Re-gearing - What gears?

[Thrill Seeker]

I run 38x14.50 and wanna make it easier to turn them and pick up speed since I wont ever need to or see me having to drive anything over 90 mph if that.

What gears are some of you with bigger tires running in front and rear and what would you recommend for me?

I don't even know how much the gears will cost or what brands to get. When I had my trans am I got factory gm gears because they were stronger.

I have heard with some suv's and trucks that had 3.73 and went to 4.10/11 got a little better mileage.

Any help and advice would be much appreciated.

[jamstoyz]

with 38's you should run 4.30's or even 4.88's
i run a 4.30 and my rear tire is about 32" tall. it revs a little high but not much. about 250 rpms more than 3.73's
i like the 4.30 a lot. when i had my old truck with 38's, my guy told me to run 5.13's but thought that was high. he said it would put my rpms about normal.

[storkerlovr]

id go at least 4:30

[Thrill Seeker]

So min. of 4:30 to help and maybe a little lower gear than that. Appreciate the info so far.

[07stroker]

I think a 4:56 would be better for 38 inch tires

[Thrill Seeker]

Originally Posted by 07stroker

I think a 4:56 would be better for 38 inch tires

Even on highway and freeway?

[jamstoyz]

Originally Posted by Thrill Seeker

Even on highway and freeway?

yes cause it will relieve a lot of stress off your motor and tranny and will put you closer to your correct rpm's and speedo being right. 6.0's have a higher redline so a bigger gear than a 4.56 would be ok on the e way. like i said, my 4.30 revs at 2250 at 70 mph on the e way and my rear tire is about 32" tall

[OregonStroker]

ya 4.56 is nice. I run them w my 37s. You can still do 90 if you want. you will beturning like 2600 rpm. made big difference on exhaust temps and is easier for the internal trans parts. Pretty good mod.

However my speedo is still off about 10mph. didnt change it at all. I thought it would but it didnt.

[Thrill Seeker]

I was looking at my rpms this morning while driving at 70mph and it was about 1750 give or take and 75mph was about 1900 give or take. I'm not sure what gears are in the truck right now. There has to be a way to figure it out without tearing it apart right? I don't know if I wanna be running that high of rpms with 4.56s and with more highway driving, 4.30s sound more efficient to me.

[Raul@Stealth Automotive]

i would go 4.56.... its not too low and not too high... if you go too low like 4.88 your rpms at 70mph will be at around 2100-2200.. you want to keep that close to 2k as possible or you will get crapy highway mpg...

i can get you a deal on a set of gears and master install kits if you want...

-Raul