Gearing Question ??

[Rusty79]

Right now I'm rolling on 33's with stock gearing in my '79 40 (which is around 3.73 or so). Any how I want to upgrade my diff gearing. What I am trying to decide is whether I should go with a 4.56 or a 4.88 R&P ??? I am running a fairly strong stock 2F. It will let me do around 75mph on the freeways here in Salt Lake with out much trouble. I don't have any intentions on doing a V8 swap... I'm sure some of you guys can appreciate a good 2F. With changing the ring and pinion I am going to be puttin some 35's on as well (for street use). My idea is to also have a set of trail tires (37's) for Moab as well as the 35's for the street. A am wondering which gearing would work the best for this application. I do use my 40 as a daily driver but some month out of the year it sees trail time almost every other day.

 

[Poser]

4:88's, and be done with it.



Good luck!

-Steve

 

[LIVERUST]

I had 4.11 with 33"/ went to 35" and 4.88's still not low enough with the F engine and 3 speed. So now I'm doing the SM465 for the granny gear. If your going with 35's or 37's I would suggest the 4.88's for sure.

Troy

 

[Rusty79]

Gentelmen, thank you for your qiuck response. I woulnd't mind hearing what type of setups that you both have (anyone else also) and what kind of sucess, how you like it, how it drives (highway and offroad), max speed, etc. The reason for my post is that I had been told in a conversation a while back that you just couldn't have realistic highway speeds with a 4.88 set up powered by a 2F. Granted a 2F is not a V8! How ever I think that my motor has more power than my friend had giving credit too.

 

[DieselFJ]

It is not necessilary a power issue, but a engine RPM issue. As you get larger number gears in you axles, your motor will need to run at a higher RPM to get to the same speed. If you start adding larger tires you reverse that situation. The idea is to get to a comfortable gearing. If you liked the way your 79 felt on p235's with 3.73, the you will need to get back to that ratio. For every 1" increase in tire size you can jump .10 in gearing and be the same ratio. So if you are running 33" tires, and 4:11 gears it would feel similiar to the stock setup(RPM, Power etc...) With a stock 4 speed and 35" tires I would run a set of 4:56. Your RPM's would be a little higher at 65, but you should be OK. By the way, your power issue would be running a 33" tire with the 3.73. If you can do that as well as you say, you do have a strong motor, the real test, is see how fast you can go up Parleys Canyon to Park City

Thanks
Scott

 

[Poser]

My 69-40 is this...


1982 2F, Weber 38, headers, DUI HEI unit, SM420, three-speed cruiser case(today), 4:88 axle gears in the Dana 60's front and rear, turning 42" Swampers...Crawls al right, rolls down the road al right too...will cruise at 75 no problem...

 

[Rusty79]

I can roll on up to Park City doing around 50 to 55 (speed between Lamb's canyon and the summit) with my truck loaded w/ a weeks worth of camping gear w/ the 3.73 gears and 33's. Last June the wife and I drove it from Salt Lake to the Bear River Station (Uintas), back to Kamas, over to Duchene, down to Price, through the San Raphel Swell (Black Dragon trail), over to Moab (did Kane Creek), and back home to SLC all in five days. My wife is pretty cool to take a trip like that for our first aniversary. Not to mention that we did the trip with the Hard Top and the doors removed. Any how it was only slow in places like Parley and Soilder Summit. The Cruiser ran like a champ though. I don't know how confident the wife was about us making it home. I think she thought I was taking her on some Kamakazi misssion. Good times.

 

[LIVERUST]

I agree about the power and highway speed. It's not about the power or lack there of, it's the high RPMs. My decision came down to whether I wanted my cruiser to be more offroad worthy or more highway worthy. If you want to continue the family 500 mile weekend excursions the 4.56's might be better. If you want to crawl slower over the ledges and rocks with bigger tires the 4.88's would be better. I daily drive my cruiser too and around the city there is no difference at all.

Troy

 

[Poser]

Orion t-case....


Will get you pleanty of off road gearing...


-Steve

 

[DieselFJ]

Been there done that, my wife is now a cruiser fanatic, it was either hate it after some of those type of trips, or they are hooked. If you plan on doing trips like that, I would not run much more than a 4:56, and 35" tires. You still have a good controled ride, and your gearing will still be ok for highway driving. I would run 4:56 up to 37" tires. You will love the new re-gearing. Although your cruiser feels good and powerful right now, wait until you regear, it will feel awsome going over those long hill climbs up the canyon like soldier summit and parleys etc.... By the way, what color is your cruiser?

