I had another hydroplaning incident at about 50 mph over the weekend and resolved to replace the OEM tires as soon as I got near a computer. I ordered the previously mentioned Pirelli PZero Nero M&S in 225/40-18. New tires and the benefit of a higher effective gear ratio and life was good! That is until The Tire Rack called me this morning. It seems that my evil plan was foiled by the load rating of the Pirelli's (an 88 vs. a 99 on the OEM tires). Screwing around with the load rating with a car this big is something that is even outside of my admittedly high risk tolerance. Tire Rack recommended the BF Goodrich G-Force T/A KDWS in 245/55-18. The 55's are the lowest aspect ratio I could go to while retaining the proper load rating. They are also a bit wider. The good news? No more Continentals and no need for the dealer to flash in a new tire size. The bad news? No change in my rear gears. It looks as if a gear swap is in my future after all...

 

Blackmagnumrt:

Before you put your money on the Goodrich G-Force, you might want to read the buyer comments on the Tire-Rack website. They ain't so good.

I've been look'n too for a tire swap.

The Conti's just aren't going to do it.

Regards,
JS

 

I looked at the comments and agree but we have so few choices right now and I will do anything to get rid of the Continentals. At $84 per tire, I will keep my fingers crossed.

 

I don't think the V6 gears are interchangable with the V8. The ring & pinions are not even the same size. The V6 rears have a 7.8" and the Hemi has a 8.3"

 

You may be right, I just know what the Dodge Service Manager told me when he looked it up (and believe me, he could be wrong). As it stands, I wouldn't even risk the swap from the V6 if it was a perfect fit. I am too worried about them holding up under the torque. I will install something heavy duty once I have all of the specs I need. Do you have a link to specific information about the R/T's rear end?

Nick

 

Does the Magnum RT have a posi rear end? I didn't think it did, but with the traction control turned off, my car leaves two very nice tire marks. Just like it had posi, two strips about 6 feet long. Maybe it is the extra weight on the back tires, with the battery mounted in the rear.

Car seems to have more torque with the Flowmasters installed, the burnout was done before the muffler install.

Bob

 

Mopars NEVER have a posi rear end. That's GM (Generic Motors) terminology. For Mopars, a limited slip differential is called a sure-grip. If you see 2 tracks of black rubber, it's a sure-grip.

Sorry, it's just a pet peave of mine.

 

I don't care what you want to call it. It's either an open differential, a limited slip, dog (locking) clutches, or a closed differential. I know it's not the latter 2.

I'm assuming it has a limited slip. However, I have never seen it mentioned, so I'm not sure. I'm trying to find some info on it right now. I'll let you know what I find.

 

Phantom,
Let me know what you find out. I was at 2 dealers today to find information on a gear swap. While both confirmed that their diagnostic tool could flash in new gears (i.e. the good news), neither could provide useful information about the rear itself. I need all of the specs to find out what I can fit in there. Any leads would be greatly appreciated. As soon as I can find a match, the 2.82's are gone.
Nick

 

It's a Sure-Grip. An open rear is also called the one wheel squeal since only one wheel gets power. If you leave 2 tire marks, it has to be a Sure-Grip. For now, my Road Runner has an open rear, but I'll be putting a Sure-Grip in it soon. My Barracuda had an open rear and only left 1 tire mark when I dumped the clutch. Now, with a Sure-Grip, it leave 2 nice black patches.

Another way to tell when you're in a junkyard is to jack up the rear of the car so both wheels are off the ground. Turn one wheel. If the other wheel easily turns in the opposite direction, you've got an open rear, not a Sure-Grip.