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Post by motoman58 on Oct 28, 2008 20:24:19 GMT -5
Alright lets see some numbers! What gas mileage are you getting with your gears and tires? 4 or 6 cyl.?  |
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Post by rockcrawlintoy on Oct 29, 2008 15:14:23 GMT -5
22highway with 5.29s and 35s
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Post by yotapowa on Oct 30, 2008 2:14:23 GMT -5
I am curious to find this out for my truck. How do you calculate it when you have bigger than stock tires?
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Post by fourwd1 on Oct 30, 2008 8:02:19 GMT -5
Use this formula to determine how much your speedo/odo are off
(New Tire Diameter / Old Tire Diameter) x Speedometer MPH = Actual MPH
So if your stock tires were 28" and you now have 33" and the same stock gears, you're off by a factor of 1.2 .
So if your speedo reads 50 MPH, you're really doing 50 x 1.2 = 60 MPH.
And if your trip meter says you went 300 mi on a tank of gas, you really went 1.2 x 300 = 360 mi, which is what you'd use to calculate actual MPG.
And keep in mind if you're running larger tires on stock gearing, the engine is operating outside it's optimum powerband, so MPG will suffer.
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Post by yotapowa on Oct 30, 2008 17:28:32 GMT -5
OK, sounds easier than I thought. Is 28" the size the stock tires would've been on my 1986 Pickup?
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Post by fourwd1 on Oct 31, 2008 7:09:53 GMT -5
I just picked 28 out of the air, but it's probably real close.
The stock tire size should be on the doorjamb tag or owners manual. Probably in metric (like P215R78-15 or something). Plug that into one of the online tire size conversion calculators to get the equivalent size.
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Post by yotapowa on Nov 3, 2008 1:49:04 GMT -5
allright, sounds good
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Post by ediblecrayons03 on Nov 27, 2008 14:26:59 GMT -5
33 general grabber MTs, v6 430 gears. about 15 but i can get 20 on the hiway if i drive 65 with the tanu cover on.
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moose
New Member
Posts: 9
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Post by moose on Nov 29, 2008 19:38:02 GMT -5
I was wondering where you found that formula, been trying to figure out my g/f's lifted broncos mpg
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