Gear Ratio ?
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Gear Ratio ?
My x has a v10 and 4.30 rear. The P.O. put 245/75/16 E rated tires on it.
What does the ratio work out to be equivalent to with the smaller tires?
They are like new so I am not changing them at this point. I do tow a good bit as well and I think it helps with torque. Its a 2wd and ground clearance is ok too. Besides if I get 265 or bigger I will have a real hard time getting into my garage. My wife wont mind me storing her out side(so she can have all the room) but I hate to see my baby un protected.
What does the ratio work out to be equivalent to with the smaller tires?
They are like new so I am not changing them at this point. I do tow a good bit as well and I think it helps with torque. Its a 2wd and ground clearance is ok too. Besides if I get 265 or bigger I will have a real hard time getting into my garage. My wife wont mind me storing her out side(so she can have all the room) but I hate to see my baby un protected.
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Joined: Jan 2011
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My math might be fuzzy this early, but I'll give it a shot. Methinks this is the right way to figure it. 
A quick check shows a Michelin LTX MS2 takes 683 revolutions per mile in size 245 and 657 per mile in 265. About 104%. Multiply that by 4.30 and you get 4.47.
Other brands should have a very similar difference in RPM's. Your speedo is off by 4% low and the weight rating is about 400lbs less per tire.
A quick check shows a Michelin LTX MS2 takes 683 revolutions per mile in size 245 and 657 per mile in 265. About 104%. Multiply that by 4.30 and you get 4.47.
Other brands should have a very similar difference in RPM's. Your speedo is off by 4% low and the weight rating is about 400lbs less per tire.
Hotshot
Joined: Oct 2005
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From: Florida
Using Automotive Calculators offer to you by Ford Trucks Enthusiasts | www.ford-trucks.com I come up with 4:47 also.
The 265/75/16 tires are 31.65" in diameter
The 245/75/16 tires are 30.47" in diameter
If you use the automotive calculator I link to and put 31.65" as the "orginal" tire diameter and the 30.47" as the "new" tire diameter and put 4:30 as the gear ratio...it calculates 4:47
So two independent methods yields the same 4:47 ratio...
Joe.
The 265/75/16 tires are 31.65" in diameter
The 245/75/16 tires are 30.47" in diameter
If you use the automotive calculator I link to and put 31.65" as the "orginal" tire diameter and the 30.47" as the "new" tire diameter and put 4:30 as the gear ratio...it calculates 4:47
So two independent methods yields the same 4:47 ratio...
Joe.
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