Changing gear size

[TyCorr]

I will probably change mine since I hate seeing it rev so high when cruising 80 for hrs some times. The occasional buz to 100 makes it hit 3000rpm. But I probably shouldn't be doing that much anyway.

Thats exactly what point Im attempting to make....I would rather be able to kick off the overdrive on my old SD and turn 2400 going down the interstate than having it be there in OD...

I do agree that my 3.73's are a little under but with tuning and a decent charger(im running a 38r) the truck makes boost before I even noticed anything deficient in the gearing. If Id put on my big boy pants and get myself some inj's, and finish my fuel system Id have enough power to completely disregard the fact that I have stock gears.

Erik, you think running 4.10's on my current setup 6"/37's would be ok when I switch to 35x13.5's/20x12? Ive ran stock gearing sooooo long Id hate to switch now only to find that 4.10s are toooo much with a 35.

 

[TyCorr]

THe best place for tire/gearing info is from a REAL 4x4 shop. Before I owned a diesel i was big into the offroad world.
Most of us were. Ive had a lifted truck in the garage since 1995. All gassers and two 7.3's.

First to get the best possible mileage you need to be in the powerband while at cruising speed. 3.73's have no place with a 40" tire. Neither does a 4.10 for that matter.
I dont think anyone is saying this. The conversation has gone fubar.

Second, i dont want to hear about people complaining of mileage while daily driving a "RACE" tune, running 40" tires and running 80mph. There are three things right there you can change to get better mileage.

QUOTE]

Some people get their best mpgs in race tunes. Im guessing its the way they drive it in that tune that makes the difference.

 

[Erikclaw]

Erik, you think running 4.10's on my current setup 6"/37's would be ok when I switch to 35x13.5's/20x12? Ive ran stock gearing sooooo long Id hate to switch now only to find that 4.10s are toooo much with a 35.

I think you will be fine. I just noticed today that my "37's" are really 36" tall. That fact alone I think I am going to 4.10's. sh!t, when they wear, they will be 35's. LOL Ty I think running 4.10 and 35's should be alright. As long as they are really 35" tall.

 

[Charles]

Some people like driving really slow tractors because back in their gasser days when they were actually making ~170rwhp they had to run over 5:1 ratios to get the little gerbil wheel spinning fast enough to move the truck.

Then they buy a diesel with a powerband ratio twice as wide, and a peak power rpm half as high, but it doesn't seem obvious that the final drive will need to be appropriately reduced?


Lastly..... if you plan to have any real fun with a truck, then some of the gearing options being thrown out here are just stupid. The last time I dynoed I was still making right at 600rwhp at ~135mph. This is why I've shown so many sports cars my tailights, whereas some of you tractor drivers couldn't outrun a golfcart.

Don't any of you actually like to haul ass? I mean my 550 has 4.88's in it..... but all it ever does is pull a trailer. And it's annoying as HELL even with just an empty trailer. For a DD???? Some of you are on crack.

 

[TANK'S 250]

I got clocked doing 127mph is my "big fat tractor".

 

[Charles]

I got clocked doing 127mph is my "big fat tractor".

I am just about running that by the end of an on-ramp. To merely be happy to get there at all is definitely the mentality of a tractor driver, lol. Around 120mph I'm just getting into peak power in OD, not straining toward the limiter.

 

[TANK'S 250]

I am just about running that by the end of an on-ramp. To merely be happy to get there at all is definitely the mentality of a tractor driver, lol. Around 120mph I'm just getting into peak power in OD, not straining toward the limiter.

I am very happy with it.....are you running 40" tires during your "on-ramp runs"?....


Is my truck fast?....depends what a individual considers fast..

....against a 400hp Porsche on the street?.....no..
...against a 1,200hp Ford rolling on 22's and 35's...nope..
...against a 1,400hp Dodge race truck ...nope..

But take those same vehicles...I'll smoke them all day long through 1/4 mile of 2' deep mud....and still drive 1,100 miles to take the entire family to Disney World.

Does my truck go just as fast as yours in a 65mph zone?......yes.


Fast trucks do good during 1/4 mile runs ...but what good is all that HP the other 99.98% of the time?

 

[TyCorr]

Fast trucks do good during 1/4 mile runs ...but what good is all that HP the other 99.98% of the time?

Better driveability. Theres no law that says you have to upshift at any particular rpm. If you need power, you've got six chances to find the right combination of power vs speed. An automatic is even more adaptive during driving. Those four gears can be split constantly, without limit...

Like I said I wouldnt go any lower than 4.10's.

 

[White_monster]

When I geared my offroading truck I took the approach Tanks thinking about due to the nature of going slow and needing the off idle performance of highway drive ability. For highway gears I suffered a lose on the bottom end, can't notice it but maybe the trans can, and went higher gears for better highway drivability due to spending most of the time there. Just my opinion thou. Gear your truck to what you use it for.

