Facts to consider before towing.

I'm going to copy this here from the old forum. Good information here from someone who did their homework.

Steve



Background on towing terminology can be found at http://www.rvtimes.com/arch/RVT69HTML/69towing.html
or
http://www.dodge.com/towing/D/basic...conditions.html

2003 Ram Truck 1500 Laramie, Regular Cab, 4x2, Short Bed, Automatic 5-Speed w/20 inch Tires, 5.7L V8 engine:

With 3.92 Axle Ratio You Can Tow 8050 lbs
Gross Vehicle Weight Rating (GVWR) = 6350 lbs
Payload (GVWR-Curb Weight) = 1570 lbs
Curb Weight = 4777 lbs
Curb Weight Front/Rear = 2672 / 2105 lbs
GAWR Front/Rear = 3650 / 3900 lbs
Gross Combination Weight Rating (GCWR) = 13000 lbs

The base 4x2 SLT 120" wheelbase Ram Truck has a GVW rating of 6350lbs. The Standard 20" Tires on the base truck are P275/55R20 BSW Goodyear Eagle LS Tires
http://www.goodyeartires.com/goodye...+S&sidewall=VSB

These tires have a max load rating of 2403lbs with a speed rating of 'S', which is 112mph.

Let's for a moment assume that we collectively know nothing about this vehicle other than what is available in the media and that we throw out all rumors and assumptions...

Listed below are some speculative reasons the SRT-10 might be tow-limited based on some brainstorming that I did:

Powertrain Changes that could affect tow rating:
The engine is basically the 2003 Viper engine with some relatively minor modifications.

"The only difference between the Ram SRT-10 engine and the V10 under the hood of the Viper in your garage is the air intake (airbox), exhaust system, engine and transmission mounts, oil pan, and the cooling system borrowed from the Cummins-powered Rams." (January '04 Truckin pg 40)

I'd guess that the power output is very close to that of the Viper, which should definitely not be a limiting factor for towing. 500HP and 525lb-ft of torque with the broad banded curves should go a long way...

Suspension Changes that could limit tow capability:
from http://www.daimlerchrysler.de/media...rt10_2004CY.pdf

"Working with the fully hydroformed Dodge Ram frame, one of the stiffest in the industry, PVO added a custom-tuned suspension, dropping the Ram SRT-10 an inch in the front and 2.5 inches in the rear. New front and rear strut assemblies and a rear sway bar were added to handle the increased cornering loads."

The rear of the vehicle was lowered primarily by placing the axle tubes over the spring packs along with what looked like new snubbers mounted to the frame (see the pic at the top of page 42 in the Jan '04 issue of Truckin Magazine) The rear leaf springs are also 53% stiffer than the base 1500 Ram (according to the text on page 24 of the Jan/Feb Truck Trend article on the SRT-10) Soo, although riding at a lowered ride height might be a contributing factor to the vehicle's limited mfgr. tow rating, I don't think that it is the biggest one.

Another thing to consider is the dynamic tuning on the vehicle which includes things like sway bar rates, spring rates, shock absorber valving, bushing rates, and how they all interact as a whole 'package'. Most of the articles I've read about the SRT-10 mention that it feels more like a sports car than a truck. PVO has said from the beginning that this was it's intention... although I wouldn't buy a truck that couldn't be used as a truck.

Tire Information that could affect tow rating:
A good explanation of tire load ratings can be found at
http://www.tirerack.com/tires/tiret...neral/speed.htm
or
http://www.tiresafety.com/size_class/size_nav2.htm

According to Pirelli's Website, the tire offered on the SRT10 is a 305/40 ZR22TL 114WM+S(e) which means that its a 'reinforced' tire that has a load index of 114, which is a loading capability of 2601lbs per tire and a W speed capability of up to 168mph at a maximum pressure of 41psi. Like most vehicles, I'd be willing to bet that the SRT-10 tires are recommended to be set at around 8-12% less than max placard pressure rating for the tire, which would be between 36 and 38psi for optimum performance without sacrificing ride & handling and would mean that the load rating would probably decrease a bit here as well. Additionally it is important to note that the load rating of the tire also varies on temperature and speed... so take all these numbers with a grain of salt.

Now, knowing that weight distribution of the SRT-10 is 56% Front / 44% Rear with a curb weight of 5080lbs (as tested in Jan 04 Automobile Magazine page 58) that means that the SRT-10 Curb Weight Front/Rear = 2844 / 2236 lbs (compared to the base truck's Curb Weight Front/Rear = 2672 / 2105 lbs). Since the tire load ratings are comparable and both trucks share similar suspension components (SRT10 is supposed to have a beefier axle and brakes) one could speculate that the suspension and tires aren't the limiting factor here.

The point is that the tires should be able to handle the load of *some* towing at highway (not 150 mph) speeds especially since the base Ram 1500 has less of a load rating on its tires and has a GVW of 6350lbs and can tow about 8000lbs.

Drivetrain Changes that could affect tow rating:
Info / articles of interest on the Tremec T56 Box:
http://www.tremec.com.mx/catalogo/T-56/servicet56.pdf
http://www.5speedtransmissions.com/vipert56.html
http://www.chevyhiperformance.com/t...s/148_0305_t56/
http://www.pickuptruck.com/html/aut...lightning2.html

The Viper Transmission (Tremec T56) has proven to be very durable over the years. I believe they even had little to no problems with the same basic design during the Viper GTSR racing days. I also doubt the driveshaft would be an issue for towing. The Dana 60 Axles are historically bulletproof. What does this leave?

In my opinion, the clutch would be the so called 'fuse' in the system if you attempted to tow with this vehicle. We all have probably seen some toolbag smoke his or her clutch trying to aggressively launch a vehicle. Now imagine launching a vehicle that weighs 5000+lbs, has 22" wheels and grippy 10" wide tires and inadvertantly slipping the clutch a tad with 425+ lb-ft of torque available just above idle... Now add a trailer to the equation and you have a potential warranty item based solely on the driving habits of the owner, which we all know the manufacturer can't control.

A clutch's life is greatly affected by a number of factors. If you ride the clutch, drive or constantly accelerate quickly, or leave the clutch partially depressed for a long time when taking off (more likely when towing), the clutch will wear out faster. Also driving in a hilly area (again worse with a trailer) or in stop and go traffic the clutch will also wear faster. The clutch can also fail prematurely if the transmission input shaft leaks oil onto the clutch disc caused by repeated heating or overheating. A second clutch's life will likely be shorter than the first if the pressure plate is not replaced or the flywheel is not machined properly... and then the vicious warranty cycle begins.

I'd bet that this is the primary reason PVO has a no-tow rating on all their SRT products along with the 3/36 warranty.

Just some thoughts.

-toohigh