Tire Size

[tractorman21]

I am looking at a 1997 Super Duty for sale,that's in really good shape,with only 90,000 miles on it.
I want it for my Landscaping business,but i have a few questions about it.
It's a dually and the rear tire size is 235/85/16 and it has a 5.13 rear axle ratio.
What's the tallest tire i can put on it to kill some of the rear gear?
Would it be cheaper to change the rear gear to a 4.56,or maybe a 4.11?

Thanks for any thoughts.

 

[BIG JOE]

I am looking at a 1997 Super Duty for sale,that's in really good shape,with only 90,000 miles on it.
I want it for my Landscaping business,but i have a few questions about it.
It's a dually and the rear tire size is 235/85/16 and it has a 5.13 rear axle ratio.
What's the tallest tire i can put on it to kill some of the rear gear?
Would it be cheaper to change the rear gear to a 4.56,or maybe a 4.11?

Thanks for any thoughts.

I'd think by the time you bought 4 tires, tall enough to kill the 5.13 ratio.. you'de be fairly close to what it would cost for a used rear Axle setup, of your choosing.

Not to mention what tall (enough) tires might do to Bumper/Hitch height, and so on ? Depending on where the 97 fits into your business.

 

[JLDickmon]

315/75R16's

 

[tractorman21]

Spacers

315/75R16's

Will the 315/75/R16's fit on the stock ford rims? Will i need to use spacers for the dual rear tires?

 

[Patrick Feeley]

I'd just find another dually rear end with 4.10's (or change gears on the original). Anything larger than the 235's will cause the rear tires to rub between the duals. You could use spacers, but any spacers need to take into account that the wheels center via the hubs and not the lugs. There's barely enough hub on a stocker for the outer wheel to center on. Cheers!

 

[JLDickmon]

Will the 315/75/R16's fit on the stock ford rims? Will i need to use spacers for the dual rear tires?

oh crap..
I missed where you said that was a dually...

negative. the stock rims are too narrow..

I'd say your best bet is change the rear gear (hoping it's 2WD not a 4x4)...
4.56 would be my choice..

5.13's.... holy crap.. maybe the previous owner was a landscaper and pulled stumps rather than grinding them???

 

[BJS]

finding a rear to swap out is not going to happen because it is not the standard F350 rear the '97 superduty is essentially an F450 IIRC he will have a dana 110 rear or something like that. If memory serves me right the lowest numerically gears available stock were a 4.88

Oh and the frame widths are different so swapping axles will be a bit more than a bolt in affair if you are going to the standard F350 axles. The most cost effective answer is going to be just to slow down.