RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

I have posted this once today, but for some reason it did not post.
If anyone finds it, sorry for the duplicate post.

Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
the 4.11 ratio would be better for me. I currently have 31" BFG All
Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
sort in the future when these wear out. I will never upgrade to
bigger than a 33" tire. As for off-roading, I do some light trail
riding and the occasional hop in the mud puddle when I find one that
looks fun. 80% of my driving is highway at approximately 70 miles
round trip at a speed of anywhere from 60-70 mph. The other 20% is
split between city driving (10%), and off-roading (10%). My main
goal
is to get my Jeep to drive as close as possible to the way it did
bone
stock (being able to use my 6th gear on the freeway) and to prevent
excessive wear and tear on my clutch and engine parts. Someone
please
help! : D

'06 TJ (4.0L with I-6)
6 speed manual
Dana 30 front/35 rear
current 3.07s


P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
(like
44s)? I don't know if this makes any difference as far as which gear
ratio to go with, but where I live (upstate NY), there can be quite a
bit of snow from Dec. - Apr.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 21, 11:47 am, Tracie <brain...@upstate.edu> wrote:
> I have posted this once today, but for some reason it did not post.
> If anyone finds it, sorry for the duplicate post.
>
> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
> the 4.11 ratio would be better for me. I currently have 31" BFG All
> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
> sort in the future when these wear out. I will never upgrade to
> bigger than a 33" tire. As for off-roading, I do some light trail
> riding and the occasional hop in the mud puddle when I find one that
> looks fun. 80% of my driving is highway at approximately 70 miles
> round trip at a speed of anywhere from 60-70 mph. The other 20% is
> split between city driving (10%), and off-roading (10%). My main
> goal
> is to get my Jeep to drive as close as possible to the way it did
> bone
> stock (being able to use my 6th gear on the freeway) and to prevent
> excessive wear and tear on my clutch and engine parts. Someone
> please
> help! : D
>
> '06 TJ (4.0L with I-6)
> 6 speed manual
> Dana 30 front/35 rear
> current 3.07s
>
> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
> (like
> 44s)? I don't know if this makes any difference as far as which gear
> ratio to go with, but where I live (upstate NY), there can be quite a
> bit of snow from Dec. - Apr.

Hi Tracie

I currently have 33' Dunlop Mud Rovers with 3.73 gears on my YJ. When
I went to 3.73 I was running 31" tires and the jeep performed well
both on and off road. When I went to the 33's I found that I really
needed 4:10/4.11. Best bet is to only do it once.

As far as axles go, your D30 in the front should be OK as long as you
are careful. There are a couple of people in my club who run 33"
tires on D35 rears (at 3.73) without any problems, but they are mostly
experienced drivers who are very careful, don't spin tires, and avoid
bouncing. I have had to help change axle shafts for other, less
experienced folks in the club who have locked 33s on locked D35s.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
> I have posted this once today, but for some reason it did not post.
> If anyone finds it, sorry for the duplicate post.
>
> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
> the 4.11 ratio would be better for me. I currently have 31" BFG All
> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
> sort in the future when these wear out. I will never upgrade to
> bigger than a 33" tire. As for off-roading, I do some light trail
> riding and the occasional hop in the mud puddle when I find one that
> looks fun. 80% of my driving is highway at approximately 70 miles
> round trip at a speed of anywhere from 60-70 mph. The other 20% is
> split between city driving (10%), and off-roading (10%). My main
> goal
> is to get my Jeep to drive as close as possible to the way it did
> bone
> stock (being able to use my 6th gear on the freeway) and to prevent
> excessive wear and tear on my clutch and engine parts. Someone
> please
> help! : D
>
> '06 TJ (4.0L with I-6)
> 6 speed manual
> Dana 30 front/35 rear
> current 3.07s
>
> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
> (like
> 44s)? I don't know if this makes any difference as far as which gear
> ratio to go with, but where I live (upstate NY), there can be quite a
> bit of snow from Dec. - Apr.

