gearing
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From: nj
Originally Posted by wheelMA1
What will be the main use of this rig? 4.56s will give you great offroad romp, but you will sacrifice on road gas mileage. A decent compromise is 4.10s.
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From: MA
Auto, or stick? What kind of on road driving conditions will this see on a regular basis (flat, urban type....or rough, hilly, country... or both)? Check out some of the calculators on http://www.4lo.com/ . The mileage that will suffer will be at highway speeds, because it will be pulling more rpms.
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wheelMA1 The mileage that will suffer will be at highway speeds, because it will be pulling more rpms.
I have 4.56 gears in my 1993 ford bronco with 39's and i just recently drove it to the beach and my rpms where at around 3,000 which i know puts a lot of stress on my engine, so i was wondering if this is a result of having geared up or if i dont have good enough gears for 39's. Thanks
I have 4.56 gears in my 1993 ford bronco with 39's and i just recently drove it to the beach and my rpms where at around 3,000 which i know puts a lot of stress on my engine, so i was wondering if this is a result of having geared up or if i dont have good enough gears for 39's. Thanks
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From: MA
3000 with 39"s? What do you have for a tranny? That sounds high for that size tire, and those gears. Are you sure your tach is reading properly? You might want to check out that 4lo site I linked earlier. Something doesnt make sense with the info you gave me.
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Yea this problem doesnt make sense to me either at all. I have the stock auto tranny for my 1993 Bronco XLT 5.8. Would my rpms go up with having to high of a gear or too low of a gear for my tires?
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From: MA
I dont think the gears are the problem here. If you plan on streeting this vehicle at all, 4.56 is where you want to be IMO. Your rpms would go up if you had too low of a gear (numerically higher). You might want to rev your vehicle, and see if the tach matches what you think its revving at, by ear. Does anyone know if there is another way to tell what rpm you are running at, without the tach? I am at a loss.
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Hey guys! I am new hear and glad I finally found a all Bronco Forum! I have a gear questions too... I have a 1990 Bronco with 39 1/2 inch tires. Its got a 351 Windsor. It has a 8 inch suspension lift and a 3 inch body. I currently have 3:55 gears. It doesnt have very much get up and go which is to be expected. I have been wanting to switch to 4.10's but not sure. I cannot afford to get worse gas mileage. I will not be doing much IF any highway driving. I only use it for in town driving and mudding. LMK which gears would be best for my rig without getting worse mpg. Thanks.
Kyle
Kyle
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From: MA
Welcome to FTE BigBody! Check out http://www.4lo.com/ and see if you can run some numbers, to get the answers you desire. If it were me, I would run 4.56s with a tire size like that (you could go even lower if you wanted some great low end power!!). I bet your gas mileage SUCKS with those 3.55s and 39.5" tires. You do realize that you truck is probably running like a dog with that combo. If you were to change to a better gearing, your mileage will probably increase, due to a more efficient mechanical advantage (what lower gears will give you for turning those big 'ol meats). Now a bit off topic. Do not be afraid to use the search function. The archives of FTE are huge.... and expanding every day. Hope to see you around the boards.
Rich
Rich
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Hey, wow! Fast replies even! I do not know some of the numbers so I cannot complete the caculator on that site. You say 4.56's? What differences will there be in how it drives? Also, I think 4.56's is the lowest that fit or is sold in the Ford 8.8 rearend.
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From: MA
Hello. Not all replies are that fast, you just lucked out I guess 
. With 4.56s, that should greatly help your low end get up and go. It should accelerate MUCH better, and have better pulling power. You have 39.5" tires with the 8.8. Wow. Just to let you know, the biggest tire the 8.8 can normally stand is a 37". They just are not very reliable past that. Most guys who run big tires swap out with a much beefier axle like a dana 60. You might be right about 4.56 being the lowest, but that goes back to my previous statement about swapping axles.
. With 4.56s, that should greatly help your low end get up and go. It should accelerate MUCH better, and have better pulling power. You have 39.5" tires with the 8.8. Wow. Just to let you know, the biggest tire the 8.8 can normally stand is a 37". They just are not very reliable past that. Most guys who run big tires swap out with a much beefier axle like a dana 60. You might be right about 4.56 being the lowest, but that goes back to my previous statement about swapping axles.
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Hey, what baout the RPMS? It usually drives around 1500 or so. Would it be a lot higher with 4:56? I could not afford a beefier axle.
I am a young one. I bought the truck the way it is and looking to personalize it and do a little modifying. It was professionally built. I asked the previous owner about getting new ring and pinions and he said I shouldn't b/c I would get worse gas mileage and b/c the 3:55 was new.
Kyle
I am a young one. I bought the truck the way it is and looking to personalize it and do a little modifying. It was professionally built. I asked the previous owner about getting new ring and pinions and he said I shouldn't b/c I would get worse gas mileage and b/c the 3:55 was new. Kyle
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From: MA
http://www.4lo.com/calc/geartable.htm That table should tell you where you want to be. You say it drives at 1500...what speed is that? The previous owner had no idea what he was talking about, in respect to worse mileage. The axle you have doesnt have to be swapped, but most guys that romp theirs offroad find themselves spending more replacing components than a swap would be, in the long run. I am sure there are guys with big broncos, who have similar sized tires and setups, who dont have these issues.
Rich
Rich
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Hey, Thanks for your help Rich! I appreciate it! One last questions... Do you have any idea it what it cost to have new front and rear ring and pinions bought and installed? Completely done by a mechanic. LMK. Thanks.
Kyle
Kyle