Ratio > tire size, Question
#1
01-26-2013, 08:04 PM
Ratio > tire size, Question
I have a 150. 4 spd auto w/ 17 " rims.
I wondering if its possible to obtain a higher "gear ratio" changing to rims of larger dia. I know it's just the wheels and not the actual gear ratio being changed,
What I'm looking to achieve is better fuel mi. And lower rpms while driving hwy speeds, now I'm running at 2k at 60 mph.
This is also under warranty so I really can't make internal or transmission changes, not sure if I could get away with switching out the rear,
And needless to say, this is the first vehicle I bought with a loan and warranty so that's the reason I'm asking for help with what might sound like a dopey question, Thanks
I wondering if its possible to obtain a higher "gear ratio" changing to rims of larger dia. I know it's just the wheels and not the actual gear ratio being changed,
What I'm looking to achieve is better fuel mi. And lower rpms while driving hwy speeds, now I'm running at 2k at 60 mph.
This is also under warranty so I really can't make internal or transmission changes, not sure if I could get away with switching out the rear,
And needless to say, this is the first vehicle I bought with a loan and warranty so that's the reason I'm asking for help with what might sound like a dopey question, Thanks
#2
02-03-2013, 01:34 PM
you want better gas mileage drive 55, i drive 52 cause thats when my turck bangs into overdirve and it added 5 mpg. yes adding larger tires will give it a hihger ratio. but it will also make it a dog in acceleration
#3
02-04-2013, 09:00 AM
Yea! I understand the savings of driving at 55 but, around here that isn't possible most of the time, especially if your on an interstate or parkway, that'll get you in trouble pretty fast. But I do agree!
The main concern is the ratio, this Trans, could use a fifth gear or bigger rear to change the winding sensation I experience at 55 to 60+.
The real problem I have is the fact that this has a full coverage warranty which for now I have to keep, otherwise I'd be looking for a differential rebuild or something like that,
This was to good of a deal to pass up at the time I bought it,
With just 48 k and new condition, I jumped right on it.
Thanks for the good advice, I thought I'd get a little better performance at the top end without to much lag off the start. Thanks
The main concern is the ratio, this Trans, could use a fifth gear or bigger rear to change the winding sensation I experience at 55 to 60+.
The real problem I have is the fact that this has a full coverage warranty which for now I have to keep, otherwise I'd be looking for a differential rebuild or something like that,
This was to good of a deal to pass up at the time I bought it,
With just 48 k and new condition, I jumped right on it.
Thanks for the good advice, I thought I'd get a little better performance at the top end without to much lag off the start. Thanks
#4
02-04-2013, 09:58 AM
max the gas mileage? Get the tallest, skinniest rubber you can buy in the PROPER load range.
The outside diameters of tires can be compared at the on-line tires seller known as Tire America.
Rims may not be the problem. A 255-55-17 just for talking purposes may become taller with a set of 285-75-17...
The 255 and the 285 are the tread width in mm.
The 55 and the 75 are the sidewall height as a % of the tread width.
~255 x 0.55=140.25mm side wall height x 2=280.5mm tall tire.
~285 x 0.75 = 213.75 mm side wall height x 2 =427.5 mm tall tire.
That doesn't seem correct, but you better check with Tire America on line...of course Ford Engineering figured out all this already and supplied your truck with the best possible combo for gas milage...after all Obama has mandated that the CAFE, Corporate Average Fuel Economy, for each manufacture must make [fill in the blank for MPG as per model/make/year]...so what this boils down to is that Ford has to sell x amount of little **** boxes to bring the fuel economy of the fleet [everything they sell] up, inorder to keep making big Ford Trucks, which tend to pull the CAFE down, but maximize Ford Profits.
skip.
UCS-->"The 255mm and 285mm measurement of a tire is the section width of the tire. The section width is measured from inner sidewall to outer sidewall with normal tire pressure and no load on the tire. The actual tread width of a tire normally runs 30-35% smaller than the section width of a tire." Thank you. I stand corrected. The gist of the idea is correct though.
The outside diameters of tires can be compared at the on-line tires seller known as Tire America.
Rims may not be the problem. A 255-55-17 just for talking purposes may become taller with a set of 285-75-17...
The 255 and the 285 are the tread width in mm.
The 55 and the 75 are the sidewall height as a % of the tread width.
~255 x 0.55=140.25mm side wall height x 2=280.5mm tall tire.
~285 x 0.75 = 213.75 mm side wall height x 2 =427.5 mm tall tire.
That doesn't seem correct, but you better check with Tire America on line...of course Ford Engineering figured out all this already and supplied your truck with the best possible combo for gas milage...after all Obama has mandated that the CAFE, Corporate Average Fuel Economy, for each manufacture must make [fill in the blank for MPG as per model/make/year]...so what this boils down to is that Ford has to sell x amount of little **** boxes to bring the fuel economy of the fleet [everything they sell] up, inorder to keep making big Ford Trucks, which tend to pull the CAFE down, but maximize Ford Profits.
skip.
UCS-->"The 255mm and 285mm measurement of a tire is the section width of the tire. The section width is measured from inner sidewall to outer sidewall with normal tire pressure and no load on the tire. The actual tread width of a tire normally runs 30-35% smaller than the section width of a tire." Thank you. I stand corrected. The gist of the idea is correct though.
Last edited by skip1930; 02-05-2013 at 09:20 AM.
#5
02-04-2013, 10:39 AM
Did you purchase this truck from a Ford dealer? If so, make contact with them and explain your situation. They may be able to change ratio, and still maintain warrenty. What's the worst they could say? It may be cheaper in the long run to ask. Otherwise you risk spending money and time experimenting with rims, tires, different brands and still not happy. It's worth a shot.
#6
02-04-2013, 11:35 PM
Hey thanks! Both of these 2 last responses make sense as well,
I'll ask the dealership but really don't expect too much help in that area, they sold it to me in decent shape and like Skip said, it's what Ford intended ,
Thanks for the advice, I'll let u know how I make out
I'll ask the dealership but really don't expect too much help in that area, they sold it to me in decent shape and like Skip said, it's what Ford intended ,
Thanks for the advice, I'll let u know how I make out
#7
02-05-2013, 06:05 AM
"The 255 and the 285 are the tread width in mm."
Not stepping on toes, but this part is incorrect.
The 255mm and 285mm measurement of a tire is the section width of the tire. The section width is measured from inner sidewall to outer sidewall with normal tire pressure and no load on the tire. The actual tread width of a tire normally runs 30-35% smaller than the section width of a tire.
Not stepping on toes, but this part is incorrect.
The 255mm and 285mm measurement of a tire is the section width of the tire. The section width is measured from inner sidewall to outer sidewall with normal tire pressure and no load on the tire. The actual tread width of a tire normally runs 30-35% smaller than the section width of a tire.
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