PDA

View Full Version : 4.10 gears and 235's?


CheapXJ
August 6th, 2003, 02:02
4.0/aw4 with 4.10 gears and 235/75 R15s

anyone running this combo?

seems to me like it won't be all that bad

and if you're wondering, the 4.0L/AW4 is replacing a 2.5L/AX5 in an 87 MJ. it's already got 4.10 gears, and I am NOT swapping something else in there.

It will see alot of highway miles, but it'll be doing some towing too

woody
August 6th, 2003, 03:57
Not exactly the same, but ran 31s with 4.56:1 in the axles with great results.

My other XJ will get 4.56:1 to run 30-31" tires in a DD mode, and my 2WD MJ will get at least 4.10:1 to spin 245/60s

After suffering so long with 3.07 and 3.55 with 33", I like deep gears.

YMMV

Amund
August 6th, 2003, 04:20
I'm running 4,11 with 31" tires. 4,0 HO and aw4. I think the revs are way too high on the highway! But my lockup isn't locking up, something electrical not hooked up (I swapped this one in instead of a 2,5 as well), that may do a lot.

Eagle
August 6th, 2003, 05:14
235/75R15 and 4.10 gears works out to 2950 RPM at 60 MPH in direct (1:1) gear (3rd with auto, 4th with 5-speed), and somewhere around 2125 to 2150 in overdrive (depending on OD ratio).

The old AMCs in pre-overdrive days were typically geared to run 2500 RPM at 60 so you should be in fine shape.

techno1154
August 6th, 2003, 09:44
:) I am happy someone brought this up. I want to regear to 4.10 and run nothing larger than 30 tires. I am running now 235-75-15 with 3.55 and does 75 MPH on the highway at say 2,300 RPM. An extra 200 - 300 will not hurt the 4.0L I think and it will definiately prevent the AW4 from hunting between 3 and 4 when going up those long hills with the cruise control on.
From what I was made to understand, anything larger than 30 would require an outside mounting bracket for the spear and a suspension height increase to prevent rubbing at flex.
:dunno:

XJWheelie
August 6th, 2003, 12:52
I saw a chart one time that told what gears to use with each tire combo, but I can't find it now; does anyone know where I might look for it online?

Robert

LRRH
August 6th, 2003, 15:02
www.4lo.com/calc/geartable.htm

Eagle
August 6th, 2003, 21:32
Originally posted by XJWheelie
I saw a chart one time that told what gears to use with each tire combo, but I can't find it now; does anyone know where I might look for it online?

Robert

I don't have it on-line, but if you want a copy of my spreadsheet send me a PM with your e-mail address. Unlike the on-line calculators, mine is based on tire manufacturers' revolutions-per-mile figures, so it should be more accurate.

Also let me know if you prefer Excel or Quattro Pro format. It was made up in Quattro Pro but it seems to have survived translation into Excel fairly well.