If you want it too run like it does now the ideal gear ration would be
3.07*33/31 = 3.27 rounded up to what is available. 3.55 seems to be
available. The 3.73 or 4.1 would give you better performance off road
but your fuel economy would suffer on the road.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

nrs wrote:
> On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
>> I have posted this once today, but for some reason it did not post.
>> If anyone finds it, sorry for the duplicate post.
>>
>> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
>> the 4.11 ratio would be better for me. I currently have 31" BFG All
>> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
>> sort in the future when these wear out. I will never upgrade to
>> bigger than a 33" tire. As for off-roading, I do some light trail
>> riding and the occasional hop in the mud puddle when I find one that
>> looks fun. 80% of my driving is highway at approximately 70 miles
>> round trip at a speed of anywhere from 60-70 mph. The other 20% is
>> split between city driving (10%), and off-roading (10%). My main
>> goal
>> is to get my Jeep to drive as close as possible to the way it did
>> bone
>> stock (being able to use my 6th gear on the freeway) and to prevent
>> excessive wear and tear on my clutch and engine parts. Someone
>> please
>> help! : D
>>
>> '06 TJ (4.0L with I-6)
>> 6 speed manual
>> Dana 30 front/35 rear
>> current 3.07s
>>
>> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
>> (like
>> 44s)? I don't know if this makes any difference as far as which gear
>> ratio to go with, but where I live (upstate NY), there can be quite a
>> bit of snow from Dec. - Apr.
>
> If you want it too run like it does now the ideal gear ration would be
> 3.07*33/31 = 3.27 rounded up to what is available. 3.55 seems to be
> available. The 3.73 or 4.1 would give you better performance off road
> but your fuel economy would suffer on the road.
>

Not necessarily. Her original tires were 225s I believe. If so her
original tires should be about 29", which would be close to the same
effective ratio as 3.55s with 33" tires. Going to 4.11s would result in
approximately 15% more RPM to attain the same speed. You have to
remember that going up in RPM doesn't cause a loss in fuel economy if
the gearing was too high to begin with. Since her highway RPM is below
the torque peak RPM of the engine, it is very possible she will see the
same, or even slightly improved economy. Besides, she is having to use
only 5th gear on the highway now, so obviously she needs more gear ratio.

Chris

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 21, 1:58 pm, c <c...@me.org> wrote:
> nrs wrote:
> > On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
> >> I have posted this once today, but for some reason it did not post.
> >> If anyone finds it, sorry for the duplicate post.
>
> >> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
> >> the 4.11 ratio would be better for me. I currently have 31" BFG All
> >> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
> >> sort in the future when these wear out. I will never upgrade to
> >> bigger than a 33" tire. As for off-roading, I do some light trail
> >> riding and the occasional hop in the mud puddle when I find one that
> >> looks fun. 80% of my driving is highway at approximately 70 miles
> >> round trip at a speed of anywhere from 60-70 mph. The other 20% is
> >> split between city driving (10%), and off-roading (10%). My main
> >> goal
> >> is to get my Jeep to drive as close as possible to the way it did
> >> bone
> >> stock (being able to use my 6th gear on the freeway) and to prevent
> >> excessive wear and tear on my clutch and engine parts. Someone
> >> please
> >> help! : D
>
> >> '06 TJ (4.0L with I-6)
> >> 6 speed manual
> >> Dana 30 front/35 rear
> >> current 3.07s
>
> >> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
> >> (like
> >> 44s)? I don't know if this makes any difference as far as which gear
> >> ratio to go with, but where I live (upstate NY), there can be quite a
> >> bit of snow from Dec. - Apr.
>
> > If you want it too run like it does now the ideal gear ration would be
> > 3.07*33/31 = 3.27 rounded up to what is available. 3.55 seems to be
> > available. The 3.73 or 4.1 would give you better performance off road
> > but your fuel economy would suffer on the road.
>
> Not necessarily. Her original tires were 225s I believe. If so her
> original tires should be about 29", which would be close to the same
> effective ratio as 3.55s with 33" tires. Going to 4.11s would result in
> approximately 15% more RPM to attain the same speed. You have to
> remember that going up in RPM doesn't cause a loss in fuel economy if
> the gearing was too high to begin with. Since her highway RPM is below
> the torque peak RPM of the engine, it is very possible she will see the
> same, or even slightly improved economy. Besides, she is having to use
> only 5th gear on the highway now, so obviously she needs more gear ratio.
>
> Chris- Hide quoted text -
>
> - Show quoted text -

