max tire size with 3.42's

will1551 · Post by **will1551** » Tue Jul 08, 2008 6:48 pm

What is the max tire size i can run while keeping reasonable milege/power with my stock 3.42 gears? reason im asking is im trying to decide if i want to add a body lift to my truck and either 31x1050's or 33x1050's, but im not sure i can afford new gears. btw right now i am running 30's w/cranked t-bars and a 1.5 inch aal and getting about 17mpgs w/ my extended cab 4x4.

Post by **HenryJ** » Tue Jul 08, 2008 7:42 pm

Stay where you are. That is about as good as it will get.

F9K9 · Post by **F9K9** » Tue Jul 08, 2008 7:45 pm

HenryJ wrote:Stay where you are. That is about as good as it will get.

Glad you chimed in there and glad I kept quiet.

will1551 · Post by **will1551** » Wed Jul 09, 2008 6:46 am

dang even the 31's are going to be hard on my engine w/o new gears!? ok what gearing are most people with 33's running? 4.10's or 4.56?

Post by **HenryJ** » Wed Jul 09, 2008 10:07 am

will1551 wrote:...what gearing are most people with 33's running? 4.10's or 4.56?

I would bet the majority have not changed gearing and are running 3.73

will1551 · Post by **will1551** » Thu Jul 10, 2008 9:25 am

ok so i might be able to find a blazer/s-10/sonoma in the junkyard with 3.73 gears and swap em out then

! Ive also been wondering how much my milege would drop with the addition of the 33's? I know it wont be near what im getting currently, i just want to know what to expect.

Post by **Walt** » Thu Jul 10, 2008 9:50 am

Just to give you an example: I have 3.73 gears, and I'm running 31x10.5x15 BFG AT/KO's. I might one day make the jump to 33x10.5x15's, but I'd never bother going higher, even if I could. IMO, you would probably hate the performance/sluggishness with 3.42's and 31's.

green02crew · Post by **green02crew** » Thu Jul 10, 2008 2:05 pm

See I have the 3.73s and they do well for towing and whatnot but I would rather not tow as well and gain fuel economy and just run a smaller tire as well. Haha wanna trade gears?!?

will1551 · Post by **will1551** » Thu Jul 10, 2008 4:27 pm

hell yeah i do!

bwenny247 · Post by **bwenny247** » Fri Jul 11, 2008 12:52 pm

I had 3.42's with 33X12.50 mud terrains. I did a lot to enhance power, and I never felt underpowered when accellerating. the truck always pulled hard.

millage was respectable for a lifted truck with 33's. as low as 12/13 MPG in the winter city driving, and as high as 19 MPG.....once, lol!

Power while cruising was good at 55-60 MPH. the truck would only downshift on really steep hills. It would pull up long flatter hills without a problem.

Power on the freeway was my biggest issue. being lifted, at 70-75 MPH, the trucks pushing a lot of air and with 12.50 tires you've induced a lot of rolling resistance. the truck would constantly downshift and I would sometimes drive in 3rd gear to avoid that.

I never towed with the truck so I have no input there.

again this was with a 33X12.50 mud terrain. Big heavy meats.
I often wondered what it would have been able to do if I followed the "Marvelous Mystery Lift" like Brule, no suspension lift and 33X9.50 alterrains. I think the truck would have ripped and had real respectable Milage.

just throwing my extended $.02 in

will1551 · Post by **will1551** » Fri Jul 11, 2008 6:07 pm

wow tthats better mileage than i expected. so far the only engine mods i have are cold air intake and tb mod. At this point all im really concerned about is whether or not my cold air will be a problem with the body lift and if i need the skidz/cut fenders in order to run the 33's? any feedback?

Post by **HenryJ** » Fri Jul 11, 2008 7:52 pm

You will need to cut fenders a little to run 31's comfortably. 33's require real cuts.
Do a little searching and reading. The Marvelous Mystery Lift shows what needs to be done.

I don't know what CAI you have, but the 1" TB spacer helps align things.

