Mieser

The truck has the Getrag in it with stock 3.55 gears....

What gears would you run with true 38.5" tall tires ( 121" Cir )???





The truck isn't really getting lifted. The front is leveled with new springs but the rear is stock for a '92 with the taller block. The fenders are getting sectioned front and back ( 6" longer total ), the rear tubbed, and the front inner fenders redone.

Thoughts on gearing?

Ramrod90

It's a cummins, you don't need gears.....just more power LOL

apwatson50

Depends on what you're doing with the truck, if you're going to rock crawl with it, then really really low, but otherwise, i'd say 4:10's would work out pretty good for highway cruising and taking off.

Mieser

I have been running around with some 315/75r16s that came on the truck with the stock 3.55 gears.

Its been ok, but I think the gearing is just a little tall overall. I am always fighting between 4-5 and 3-4

I am torn between 4.10s and 4.56s

I have a set of 265/75r16s that I put on the truck last night with the stock rims. This is the first time I have driven the truck with stock gearing, I kinda like it. I will have to see what the mileage does?

Other options....

-4.30 gears would be a GREAT choice but I would have to swap in a D80 or something.

-4.10 gears and an early G56 looks like it could work out sweet.

DevilzTower

I'm digging this man, I like the look of no lift and big rubber. Start another thread (if you would care to) about some of the steps you're taking to fit 38.5s. It appeared when I first started to look at it that it just might be easier to tub the front and the back instead of messing with extending the inner fender in the front, thoughts?

Evil Ram

Im running 38's with stock gears and didnt feel to much difference between the stock tires-just a tiny bit loss of power. I plan on slapping on some 39.5's in the future, when i do im going with the 4:10's but then again i dont do any towing except for a couple quads in the bed. Honestly dont think 4:56's are nessesery with the kind of torque the CUMMINS puts out-JMO

Mieser

These tires measure out to a very true 38.5" tall. That is about what most 40s/39.5s are. I noticed a big difference going back down to the stockish sized 265s. The biggest difference is not having to fight between 4-5 on the passes around here. I live at 6500-8000ft and go up to 10000+ on the bigger passes.

4.10s would put me right about where I was with the 315s/3.55 combo. I think its within 50rpm total. These tires are also heavy (115lbs + wheel) so that is swaying me more towards the 4.56 route?

Remember it a Getrag so I don't want to abuse it too much in 5th. With the 315s/3.55 combo I really needed a 4.5 gear to avoid putting too much power to the tranny at like 1600-1700 rpm in 5th going up hills. 4th was just too low for the hills empty.

4.10s would sure be easier....

As far as my buildup. There is a hotlink in my sig line. I have a lot of information in that thread. Its a lot of work to section the fenders but I think its going to be worth it in the end. The truck will be stock height on basically 40s. The truck needs some bodywork and paint as you can see!

apwatson50

Have you turned the pump up at all? IF not do that, and a 3200 rpm gov spring, and then you can rev out if 4th more when you're on the passes, and just use 5th on the flat. This is of course with 4:10 gears.

Mieser

The engine is still bone stock except the previous owner hacked the exhaust just after the t-case......

After crunching some numbers in an excel spreadsheet I think 4.56s would be too low. That would be a 240rpm gain over the 315s/3.55 combo. Going from 315s to 265s was a night and day difference and that was only 180rpm gain.

For the next ten minutes I am going to lean toward 4.10s....boy that would be easy. 14 bolt rear and rear ford D60 low pinion gears....$200 bucks tops.

I wish that I could get 4.30 gears...that would be really nice. 4.30s and an early G56 is within like 10rpm of the drop from 315s to 265s. Even 4.10s with a G56 is looking pretty dang nice!

I was getting great mileage before with the 315s/3.55 combo. There is a log post from a 2000 mile trip I just took to pick up the shell and tires. I AVERAGED over 20mpg for the trip. Best of just over 24mpg.

I wish I could find a nice 8-10 speed with 4wd for the truck

The_Head

gear vendors?

MoPowa

thats bad edit!!
i'd like to do exactly what your doing only with airbags to help the ride. Nothing like a truck with big *** tires that you can still tolerate on the highway.....not have to be worried about tipping on a hairpin corner :P
But hey, to each their own right
Cant wait to see your progress

Mieser

I think after the truck is mostly done ( as far as weight changing ) it will get a set of Alcan springs to eliminate the rear blocks and level the front correctly. Alcan is pretty close to me so it should work out ok. Then maybe a set of 2.5" or 3.0 dia shocks and air bumps

Crazy Matt

Nice looks like my beater but nicer

Hutch

Here's a calculator that may help:

http://www.onlineconversion.com/bigger_tires.htm

Hutch

Mieser

It was actually in decent shape other than one munched fender, one bad door, the tailgate needed replaced, and its 3/4 covered in black roll on bedliner stuff. Oh yeah the interior was rattle canned red. The exhaust was hacked off after the T-case. The tires where almost bald. It didn't have a front driveshaft

It does run great though and gets 20mpg or better.

Its going to be pretty sweet if it turns out like what I have in my head. I'm not really dumping a ton of money in it, but lots of time and handmade parts.