Ok, that's true. To get close to stock you would need 3.07*33/28 =
3.62. So 3.73 would probably work well. I don't know enough about
the engine to know the ideal RPM so who knows, maybe 4.1 would be
better than stock. I do know it would be better off road.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

nrs wrote:
> On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
>> I have posted this once today, but for some reason it did not post.
>> If anyone finds it, sorry for the duplicate post.
>>
>> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
>> the 4.11 ratio would be better for me. I currently have 31" BFG All
>> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
>> sort in the future when these wear out. I will never upgrade to
>> bigger than a 33" tire. As for off-roading, I do some light trail
>> riding and the occasional hop in the mud puddle when I find one that
>> looks fun. 80% of my driving is highway at approximately 70 miles
>> round trip at a speed of anywhere from 60-70 mph. The other 20% is
>> split between city driving (10%), and off-roading (10%). My main
>> goal
>> is to get my Jeep to drive as close as possible to the way it did
>> bone
>> stock (being able to use my 6th gear on the freeway) and to prevent
>> excessive wear and tear on my clutch and engine parts. Someone
>> please
>> help! : D
>>
>> '06 TJ (4.0L with I-6)
>> 6 speed manual
>> Dana 30 front/35 rear
>> current 3.07s
>>
>> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
>> (like
>> 44s)? I don't know if this makes any difference as far as which gear
>> ratio to go with, but where I live (upstate NY), there can be quite a
>> bit of snow from Dec. - Apr.
>
> If you want it too run like it does now the ideal gear ration would be
> 3.07*33/31 = 3.27 rounded up to what is available. 3.55 seems to be
> available. The 3.73 or 4.1 would give you better performance off road
> but your fuel economy would suffer on the road.
>

Unfortunately the flying bricks we drive don't react the same as cars
when it comes to low revs.

Once you get the axles 'into' the air stream by raising the body away
from them with a suspension lift, it reacts 'strongly' to wind resistance.

On a lifted Jeep, anything much below 2000 rpm at highway speed will
start the engine lugging so you need way too much gas pedal to keep up
with wind twitches or slight hills.

Everyone I know and that has posted on the newsgroups that has 'dropped'
the overdrive with large tires and tall gears gets better mileage at
highway speeds.

My CJ7 came with overdrive (5th) and 3.31 gears or 'mileage' gears.
When I lifted it 3" and put 33's on, my mileage dropped by about 8 mpg
after calibrating the odometer when I drove it the same as before using
all the gears. It just 'doesn't' like 1750 rpm at 65 mph...

As soon as I stopped using 5th so I stayed in the 2300-2400 rpm range at
65 mph, my mileage jumped way up and has stayed a consistent 23 mpg to
this day.

Now I do have a manually 'tuned' carb engine with a 'hot' spark and
timing curve that insists on 91+ octane with a super light fiberglass
body (it only takes two people to 'easily' pick up the whole body tub
'with' the seats and roll bar in it) so the thing is basically an engine
on wheels that goes like a scalded cat, but still.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http :// www .imagestation,com /album/pictures.html?id!15147590
(More Off Road album links at bottom of the view page)

