gearrrrzzz

[felskee]

i have 33s right now and plan to get 35s in the future. i still have these horrid 3 42s so before i get my new tires i need help on my decision on 456 or 488 gears?? how would it be with 33s and 488?

 

[JenneK]

Try a google search for gear ratio calculator. Determine where you want your target RPM to be for a target speed.

Let's say 60mph w/stock tires and 4.10 rear end gives you an RPM of 1950. If you like that RPM for that speed let it be the basis on what gear ratio you need for the new tire size.

Those 4.88s with your 33s will really wake your truck up! Right now you're suckin' wind. My basic calculations show your engine is turning around 1465 rpm at 60 in OD. 4.88s will put it close to 2100rpm. Right where you really need to be, IMO.

 

[SunlitComet]

absolutely horrible gas mileage. 33 and 4.88 gears sounds like a very bad combination. until you fix it your shift pattern will be out of quack too.

---------- Post added at 05:40 AM ---------- Previous post was at 05:33 AM ----------

why are you using stock sized tires but a 4.10 gear. is it not best to use the stock gear he has and compare it to new tire size and gear to see rpm/speed difference. between the stock build at a more realistic driving habit 70 mph(1848) and 33's w/4.88 at 70mph(2435) that is 587 rpm difference. 2435 at 70 mph is not good for highway mileage. but will be excellent for full time wot and mudding. a 4.1 would put you 2046 rpm and is an excellent balance between power and mileage. at 2435 at 70mph mileage will just be rotten. that would still give you a slight boost over stock setup and make up for tire/wheel combo weight.

perhaps you can be more specific if you want mileage, massive power with a loss of efficiency or a compromise. you did say you want more then stock but I don't recall how far you are willing to take it. or what duty you expect to put your suv thru. it will help in determining a better gear for your needs.

 

[purple 'hoe]

Again

4.56's. He'll have good power for mud with either 33's or 35's. 4.10's and 35's in mud is going to suck for him. He needs to figure out what he wants to do with this truck, BEFORE he start's building it.

 

[felskee]

its my dd. i go mudding whenever we get rain. i dont do alot of highway deiving 90% city and i never said i had 410s

 

[DirtyBlackHoe]

I would definitely NOT run 4.88's with 33's or 35's on the Vortech style motors. I had 4.88's and 35x14.50 grapplers on my OBS Tahoe and I hated it...sucked fuel like a son of a ***** and always felt like I was OUT of the power band. The OBS motors don't like to rev and have rpm's like the LS style motors do. I went with 4.88 cause I had a ton of weight added to the vehicle and planned to go 38's but I hated it with 4.88's and 35's.

 

[SunlitComet]

have you tried mudding in 4wd low?
or is it always in 4wd hi? comments? thoughts? likes/dislikes? whar gear do you set your tranny in or do you leave it on auto?

 

[99TanHoe]

I'll throw in my 2 cents, I just went through this decision myself and am pleased with the outcome. I bought a 99' with a 6" lift and 315/70R17's (34.3" according to the conversion formula) that hadn't been regeared yet, it also had 3.42 gears and was a complete dog.

I asked alot of questions here and did alot of research on the internet. In the end I went with the recommendation of the Off-Road shop and the Gear Company. Both of them said 4.56 for 34" - 35" tires. As others have said 4.88 would be too low. You won't need 4.88 unless your going up to 37" tires.

Right now with about 50% wear on the 315's I'm running about 2150rpm at 65mph, which is higher than what the gear charts claim but my tires are wore and tires are actually a little smaller in diameter than the tire conversion formula will tell you, even when they are new.

Today I was on the interstate and I was running 2300rpm with the cruise set at 71mph. At 75-80mph I was around 2500rpm. Power is great, it accelerates really well. With stock tires and stock gears you should be around 1800-2000rpm at 70mph.

My gas mileage has been running just below 13mpg with mixed driving and about 14mpg with the cruise set at 70 - 75mph interstate only driving. This isn't as good as I would like but compared to some of the mpg reports I've heard on this forum its really not that bad for a lifted Hoe with over-sized tires.

I'll probably go up to 35's when I buy new tires this fall. The 35's should get my rpm's closer to stock numbers and I don't think I will experience any power loss just stepping up one tire size.

Good luck with your decision. PM me if you have any specific questions. Like I said earlier I just went through the "which gear" decision process and I am mostly happy with the outcome.

 

[felskee]

@sunlight i never use 4low unless its monster hole.. But normal messin around i go in 4hi ethoer 1st gear or drive...
@tanhoe how much was your regear? What brand? Andy biggest question is hows the power?
roast em and beat someone stop light to stop ligt?

 

[99TanHoe]

@sunlight i never use 4low unless its monster hole.. But normal messin around i go in 4hi ethoer 1st gear or drive...
@tanhoe how much was your regear? What brand? Andy biggest question is hows the power?
roast em and beat someone stop light to stop ligt?

The gears and rear diff DuraGrip alone were $2700 parts and labor. I had the MagHytec installed at the same time so that was another $250 + $46 shipping, so the total job was a little over $2900.

The gears and DuraGrip were Yukon Brand.

The power is great, there's no comparison between the 3.42's and the 4.56. I cross a bridge over a river to get to work everyday, its about 150' tall, pretty much straight up and I can gain speed pretty easily. In my 95' TBI Tahoe with 3.73 gears and 265 tires, I had to really get into it just to maintain speed.

Haven't raced or roasted the Hoe and don't intend to. If I'm going to blow a rearend I'm going to do it in the mud. If I want to race I borrow my wife's F-150 Ecoboost, that baby will roll. 360hp - 420torque I already outran a 3/4 ton with a 6.0 and can't wait for some poor fool with a Hemi truck to challenge the Ecoboost. It will be really fun to embarrass a Sam Elliot truck with the little V6. It will be a beautiful thing indeed.