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Old 07-28-2013, 10:25 PM   #1
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RPM's

I have had my 02 Wrangler X for about 2 months now. At about 60mph it is at 3000RPM's...Is this normal?
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Old 07-28-2013, 10:36 PM   #2
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What tranny and tire size are you running?

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Old 07-28-2013, 11:45 PM   #3
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No. Even if you had stock tires and an automatic that is high. I have a 2000 5 speed And 4th gear is the same as 3rd on an auto. My axles came with 3.73. I run a little over 2000 at 60 in 4th I think with 31's. my guess is the previous owner re geared and had much bigger tires, then either kept them for his new rig or they were so bald he put smaller cheaper ones on to sell it. Good news is you can buy se bigger tires and not re gear.
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Old 07-29-2013, 12:17 AM   #4
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Im with 30's and stock 3.73 gears and run about 2100 rpm at 60mph.

Apparently, they guy who owned it before, had like 35's on it and got it re geared.
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Old 07-29-2013, 03:33 AM   #5
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I have a 97 TJ with 3 speed auto (33" tires and 4.10 gearing)
60 mph - 2700 RPM (approx.)
65 mph - 2800 RPM (approx.)
70 mph - 3000 RPM
75 mph - 3250 RPM

When I had stock gearing (3.07) and 33" tires,the RPMs were much lower but I had the pedal to the metal just to get along on the highway - especially going uphill or punching a head-wind and the auto would keep shifting down.

Now (with 33's and 4.10's) the RPMs are higher but I'm using a lot less accelerator to get along.
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Old 07-29-2013, 04:15 AM   #6
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Same as Wesboy. Now I'm IMO a little too high to run comfortably at highway speeds. But it does cruise around town a little better. Sounds to me like you might have 4.56s or 4.88s. We need to know what trans and engine and tire size you have.
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Old 07-29-2013, 08:17 PM   #7
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Ok let me make sure I clarify...at 60mph it runs about 3000RPM. It is an automatic, 4.0 and it has 30's that came on it. So will the bigger tires help with the RPM's and the gas mileage?
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Old 07-29-2013, 08:30 PM   #8
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The higher gearing number you have, (3.07,3.73, 4.10 ect..) the faster your axles will spin, according to your input shaft speed.

If the drive shaft speed going INTO your axle is say, 100RPM and you have an axle gearing ratio of 3.73 : 1, your axle shafts(that spin your tires) will spin at a rate of 373 RPM.

The higher ratio you have, the faster your tires will spin, according to your input shaft's speed.

This is helpful for acceleration and traveling at highway speeds. You cant drive 60MPH at 1500 rpm. youd be bogging the hell out of the engine.

Stock, 30in tires and 3.73 gears, i run about 2100 RPMs at 60MPH.

If i were to get bigger tires, my RPMs at 60MPH would drop because the tires wouldn't be spinning as fast because they have more distance to travel to make one rotation than a smaller tire.(bigger circumference vs smaller circumference)

If you re-geared back down, you would get better gas mileage. As for getting bigger tires, one would think that it would help your gas mileage by keeping your RPM's lower. I can't speak from experience though.
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Old 07-29-2013, 08:45 PM   #9
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Quote:
Originally Posted by jherrington View Post
The higher gearing number you have, (3.07,3.73, 4.10 ect..) the faster your axles will spin, according to your input shaft speed.

If the drive shaft speed going INTO your axle is say, 100RPM and you have an axle gearing ratio of 3.73 : 1, your axle shafts(that spin your tires) will spin at a rate of 373 RPM.

The higher ratio you have, the faster your tires will spin, according to your input shaft's speed.

This is helpful for acceleration and traveling at highway speeds. You cant drive 60MPH at 1500 rpm. youd be bogging the hell out of the engine.

Stock, 30in tires and 3.73 gears, i run about 2100 RPMs at 60MPH.