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 21, 2:09 pm, Mike Romain <roma...@sympatico.ca> wrote:
> nrs wrote:
> > On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
> >> I have posted this once today, but for some reason it did not post.
> >> If anyone finds it, sorry for the duplicate post.
>
> >> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
> >> the 4.11 ratio would be better for me. I currently have 31" BFG All
> >> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
> >> sort in the future when these wear out. I will never upgrade to
> >> bigger than a 33" tire. As for off-roading, I do some light trail
> >> riding and the occasional hop in the mud puddle when I find one that
> >> looks fun. 80% of my driving is highway at approximately 70 miles
> >> round trip at a speed of anywhere from 60-70 mph. The other 20% is
> >> split between city driving (10%), and off-roading (10%). My main
> >> goal
> >> is to get my Jeep to drive as close as possible to the way it did
> >> bone
> >> stock (being able to use my 6th gear on the freeway) and to prevent
> >> excessive wear and tear on my clutch and engine parts. Someone
> >> please
> >> help! : D
>
> >> '06 TJ (4.0L with I-6)
> >> 6 speed manual
> >> Dana 30 front/35 rear
> >> current 3.07s
>
> >> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
> >> (like
> >> 44s)? I don't know if this makes any difference as far as which gear
> >> ratio to go with, but where I live (upstate NY), there can be quite a
> >> bit of snow from Dec. - Apr.
>
> > If you want it too run like it does now the ideal gear ration would be
> > 3.07*33/31 =3D 3.27 rounded up to what is available. 3.55 seems to be
> > available. The 3.73 or 4.1 would give you better performance off road
> > but your fuel economy would suffer on the road.
>
> Unfortunately the flying bricks we drive don't react the same as cars
> when it comes to low revs.
>
> Once you get the axles 'into' the air stream by raising the body away
> from them with a suspension lift, it reacts 'strongly' to wind resistance.
>
> On a lifted Jeep, anything much below 2000 rpm at highway speed will
> start the engine lugging so you need way too much gas pedal to keep up
> with wind twitches or slight hills.
>
> Everyone I know and that has posted on the newsgroups that has 'dropped'
> the overdrive with large tires and tall gears gets better mileage at
> highway speeds.
>
> My CJ7 came with overdrive (5th) and 3.31 gears or 'mileage' gears.
> When I lifted it 3" and put 33's on, my mileage dropped by about 8 mpg
> after calibrating the odometer when I drove it the same as before using
> all the gears. It just 'doesn't' like 1750 rpm at 65 mph...
>
> As soon as I stopped using 5th so I stayed in the 2300-2400 rpm range at
> 65 mph, my mileage jumped way up and has stayed a consistent 23 mpg to
> this day.
>
> Now I do have a manually 'tuned' carb engine with a 'hot' spark and
> timing curve that insists on 91+ octane with a super light fiberglass
> body (it only takes two people to 'easily' pick up the whole body tub
> 'with' the seats and roll bar in it) so the thing is basically an engine
> on wheels that goes like a scalded cat, but still.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http :// www .imagestation,com /album/pictures.html?id=3D2115147590
> (More Off Road album links at bottom of the view page)- Hide quoted text -
>
> - Show quoted text -

Mike,

I=B4m going to start paying attention to my RPMs when I'm on the
highway. Right now I'm running 30 inch tires with 4.56 gears (up from
the original 4.10) and like it a lot. I plan to put 32 inch tires on
it next year. It will be interesting to see how it runs then.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 21, 3:31 pm, nrs <neale...@yahoo,com > wrote:
> On Sep 21, 2:09 pm, Mike Romain <roma...@sympatico.ca> wrote:
