Manual locking hubs....any difference in MPG?

off-roader

Expedition Leader
What type did you get? I am looking at a Tuff Pans set for the front of my 99. I am emailing them to see if they will work on Gen 2.5.
View attachment 99709
Yes they will. Remember, aside from the obvious body, engine and R&P gear ratio changes, the gen 2.5 IS a Gen 2.0 and the rest of the running gear (including the axles/differential assembly excluding the R&P) are the same.
 
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Monterorider

Adventurer
And where are you guys getting these hubs? I'm interested primarily for drivetrain wear reduction.

And for Mr. Scrubber, I've been seeing 21-22 mpg hwy 14-15mpg mixed (mostly city) with my 33x12.50s..... (miles adjusted accordingly for tire size)
22 mpg on fat 33s. I'll believe it when I see it. Mixed mileage seams reasonable. Through in some manual hub you'll get close to 30 hwy.

Although I wonder what "I've been seeing .." really means. I had been seeing 30 mpg driving 26000lb truck. That's briefly downhill with tailwind. Averaged though about 6-7 tough moving from Kansas City to Portland. :smiley_drive: That was at $5 a gallon for diesel in 08. Gladly my employer picked up a tab.
Measurements of mileage on anything less than tankful is meaningless.
 
Yes, I religiously check my fuel mileage and I rarely fill up before the gas light comes on.

Maybe I should clarify, the hwy mileages I mentioned was from a trip where I traveled at 65mph on the interstate From Dallas to Alexandria, LA- 340 miles each way. Two consecutive tanks one at 22mpg and the second at 21 (sped up to 70) and it was all hwy.

On the way back, on the same hwy, i got 19 and 20mpg.

Sorry for the off topic chatter....
 

Monterorider

Adventurer
22 adjusted for tire size I take?
Between 2 Monties I've had, best I've seen was close to 20 mpg on Gen 2 stock 31s which was like 12 years ago just after I got it, 18 on 33s, flat land at high elevation, under 65 mph. Gen 3 18 stock tires and about 16 with 33s. One would think Gen 3 would be more aerodynamic than Gen 2 and get better millage. That is with caviat that I usually go speed limit +5-8. I have not had a nerve trying to slow down to 55 or something. I can tell that each + 10 mph costs me at least 1 mpg in Power Wagon.
 

scrubber3

Not really here
When you pass 60MPH fuel efficiency starts to nose dive drastically in almost every vehicle on the planet. Nearly all vehicles made have been geared for averaging 45 to 55 MPH to achieve maximum efficiency. Hence the reason for the significant drop in fuel efficiency after those speeds are exceeded. Some cars being made today are designed to run with the increased average speed and maintain some efficiency above 60, but just barely. Now.... if we could only alter the atmosphere. :Astrologist:
 

RichardT

Adventurer
I've been debating about installing some manual locking hubs, but after a little bit of searching, I'm having a hard time finding anyone who makes them for my 95 SR.......which have you guys installed?
 

scrubber3

Not really here
The hubs fit SR and LS just the same I believe. I have the ones that tuff pans make and they work fine.
 

off-roader

Expedition Leader
I've been debating about installing some manual locking hubs, but after a little bit of searching, I'm having a hard time finding anyone who makes them for my 95 SR.......which have you guys installed?
There a 4 brands currently 'available'...
Aisin made the OE units and are highly regarded over all others due to their reliability and simplicity.
Tuffpans sells what look like aisin knock offs from china. So far they've been reliable.
Rugged Ridge also make a set
Superwinch also makes a manual hub set although I'm not sure they're still in production.
 

Monterorider

Adventurer
How do you guys adjust the tire size to match the actual mileage?
I'm running 33s on my 2.5 gen
Using tire spec method!
Suppose you have Yokohama Geolander. Lookup specs http://www.tirerack.com/tires/tires...5GEOATS&vehicleSearch=false&fromCompare1=yes# click specs.
Stock size 265/70R15 - 700 Revolutions per mile
You've got 285/75R16 - 623 Revolutions per mile.
Take your odometer reading (whatever number of miles)
miles * (700/632) = miles * (~1.1235) = actual number of miles traveled. Calculate you mpg based on that.
Just like Ray said about 12% difference. So say if you calculate based on odometer 15 mpg, your real mpg is +12% = 16.8.

Of course true/real mpg is different. Usually speedometer/odometer is off somewhat. It overstates speed and odometer by 2-5% usually. Hence mpg is as well. To get true value you have to subtract that difference from above percentage.

Use GPS or well know distances to figure that out. From personal experience on Montero my actual speed is only about 2-3 mph above shown on speedometer at 60+ mph on 285/75R16. Which points to only 5% difference in speed/odometer/mpg.

If you have GPS and who doesn't. Get on level interstate. Set you cruise to say 70 mph or 60 doesn't matter that much but higher gives you more accurate reading (77 v 70 is easier to tell than 11 v 10). Stay legal please. Once you get steady going record your speedometer and GPS speed reading. Or better yet travel say 100 miles by odometer and compare that with GPS trip data
GPS speed/distance divided by speedometer/odometer reading will give you true coefficient to adjust calculated mpg. I my case it's only about (1.05) or+5%.
 
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off-roader

Expedition Leader
My calculations are pretty simple and straight forward actually. The 33" tire is ~12% larger than the 29" tire hence it's a 12% increase in speed regardless of how accurate the speedometer is.

Now that said it is important to know your actual speed and in my experience comparing the speedo against several gps units, the OE speedometer has been accurate to within 1-2mph or so at freeway speeds.:ylsmoke:
 

eurosonic

Expedition Leader
Ok, so with 12% difference it looks like best Im getting with 33s is around 15 mpg. Hopefully the new hubs will kick it up a bit.
 

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