Just curious to see what people are getting with these bricks with different wheel/ gear/engine setups.
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What's everyone's speed at 3k RPM?
- Thread starter Nicholas
- Start date
OP
Mines about 65 in 6th at 3k on my 3.73s. Bet your acceleration feels like a tesla in your jeep with 4.88s on those tires
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Runs as good as the 2.4 can I suppose. Certainly not a speed demon but far better than the 3.73's it had.
Roughly 77 mph at 3000. 5.38 gears, 35" (34.8) tires, 42RLE transmission.
OP
Kiwi TJ
I don't suffer from insanity I enjoy every minute
Supporting Member
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What is this 70+mph you speak of ??? :thinking:
Jeepaholic
TJ Enthusiast
:drive:
I've never tried to hit 3k in 6th, because that is hauling ass! According to grim jeeper calculator, 95 mph! I've only had it up to about 80, any faster is stupid in my opinion....6 speed, 35x12.5x15, 3.73s. Getting 4.88s tomorrow though! Calculator says 73 mph @ 3k rpm with those. Thinking i might have over geared now reading that...lol! Just got done loading it up!
Xposure
TJ Enthusiast
Nope. That sounds about right. You'll like your lower gearing.
I go pretty much exactly 80 mph at 3k with my 5 speed, 4.56's, and 33's. Pretty happy with that combination. If I didn't drive it on the highway so much, I would've gone with 4.88's. Nice having a little less wear on everything with the 4.56's.
OP
81 mph @ 3,000 rpm observed with calibrated speedometer and confirmed by GPS. '06 LJ Rubicon, 4.0l, 42RLE, NP241OR, 5.38 gears, Mickey Thompson Baja ATZ P3 "metric" 35's (315/75) on 8" rims and inflated to 26 psi.
Note: Gear calculators, while helpful for choosing an appropriate gear ratio, will not yield 100% accurate "real world" mph @ rpm results using manufacturers' published tire diameters which typically measure a mounted and inflated tire off the ground vs. the actual rolling radius or rolling circumference of a tire on the ground at speed. For example, grimmjeeper.com calculates 83 mph at 3,000 rpm for my transmission, transfer case, gear ratio and published tire diameter vs. an actual 81 mph at 3,000 rpm. Its not a huge difference, but a difference nonetheless.
Note: Gear calculators, while helpful for choosing an appropriate gear ratio, will not yield 100% accurate "real world" mph @ rpm results using manufacturers' published tire diameters which typically measure a mounted and inflated tire off the ground vs. the actual rolling radius or rolling circumference of a tire on the ground at speed. For example, grimmjeeper.com calculates 83 mph at 3,000 rpm for my transmission, transfer case, gear ratio and published tire diameter vs. an actual 81 mph at 3,000 rpm. Its not a huge difference, but a difference nonetheless.
Something I've realized on Grimmjeeper, is that the OD gear for the nv3550 is not accurate. GJ lists it as .73, while everywhere else says .78
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Same wheel rpm with a bigger tire is going to mean more vehicle speed.
3k engine rpm with the same gearing means same wheel rpm.
Circumference of 35" is 1.0606 times larger than the circumference of a 33".
1.0606 x 80 mph = 84.848 mph.
Edit: Might have misinterpreted the question of "how" here, but I'm gonna leave this here anyway.
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