>
>
>
>
>
> > nrs wrote:
> > > On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
> > >> I have posted this once today, but for some reason it did not post.
> > >> If anyone finds it, sorry for the duplicate post.
>
> > >> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
> > >> the 4.11 ratio would be better for me. I currently have 31" BFG All
> > >> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
> > >> sort in the future when these wear out. I will never upgrade to
> > >> bigger than a 33" tire. As for off-roading, I do some light trail
> > >> riding and the occasional hop in the mud puddle when I find one that
> > >> looks fun. 80% of my driving is highway at approximately 70 miles
> > >> round trip at a speed of anywhere from 60-70 mph. The other 20% is
> > >> split between city driving (10%), and off-roading (10%). My main
> > >> goal
> > >> is to get my Jeep to drive as close as possible to the way it did
> > >> bone
> > >> stock (being able to use my 6th gear on the freeway) and to prevent
> > >> excessive wear and tear on my clutch and engine parts. Someone
> > >> please
> > >> help! : D
>
> > >> '06 TJ (4.0L with I-6)
> > >> 6 speed manual
> > >> Dana 30 front/35 rear
> > >> current 3.07s
>
> > >> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
> > >> (like
> > >> 44s)? I don't know if this makes any difference as far as which gear
> > >> ratio to go with, but where I live (upstate NY), there can be quite a
> > >> bit of snow from Dec. - Apr.
>
> > > If you want it too run like it does now the ideal gear ration would be
> > > 3.07*33/31 =3D 3.27 rounded up to what is available. 3.55 seems to be
> > > available. The 3.73 or 4.1 would give you better performance off road
> > > but your fuel economy would suffer on the road.
>
> > Unfortunately the flying bricks we drive don't react the same as cars
> > when it comes to low revs.
>
> > Once you get the axles 'into' the air stream by raising the body away
> > from them with a suspension lift, it reacts 'strongly' to wind resistan=
ce.
>
> > On a lifted Jeep, anything much below 2000 rpm at highway speed will
> > start the engine lugging so you need way too much gas pedal to keep up
> > with wind twitches or slight hills.
>
> > Everyone I know and that has posted on the newsgroups that has 'dropped'
> > the overdrive with large tires and tall gears gets better mileage at
> > highway speeds.
>
> > My CJ7 came with overdrive (5th) and 3.31 gears or 'mileage' gears.
> > When I lifted it 3" and put 33's on, my mileage dropped by about 8 mpg
> > after calibrating the odometer when I drove it the same as before using
> > all the gears. It just 'doesn't' like 1750 rpm at 65 mph...
>
> > As soon as I stopped using 5th so I stayed in the 2300-2400 rpm range at
> > 65 mph, my mileage jumped way up and has stayed a consistent 23 mpg to
> > this day.
>
> > Now I do have a manually 'tuned' carb engine with a 'hot' spark and
> > timing curve that insists on 91+ octane with a super light fiberglass
> > body (it only takes two people to 'easily' pick up the whole body tub
> > 'with' the seats and roll bar in it) so the thing is basically an engine
> > on wheels that goes like a scalded cat, but still.
>
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> > Canadian Off Road Trips Photos: Non members can still view!
> > Jan/06 http :// www .imagestation,com /album/pictures.html?id=3D2115147590
> > (More Off Road album links at bottom of the view page)- Hide quoted tex=
t -
>
> > - Show quoted text -
>
> Mike,
>
> I=B4m going to start paying attention to my RPMs when I'm on the
> highway. Right now I'm running 30 inch tires with 4.56 gears (up from
> the original 4.10) and like it a lot. I plan to put 32 inch tires on
> it next year. It will be interesting to see how it runs then.- Hide quote=
d text -
>
> - Show quoted text -

