Changing Tires

Okay folks - after reading a lot over the last several months and contributing where I can, I have a question of my own that I hope you folks can help me with.

I have a 2004 F350 crew cab 4WD Powerstroke. It comes with 3.73 differentials. It also came with stock (wimpy looking) 265/75R16 tires (Pirelli Scorpian STRA). Actually the tires seem pretty nice, but are obviously road tires and just "look" small on the truck. I am looking at going to 295/75R16 - either the load range D BFG All Terrains which have the same load capacity as the 265 load range E or to the Bridgestone Revo's (cause they are great tires).

My question is this: Changing the tire diameter effectively changes my differential ratios from 3.73 to 3.55 Does anyone know how to determine how much this is going to change my towing capacity? Is there some formula out there or such? I don't want to go through the trouble and expence of change the differential ratios.

Thanks for your ideas.

Don

Reply to
Don
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determine

I have a 96 F-250 PSD auto with a 3.55 rear end and BFG 285/75/16D's. I tow 10-12K on the bumper and hardly know it's there. You better check closely to see if you can get a 295 on the rear without them rubbing each other. Keep in mind that each time the tire flexes, the sidewalls move toward each other.

Reply to
Say What?

Reply to
davcook

I believe his truck is SRW.

: > I have a 2004 F350 crew cab 4WD Powerstroke. It comes with 3.73 : > differentials. It also came with stock (wimpy looking) 265/75R16 : tires : > (Pirelli Scorpian STRA). Actually the tires seem pretty nice, but are : > obviously road tires and just "look" small on the truck. I am looking : at : > going to 295/75R16 - either the load range D BFG All Terrains which : have the : > same load capacity as the 265 load range E or to the Bridgestone : Revo's : > (cause they are great tires). : >

: > My question is this: Changing the tire diameter effectively changes : my : > differential ratios from 3.73 to 3.55 Does anyone know how to : determine : > how much this is going to change my towing capacity? Is there some : formula : > out there or such? I don't want to go through the trouble and expence : of : > change the differential ratios. : >

: > Thanks for your ideas. : >

: > Don : >

: >

: : I have a 96 F-250 PSD auto with a 3.55 rear end and BFG 285/75/16D's. I : tow 10-12K on the bumper and hardly know it's there. You better check : closely to see if you can get a 295 on the rear without them rubbing : each other. Keep in mind that each time the tire flexes, the sidewalls : move toward each other. : :

Reply to
Mellowed

This is just a layman's casual response. You are losing about 4.5% in torque. So, if you are pulling maximum loads, you will feel the difference. Otherwise, probably not a big deal.

Reply to
Mellowed

Reply to
davcook

Never Forget

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Reply to
AbitRip

Just wanted to say thanks for all the information and suggestions. Mellowed had a great point, I'm only loosing 4.6%! Plus the new effective 3.55 ratio should boost my fuel milage when running unloaded. Thanks again.

Don

Reply to
Don

Uhhh...

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is an art gallery! Do you have the correct address. I'd like to see what they have. Thanks.

Reply to
Don

a simple goole search returned what you are looking for:

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But it appears to be down, hope they aren't out of business. Here is the info from Gooles Cache of their page:

DUAL DESIGNS, INC.

1974 365TH STREET EARLHAM, IOWA 50072 PHONE: 515-834-2239 FAX: 515-834-2698

Russ

Reply to
Russ Braaten

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