If i were to get bigger tires, my RPMs at 60MPH would drop because the tires wouldn't be spinning as fast because they have more distance to travel to make one rotation than a smaller tire.(bigger circumference vs smaller circumference)

If you re-geared back down, you would get better gas mileage. As for getting bigger tires, one would think that it would help your gas mileage by keeping your RPM's lower. I can't speak from experience though.
Yes. My 4.10s dropped my mileage 2-3 mpg on the highway. Not a happy camper.
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Old 07-29-2013, 09:18 PM   #10
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I like power it has...it really is pretty quick...so maybe I shouldn't re gear back down..
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Old 07-29-2013, 09:38 PM   #11
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Quote:
Originally Posted by jamiealex31 View Post
I like power it has...it really is pretty quick...so maybe I shouldn't re gear back down..
Of course it's fast, you're running it like a race car keeping it at those RPM's. keeping your engine at that high of rpms WILL wear on your engine over time faster than it would if you were at proper gearing.
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Old 07-29-2013, 09:51 PM   #12
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Ok so advice would be to gear it back down to save the vehicle in the long run?
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Old 07-29-2013, 10:08 PM   #13
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Quote:
Originally Posted by jamiealex31 View Post
Ok so advice would be to gear it back down to save the vehicle in the long run?
No. Does your Wrangler have a lift? Re-gearing will cost you too much money for little to no benefit. Get bigger tires.
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Old 07-31-2013, 09:03 PM   #14
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No it doesn't have a lift...I just don't want to wear the motor out running it at that high of RPM's.
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Old 07-31-2013, 09:10 PM   #15
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Quote:
Originally Posted by jamiealex31 View Post
No it doesn't have a lift...I just don't want to wear the motor out running it at that high of RPM's.
Well, you could
1. Re gear. $1-2k
2. Put a lift kit on it, and put the correct size tires on it. $1.5k
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Old 07-31-2013, 09:13 PM   #16
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Quote:
Originally Posted by jamiealex31 View Post
No it doesn't have a lift...I just don't want to wear the motor out running it at that high of RPM's.
You need to make sure it's a gearing issue and not a transmission issue before jumping right to a regear. Jack up the back wheels, and count the number of revolutions the driveshaft makes in two revolutions of the tire. That will be your gear ratio. Then post it on here and someone can tell you if your engine is running at the right rpm according to your ratio.
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Old 07-31-2013, 09:33 PM   #17
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Quote:
Originally Posted by Water Dog View Post

You need to make sure it's a gearing issue and not a transmission issue before jumping right to a regear. Jack up the back wheels, and count the number of revolutions the driveshaft makes in two revolutions of the tire. That will be your gear ratio. Then post it on here and someone can tell you if your engine is running at the right rpm according to your ratio.
His transmission has nothing to do with his high rpms. He has a manual anyways.
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Old 07-31-2013, 09:41 PM   #18
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^^Don't think he has a stick according to him. It could be a problem with a slipping torque converter at high speed, or a tranmission not shifting into 3rd gear.

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Ok let me make sure I clarify...It is an automatic, 4.0 and it has 30's that came on it.
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Old 07-31-2013, 10:32 PM   #19
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Oops, I was looking at the wrong poster.


I would still bet against it being the transmission though.
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Old 07-31-2013, 10:51 PM   #20
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Can we identify the gears first then go from there?
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Old 07-31-2013, 10:57 PM   #21
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Can we identify the gears first then go from there?
Sure we can. I've got no problem with it. I was still just saying that I doubt it's the trans.
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Old 07-31-2013, 10:57 PM   #22
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I doubt it is either but first things first right
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Old 08-01-2013, 12:36 AM   #23
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I doubt it too, just don't want to see someone throw a bunch of wasted $'s away.
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Old 09-10-2013, 08:02 PM   #24
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To the OP, whatever came of this? I am interested because my 02 4.0L with auto also revs at about 3000 at 60. The tag on the front diff says 3:73 but it has these dinky 225/70's on it. I'm saving my pennies for new tires. If 30's would get it down to 2100 at 60, I'd be happy with that.

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