going lower then 3.54???

[TxDieselKid]

Would if be to bad if I went to a lower grear then a 3. 54? I notice from this chart that a 3. 42 gear is around right? I NEVER tow, just want some better milage and still be able to drive around 75 on the highway. What would this do to acceleration? It would slow it down wouldn't it?



TIA,

Andrew

 

[Posm]

I don't believe that this would help. I changed to 235/85/16 tires from 245/75/16 and that would have the same effect as 3. 36:1 ratio. I did not experince an increase in mileage and did experince a decrease in off the line power. In all the posts that I have surveyed, I do not believe the 4. 10:1 trucks get worse mileage than the 3. 54:1 trucks. I see wind resistance as a bigger factor. I can change my mileage 20% by going 73 as apposed to 68. Some of the change may be RPM or "sweet spot" related but the tire size change makes me think it is mostly wind resistance.

 

[klenger]

If you do the math on a purposed savings of %10 (which I'm sure you would not get), it would take over 100,000 miles to recover a $1000 investment. If you have a 4x4, you have to do two axles. All that just to give up some performance does not make sense. The only advantage I see is that the CTD runs quieter at lower RPM's.

 

[MCummings]

Two ways to do the rear-end ratio change,, ok, three... kinda. .



You can go for an Overdrive unit,, I think the gear-Vendors or US Gear would do you good. (About $2K Good )



You can change your rear-end ratio,, I was, and still am very interested in doing this.

Give reider racing a call http://www.reiderracing.com/

They have complete Ring&Pinion sets for you.

The 3. 23 ratio is available for Dana 80,, you have a Dana 70, not too sure what is actually available,, but it looks like a ratio between 3. 00-3. 08 and 3. 42-3. 45 is available.



The best South Texas way to do it.....





BIGGER TIRES!! This would actually be nearly the same price as a gear change,, although not as permanant. . If you go for (_big_) tires it would still probly be cheaper. If you want good MPG still,, go for a tall skinyy tire,, Like a 255/80 or the like. .

The first number, "255" is how wide the tire is,, the second number is a ratio. "80" means the sidewall is 80% of the Tread area ( 204millimeter's tall )



So if you are looking at metric sized tires,, they go like this. .

245/50

245/75

245/80

245/85

All those sizes have the same width of rubber touching the ground at all times. (There are slight differences between brands and "models")



245/50 has 122. 5 millimeters of sidewall. .

245/85 has 208. 25 millimeters of sidewall. .



The "85" size tire will put your truck 42. 88 millimeters higher than the 245/50 size tire,, even though the tire is still the same width.



Hope I didn't bore you to death,, hope it helps.



MerrickNJr



EDIT: just saw that you linked to Rieder racing,,, maybe next time I'll pay more attention,

 

[Mactruck]

MHO, You are going to miss the sweet spot (1800 - 2000 RPM) by reducing your ratio. If anything go with the bigger tires ( Cheaper ).



Me personally. I'm looking at getting the 3. 73 ratio that Garrett (Big White Beast) runs on his truck. I have the 3. 54 ratio running 295/75R16's and feel a little lag in the transmission when it shifts.



It is a debate though considering the cost to change a ring & pinion on a 4X4

 

[Mopar-muscle]

mactruck , if you DTTize your trans alot of that lag will go away ...



i'm thinking of changing from 3. 54's to 4. 10's , i knew i should have ordered it that way .



the 3. 73 is a possibility , but i have 4 wheel ABS and i don't think abbot has the speedo fix figured out yet ?????

 

[TxDieselKid]

well here's the idea...

The "Texas Tilt" as some call it is out beacuse of looks. The tires that I got just look too sweet to get an off-set. The Gear Vendors is out because of $$$.



The idea is to run about 1750rpm, at about 75mph. I figure that something in the 3. 43 range would be close. I have no want, need, or care to go to 3. 73 unless I start towing, which I doubt will ever happen. Maybe if I win the lottory and buy a CTD to keep as a track only truck, then 3. 73 would be good.



$1,000??? Wow, that's if you take it somewhere to get it done i would think, not that much for the do-it-your-selfer though huh?



Thanks guys, and just keep the thoughts coming,

AJB

 

[Ross]

gear swap

Unless you have experience in setting up ring gear and pinions, I would advise against it for the do-it-yourselfer. It's somewhat of a black art. Getting pinion lash just right is not easy, even if you have the right tools. Old timers that do it all the time can do it by "feel. " But even then, you need to use the marking grease to verify that the gear contact is appropriate. I have never done this, so I don't know all the details, but I have seen this done before.



My old friend is a certified master mechanic and builds some of the meanest race motors I've seen, and he sends his axle gear swaps to someone else to do. Something to think about. Just a little bit off of the proper set up and the gears will howl, whine, and sometimes munch themselves up in a few hundred miles.

 

[TxDieselKid]

Kung Foo Axles....

Well Ross, thanks for saving me a HUGE mess. That would not have been to good to see. They make it look so easy on Shadetree, and Horsepower TV.



I know that I can get someone from the TDR to help, Okie wasn't it TXRam who helped you put in a set of gears?



I just think that this would be the right deal for me, but I have been wrong before... ... "the truck will help me in milage so I won't be spending as much!" Little did I know about the BOMB bug then.



AJB