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Post by Chuck on Dec 16, 2005 10:31:26 GMT -5
I've seen a few gear ratio calculators around, and they all save a lot of time compared to doing the math the hard way, but so far this is the best one I've run across: www.balsa.no/bil/calcs/gearcalc/Lots of common Ford, Chebby, and Chrysler automatic and manual transmissions already listed, including the T-18 and NP435, along with about 21 common transfer cases. It will give you vehicle speed in all gear combinations with whatever axle ratio you pick. Great time saver. For those of you running Ford stuff (yeah, I know, that's me and maybe one other guy here, lol) it will even list all the close speedometer gear combinations and error. Thank the guys on the Full Size Bronco board for pointing this one out to me.
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Post by bensredyj on Dec 16, 2005 13:12:10 GMT -5
Great BUT where is an AX-5,15 or NV 3500's
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Post by Chuck on Dec 16, 2005 15:04:46 GMT -5
You're out of luck there -- I don't even see any sort of link to the creator of the site, otherwise I'd ask about adding a few things. However, you can still plug in the T-18 or NP-435 to get speed figures in fourth gear (1:1), and then just multiply by the transmission gear ratio you need if you need data for another transmission. Still a lot quicker than having to figure out the basics including tire rolling diameter, etc.
For instance, I don't see the T-5 in there either. However, it's pretty easy to find out that the OD ratio in the late T-5 is 0.68, so if I wanted to know what RPM I'd be doing at 60 with 33's and 4.10's, I can select the tire and gear combination off the chart, and get 2500 on the T-18. Hence, the T-5 is 2500*0.68=1700rpm.
The pain in the butt part is getting axle RPM vs. vehicle speed, because there are two or three unit conversions that take some time. If you have a tool that will give you driveshaft RPM as a function of vehicle speed for a given tire and set of rear gears, it's very simple to get engine RPM in any transmission gear for that. Plus, like I said, if you're lucky enough to have one of the 45 transmissions on the list ...
Maybe one day if I ever get bored I'll set up a spreadsheet to run the same graph for any set of transmission ratios. I'm sure there are a few around, but I haven't run across one yet. Meanwhile, this is still quicker than the nothing-but-a-calculator approach by far ...
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Post by Lyle on Dec 16, 2005 18:09:13 GMT -5
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Post by kwrangln on Dec 17, 2005 11:16:17 GMT -5
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Post by shoulder on Dec 17, 2005 14:42:25 GMT -5
Hi I might be able to help you out with that balsa.no site .. I need information about ratios, if you have them I'll add right away. Update: NV3500N, NV3500W, NV3500HD, AX-5 and AX-15 is added. Sam Norway
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Post by Chuck on Dec 27, 2005 12:25:04 GMT -5
I take it you're the site/calculator creator? If so, thanks for a great and useful little tool! ;D Here are a few more good ones for you: ZF S5-42 and S5-47 (five speed used in F-250 and F-350) Gas: 5.72, 2.94, 1.61, 1.0, 0.76 (5.24 reverse) Diesel: 5.08, 2.60, 1.53, 1.0, 0.77 (4.66 reverse) ZF S6-650 (six speed used in more recent F-250 and F-350, as well as late heavy GM's) 5.79, 3.30, 2.10, 1.31, 1.00, 0.72 (5.23 reverse) I also just spotted this page when I was hunting for the ZF6 ratios. Lots of info on some of the other late model Ford transmissions, including the M5 used in the Ranger and Explorer: vibratesoftware.com/html_help/html/Ford/Ford_Transmissions_Main.htm
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Post by shoulder on Dec 28, 2005 5:49:36 GMT -5
Updated.
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Post by Sticks on Dec 28, 2005 8:50:54 GMT -5
Being that I don't have a tach, I tried punching the typical D35 gear ratios in to see where the RPM's would be vice MPH...maybe finding out what ratio I really have.
4.88's on 35's put me at 3000 RPM @ 65mph. Which feels really close to me, not knowing exactly...
4.11's put me around 2600 rpm...hmmm...somehow that feels low.
I guess I ought to hook up the tach, huh? That, or find another way to determine the ratios?
Cool calulator though.
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Post by Chuck on Dec 28, 2005 11:04:08 GMT -5
Excellent! Might want to check the ratios on the S6-650 though -- right now it's got fourth as 2.31 rather than 1.31.
A few more useful ones: T5: 2.95, 1.93, 1.29, 1.00, 0.73 T5 WC: 3.35, 1.93, 1.33, 1.00, 0.68 T5 Z: 2.95, 1.94, 1.34, 1.00, 0.63
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Post by CORE 4WD on Dec 28, 2005 18:19:02 GMT -5
Pop the diff cover and count teeth. Divide ring gear by pinion. Or jack up rear end and mark tire and driveshaft. Have one person rotate tire two revolutions (if open) and you count how many times driveshaft rotates. 4 times around nets 4.10 and almost 5 times would be 4.88...
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Post by Chuck on Dec 29, 2005 13:37:21 GMT -5
Or if you want it really accurate, are a perfectionist, or are too drunk to measure 4.1 turns (vs. 4.3 for 4.33's or 3.7 for 3.73's, etc) correctly -- rotate it 20 times, and then it's 41 turns of the pinion for 4.10's, and 49 for 4.88's ... etc.
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Post by shoulder on Jan 1, 2006 5:41:43 GMT -5
Excellent! Might want to check the ratios on the S6-650 though -- right now it's got fourth as 2.31 rather than 1.31. A few more useful ones: T5: 2.95, 1.93, 1.29, 1.00, 0.73 T5 WC: 3.35, 1.93, 1.33, 1.00, 0.68 T5 Z: 2.95, 1.94, 1.34, 1.00, 0.63 Thanks for pointing out errors, T5's added. Sam
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