If it makes any difference, my original tires were the 215/75/15. I
do not have a lift on now. Just thought about it in the future.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

Tracie wrote:
> On Sep 21, 3:31 pm, nrs <neale...@yahoo,com > wrote:
>> On Sep 21, 2:09 pm, Mike Romain <roma...@sympatico.ca> wrote:
>>
>>
>>
>>
>>
>>> nrs wrote:
>>>> On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
>>>>> I have posted this once today, but for some reason it did not post.
>>>>> If anyone finds it, sorry for the duplicate post.
>>>>> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73 or
>>>>> the 4.11 ratio would be better for me. I currently have 31" BFG All
>>>>> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
>>>>> sort in the future when these wear out. I will never upgrade to
>>>>> bigger than a 33" tire. As for off-roading, I do some light trail
>>>>> riding and the occasional hop in the mud puddle when I find one that
>>>>> looks fun. 80% of my driving is highway at approximately 70 miles
>>>>> round trip at a speed of anywhere from 60-70 mph. The other 20% is
>>>>> split between city driving (10%), and off-roading (10%). My main
>>>>> goal
>>>>> is to get my Jeep to drive as close as possible to the way it did
>>>>> bone
>>>>> stock (being able to use my 6th gear on the freeway) and to prevent
>>>>> excessive wear and tear on my clutch and engine parts. Someone
>>>>> please
>>>>> help! : D
>>>>> '06 TJ (4.0L with I-6)
>>>>> 6 speed manual
>>>>> Dana 30 front/35 rear
>>>>> current 3.07s
>>>>> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
>>>>> (like
>>>>> 44s)? I don't know if this makes any difference as far as which gear
>>>>> ratio to go with, but where I live (upstate NY), there can be quite a
>>>>> bit of snow from Dec. - Apr.
>>>> If you want it too run like it does now the ideal gear ration would be
>>>> 3.07*33/31 = 3.27 rounded up to what is available. 3.55 seems to be
>>>> available. The 3.73 or 4.1 would give you better performance off road
>>>> but your fuel economy would suffer on the road.
>>> Unfortunately the flying bricks we drive don't react the same as cars
>>> when it comes to low revs.
>>> Once you get the axles 'into' the air stream by raising the body away
>>> from them with a suspension lift, it reacts 'strongly' to wind resistance.
>>> On a lifted Jeep, anything much below 2000 rpm at highway speed will
>>> start the engine lugging so you need way too much gas pedal to keep up
>>> with wind twitches or slight hills.
>>> Everyone I know and that has posted on the newsgroups that has 'dropped'
>>> the overdrive with large tires and tall gears gets better mileage at
>>> highway speeds.
>>> My CJ7 came with overdrive (5th) and 3.31 gears or 'mileage' gears.
>>> When I lifted it 3" and put 33's on, my mileage dropped by about 8 mpg
>>> after calibrating the odometer when I drove it the same as before using
>>> all the gears. It just 'doesn't' like 1750 rpm at 65 mph...
>>> As soon as I stopped using 5th so I stayed in the 2300-2400 rpm range at
>>> 65 mph, my mileage jumped way up and has stayed a consistent 23 mpg to
>>> this day.
>>> Now I do have a manually 'tuned' carb engine with a 'hot' spark and
>>> timing curve that insists on 91+ octane with a super light fiberglass
>>> body (it only takes two people to 'easily' pick up the whole body tub
>>> 'with' the seats and roll bar in it) so the thing is basically an engine
>>> on wheels that goes like a scalded cat, but still.
>>> Mike
>>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>>> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
>>> Canadian Off Road Trips Photos: Non members can still view!
>>> Jan/06 http :// www .imagestation,com /album/pictures.html?id!15147590
>>> (More Off Road album links at bottom of the view page)- Hide quoted text -
>>> - Show quoted text -
>> Mike,
>>
>> I´m going to start paying attention to my RPMs when I'm on the
>> highway. Right now I'm running 30 inch tires with 4.56 gears (up from
>> the original 4.10) and like it a lot. I plan to put 32 inch tires on
>> it next year. It will be interesting to see how it runs then.- Hide quoted text -
>>
>> - Show quoted text -
>
> If it makes any difference, my original tires were the 215/75/15. I
> do not have a lift on now. Just thought about it in the future.
>

That is why I was thinking 4.11s to match or for the 'power feel', once
lifted, 4.56's.

You can easily check your mileage as the modifications happen. You do
enough highway driving that it can be figured easy which gear works the
'best' for 'you'.

You don't need to run full tanks for tests, you can fill up after each
highway run or two, or each circuit of your normal daily 'route'.