Try to keep the thread on subject, and feel free to bring an old one back to life.

If you are worried about power and mileage, go no further than adding a cat back. The 30" tires and 3.42 gears are as good as it will get.

If you have $5000 or so to spend on mods you can run 33's and maintain the stock mileage figures.

will1551 · Post by **will1551** » Sat Jul 12, 2008 9:41 am

Thats a negative on the 5000 to spend. Im 18 and just graduated highschool so funding is low. I have the k&n fipk or whatever its called. i also already have a cat back exhaust setup (2.25 inch pipes and a glasspack splitting into duals straight out the back)

Post by **HenryJ** » Sat Jul 12, 2008 11:31 am

Stick with 30's

Bigger than that is a snowball rolling down hill out of control.

Tires>spacers>springs>cutting>regear>thermostat>fans>alternator>radiator>programmer>the list just keeps going.

Be happy with it for a few years and once it is paid off and the new career has money in your pocket, then dive in deep.

will1551 · Post by **will1551** » Sat Jul 12, 2008 11:53 am

unfortunatly i dont think i can wait any longer now that the truck is paid off! the way i see it i can afford it if i do it in the order as follows: already have tb crank and rear springs (not boise spring works but will do), cutting is free so all i need is the bodylift which at this point is around 250 bucks, next would be wheels and tires ( planning on bfg at/ko on 15 inch black steelies) which would be about $1000 give or take which would be purchased around christmas, and i figure i can get by with my stock gears for about six months after that unless i can find an old s-10 or blazer in the local junkyard with 3.73's (and if im lucky a gov loc). this is why i like the idea of the mystery lift! you can just add to it as you aquire the parts. OK i have one more question for you henry j: i know i need to cut the fenders in order to clear the 33's but would it be possible to to run the tires without cutting for just a few weeks? or even a day or two?

Post by **HenryJ** » Sat Jul 12, 2008 11:59 am

will1551 wrote: i know i need to cut the fenders in order to clear the 33's but would it be possible to to run the tires without cutting for just a few weeks? or even a day or two?

No. Measure the wheel wells. They are only 31"
You would not be able to install the wheel and tire let alone turn the wheel.

will1551 · Post by **will1551** » Sat Jul 12, 2008 5:33 pm

ok. thank you for all the info, it has been extremely helpful! im sorry for all the questions, but id just rather find out now than in the driveway.

a2b · Post by **a2b** » Mon Jul 21, 2008 11:12 am

finding gears is the cheap part. even if you buy them new, they are cheap. the expensive part is the labor. getting someome to setup your gears is gonna cost a 800 bucks or higher. and you getting 3.73 gears out of a junk yard is a rather big job.

if you are going to run 31's to 33's....get the 4.10's.

i had 4.10's and 31's and it was a good combo for the stock hp.

kermit · Post by **kermit** » Tue Jul 22, 2008 7:28 am

I have 3.42 gears and I am running 33x10.5 ATs with a 2" body lift, tbar crank, BSW spring kit, and skidz cut out flares. The only performance mod I have is a drop in K&N air filter and cut out air box.

I would have to agree with bwenny247 on the performance. The truck will go anywhere in 4wd.
backroads are no problem. The 55-65 mph range is perfect, but once you go faster than that the truck goes 'gear hunting' on hills and on the interstate. I just drop into 3rd when that happens.

As far as gas mileage... it has ranged anywhere from 13 to 17 mpg, depending on where and how I drive.

I don't have the money to switch gears, but I have often wondered what kind difference it would make.

turkeestalker · Post by **turkeestalker** » Fri Jul 25, 2008 2:45 pm

a2b wrote: if you are going to run 31's to 33's....get the 4.10's.

i had 4.10's and 31's and it was a good combo for the stock hp.

May I jump in and ask what kind of mileage you got with that combination? Further, I've a buddy who does suspension lifts as a side job on weekends for local dealers. He is insisting that I just go with something like the BDS 5" rather than a BL. Claims he can get it for under $500 for me. How would things look with say 31's and a 5" lift with spacers? Would it look undersized in regard to the tires vs. the lift?

