2nd Gen Non-Engine/Transmission 4.10 gears, 2000 rpm, 265-75-16, 57mph?

[nwilliams98]

Hi all,

I'm turning 2000 rpm at 57 mph with 4. 10 gear, 265-75-16 tires. Does anyone else have this setup? Can you comment on your speed at 2000 rpm?



Some of the calculators say 61. 5 mph for that rpm. Thats almost 5 mph difference. I don't think changing from 245 to 265 would cause that big of a difference (more like 4%)? Maybe my speedo is off?



Thanks in advance.

Nate

 

[klenger]

I have that same setup. I think I'm at about 2000 RPM at 60-ish MPH. If you changed from 245's to 265's, and didn't recalibrate the spedo, your numbers will be off. Best way to check it is to borrow a GPS. Real simple to check it that way. I think you need to change a gear in the spedo system to recalibrate for your truck. The newer ones are programable.

 

[WadePatton]

Originally posted by klenger

If you changed from 245's to 265's, and didn't recalibrate the spedo, your numbers will be off.

If you don't reset the speedo, it will read exactly the same speed for any given RPM.



With 3. 54 and 265 I get 70-ish at 2000.

 

[klenger]

I think that's what I was trying to say.

 

[nwilliams98]

I checked 2000 rpm again and found the truck to do closer to 56mph. I realize that the speedo needs to be reset for the bigger tires. The only thing I'm having trouble with is that even with a corrected speedo for the 4% difference in tire size I'm going to end up at 58. 2 mph which still seems much lower than everyone else. I'm going to borrow a gps next week to get to the bottom of this. Maybe the tach is off? Any other suggestions?

 

[WadePatton]

If you have access to marked roads--like interstate, go out and do it the old fashioned way.



Note your odometer to the tenths. Drive x miles without doing a lot of lane changing. Check your actual (milepost) mileage against your recorded (odo) mileage.



The longer the run the better. 3-5 miles is my minimum.



I can explain more if you need help with the math.

 

[mopars1]

I had a 2000 one ton that had the 4. 10's and 235 tires. At 2000rpm the speedometer read 60mph. I now have a 2001. 5 with 265's with a lower profile than the 235's on the one ton, and have 3. 55 gears and at 2000rpm the speedometer shows 70mph.

 

[StinkyCheeze]

I also have 4:10 With 6SPEED and have seen aproximately 59/60 mph at 2000 rpm 265/75/16 stock michelin LTX/MS tires on stock aluminum 8 x 16 wheels. Recently had speedometer checked (speeding ticket tactic) and found it "DEAD ON" at this speed (also checked on interstate mile posts.



PS: I think this engine likes to run at high rmp. It teally evens out and sounds smooth at 2500 rpm yielding 75 MPH (16 mpg in ideal conditions: empty, flat/smooth highway, sun at my back... )

 

[Wester]

My numbers are about the same as you

I've got a 2001, 5sp. with the 4:10's. Tire size is 235/75/16 (?)

and 2000 rpm puts me dead on 60 mph. Sounds like we are close to the same. If I run 75 mph to keep up with traffic, my rpm's are like 2300 or 2400. It is wound up, but it doesn't seem to bother the mighty 5. 9 I have been meaning to post a question to some of the operators with lots of time behind a Cummins to see if I am being rough on it at 2500 RPM... Maybe they will read this and reply... .

 

[JHerrlich]

Wester,



From what I understand, these engines are made to run at 100% duty cycle. That means run at redline 'till recommended overhaul. Someone go ahead and correct me if I'm off base.



BTW, mine ran at dead 60@2000 RPM. That was verified w/ my GPS. Now that I have 315/75's on I'm right at or just below 65@2000 RPM.

 

[geusterman]

You may not believe this but I am 1250 rpm at 60mph. 1500 rpm at 70. Nice cruiser. George

 

[milehigh.o.]

I just tested mine at lunch. I was about 58mph @ 2000 rpm's. I have the 6spd H. O. with 4. 10 gears, 265/75/16 michelins.



I would love to trade out of these gears and lower down. Dealer quote was way crazy on the price. :--)



Anyone wanna trade, must have low miles?

 

[cmckinney]

Running 2000 RPM I am at around 68-69 MPH with 3. 54 and 265/75/R16 tires.



-CM

 

[WadePatton]

I'd get that in the Classifieds--I'm sure somebody does. Especially if they tow heavy without mods.



Dealer should have quoted you 3. 5-4x what a truck racing shop would have charged. SOP.

Originally posted by milehigh. o.





I would love to trade out of these gears and lower down. Dealer quote was way crazy on the price. :--)



Anyone wanna trade, must have low miles?

 

[NVR FNSH]

57-60mph sounds about right for 2000 RPM/4. 10s/265s. I run 4. 10s with 315/75R16s and according to my GPS I'm going 66mph at 2000 RPM For the same engine RPM you will be travelling slower than I do since your tires are a smaller diameter (really it's a shorter loaded radius)



The cheapest way to cut your cruising RPM is to install taller tires.



Brian