Mike

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 21, 3:01 pm, Tracie <brain...@upstate.edu> wrote:
> On Sep 21, 3:31 pm, nrs <neale...@yahoo,com > wrote:
>
>
>
>
>
> > On Sep 21, 2:09 pm, Mike Romain <roma...@sympatico.ca> wrote:
>
> > > nrs wrote:
> > > > On Sep 21, 10:47 am, Tracie <brain...@upstate.edu> wrote:
> > > >> I have posted this once today, but for some reason it did not post.
> > > >> If anyone finds it, sorry for the duplicate post.
>
> > > >> Anyhoo, I definitely want to re-gear but I am not sure if the 3.73=
or
> > > >> the 4.11 ratio would be better for me. I currently have 31" BFG A=
ll
> > > >> Terrain T/A KOs, but will definitely upgrade to a 33" tire of some
> > > >> sort in the future when these wear out. I will never upgrade to
> > > >> bigger than a 33" tire. As for off-roading, I do some light trail
> > > >> riding and the occasional hop in the mud puddle when I find one th=
at
> > > >> looks fun. 80% of my driving is highway at approximately 70 miles
> > > >> round trip at a speed of anywhere from 60-70 mph. The other 20% is
> > > >> split between city driving (10%), and off-roading (10%). My main
> > > >> goal
> > > >> is to get my Jeep to drive as close as possible to the way it did
> > > >> bone
> > > >> stock (being able to use my 6th gear on the freeway) and to prevent
> > > >> excessive wear and tear on my clutch and engine parts. Someone
> > > >> please
> > > >> help! : D
>
> > > >> '06 TJ (4.0L with I-6)
> > > >> 6 speed manual
> > > >> Dana 30 front/35 rear
> > > >> current 3.07s
>
> > > >> P.S. Would I also need to upgrade my Dana 30/35 to a bigger one
> > > >> (like
> > > >> 44s)? I don't know if this makes any difference as far as which g=
ear
> > > >> ratio to go with, but where I live (upstate NY), there can be quit=
e a
> > > >> bit of snow from Dec. - Apr.
>
> > > > If you want it too run like it does now the ideal gear ration would=
be
> > > > 3.07*33/31 =3D 3.27 rounded up to what is available. 3.55 seems to =
be
> > > > available. The 3.73 or 4.1 would give you better performance off ro=
ad
> > > > but your fuel economy would suffer on the road.
>
> > > Unfortunately the flying bricks we drive don't react the same as cars
> > > when it comes to low revs.
>
> > > Once you get the axles 'into' the air stream by raising the body away
> > > from them with a suspension lift, it reacts 'strongly' to wind resist=
ance.
>
> > > On a lifted Jeep, anything much below 2000 rpm at highway speed will
> > > start the engine lugging so you need way too much gas pedal to keep up
> > > with wind twitches or slight hills.
>
> > > Everyone I know and that has posted on the newsgroups that has 'dropp=
ed'
> > > the overdrive with large tires and tall gears gets better mileage at
> > > highway speeds.
>
> > > My CJ7 came with overdrive (5th) and 3.31 gears or 'mileage' gears.
> > > When I lifted it 3" and put 33's on, my mileage dropped by about 8 mpg
> > > after calibrating the odometer when I drove it the same as before usi=
ng
> > > all the gears. It just 'doesn't' like 1750 rpm at 65 mph...
>
> > > As soon as I stopped using 5th so I stayed in the 2300-2400 rpm range=
at
> > > 65 mph, my mileage jumped way up and has stayed a consistent 23 mpg to
> > > this day.
>
> > > Now I do have a manually 'tuned' carb engine with a 'hot' spark and
> > > timing curve that insists on 91+ octane with a super light fiberglass
> > > body (it only takes two people to 'easily' pick up the whole body tub
> > > 'with' the seats and roll bar in it) so the thing is basically an eng=
ine
> > > on wheels that goes like a scalded cat, but still.
>
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> > > Canadian Off Road Trips Photos: Non members can still view!
> > > Jan/06 http :// www .imagestation,com /album/pictures.html?id=3D2115147590
> > > (More Off Road album links at bottom of the view page)- Hide quoted t=
ext -
>
> > > - Show quoted text -
>
> > Mike,
>
> > I=B4m going to start paying attention to my RPMs when I'm on the
> > highway. Right now I'm running 30 inch tires with 4.56 gears (up from
> > the original 4.10) and like it a lot. I plan to put 32 inch tires on
> > it next year. It will be interesting to see how it runs then.- Hide quo=
ted text -
>
> > - Show quoted text -
>
> If it makes any difference, my original tires were the 215/75/15. I
> do not have a lift on now. Just thought about it in the future.- Hide qu=
oted text -
>
> - Show quoted text -

The math for those tires would be 3.07*33/27.7 =3D 3.66. So to keep it
like stock you would use 3.73. Numerically higher if you want get your
RPMs higher on the highway or for better off road performance.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

Tracie, if it were mine I'd go with the 4.10's now. That way you pay for the
gear change once. You'll get slightly worse gas mileage so I guess you'll
pay for the second gear change over time in increased fuel costs, but at
least you won't have an extra big hit to your wallet when you go to 33's.

4.10 and 33's will be pretty much the same as 3.73's and 31's. Rubicon TJ
Wrangers had 4.10/31's from the factory, BTW.

"Tracie" <brainart@upstate.edu> wrote in message
news:1190404899.899721.270550@w3g2000hsg.googlegroups,com ...
On Sep 21, 3:31 pm, nrs <neale...@yahoo,com > wrote:
> On Sep 21, 2:09 pm, Mike Romain <roma...@sympatico.ca> wrote:

If it makes any difference, my original tires were the 215/75/15. I
do not have a lift on now. Just thought about it in the future.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

