- Joined
- Aug 7, 2007
- Messages
- 1,739
- Reaction score
- 540
- Points
- 113
- Location
- Costa Mesa, CA
- Vehicle Year
- 2002
- Make / Model
- Ford
- Engine Type
- 4.0 V6
- Engine Size
- 4.0 SOHC
- Transmission
- Manual
- 2WD / 4WD
- 4WD
- Tire Size
- 33"
I recently upgraded my off-road tires to 33" and installed 4.56 gears to work with the taller tires. I run 31" tires for daily use and towing. I knew the 31'" tires would be far from idea with the 4.56 gears but thought it would still be reasonable.
Back and forth to work on So Cal freeways, I typically drive around 80 to keep up with traffic. At 80 mph my speedometer is reading 90 mph and that means I am right on the edge of the speed cutoff and the engine is at the shut down point if I happen to go any faster. I can even feel a slight vibration that normally starts at around 90 mph which I think is a resonance in the driveshaft that gets bad when approaching 95 mph.
I do have a re-flash on the computer that raises the speed cutoff and I can have the speedometer recalibrated but that doesn't change the rpm of the driveshaft at 80 mph. It looks like I am going to have to slow down a little on the freeways when I have these 31" tires mounted and just learn to stay out of the way for faster traffic.
It will make towing easier and I only run about 72 mph when towing so no problem there.
The 31" tires w/ 4.56 is probably going to hurt my gas mileage also. All in all it pretty much sucks.
Back and forth to work on So Cal freeways, I typically drive around 80 to keep up with traffic. At 80 mph my speedometer is reading 90 mph and that means I am right on the edge of the speed cutoff and the engine is at the shut down point if I happen to go any faster. I can even feel a slight vibration that normally starts at around 90 mph which I think is a resonance in the driveshaft that gets bad when approaching 95 mph.
I do have a re-flash on the computer that raises the speed cutoff and I can have the speedometer recalibrated but that doesn't change the rpm of the driveshaft at 80 mph. It looks like I am going to have to slow down a little on the freeways when I have these 31" tires mounted and just learn to stay out of the way for faster traffic.
It will make towing easier and I only run about 72 mph when towing so no problem there.
The 31" tires w/ 4.56 is probably going to hurt my gas mileage also. All in all it pretty much sucks.