Gear ratio calculator updates

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derf
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Gear ratio calculator updates

Post by derf »

So as some of you know, I run the www.grimmjeeper.com/gears.html page.

I have finally gotten off my duff and made some long overdue updates.

I added a number of transmissions and transfer cases earlier this month. But I got two updates in tonight that have been bugging me for a while.

First is that I finally figured out how to make the forms not resize when you go between things on the list and "enter your own numbers". That was annoying me for a long time. Now the forms stay lined up from side to side when you make any change, which is nice.

Second is that I added a selection for tire size. Now you can grab the "revolutions per mile" off a tire spec and use that in the calculator to get a more accurate estimation of your RPMs and speeds.

Do keep in mind that the revolutions per mile end up giving you a diameter that is smaller than the advertised "outside diameter". Sometimes by quite a bit. I know the "35 inch" tires on my Wrangler have an advertised outside diameter of 34.4" but the actual rolling diameter ends up being closer to 33.5".

So if you have a few minutes, go through the calculator and see if I screwed anything up. Thanks.
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dodgerammit
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Re: Gear ratio calculator updates

Post by dodgerammit »

Thank you for what you do!
84 Grand Waggy-Radio Flyer (Garnet Red/3M Ebony Metallic woodgrain, with honey interior) AMC 360 :cry: 2004 4.8LS/Advance Adapter/727/242 D44/AMC20 Serehill tailgate and headlight harnesses :fsj: Ongoing thread-viewtopic.php?t=11897

92 Wrangler Islander 4.0/32RH/231 D30/D35 RHD
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Brly
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Re: Gear ratio calculator updates

Post by Brly »

Just checked out the changes. Looks great to me. Thanks for putting that together!
1966 Jeep J3600 Gladiator - AMC 327/T18/D20
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Stuka
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Re: Gear ratio calculator updates

Post by Stuka »

Adding the revolutions per mile is cool. When I programmed in the tire size on my JK I measured from the ground to the center of the hub, and then multiplied by two. This made my speedo match the GPS. It also matches what your page shows when I enter the tires revolutions per mile. So pretty cool :)
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
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derf
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Re: Gear ratio calculator updates

Post by derf »

I've been meaning to add the revs per mile for a while now. Just never took the time to figure it out.

MReese Wagoneer
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Re: Gear ratio calculator updates

Post by MReese Wagoneer »

I like that calculator ,,!!!!!
:fsj:
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BaldBeardedBastard
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Re: Gear ratio calculator updates

Post by BaldBeardedBastard »

Awesome updates!


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Rod2
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Re: Gear ratio calculator updates

Post by Rod2 »

I just found this thread. Wow! What a source of info for what I have to do to put my truck on the interstate with 4.10/4.09 44/60 Danas. Thank you very much!
'73 J4000 'WOOD GO' 360, 2100 MC, T-18, D-20, 60-2 rear, D-44 closed knuckle front with Warn lock-o-Matics, Eaton E-lockers both, Pertronix module, AC, PS, Hydro-boost, AirLift bags front and rear, 33x15 Goodyear MTR's, Pacer 15x8 aluminum Bullet Holes, Summit line lock, 3rd brake light, tilt column from '77 Firebird, 12000 MileMarker on cradle, hitch receiver on both ends
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