question from a new rookie

[PRush]

I am very familiar with the maximun cruising speeds for my 2001 New VW Bettle TDI as I use the TDI to commute from NW FL. to our corporate offices in La. quite often, about 368 miles each way. 80-90 mph produces no ill effects.

Wednesday I am making the same run with my new 2003 HO, 48RE, 3. 73, Laramie Quad, 4x4, SRW, stock 17" wheels & tires. I have 7,000 miles of careful breakin on this wonderful beast. First oil & filter change @ 1,000 mi. , second @ 3,500 mi. , THIRD @ 7,000 mi. I have ranged highway speeds from 60- 90 mph. I have not experienced one problem thus far.

The run will not include any load or trailering.

My question is: What is my maximun safe cruising speed/rpm for an extended time for the engine & gearing for the beast that my ass is astradle.

 

[hammersley]

No Carefull Breakin!!!!

Never Baby the Cummins - It isn't like any other engine you've had - It Requires No Break In - Run it like you Stole It! It has to be worked HARD to break in properly. All the other engines require babying to seat items properly - not so with this engine. Have you hitched any weight to her and worked her? Putting 6-8,000 is a great way on a new engine. Regarding speed - the thing you must be careful about is the EGT Temperatures for extended running. Do you have any guages as yet? What RPM's are you turning at 90 MPH?

 

[PRush]

New Rookie

No guages as yet. 90 mph @ about 2200-2300, 72-73 mph @ 2000. Approximates. Does that seem right? Don't want to hurt her but I have been running as if I stole her.

 

[timjones]

At 90 your turning about 2600, Thats abit high for crusing. the biggest problem is not the engin but the tires. The "E" rated tire you dont want to run more than 80 for any long peroid of time, they'll over heat and chuck the tread. If your ambiant air temp is more that 85* you should drop the speed to 70-75. By the way your fuel mile at 85 is about 14mpg, instead of 18 at 75.

 

[Fireman]

Tim is right on about the tires.



You shouldn't have a problem with your EGT down there with a stock truck.



Fireman

 

[Dean Upson]

I feel that 70-75 would be the maximum speed that I would feel safe for an extended period of time and this would not be towing my fiver (58-62). We cannot travel (safely) as fast here in the northeast as in some other parts of the country because of the traffic and the very high probabliliy of getting a speeding ticket.



Dean

 

[DLeno]

whats this about a load range E tire getting hot? explain this, as well as the practice of putting D load range tires on there.



For example, I put 285/75 16 BFG AT KOs on my 2002. they are rated for almost 3200 lbs per tire, which exceeds the axle loading limits for the truck. I noticed that the 285/70 17 BFG is 100lbs less rating but still a D rated tire. there must be something more than matching weight ratings to expected loads.