GEARS GEARS GEARS, Please read before posting gear questions - Page 3 - Ford Bronco Forum
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post #41 of 330 (permalink) Old 12-28-2005, 05:26 PM
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Quote:
Originally Posted by dach
My stock FSB 351w is 31" with 3.08

I want to go 35" with 3.54

They are the same ratio but is it enough for the 35" or is it better going to 3.73??


Why in USA a lot of people go 4.11 / 4.56 ??

The 4.11/4.56 gearings allow for your motor to turn the 35" tires just as easily as if the bronco was driving on the stock tires. If you try and put on 35" tires with 3.54 gears you are going to get poor gas mileage and it will be much harder on the engine getting the vehicle up to speed. You will also not have any low end "grunt" when trying to crawl up rocks or steep hills, or even just getting up to speed on the highway.

Good Luck
And welcome to FSB, I don't think we have many members from Belgium

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Quote:
Originally Posted by 302 & 3-inline6's
my rear is getting real sloppy
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post #42 of 330 (permalink) Old 12-28-2005, 05:43 PM
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First off, a very handy tool one of the other guys here linked up the other day ... excellent rpm calculator for various gears, transmissions, tires, and transfer case combinations. It's the quickest and cleanest tool I've seen yet for checking engine speed for different conditions, plus the owner of the site has been very quick to add different transmissions on request.

Second -- usually your primary concern with gearing is getting your operating RPM where you want it to be at your usual cruise speed. This has a huge effect on both economy and acceleration. Most of the engines used in the Bronco will get best economy if they're turning around 1700-2000RPM at cruise, from what I've seen. Too low and you fall out of the powerband (and efficiency band) of the engine, and too high you lose too much to friction losses at cruise.

With your current gearing, 31's, and non-OD tranny, you're right about there with your current combo -- about 2000rpm at 60mph. Keep in mind, though, that a lot of the guys with slightly later trucks have an overdrive tranny, and get about the same operating RPM with 4.10's and overdrive, on the same tires.

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post #43 of 330 (permalink) Old 12-29-2005, 04:18 AM
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hem...
my axle code is 18 = 3.08
at cruise 65 mph = 2300 rpm.

It's C6 but non AOD. Chuck is maybe right with his explanations about AOD. In Belgium everybody cruise at 75 mph.

3.55 will fit good due to the same ratio or I put 3.73 due to the extra weight of wheels and tyres??


I think I'm the only one from Belgium. Because we are plenty of beer in Belgium.
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post #44 of 330 (permalink) Old 12-29-2005, 08:35 AM
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Stella Artois is a Belgian beer right?

There are a lot of breweries in Belgium for sure,
I would personally go with the 3.73's out of your two choices, but then again, if it were me I would go with the 4.11's. But that's because I use my rig primarily for towing and the trail. I don't cruise the highway in it daily so I didn't build it based on what Rpm's i'd run on the highway. What it comes down to is what you use your bronco for the most. Do you go offroad alot, or do you use it mostly for driving 75 on the highway?

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Originally Posted by 4x4bronco925 View Post
Oldyeller seems to be in-human. He never makes mistakes and is always right. Enough said.

Quote:
Originally Posted by 302 & 3-inline6's
my rear is getting real sloppy
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post #45 of 330 (permalink) Old 12-29-2005, 09:14 AM
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The most popular beer in Belgium is Jupiler. But we have a lot of special beer, 400 and more..

I use on highway and offroad.
I want to keep the same rpm.
The engine 351W is torky engine isn't?
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post #46 of 330 (permalink) Old 12-29-2005, 01:10 PM
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What do you prefer for your ring?

http://store.summitracing.com/defaul...=egnsearch.asp

Tell me what's the best quality but not too much for my FSB 35'...
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post #47 of 330 (permalink) Old 02-09-2006, 07:36 PM
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Try this chart from Jefff's Broco Graveyard catalog. http://www.supermotors.org/getfile/2...e/100_3392.jpg

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post #48 of 330 (permalink) Old 02-12-2006, 08:54 PM
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I thought I'd add a little real world info.

I installed 5.38:1 gears yesterday. I took a quick 2 mile run down the hiway moments ago to see what my rpm's would be like at 65 mph(mph measured with a GPS unit). Here's what I got:

Trandmission - e4od
Axle - Sterling 10.25
Gears - 5.38:1 Yukon
Tires - 38.5 x 14.50 x 16.5 TLS SX
Actual tire height - 36.5" (tires at 1/2 tread or so)
PSI - 25
Speed - 65 MPH
RPM's - 2400
Bling factor - can "cherp" the tires from a stop
Estimated milage - 6MPG city or hiway/3 gallons per mile in 4 low
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post #49 of 330 (permalink) Old 03-15-2006, 11:35 PM
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Quote:
Originally Posted by Chuck
First off, a very handy tool one of the other guys here linked up the other day ... excellent rpm calculator for various gears, transmissions, tires, and transfer case combinations. It's the quickest and cleanest tool I've seen yet for checking engine speed for different conditions, plus the owner of the site has been very quick to add different transmissions on request.
Is it me or are the HI / LO backwards? The colors on the graph? Says LO is faster than HI...