 

[Rusty79]

Right now its' white w/ a primer hood. This last fall I did a sort of Frankenstein tub rebuild. I welded in the firewall from my old body into a salvaged tub. I also sandblasted and POR15ed my frame, gave it a two inch body lift (Man-A-Fre), O.E. powersteering, and some rock lights mounted to the frame for night wheeling. I still need to finish up some minor welding and body work from the tub rebuild then I am going to repaint it the original Alpine White in the spring. PPG one coat acrylic enamel with a slight orange peel texture so new scratches won't show quite as good. I will probably post some pictures soon,

 

[Rusty79]

I was thinking more about the gearing thing and thought that maybe I should explain more about my drivetrain as it pertains to the gearing. My goal is the following; H55 tranny + AA Rock Box + Orion t-case. This is what I am going to do.... it's only a matter of time (and money of course). Maybe it would be a good idea to go with 4.56 to keep the highway performance. I am sure that the Rock Box or the Orion would more than compensate for the difference between 4.65 and 4.88. What do any of you think?

 

[haystax]

Ambitious goal, but save your money on the Tcase or doubler, who needs 250:1??

I'd say do the Orion OR the Rock Box - probably just skip those and go with Marlin's Toybox if I were you. I think you'll get more bang for the buck with a tranny or T-case/doubler upgrade than messing with your R&P ratios. Although 3.73s w/ 37s is probably not a doable deal.

 

[Poser]

I was thinking more about the gearing thing and thought that maybe I should explain more about my drivetrain as it pertains to the gearing. My goal is the following; H55 tranny + AA Rock Box + Orion t-case. This is what I am going to do.... it's only a matter of time (and money of course). Maybe it would be a good idea to go with 4.56 to keep the highway performance. I am sure that the Rock Box or the Orion would more than compensate for the difference between 4.65 and 4.88. What do any of you think?

So you going to stretch the frame 12" or so to give a workable, reliable rear driveshaft???

 

[DieselFJ]

Go with an h55f, and a split t-case with 3 to 1 ratio. Then run 35" tires and 4:56's, couldn't get much better than that.

Scott

 

[Rusty79]

The H55 is 4" longer than my four speed and the Rock Box is 5" long. Thats a 9" increase in my drive train. This I understand but if stretch the wheelbase 6 or 7 inches I think it is very doable. I don't think that I would have much of a problem with knocking 2-3 inches off of my drive shaft.
As of yet I haven't looked into the Marlin products. I am interested in seeing what they have. The thought of stacking the previouly mentioned components came about from talikng to Advanced Adapters. What I had wanted to do was mate the H55 to the Orion. Call me carzy but I thought it sounded like a cool idea. They said it could be done with mounting both to the Rock box. I am not looking for a 250:1 ratio (even though it would crawl like a snail) but it was more of the variety ratio options available. May be my thinking is WAY out side of the box. Anyhow all of your suggestions sound good. I am just curious to see what other people think! Thats why I am asking questions.

 

[haystax]

If I have to hear "outside the box" one more time, I'll probably puke. What is so "OTB" about stacking that kind of gear reduction together? Sure it can be done but I wouldn't exactly trust an AA salesman to make the decision to use two of his $$$ products in your application. If you're not looking for that kind of crawl ratio, why do you want to buy those two products - just to say you have them?

Not here to bust your balls but this sounds a little overkill to me, there are numerous ways to go about gearing, all of which seem more practical than the AA spec'd route you are leaning towards.

 

[PabloCruise]

Go with an h55f, and a split t-case with 3 to 1 ratio. Then run 35" tires and 4:56's, couldn't get much better than that.

Scott

What split-case has 3:1?

 

[DieselFJ]

Here is a link where you can get the 3to1 gears, they are actually 3.05 to 1.

http://www.marks4wd.com/lc-extra-low-tc-gears.htm

This is what I would like to do eventually.

Scott

 

[Rusty79]

Haystax your're not busting my balls. I was being sarcastic with the "out-of-the-box-thinking" comment. Can any one on here think of a way to mate an H55 to an Orion t-case. Those are just two components that I would like to use together. Whats up with the Volkl avatar? Do you ski? My buddy got a pair of V-Pros last season and loved em. I would like to buy a pair of Karmas for next season. Any way...... What kind of drivetrain setup do you have going?