I just got 32.7" diameter entering 285/70-17. Tirearack calls the Rugged Trails 33" but my BFG AT LT285/70/17 are definitely taller at 35 psi. BFG spec calls the AT 32.8".

These calculators can't forsee some of the manufacturers' specs. As an example the BFG AT LT315/70/17 looks like a 315mm width tire. But BFG specs state it is a 12" width, (a 305mm). The height measurements are very close at 34.4" calculator, and 34.5" spec.

Btw I've read of people dumping the 34.5" 315s and going back to a 33" because there torque converter wouldn't lockup on grades, etc.

I haven't heard that yet? 33's (or 32.8's) would be better since it is stock but they also look to small when combined with a 6" lift.

I guess larger tires-more weight insufficient gear ratio for the converter stall range or the engine is not capable of the appropriate rpm range (too small a duration camshaft, inadequate valve springs, too low compression, etc.) Symptoms include high "revs" to pull away from stop, "marshmallow" accelerator feel when driving at part throttle, transmission and possibly engine overheating, and a pronounced engine rev when nailing the throttle from a cruising speed*. I haven't experienced any of this so far but it would explain the lockup.

*Torque Converters Explained online

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2004 White SE, CC, BT, Off Road 4x4
• Banks Monster Exhaust • Pro Comp 6" Stage II • PRG Radflo External Reservoir Coilovers w/King Springs • EBC Slotted Rotor • Yellow Stuff Pads
• PRG OR Traction Bars • American Racing Chamber w/Teflon 17" • BFG T/A KO 315/70 17 • Active Tuning Grounding Kit
• FramBoost Air Intake • XM Satellite Radio • Hoppy Assist Tailgate • Grillcraft Black Mesh Grille • TruTrac

Wahoo

Check out post #5 http://www.titantalk.com/forums/tita...ml?#post621250

Ya, with a 6" lift you need 35s. The Dunlop MTs look promissing as far as weight. At 56lbs. only 1 pound more than my 33" BFG ATs! The larger diameter will still rob you of some power, but the unsprung weight/rotational mass savings of these lighter 35 might help. Every pound of heavier tires and wheels are suposed to be like 10 lbs. in the truck bed. And the rotational mass has to do with getting them rolling. For longer non-stop trip the fly-wheel effect might offset the extra weight, but in stop n go, not good.

Interesting read. I'm getting between 11-13 mpg mixed driving on my 315's which isn't a huge difference than when I was running my 285's which was pretty much 13 mpg. This will be my first weekend of serious towing and will be watching it closely just for sh#ts and giggles. I've never seen anything like some claim around 15 mpg and up. I bet Greg's new gears will help if they ever come out. I'll also be watching the slight inclines to see if I'm having torque issues.

Thanks,
PB

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2004 White SE, CC, BT, Off Road 4x4
• Banks Monster Exhaust • Pro Comp 6" Stage II • PRG Radflo External Reservoir Coilovers w/King Springs • EBC Slotted Rotor • Yellow Stuff Pads
• PRG OR Traction Bars • American Racing Chamber w/Teflon 17" • BFG T/A KO 315/70 17 • Active Tuning Grounding Kit
• FramBoost Air Intake • XM Satellite Radio • Hoppy Assist Tailgate • Grillcraft Black Mesh Grille • TruTrac

Wahoo

5.1 % is correct sir

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I use my Garmin StreetPilot III to monitor my speed and distance as I travel. I've found the Titan's speedometer and odometer to be extrememly accurate. I've noticed less that .2mph difference. That's as close as I can guess based on needle position. The Cruise control is also very accurate.

I have the big tow package and stock SE wheels and tires on my '05 KC.

Red

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy