Dale's 2021 JT sport build not named yet

Dale72

Dale72

Hooked
benatc1 said:
I think it will be enough too, my jeep gets pretty heavy when we all go camping though so might want bit more. I need to look at RPMs too at cruising speed between the 2
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Yeah 5.13s might be better. Especially since I will be adding more weight when I start putting things on it for camping
 
Lperdue

Lperdue

Active Member
Dale72 said:
With the 8 speed transmission I was told all you need is 4.88s even with 37's.
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I'm currently running 5.13's with 38 ridgegrapplers and am sitting at around 15-17 mpg at 65 mph (little to no head wind).

Depending on your driving I found that moving to 5.13's in 8th gear has a final drive ratio similar to running with 4.10's in 7th (see photos). And with a good head wind or hill I still drop down to 7th even now. Due to the gladiator being so heavy and if your doing any towing, live in a hilly/mountainous area, and or deal with heavy head winds I recommend going with 5.13's.

Most recent example was on the way to the new years run due to high winds/hills is was stuck in 6-7 gear most of the trip trying to stay at 70 mph and that's with 5.13's not sure how I would feel at 4.88s.

I should also note that putting the rpms to low will put the 3.6 out of its powerband and usable torque and might even cause it to start hunting for gears more often.

1643395368905.png 1643395397800.png 1643395456362.png
 
benatc1

benatc1

Hooked
Lperdue said:
I'm currently running 5.13's with 38 ridgegrapplers and am sitting at around 15-17 mpg at 65 mph (little to no head wind).

Depending on your driving I found that moving to 5.13's in 8th gear has a final drive ratio similar to running with 4.10's in 7th (see photos). And with a good head wind or hill I still drop down to 7th even now. Due to the gladiator being so heavy and if your doing any towing, live in a hilly/mountainous area, and or deal with heavy head winds I recommend going with 5.13's.

Most recent example was on the way to the new years run due to high winds/hills is was stuck in 6-7 gear most of the trip trying to stay at 70 mph and that's with 5.13's not sure how I would feel at 4.88s.

I should also note that putting the rpms to low will put the 3.6 out of its powerband and usable torque and might even cause it to start hunting for gears more often.

View attachment 371613 View attachment 371614 View attachment 371615
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Thanks for posting that, 100 rpms isnt that much a difference in 8th imo to get a little more gear out of it
 
Dale72

Dale72

Hooked
Lperdue said:
I'm currently running 5.13's with 38 ridgegrapplers and am sitting at around 15-17 mpg at 65 mph (little to no head wind).

Depending on your driving I found that moving to 5.13's in 8th gear has a final drive ratio similar to running with 4.10's in 7th (see photos). And with a good head wind or hill I still drop down to 7th even now. Due to the gladiator being so heavy and if your doing any towing, live in a hilly/mountainous area, and or deal with heavy head winds I recommend going with 5.13's.

Most recent example was on the way to the new years run due to high winds/hills is was stuck in 6-7 gear most of the trip trying to stay at 70 mph and that's with 5.13's not sure how I would feel at 4.88s.

I should also note that putting the rpms to low will put the 3.6 out of its powerband and usable torque and might even cause it to start hunting for gears more often.

View attachment 371613 View attachment 371614 View attachment 371615
Click to expand...
Well with the cruise set at 70 I'm getting 14.5. And when I dropped it to 65 I'm getting 15.4.
 
Lperdue

Lperdue

Active Member
Dale72 said:
Well with the cruise set at 70 I'm getting 14.5. And when I dropped it to 65 I'm getting 15.4.
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Yea I found that as soon as I hit 70 MPG drops pretty quick. Quick question what gear ratio is your JT? Also I'll do a 50-100 mile loop later today to give you more accurate numbers.
 
Lperdue

Lperdue

Active Member
benatc1 said:
Thanks for posting that, 100 rpms isnt that much a difference in 8th imo to get a little more gear out of it
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To be honest going with 4.88's will pretty much put you back at stock for a Rubicon or Mojave
[4.10*37]/32=4.74 gear ratio and I used 32 inch tall tires in this calculation because BFG run small and are not true 33's.

But the only issue is that it doesn't account for drag due to lifting of the JT or how much heavier the wheels themselves are. Because of this a little extra gearing is needed.
 
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