331 gears?

331 gears?
SANDBLASTER

SANDBLASTER

Jeeper
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Location
Kaufman County, Texas
Vehicle(s)
CJ-7
258 inline six,4speed ,AMC 20/30diffs,331 gears
FRONT AUSSIE LOCKER,BDS 3 INCH SUSPENSION LIFT, 33X1250X15 BFG AT'S
Will my CJ7 , AMC 258 i6 / 4.2l , with 331 gears be able to handle 33x1250x15 tires
3 inch lift, trac-lock rear, aussie locker front...
 
IOPort51 said:
define "handle". Are you looking for an 8 second quarter mile?:cool:
Click to expand...
My tranny is a 4 speed with the AMC 258 i6 / 4.2l - AMC 258 i6 / 4.2l six I'm just trying to be sure I have enough engine and tranny to have no un-forseen problems moving up to a 33 inch tire x 1250 x 15...(question based on another post I read)
 
SANDBLASTER said:
Will my CJ7 , AMC 258 i6 / 4.2l , with 331 gears be able to handle 33x1250x15 tires
3 inch lift, trac-lock rear, aussie locker front...
Click to expand...

On the highway it won't have much power.
Off road it will have NO power.
Having never ran that combo that is just my 2 cents.
 
Here's a link to a cal. to help you figure out your rpm's Gear Ratio Calculator

Your new tires are not only taller, they are also wider so it will take more power to turn them.
Most people want something closer to 4.10's with 33's.
 
Howdy,

Everything I have ever read on tires to gear ratio is this; 33 inch tires for best economy is 4.10 rpm @ 60 mph is 2350. I plan on running 3.73 when I go to 33 inch. This is because my CJ will not likely see anything over 60 mph. My rpm at 60 should be 2500 or so.
Most 4x4 parts houses online have a tires section and gear to tires section
Haven't talked this much in about two months WoW :notworthy:

Have a Great day
 
wilurb63 said:
Howdy,

Everything I have ever read on tires to gear ratio is this; 33 inch tires for best economy is 4.10 rpm @ 60 mph is 2350. I plan on running 3.73 when I go to 33 inch. This is because my CJ will not likely see anything over 60 mph. My rpm at 60 should be 2500 or so.
Most 4x4 parts houses online have a tires section and gear to tires section
Haven't talked this much in about two months WoW :notworthy:

Have a Great day
Click to expand...
SOMEONE HELP ...:confused: So I recon I should just stay with the 31's on the cj now gona look strange with A 3 INCH LIFT ???
 
I have a T-18 with 33's and 331's... it isn't great, but it gets the job done... the plan is to go to 4.10's or perhaps 4.56's if I plan on 35's...

So, where do you feel it? Well, I feel it on the top end somewhat, not more then 60-65 without a lot of noise from the motor.

On the low end, the granny compensates fine.

cb
 
Well, you made me talk somemore. Who said anything about tire size?

You asked about Gear Ratio 3.31 and running 33's and I said you need to run either 4.10 or 3.73. If you go with the 33's use a good quality 4" lift and no tire rub.............there I go again talk,talk.............Later
 
SANDBLASTER said:
SOMEONE HELP ...:confused: So I recon I should just stay with the 31's on the cj now gona look strange with A 3 INCH LIFT ???
Click to expand...

Here's my $.02 With the gears you have, I would keep to the 31's you have. You'll still be able to have a decent low and mid range power, and not have any ill effects at highway speed. Go too big, and you'll just end up with poor performance all around. As long as you ony have 3" under it, the lift with 31's should look just fine.
 
I don't think you will have to worry about your drive train as much as you will with your body, 33'' tires and your going to need at least a 4'' suspension lift, or your 3'' plus a body lift for the tires to clear. Thats just my .02:). Don't get me wrong you would notice the power loss.
 
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I had the 33" tires and 3.31 gears it will slow down a little with the extra tire under it. :chug:
 
To answer your first question we would need to know the gear ratio of your Transmission . As far as handling the 33's it depends on your use. High gear unless it's an Overdrive , and those are usually on 5 speeds, have a one to one ratio. So with 33's running down the highway at 65 you would be running about 2191 rpm. With 31's you would be at 2332 rpm. I run 31's on my '81 CJ5 with the same motor, a 4 speed T18A (6.32:1 low gear), Dana 20 xfer case and 3.31 gears. I have a 3" lift and I don't think it looks bad at all. In fact I like the looks of it. I have run it over the Rubicon several times with no problems and it goes down the highway just fine. 33's would look a little heftier but for rock climbing I like a low center of gravity which I get with the 31's. I can also maneuver better with the smaller tires which helps me get around things others have to go over. I think your jeep could handle the 33s just fine but you would see a little loss of performance and maneuverability off road. Use the chart that Old Dog posted above and it will help you make the choice.



Tommy
 
THANKS TOMMY, but this thread is from Jan.2010,:)
 
Run the 3.31's. When you up size to 35" tires change your gears.
 
SANDBLASTER said:
SOMEONE HELP ...:confused: So I recon I should just stay with the 31's on the cj now gona look strange with A 3 INCH LIFT ???
Click to expand...
31's will look fine with a 3" lift. Running 33's with that gearing will not only net you bad acceleration, and horrible bottom end torque, but it will also pay a price on your clutch.
 
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