Dum Bass with a wicked thick skull, ( as many of you already know ), who doesn't know squat and is just asking yet another stupid question.

Post by **HenryJ** » Fri Jul 25, 2008 2:53 pm

turkeestalker wrote: I've a buddy who does suspension lifts as a side job on weekends for local dealers. He is insisting that I just go with something like the BDS 5" rather than a BL. Claims he can get it for under $500 for me.

Normally I would agree with him, but not in our case. I think your buddy will give you a different story on the price of the suspension lift when he does a little more home work. Then expect another $1000 involved for the installation. Half that if He works for free. Things like a front driveshaft, exhaust modifications, shocks, wheels, the list continues. The kit is not all inclusive.

31" tires can look "Ok" with the 5" lift if the rearspacing is right to widen it out proportionately.

Do some research and I think you will find the body lift to be a better choice in this application.

turkeestalker · Post by **turkeestalker** » Fri Jul 25, 2008 2:57 pm

Thanks Brule, I kind of suspected that he wasn't familiar with smaller trucks, let alone ours, which seems to have more limitations than some others might. I would however still like to know what sort of mileage gains could be expected from changing gears.

Post by **HenryJ** » Fri Jul 25, 2008 3:10 pm

Don't expect mileage gains. If I recall correctly his mileage dropped a little , but the power was great.

Can you say 4.10?

We may never know exactly how mileage was since I don't think he ever had the speedometer corrected for the gear change.

bwenny247 · Post by **bwenny247** » Mon Jul 28, 2008 1:41 pm

pic of a crew with 5" BDS and I believe 31's

http://www.bds-suspension.com/php/Produ ... .php?pid=2

a2b · Post by **a2b** » Tue Aug 05, 2008 9:06 am

ya i dont know the mileage but i drove it like a race car since i had all sorts of power that i wasnt used to.

to get the BDS 5" just to put 31's on is a bit overkill.

your buddy is one of those guys who rant about body lifts and says that suspension lifts are "better".

"better" shouldn't be in the vocabulary. one isn't better than the other, they serve different purposes and one can allow you to do thing that the other cant.

the way GM designed our vehicles are a staple reason of why body lifts can be very important and useful.

here are some other reasons, some jeeps use body lifts to tilt drive train to make the rear drive shaft angle better.

some toyotas used body lifts to lift their transercase up into the frame rail so it doesnt get hung up on rocks.

its about how you build it and the purpose you are building it for. not what is "better"

F9K9 · Post by **F9K9** » Tue Aug 05, 2008 3:32 pm

a2b wrote:..............here are some other reasons, some jeeps use body lifts to tilt drive train to make the rear drive shaft angle better.

some toyotas used body lifts to lift their transercase up into the frame rail so it doesn't get hung up on rocks.

its about how you build it and the purpose you are building it for. not what is "better"

Actually jeep does the BL for the transfer case as well. They also do it to install after marked fuel tank shields and to raise the the tanks. They also need the 1" BL for '03 and later Wranglers to do a "tummy tuck to get rid of that gawd awful "shovel that was the oem tc skid.

turkeestalker · Post by **turkeestalker** » Tue Aug 12, 2008 3:45 pm

Didn't the little 4 poppers with a manual tansmission come with 410 gears to give them more power? In light of that, a really stupid question would be.....are the internal units the same from front to rear? Yep, he actually asked!

a2b · Post by **a2b** » Wed Aug 13, 2008 3:01 pm

turkeestalker wrote:Didn't the little 4 poppers with a manual tansmission come with 410 gears to give them more power? In light of that, a really stupid question would be.....are the internal units the same from front to rear? Yep, he actually asked!

ya, alot of car makers put 4.10's behind their 4cyl motors and usually those motors are more of a higher reving motor than our v6's sometimes.

and no the diffs arent the same front and rear. the gears arent the same size and the diff parts are different.