Checking My Numbers...
Thread Starter
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Freshman User
Joined: Aug 2008
Posts: 47
Likes: 0
From: Livingston, Texas
Checking My Numbers...
As some of you know I'm seriously considering a swap from my C6 to a ZF5. I have 4.10's and want better mileage and more shift control.
Using the calculator here I used 3000 RPM with 31" tires to get 70.4 MPH. Since the C6 is 1:1 and the ZF5 is either .77 or .76:1 depending on whether it's close or wide ratio I took .23 (the difference between 1 and .77) and multiplied it X 3000 RPM which equals 655.5. I then subtracted 655.5 from 3000 to get 2310 RPM at 70.4 MPH. I just want to verify that this is the right result. Very good if it is. Should improve mileage a good bit. I know that some of y'all are good with the numbers and just want a second, or third opinion.
Thanks again. I always know I can come here and get good answers.
Using the calculator here I used 3000 RPM with 31" tires to get 70.4 MPH. Since the C6 is 1:1 and the ZF5 is either .77 or .76:1 depending on whether it's close or wide ratio I took .23 (the difference between 1 and .77) and multiplied it X 3000 RPM which equals 655.5. I then subtracted 655.5 from 3000 to get 2310 RPM at 70.4 MPH. I just want to verify that this is the right result. Very good if it is. Should improve mileage a good bit. I know that some of y'all are good with the numbers and just want a second, or third opinion.
Thanks again. I always know I can come here and get good answers.
Postmaster
Joined: Dec 2002
Posts: 3,594
Likes: 2
From: Southern Oregon USA
There are several gearing calculators on the net. Here's one that I use:
4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators
i came up with 2364 rpm at 70 with your combination
Jason
4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators
i came up with 2364 rpm at 70 with your combination
Jason
Thread Starter
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Freshman User
Joined: Aug 2008
Posts: 47
Likes: 0
From: Livingston, Texas
Thanks RC. I like that calculator too. I wondered why our numbers were off a bit and discovered that when I posted I put in the wrong tire size. 34" instead of 31. Looks like I was on the right track, but I'm no math wizard and it would be a very bad thing to get it together and not have what I expected.
Cargo Master
Joined: Nov 2003
Posts: 2,585
Likes: 1
From: Duluth, Mn.
Do You actually pull anything with Your truck? If not, consider going with 3.55's
I swapped My 4.10 to 3.55 last summer. I gained a 1/4 tank of fuel on a 200 mile trip. And can actually use 1st gear.
I swapped My 4.10 to 3.55 last summer. I gained a 1/4 tank of fuel on a 200 mile trip. And can actually use 1st gear.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Even if you do pull something, 3.55 gears are not that bad.
You might be using lower transmission gears than you are now, but the higher gears are stilll there when you need them.
The only downside to higher axle gears is the extra wear on the U joints.
You might be using lower transmission gears than you are now, but the higher gears are stilll there when you need them.
The only downside to higher axle gears is the extra wear on the U joints.
Thread Starter
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Freshman User
Joined: Aug 2008
Posts: 47
Likes: 0
From: Livingston, Texas
Right now I don't pull anything with it but I am considering getting either a bumper pull camping trailer or a decent size slide in camper for it. My work will require me to do some traveling to places I might need to bring my own house.
I may even consider a 5th wheel trailer if I can find a deal.
I may even consider a 5th wheel trailer if I can find a deal.
New User
Joined: Aug 2006
Posts: 20
Likes: 0
From: Puyallup, WA
I have the zf5 with 4.10's and I am doing 24-2500 at 70ish mph..... I am running 235/85/16's which i believe are about 31" tall
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Elder User
Joined: Dec 2007
Posts: 854
Likes: 0
From: woodville, tx
Hey easttex, granted mine is the t-19 i have 3.55 on mine and routeinly pull a l3400 kubota with several implaments, and last weekend i pulled a 35' 5th wheel with mine. the only problem i had with the 5th wheel was that the camper had been sitting for 6 years, had sunk about a foot and had 4 flats. once i got it yanked out and the tires aired up, it at 10-12k pulled easier than the kubota at about 4k. And i think the hills next door to you here in woodville are as bad as anywhere in east texas, and my old truck handles them well.
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