 

[Smokin_Joe]

I love my 3.31's on my truck. I picked up 3mph at the track too. Although I have destroyed (4) 5R'S after the gear change racing the truck.

 

[gman1]

I love my 3.31's on my truck. I picked up 3mph at the track too. Although I have destroyed (4) 5R'S after the gear change racing the truck.

What size tires?

 

[Smokin_Joe]

33''

 

[TANK'S 250]

33''

LOL LOL LOL...read the OP's first post...he's getting 40" tires...if he put gears that tall in his truck...it wouldn't make it out of a parking lot before roasting the torque converter or tranny...LOL LOL LOL

 

[TyCorr]

40's are over and done....

That was sooo five years ago...


Im running 35's and 37's from here on out.

 

[TANK'S 250]

40's are over and done....

That was sooo five years ago...

I agree....46's are the new 40's...only going bigger from here....

....GO BIG OR GO HOME!

 

[Jeff@Spartan]

Go fast or go home!

 

[Charles]

I beat a Mercedes C63 AMG with exhaust from 70 to 80mph roll-ons twice in a row until I had a couple lengths and he lifted at ~130 to 140mph. I did it while riding on 37" tires with my STOCK 3.73 gears still putting down a little over 600rwhp at that ground speed.

Only problem I had on the on-ramp with the 37's was traction. The toyo AT's sucked.


No diesel truck will ever outrun that car with a 5+ R&P set. Ever. Not even close.


Just so you know.... some of us actually put it on these guys. The ones of us not daily driving tractors. A 400hp porsche??? No problem...lol.

 

[tbsimmons]

Beating a car from 70 to 80 does not say a thing. That could be from a number of things. You were not in OD yet and did not need to downshift. He had to down shift 2 gears and was not in the power band when he down shifted, etc.
The reason you are having traction problems is not power, it is gears.
When you dont have enough gear you shock the drivetrain more, ever heard of flashing a converter. That is what you are doing.
Daily driving a tractor, well when you use these trucks for what they were built for I would blow your drivetrain up I bet in one trip to the beach. Try towing 18000#, 13.5' fiver up a LONG 7+% grade and see what the tranny temp does with 37's and 3.73 gears.

So you think you can take a 400 HP Porsche, I doubt it. There is a thing that is power to weight ratio. Hell I doubt 600 HP Superduty would take my non-stock 96 Impala that is more than 1500# heavier with a little more than 400 to the wheels. Too much weight and rolling resistance.

 

[TyCorr]

Beating a car from 70 to 80 does not say a thing. That could be from a number of things. You were not in OD yet and did not need to downshift. He had to down shift 2 gears and was not in the power band when he down shifted, etc.
The reason you are having traction problems is not power, it is gears.
When you dont have enough gear you shock the drivetrain more, ever heard of flashing a converter. That is what you are doing.
Daily driving a tractor, well when you use these trucks for what they were built for I would blow your drivetrain up I bet in one trip to the beach. Try towing 18000#, 13.5' fiver up a LONG 7+% grade and see what the tranny temp does with 37's and 3.73 gears.

So you think you can take a 400 HP Porsche, I doubt it. There is a thing that is power to weight ratio. Hell I doubt 600 HP Superduty would take my non-stock 96 Impala that is more than 1500# heavier with a little more than 400 to the wheels. Too much weight and rolling resistance.

You havent been around long have you?

We went through this bs on the other site before. He HAS a 450 or 550. Its got inj's and a 38r in it as well. His 3/4 ton that he's talking about, up there, gets picked for work duty BEFORE the 450/550, aaaaand apparently when its not pinned to a trailer likes to eat expensive sports cars. Those 450/550's arent really any better off than a 3/4 ton except in stock form they have lower gears and stiffer springs. My 6" lift springs are stiffer than what they put in those 450's so thats a moot point. I used to pull a GN with a skidloader and about 5k lbs worth of chit everyday. Then on my way home that trailer would weigh 20k if not more. My truck handled en route load without squatting. The return trip it squatted but not too bad. Lift springs and tuning that include power adding and trans tuning make the need for a big heavy pig like the 550 obsolete for most guys. If I needed to run like that across the country hauling heavy loads Id get a Peterbilt or Kenworth. Ive been running 37's, 38's, and 40s with 3.73's for 265k miles. My trans slipped once last summer when it was 105* outside pulling a load but other than that Ive not had any trouble. Wore a rear R&P set out at 165kmiles. Im not seeing your point?!

Ill let him tell ya the rest...which Im sure is on its way...

 

[sirnunya]

I beat a Mercedes C63 AMG with exhaust from 70 to 80mph roll-ons twice in a row until I had a couple lengths and he lifted at ~130 to 140mph.

Beating a car from 70 to 80 does not say a thing. That could be from a number of things. .

They started at 70-80mph, and raced to 130-140mph+ before letting off. Not racing from 70mph to 80mph.