New Gears

[Guest Riggs]

well i have 3.42's in my truck right now and get horrible gas mileage. so i was thinking about getting some Richmond gears from summit.i was looking at the

 

GM 10 Bolt 8.5"

1.625" Diameter

4.10's

30 Spline

$181.95/ Each set

 

now i almost never go on the highway and is almost 90% percent city. i want to et 35" or 36" tall tires that are 12.50 or bigger wide. so if i go from 3.42's - 4.10s will it make that much of a differnece or would you suggest going to 4.56's??

 

How many MPG's do you think i would gain after a re-gear? im getting 7 now...

 

BTW in summer i will be adding headers, underdrive pulleys, and a open element k&N filter..

[2000DV4.8]

well i have 3.42's in my truck right now and get horrible gas mileage. so i was thinking about getting some Richmond gears from summit.i was looking at the

 

GM 10 Bolt 8.5"

1.625" Diameter

4.10's

30 Spline

$181.95/ Each set

 

now i almost never go on the highway and is almost 90% percent city. i want to et 35" or 36" tall tires that are 12.50 or bigger wide. so if i go from 3.42's - 4.10s will it make that much of a differnece or would you suggest going to 4.56's??

 

How many MPG's do you think i would gain after a re-gear? im getting 7 now...

 

BTW in summer i will be adding headers, underdrive pulleys, and a open element k&N filter..

 

 

For 35" tires, 4.56's would be much better. They will put less stress on the transmission, and since you don't drive on the highway much, the lower gear ratio will increase the driveability of the truck a lot.

[todoubled05]

Riggs, lol i cant help you but....... 7 mpg??? damn son.

[Guest Riggs]

Riggs, lol i cant help you but....... 7 mpg??? damn son.

 

well i have really bad gears... 3.42 tring to turn a big tire, not so much hieght but i have a really wide tire...

so now that i know i wont be driving my truck all summer.... i think its time to re-gear so next school year i can start saving money.

 

i already did the math

 

Rounded things off...

 

say i got 8 mpg

200 Miles per tank now

so if i got an extra 2 mpg....

 

thats an extra 50 miles

so now that i get 10

 

50 / 10 = 5

5 more gallons it would equal out too so i would save 20 dollars per tank so in 15 fill ups i could justify the cost of the new gears. and filling up 3 times a month it would pay off in 5 months..

 

alright back to the question please.. 4.10's or 4.56's?

[GatorFan]

I bet the truck is going to look great when you get it all done. I would go with the 4.56s as well. BTW, what name brand are those tires you have on their now?

[pj5454302]

if you arent doing much highway driving i would go with the 4.56. go big or go home!

[thecraft]

With 36" tires and 90% city driving, I wouldn't consider anything less than 4.88 gears, actually. Maybe even a 5.13 (??) ratio...

[Guest Riggs]

now thats pushing it a little i think.... i might as well go with 4.56's since i dont do any highway driving...

[pj5454302]

the lower the gears the more power you will have off the line.

[pj5454302]

enything higher than 4.56 is overkill if you ever go on the highway.

[Guest Riggs]

Alright i found a calculator and i punched this in a calculator i found on the internet and i came up between 4.10's and 4.56's so im still a little undecided but i figure i might as well go with 4.56's as i do a lot of stop and go the roads i typicly drive on are country roads and im going about 65 tops on all of them roads.... so thanks guy but im going to go ahead and get the lower gears as my tranny temp gauge also shows its working pretty hard since in a 7 mile drive to school it gets up to 150-200 degrees lol

[Ranger]

4.10s would probably be better, there's a cutoff in gear ranges and anything higher than 4.10 would require a new carrier which is extra $$...Are you gonna shove a locker in it too?

 

As for tire size, I'd guess 245/75r16 or 235/75r15 depending...It might've come with a 265 series tire but I'm not real well-versed on that year range but my buddy's 91 GMC 2500LD has a 245/75r16 spare tire.

[pj5454302]

from the factory it came with 225/75-16

 

 

Original Equipment Size 2: 245/75-16

[thecraft]

now thats pushing it a little i think.... i might as well go with 4.56's since i dont do any highway driving...

Not really, 4.88 might be a little much on the highway but they won't kill your city mileage. They will give you a little extra edge over the 4.56 gears when it comes to moving those big tires. It's not just the diameter of the tires that is increasing, but also the rotating weight and extra traction of a wider tire. All of this puts more load on the engine and rest of the drivetrain.

 

Punch in the numbers at www.4lo.com. If you're between 2000 and 2400rpms at 70mph in overdrive (0.7), then you should be fine. [EDIT] Sorry, it took me a long time to post. I didn't read a your last reply.

 

If anything, I definitely would not put 4.10s in there. 1875rpms at 70mph in overdrive is pathetic.

[Ranger]

4wds do tend to come with bigger tires, especially on the 1/2 ton models.