate its screaming along at 2500-3000+ rpm and popping in and out of torque converter lockup. Hope this helps, I've been there.

This does a lot. Any estimate on cost if I could find a rear axle and front diff in a junk yard. And is it rare to find a 3.73 truck with the g80 option

 

[atyates]

I got 285/75r16 and 4.30 gears. love it. at 70ph im at 2150 rpms

 

[Colorado2500]

I have 4.10s and 265/75/16s, and they're not too bad on the highway or interstate, about 2200 to 2400 rpms at 65-75 mph, and I can get 15 mpg consistently. 285s may be pushing it, but it depends on if you spend a lot of time on the highway or not. There are gear ratio/speed/rpm calculators on the interwebs that should give you an estimate on what rpms you'll be turning at whatever speed with your given tire size, transmission gear ratio, and rear-end gear ratio.