What speed at 2000 rpm?

linewarbr · **Posted:** Tue Oct 27, 2009 3:44 pm

What speed are you travelling in 5th gear lockup at 2000 rpm? Mine is 71 or so on the speedo, 68 via GPS.

Anyone know the stock rear gear ratio on the CRD?

RAF 3829 · **Posted:** Tue Oct 27, 2009 5:39 pm

I 'think' it's 3.42

MrMopar64 · **Posted:** Tue Oct 27, 2009 5:40 pm

Stock gear ratio is 3.73:1, axle is the Chrysler corporate 8.25" (it's the same axle from the 1960s.....)

68 is about the right speed to be going at 2000rpm in 5th LU. Sounds like the revs/mile in the body computer need to be adjusted slightly

mikey1273 · **Posted:** Tue Oct 27, 2009 5:50 pm

mine reads about 70 on the speedo also

tonycrd · **Posted:** Tue Oct 27, 2009 5:59 pm

MrMopar64 wrote:

Stock gear ratio is 3.73:1, axle is the Chrysler corporate 8.25" (it's the same axle from the 1960s.....)

Mine has 4.10's factory installed...Some exports got Dana 44 rear axles...

MrMopar64 · **Posted:** Tue Oct 27, 2009 6:37 pm

Those specs were for 2005 and newer KJs, both export and US models. Auto was 3.73, 6spd was 3.55, both with 8.25" rear axles.

I think 4.10 might have been an option with the earlier models that had slightly different drivetrain, same for the axles. I'll have to confirm tomorrow if that is the case.

Glend · **Posted:** Tue Oct 27, 2009 9:03 pm

Yep, I've got 3.73 , the Corporate 8.25 rear axle, Dana 30 up front - 2007 CRD auto. Your build sheet will have that detail. Do they still send out build sheets?

CATCRD · **Posted:** Tue Oct 27, 2009 11:49 pm

With stock tires mine would do 67mph (GPS) at 2000 rpm.

tulsa · **Posted:** Wed Oct 28, 2009 9:34 am

At 2000 RPM my speedometer reads 67MPH.

CRDMiller · **Posted:** Wed Oct 28, 2009 3:28 pm

at 2k (1999.52) rpm I'm turning 76 (76.2) mph.
65 is 1705 rpm.
70 is 1850 (or so)

3.73 gears
.67 od
32 inch rubber. (exactly 32 inch)

dirtmover · **Posted:** Wed Oct 28, 2009 5:16 pm

Stock wheels and tires:

speedometer = 118km/h
GPS = 110km/h

WolverineFW · **Posted:** Wed Oct 28, 2009 8:04 pm

dirtmover wrote:

Stock wheels and tires:

speedometer = 118km/h
GPS = 110km/h

Mine is pretty much the same give or take 1 km/h.

barnez224 · **Joined:** Fri Jan 19, 2007 11:28 am **Posts:** 130

right around 68mph for me. 70 push the rpm's just a hair north of 2K.

stoutdog · **Posted:** Sat Oct 31, 2009 4:05 pm

CRDMiller wrote:

at 2k (1999.52) rpm I'm turning 76 (76.2) mph.
65 is 1705 rpm.
70 is 1850 (or so)

3.73 gears
.67 od
32 inch rubber. (exactly 32 inch)

Wow, do the 3.73 gears make that much of a difference? I'm going 70 (GPS measured) at ~2100 rpm. My speedo is so far off that what looks like 70 (around 1900 rpm) is actually about 66.

ATXKJ · **Posted:** Sat Oct 31, 2009 5:05 pm

stoutdog wrote:

CRDMiller wrote:

at 2k (1999.52) rpm I'm turning 76 (76.2) mph.
65 is 1705 rpm.
70 is 1850 (or so)

3.73 gears
.67 od
32 inch rubber. (exactly 32 inch)

Wow, do the 3.73 gears make that much of a difference? I'm going 70 (GPS measured) at ~2100 rpm. My speedo is so far off that what looks like 70 (around 1900 rpm) is actually about 66.

Gears are the same (all the US CRD's have 3.73 unless you changed them)

He's running 235/85/16's - 32" tires

stoutdog · **Posted:** Sat Oct 31, 2009 5:52 pm

ATXKJ wrote:

stoutdog wrote:

CRDMiller wrote:

at 2k (1999.52) rpm I'm turning 76 (76.2) mph.
65 is 1705 rpm.
70 is 1850 (or so)

3.73 gears
.67 od
32 inch rubber. (exactly 32 inch)

Wow, do the 3.73 gears make that much of a difference? I'm going 70 (GPS measured) at ~2100 rpm. My speedo is so far off that what looks like 70 (around 1900 rpm) is actually about 66.

Gears are the same (all the US CRD's have 3.73 unless you changed them)

He's running 235/85/16's - 32" tires

Ahh, forgive my ignorance, but what are the stock tires? Is there any real advantage to running 235/85/16's - 32" tires and would this be an easy change? I can imagine that running 65 @ 1705 rpm = a lot better mpg than running 60 @ 1800....

Are there any disadvantages? (i.e. handling, ride comfort, etc.)

ATXKJ · **Posted:** Sat Oct 31, 2009 9:43 pm

Stock was 225/7516 - a 29.3" tire so 10% from the 235/85/16

and one of the key's from a mileage standpoint is that it was a 27lb tire paper thin - lots of flats - but better mileage

I switched to MTR's ~50+ lbs/tire - about 2-3mpg hit for tires alone (dependent on driving)

Bigger tires - are very dependent on how you drive

- if you're on the highway ~60-65 and no hotrodding -mileage is better

but stop and go - it takes more energy to accelerate - worse mileage.

What speed at 2000 rpm?

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