On Sep 23, 3:35 pm, "Matt Macchiarolo" <m...@nospamplease,com > wrote:
> Tracie, if it were mine I'd go with the 4.10's now. That way you pay for the
> gear change once. You'll get slightly worse gas mileage so I guess you'll
> pay for the second gear change over time in increased fuel costs, but at
> least you won't have an extra big hit to your wallet when you go to 33's.
>
> 4.10 and 33's will be pretty much the same as 3.73's and 31's. Rubicon TJ
> Wrangers had 4.10/31's from the factory, BTW.
>
> "Tracie" <brain...@upstate.edu> wrote in message
>
> news:1190404899.899721.270550@w3g2000hsg.googlegroups,com ...
> On Sep 21, 3:31 pm, nrs <neale...@yahoo,com > wrote:
>
> > On Sep 21, 2:09 pm, Mike Romain <roma...@sympatico.ca> wrote:
>
> If it makes any difference, my original tires were the 215/75/15. I
> do not have a lift on now. Just thought about it in the future.

Mike --
I am definitely enthusiastic! I've never been so excited about a
vehicle (and I've owned about 10 in the past 10-12 years) as I am
about my Wrangler. They are so much FUN!! Thank you for your input
regarding the gear upgrade.

Matt --
Same thing to be said to you as well. Thanks for all your input on
the gear change. I thought that the Rubi's came with 31's and 4.10's,
but I wasn't 100% sure. That helps ALOT in making my decision. That
basically means my rig will drive like a stock Rubi without any
problems (that I know of). I got a quote today of $1500-1600
(including labor but not the sales tax) for the front/rear gear
change. This is from an acutal gear shop near where I live. Does
that sound about right?

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)


"Tracie" <brainart@upstate.edu> wrote in message
news:1190650031.025885.300980@19g2000hsx.googlegroups,com ...
I got a quote today of $1500-1600
> (including labor but not the sales tax) for the front/rear gear
> change. This is from an acutal gear shop near where I live. Does
> that sound about right?

Front/back, all parts/labor included, sounds about right. It's a little
higher then when I had mine done but you need to swap the entire carriers,
the 4.10 gearsets don't fit on the 3.07 carriers. Mine originally came with
3.73's so I was good, tho I did had a limited slip diff installed in the
front, which replaced that carrier anyway.

BEFORE YOU ASK ;-) If you plan on doing a lot of off-roading (which it
sounds like you are not) then spring for the LS in the front. If not, just
get the open carrier. Same for the rear.

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

"Matt Macchiarolo" <matt@nospamplease,com > wrote in message
news:fvqdnXTxKtMAgWXbnZ2dnUVZ_rKtnZ2d@comcast,com ...
>
> "Tracie" <brainart@upstate.edu> wrote in message
> news:1190650031.025885.300980@19g2000hsx.googlegroups,com ...
> I got a quote today of $1500-1600
> > (including labor but not the sales tax) for the front/rear gear
> > change. This is from an acutal gear shop near where I live. Does
> > that sound about right?
>
> Front/back, all parts/labor included, sounds about right. It's a little
> higher then when I had mine done but you need to swap the entire carriers,
> the 4.10 gearsets don't fit on the 3.07 carriers. Mine originally came
with
> 3.73's so I was good, tho I did had a limited slip diff installed in the
> front, which replaced that carrier anyway.
>
> BEFORE YOU ASK ;-) If you plan on doing a lot of off-roading (which it
> sounds like you are not) then spring for the LS in the front. If not, just
> get the open carrier. Same for the rear.
>
It looks as if Tracie would need to get locking hubs for a LS on the front
not to affect the steering. That is my understanding of how the newer TJs
are put together anyway. That would add a few hundred.

Advice for Jeep shoppers--Stay away from any Jeep with the 3.07 axle ratio.

Cheers,

Earle

Re: RE-GEARING TO EITHER 3.73 OR 4.11 (repeat -- sorry)

Not the case, the proof is in my garage...

"Earle Horton" <el_anglo_burgues@usa,com > wrote in message
news:fd9987$6l1$1@registered.motzarella.org...

> It looks as if Tracie would need to get locking hubs for a LS on the front
> not to affect the steering. That is my understanding of how the newer TJs
> are put together anyway. That would add a few hundred.
>
> Advice for Jeep shoppers--Stay away from any Jeep with the 3.07 axle
> ratio.
>
> Cheers,
>
> Earle
>
>