BIG TIRES

[2shus]

I recently bought my truck and it came with 305/70-16 tires on it, i know thats several sizes bigger than truck calls for. I checked my speedometer with wifes new car and it was right on the money. I thought it would be 8-10 miles off. Also how does this affect gear ratios and mileage Etc. ? Any mechanical or wear or transmission problems with running this big of tires??? Iwould appreciate any info, Thanks

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1995 Dodge 2500 SLT Reg. cab 4x4 Auto,L. B. 3. 5 rears, 112,000 miles Anti lock brk sys, 305/70-16/Mickey Thompson Alum. wheels,Leer cap, Nerf Bars, C/D Player Overload springs, Reese Hitch, T. C. Lockup switch, Cats in heat needs OVH (coming soon)

[This message has been edited by 2shus (edited 03-01-2001). ]

 

[HEMI®Dart]

2shus
The previous owner probably swapped the speedometer pinion gear to match your taller tires. Its a simple & inexpensive change.

I run 305/85R16's about 36" tall. It makes the rear end gear ratio seem higher. Its not really that noticeable. The Cummins has so much torque at low rpms. With your aluminum wheels, the unsprung weight is less than stock steel wheels. This is good.

Mileage should be better on the highway. Our 12 Valve engines like the 1600-1700 RPM range for optimum mileage.

No driveline or suspension problems yet.

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Bill R
94 2500 SLT 4x4 5 Speed, 3. 54 LS, JRE 4" exhaust, Autometer Pyro, Boost & Water temp gauges, Bosch 215 HP injectors, Timing @ 14. 7º, JRE Stage III #4 plate 270/675, AFC spring kit, Scotty Air, Bully Dog Propane Injection, Roadmaster Active Suspension, Optima Red Tops, Geno's Exhaust Blanket, Espar Heater (won it!), Synthetic lubes throughout.

 

[sewman]

Here's a good site for people w/big tires http://www.dakota-truck.netTIRECALC/tirecalc.html

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94,4x,#4TST 16cm. ,5spd,4. 10LSD,35"BFG A-T,Bushwacker Flares , A-PIllarGuages,Southbend clutch,straight ex. ,RS9000.

 

[John_P]

2shus:

I have "B. G. Goodrich A/T" 285/75R/16 tires
on my 96'. Like "HEMI" I have had no
problems with my transmission or drive-
train. I now have 116,000 miles on the
truck. The tires have been on there since
it was new.

---------
John_P

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Red '96 4x4 2500 Auto 3. 54, TST #5, Major Pump Mods(By "Scheid Diesel") 370 Diamond B Injectors, Gov. Spring kit, AFC Spring kit, Banks Exhaust, Prime Loc, Cummins Chrome Kit,Psychotty Air Filter, Pro-Torque Converter, BD Valve Body, BD Pressure Loc, Isspro Gauges, Sendel 16" Alum Wheels w/ 33" BFGs

 

[Dr.Bob]

John P what did you do jack the truck up so the tires don't touch. I got 76,000 on mine and I'm on my third set... ...

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96 2500, 5 speed, Fuel preporator, K&N, Dr. performance injectors, Horton, No cat, Holes in muffler, TST #11,AFC spring kit and going broke with the price of fuel.

 

[John_P]

Dr. Bob:

I have left my truck's suspension
completely stock. The BFG 285's do
not hit at all on my truck.

I had my tire dealership "try" the
305's last time and they will rub on
my Dodge Mudguards.

I have been "off road" with the 285's
and have never had a problem.

Hope this helps to answer you question.

--------------
John_P

 

[grtescpa]

Originally posted by 2shus:
I recently bought my truck and it came with 305/70-16 tires on it, i know thats several sizes bigger than truck calls for. I checked my speedometer with wifes new car and it was right on the money. I thought it would be 8-10 miles off. Also how does this affect gear ratios and mileage Etc. ? Any mechanical or wear or transmission problems with running this big of tires??? Iwould appreciate any info, Thanks

I have a 1997 extended cab with
automatic. I went from the stock factory tires to 295 size. I did notice a change in the speedometer. by 5 mph. It actually corrected it because I was always -5mph off.
The tires need to be on wider rims. The factory rims make them look like stuffed donuts. Fuel economy dropped and the
gearing changed a little. I shift into overdrive later than befor. Also in montain driving staying out of OD seems to have less rpm than befor. I still like them. I got out of many bad places with them. Higher
ground clearence helps when your 45 degrees in one of those muddy road ditches.