On my truck the "Sweet Spot" for me is 68 mph. Even though this is alittle
fast. It puts me at 1900 rpm with my 3.54 gears. Best power and mpg for me.
Anyone have any different experiences ? This is towing my 7500# travel trailer.

 

Mine used to be around 62 mph.
Makes it tough as that is a bit over the limit onn 55mph roads. I say used to be as it changed either with the rebuilt pump or ULSD. Still working to find the new speed.

68 mph is past the speed rating of many trailer tires.

 

I agree with the 1900 or so number - - even 17 or 1800 is good on mine, but I am running 4.10 rear end and 6 speed stick. Just purrrrrrrrrrrssssssss. Pulling 16,000 pounds at that speed gives me just under 13 mpg.

 

im on the fence to gear to 4.10 or leave the 3.55's. 4th gear is dead on 1900rpm doing 58 or so with thw toyhauler, nets 12-13 mpg. gotta get to2200-2300 to hold 4th in the hills. i think ill just leave it alone.

 

hmmmmmm, depends what i'm towing and where. heavy load would be 2000rpm at 60, light loads 70 max 1800 - 1900, its not hard to tow em fast, but it can be tricky stopping them fast.

 

With a built tranny I pull by the EGT gauge rather than the rpm...unless I'm in hills. But I do try to keep it @ 1800-2000 which is @ 68 in OD.

 

2000 revs will give me about 62 mph. 4.10 rear with 6 speed Armstrong tranny. Depending on the wind, I see somewhere around 12 mpg towing the toy hauler.

 

1800 nets me about 55 with my 4'10'a, works well for the 14k fiver. Solo, at 70, about 2350, she gets thirsty, 15-16. If I keep it under 2000, it is good for 20.

 

Pulling 10k 5th wheel w/ stock truck, 67mph seems to do great on the highway pulling small grades no sweat. I'm around 12mpg usually.

 

About 1900 is the sweet spot for me too - about 67 or so MPH. (3.54's)

Which is fine if its just me and the truck camper, but when I am towing in CA the speed limit is 55 MPH. Too slow for 6th and too fast for 5th. I have a hard time towing at 55 mph.

-Vic

 

right around 2000 rpm and 70 mph or so with 3.73 gears that is about perfect, that is while pulling our 35' 12,000 lb 5er.

 

Why I swapped the ST for "E" LT's the day after I got my 5er..

 

My sweet spot is 73 mph pulling a 8000lb travel trailer. That speed & rpm combo helps when going up hills also.

 

I'm the same as you guys with the 6sp... 1900-2000 is the best speed for mpg, but for pulling hills, 2300 seems to be the number.

Towing my 16-17k 5er, I get anywhere from 9-12 depending on terrain and wind.

What I'd love to do, if I had the $$, is swap up to 4.10s and add a GearVendors overdrive. It'd be more for running empty than anything, but I do think 4.10s are a better towing gear with the manual than the 3.73s. You don't have to rev it quite as hard between shifts.

Rob

 

With the 4re auto in Calif, 55mph is kinda lugging the OD at about 1600 rpm, so I keep it in 3rd (2300 r's)when the CHP is lighting up the radar detector. Get away from the metro areas on nice pavement and OD (4th) at 1800 rpm runs about 68 mph, much like the feedback here. But it's a much smoother and quieter ride in OD. 11-12 mph in either case. That's with a 10.5k lbs toy hauler. Seems like she's screamin' @ 23-2400 rpm in 3rd. Don't like to do that for a long time, unless it's in the mountains.

Kurt W.