1979 Bronco Ranger XLT
351M
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post #50 of 330 (permalink) Old 03-16-2006, 12:44 PM
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Quote:
Originally Posted by Dave88LX
Is it me or are the HI / LO backwards? The colors on the graph? Says LO is faster than HI...
I know he does a lot of tweaking on the calculator, he may have flipped colors on something by accident ... I hadn't been paying attention to the range colors, so I hadn't noticed.

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post #51 of 330 (permalink) Old 03-16-2006, 01:28 PM
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how would one know what the gear ratio in an axle with no tag or vin code? (9inch from a 78 or 79 ford PU) supposedly the axle has the stock running gears but that could be several, i remember a thread awhile back about counting rotations of the driveshaft whille spinning the tires.....but searched an couldnt find it. am i just gonna have to pull the carrier?

ive had it in 4wd in deep mud with 40's an it never gave me a prob, but i have smaller tires now an im driving on the street more. if it snows i wanna have 4wd an light trail use but dont wanna break anything till i know for sure. im guessing 3.50 an compared to the 3.54 in front i dont think i should have that much of a problem.

i wanna be sure though, Thanks for any help i could get.

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post #52 of 330 (permalink) Old 03-16-2006, 06:02 PM
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No problemo. Method differs slightly depending on whether it's open or limited slip, so that's the first thing you check. Chock the front wheels and lift both rears off the ground, but leave it in park or in gear. Try to turn one wheel forward. If the other wheel turns backward easily, it's either open or a very worn out lsd. If it won't turn (or takes at least about 30lb-ft minimum to turn), then it's limited slip.

Now, with that out of the way, here's how you check the ratio for each.

Limited slip: Leave both back wheels off the ground, put transmission or transfer case in neutral. Use chalk or a crayon to mark the driveshaft and a spot on the tire. Rotate the back wheel forward, and count the number of full rotations as w. Have a friend count the number of full rotations of the driveshaft, and call that number d. Your gear ratio is d/w. You can get away with only rotating the wheel a couple of times, but the more rotations you count, the more accurate the results. For instance, I usually prefer about w=10, it's big enough to be accurate but makes for easy math. With my 3.55's, that means the driveshaft turns 35 and 1/2 times -- enough turns that you can actually tell the difference between a 3.50 and 3.55 ratio by whether or not the shaft makes that last half turn. If you only turn the wheel twice, you get 7.1 turns on the driveshaft. Can you really eyeball 0.1 turns accurately? If you counted 7 turns on the driveshaft, you'd get 3.50, but it's still "close enough" if you just what a rough idea of what a vehicle has.

The procedure for an open diff is very similar but just as simple. Put the tranny in neutral, but put the opposite wheel down on the ground. When you turn your wheel, since the other wheel is still, the diff will turn half as many times. This throws a factor of 1/2 into the formula. Again, counting w (wheel revolutions) and d (driveshaft revolutions), your gear ratio = 2*d/w. I usually use 20 turns of the wheel when I want to be accurate with an open diff. For my 3.55's, that means 20 turns on the wheel (with the other wheel on the ground) would give me 35 and 1/2 turns on the driveshaft again.

The cliff's notes:
Count w = number of wheel revolutions, d = number of driveshaft revolutions
LSD: Both wheels in the air, ratio = d/w
Open: One wheel on the ground, ratio = 2*d/w

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post #53 of 330 (permalink) Old 03-16-2006, 11:35 PM
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Thanks!!!

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post #54 of 330 (permalink) Old 05-17-2006, 05:17 AM
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Quote:
Originally Posted by Chuck
I know he does a lot of tweaking on the calculator, he may have flipped colors on something by accident ... I hadn't been paying attention to the range colors, so I hadn't noticed.
That was a small bug, sorry for the inconvenience.
I really appreciate feedback so I can make this little tool better.
Just let me know if something is off or missing.

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http://www.balsa.no/bil/calcs/gearcalc
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post #55 of 330 (permalink) Old 07-18-2006, 04:48 AM
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Realistically what can I expect to pay to have my bronco regeared from 3.5 to 4.56?

If I had all the parts what would/should the labor cost roughly?

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post #56 of 330 (permalink) Old 07-18-2006, 09:36 AM
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Quote:
Originally Posted by djdan
Realistically what can I expect to pay to have my bronco regeared from 3.5 to 4.56?

If I had all the parts what would/should the labor cost roughly?
If the axles were out, ~$125-225 per axle. If they are in, it could double. This will vary with the part of the country. If you search, you may find info on this since it has been discussed from time to time.

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post #57 of 330 (permalink) Old 01-16-2007, 11:19 AM
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If I currently have stock gears in my 96 bronco dana 44 front 8.8 rear w/ stock gears and I want to chane my gears to 4.56s will i need a new carrier for both axles?
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post #58 of 330 (permalink) Old 01-16-2007, 12:23 PM
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Quote:
Originally Posted by biggrbbronco96 View Post
If I currently have stock gears in my 96 bronco dana 44 front 8.8 rear w/ stock gears and I want to chane my gears to 4.56s will i need a new carrier for both axles?
Just the front.

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post #59 of 330 (permalink) Old 01-16-2007, 01:23 PM
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But if your 96 has the limited slip in the 8.8 you will need to get an open carrier for it. I got mine out of a junk yard.

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post #60 of 330 (permalink) Old 01-16-2007, 01:56 PM
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Originally Posted by ScottMoore View Post
But if your 96 has the limited slip in the 8.8 you will need to get an open carrier for it. I got mine out of a junk yard.
Why?

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