I have a 2007 Dodge 1500 Megacab, it had all the handling characteristics of a stage coach at speed, hard lurch to the left when hitting a bump while negotiating any curve to the left.
I read all the different post and learned what direction not to take, which was very helpful. I have for all practical purposes a new truck now! I purchased a new set of P265/70R17 Bridgestone/Duelers.
The whole problem was the factory tire selection, the LT Michelin was way to stout of a tire construction for my truck.
I started looking around at all the trucks and vans in my area and noticed that all the tires sizes began with the letter "P",
I also remembered a few years ago purchasing a lower grade of tires for my Lexus, the result was harsh and noisy ride from once was smooth and quiet.
My Dodge has 10,600 miles and has some signs of wear on the rack and pinion from the harsh treatment that they have endured, so that is in the process of being fixed.
I should have changed the tires sooner but its a fairly big investment if it does not fix the problem but in my case it was the answer.
Money well spent!!!

 

Welcome to DF. Let me move this over to 3rd gen for ya, get you some help.

 

A lot of it could relate to inflation pressure. If you've got the tires inflated very hard, they will be more prone to bump steer and wheel hop. Of course, they will carry more load at higher pressures also.

 

the "P" stands for "P"assenger car - the "LT" stands for "L"ight "T"ruck.
I won't put car tires on a truck - too much sidewall flex.

If you are dissatisfied wit the way LT tires ride, play with your air pressure (conservatively).

 

I was all over the map on air pressure, low was better but no comparison to the tire change. My folks have a new 2009 Ram that came from the factory with the "P" designation, my Chevy Z71 Suburban also has the "P" series.
The Gardener's Ford van also has them.

The largest load that I will carry is a couple of mini bikes so it will be no issue. The tire distributor that I get deal with has these "P" series tires on his personal truck and he thought that the "LT" series was a bit much for a 1/2 ton truck.

 

I think that it really depends on what kind of use your truck will get. If you're hauling a load often, or if you drive on trails and rough terrain, the LT tires are much more up to the task. If you're just driving around town, picking up the occasional load of mulch or moving a refrigerator once every 3 or 4 months, then P tires should be fine, provided their weight-carrying capacity is up to par.

 

Auto Manufacturers are using P-rated tires because of their Highway tread design to give their trucks a bump in MPG's and also for that smooth riding feel that everyone looks for nowadays. When I pulled the stock Suckyears off, they were very soft and I could push my finger into the tread and crush them no problem. My Coopers, I could sit on without squishing them. Huge difference. i was more afraid of blow-outs with the stock car type tires more than anything.
P-rated tires for a Megacab is NOT enough unless it's a beefy tire. You need to go by the Load index and match or exceed factory specs. You should be anywhere's from 106 and higher. Look for the load index rating to see what you got.

Tires are like shoes. Think of them like this... It's like a fat guy walking around the scrap yard or construction site with flip flops on. He's much more prone to getting a nail or a shard through his foot than a skinny guy wearing the same shoes. It's simple Physics, no hard feeling fellas.
Now, take that fatguy and equip him with boots. Much less prone to getting a nail or a shard to penetrate that boot.
Your Megacab is like the fat guy. It's very heavy and has a heavy foot print. Much more prone to a flat tire with a P-rated(flip-flops) tire or one with a lower index rating, compared to a LT tire or one with a higher rating(boots).
I know, it's a terrible anaology but it's true.

I almost forgot...bump steer. True bump steer has nothing to actually do with the tires themselves. it has to do with the improper positioning of the tierod's horizontal position in relationship to the R&P. cars or trucks that are lowered to extreme's or lifted to exrtreme's are on'es that exhibit true bump steer which is a loss of the ability to control your vehicle. Almost as if you want to turn but cannot because you hit a bump in the road..etc. Soft tires will give that front/back side slosh.

 

I think our sticking point is what is considered "bump steer". I've had cars that, when a tire hit a big bump, would pull the wheel that way towards that side of the car where the bump was. That's what I'd consider "bump steer".

But I've heard others refer to it as "bump steer" when you hit a bump during a hard turn and the tire loses traction momentarily causing the car to "bounce" or "hop" towards the outside of the turn. This is more likely in the rear of a truck with an unloaded bed. I'd call that wheel hop, but some people seem to think of it as bump steer. Perhaps incorrectly, but if that's what they're experiencing, then the solution should be to correct that issue.

I know from experience that the harder the tire, the more prone to wheel hop. Not sure about the bump steer issue - I'm not experiencing much of that with my truck. Granted, it doesn't handle like my Honda but I don't expect it to do so. The Honda's made for going around corners fast - the truck's made for hauling a load.

 

I check the load rating on the Bridgestone Dueler P265/70R17, it is rated at 113.
My thinking is that the tire is the first line of defense, it hits the bump first and what it can't absorb will be transfered to the suspension, if the suspension will not comply the energy will be transfered to the rest of the vehicle, in this case the steering column and me the driver. I understand the concept of the beefier tire but my rack and pinion are pretty beat up for only 10,600 miles, it would appear that the design is not up to the challenge of the rugged tires that came on the truck. On another note, the passengers are no longer startled when the truck take an unexpected dash into on coming traffic.

 

For comparison purposes only, the Nitto Terra Grappler comes in both a "P" and an "LT" rated tire in the 265/70R-17 size.

The P rated tire is rated 113S, with a maximum load of 2535 pounds per tire at 35 PSI. The S means that the tire is rated for 112 mph.
The LT rated tire is rated 121R, with a maximum load of 3195 pounds per tire at 80 PSI. The R means the tire is rated for 106 MPH.

A generalization is that LT tires have more plies in the sidewall and are thus more resistent to puncture - pretty important off-road. They can also withstand more air pressure as noted in my comparison.