Why you need to swap gears if going to bigger tires
I will update after I get the gears broke in but for now here are the results
Short story
I knew from past experience that swapping gears was beneficial on performance and also gas mileage
I have had OHV-KJs front diff ( with 4.10s already installed) sitting in my garage since he did his SFA, yes that long! I also had bought the rears knowing I was going to do 265-75s sooner or later.
I had talked to sprsonic ( another LOST and KJC member here in Toledo) about installing the rears but our schedules never seemed to be good for the both of us.
I installed 265-75-16 Goodyear Duratracs last November and right away loved the tires but hated the way the KJ drove. On two lane roads at 55 there was no way I could just run it in overdrive, you kicked back and forth so often that it was annoying to say the least. Only time overdrive could be used at all was to keep the speed at 75-77 at least. Then it was only turning in the 1900/2000 range.
Up here in the great Northwest part of Ohio it's flat so at the 75-77 range I could get 20-20.5 pretty easy even lifted and the 265-75s but get on two lanes and mileage dropped a bunch, the KJ was simply not running in its sweet spot.
This past Saturday, the stars aligned and sprsonic was able to install my gears for me, ( he even threw the front diff in as well since it was up on the rack) so yesterday I took it out to break in the gears and also see the difference in drivability. I put about 120 miles on with a mixture of interstate and two lane. Driving taking a break to let the gears cool down, drive again etc.
Before at 60 mph with the OD on I was at 1650-1680, with it off at 60 I was at 2475-2500
Now with the 4.10s with the OD on I am at 1950-2000, with it off at 2775-2800. Its now running in more of the sweet spot where the engine was designed to run.
With the OD on I can actually drive down the road at 55 or 60 and its not trying to find a gear to stay in, it drives like it did stock almost. ( Speedo is still off by 4 MPH , was 8 off )
Another benefit, cruising at 70 ( OD on) I used to see 20-20.5 average, now I am seeing 22 -22.5 on the same road. Back roads ( two lane) at 50-55 I was seeing a lot of 23-24 according to the scan gauge yesterday and that was with the OD on even, before it would of been 15-17.
I still want to break them in more before any long trips but so far its well worth the $$$
( or should say the money I have in mine)
NOTE: All RPMs and MPG's/speed taken from the Scan gauge and GPS before and after
So for anyone even thinking "I want to run a 32 inch tire do I need to swap gears" , the answer is "Heck yes!!!!!"
I will update after I get the gears broke in but for now here are the results
Short story
I knew from past experience that swapping gears was beneficial on performance and also gas mileage
I have had OHV-KJs front diff ( with 4.10s already installed) sitting in my garage since he did his SFA, yes that long! I also had bought the rears knowing I was going to do 265-75s sooner or later.
I had talked to sprsonic ( another LOST and KJC member here in Toledo) about installing the rears but our schedules never seemed to be good for the both of us.
I installed 265-75-16 Goodyear Duratracs last November and right away loved the tires but hated the way the KJ drove. On two lane roads at 55 there was no way I could just run it in overdrive, you kicked back and forth so often that it was annoying to say the least. Only time overdrive could be used at all was to keep the speed at 75-77 at least. Then it was only turning in the 1900/2000 range.
Up here in the great Northwest part of Ohio it's flat so at the 75-77 range I could get 20-20.5 pretty easy even lifted and the 265-75s but get on two lanes and mileage dropped a bunch, the KJ was simply not running in its sweet spot.
This past Saturday, the stars aligned and sprsonic was able to install my gears for me, ( he even threw the front diff in as well since it was up on the rack) so yesterday I took it out to break in the gears and also see the difference in drivability. I put about 120 miles on with a mixture of interstate and two lane. Driving taking a break to let the gears cool down, drive again etc.
Before at 60 mph with the OD on I was at 1650-1680, with it off at 60 I was at 2475-2500
Now with the 4.10s with the OD on I am at 1950-2000, with it off at 2775-2800. Its now running in more of the sweet spot where the engine was designed to run.
With the OD on I can actually drive down the road at 55 or 60 and its not trying to find a gear to stay in, it drives like it did stock almost. ( Speedo is still off by 4 MPH , was 8 off )
Another benefit, cruising at 70 ( OD on) I used to see 20-20.5 average, now I am seeing 22 -22.5 on the same road. Back roads ( two lane) at 50-55 I was seeing a lot of 23-24 according to the scan gauge yesterday and that was with the OD on even, before it would of been 15-17.
I still want to break them in more before any long trips but so far its well worth the $$$
( or should say the money I have in mine)
NOTE: All RPMs and MPG's/speed taken from the Scan gauge and GPS before and after
So for anyone even thinking "I want to run a 32 inch tire do I need to swap gears" , the answer is "Heck yes!!!!!"
