When to switch from 3.73's to 4.10's?

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

dloc_jeep_KJ wrote:

QuestMan wrote:

Quote:

4.10's front - $345.63 http://www.trademotion.com/partlocator/ ... atalogid=0

1st: You can switch out the gears in the front? I kind of thought you'd have to replace the entire front diff.

2nd: Any advantage in changing to 4.10s for 245/70/16s? Or is it only worth it once you go with bigger tires?

it couldnt hurt but there is really more of a need with a bigger tire size. yes u can switch the gears out in the front but need to do the rear at the same time and u wont need a new front diff. also ARB sells a compresser for there air lockers might be a little more though but u could order it from where ever u get the lockers from.

I've run 4.10's with 245/70R16's and 245/65R17's. They will give you faster acceleration and will improve torque at lower speeds. It will cost you at high speeds though. You'll lose some gas milage and you'll run a higher rpm at the same speeds.

Hood297 · **Posted:** Sun Feb 03, 2008 10:09 pm

dieselenthusiast wrote:

Hood297 wrote:

http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2009029/p-2009029/N-111+10201+600015236/c-10101

I originally set out just to get it for the air horns.
I'm going to split the one air line coming out into 3 (1 to air horns, 1 front, 1 rear)

Where are you going to mount your compressor and air tank?

It is already mounted and has been pumping away for about a year now...

here is a pic.

durangotang · **Posted:** Sun Feb 03, 2008 11:39 pm

haha those air horns are almost profane haha

dieselenthusiast · **Posted:** Mon Feb 04, 2008 12:28 am

We are planning to tow with the KJ, so the 4:10 gears would probably help for towing once the 32” tires go on. I’m assuming that my factory chrome clad wheels are pretty light weight, so perhaps the lighter wheel will help save some weight due to the heavier tires. Will my EVIC (tire pressure gauge) still be able to accurately read the tire pressure when swapping to the big tires?

ohv_kj · **Posted:** Tue Feb 05, 2008 12:17 am

Hood297 wrote:

do it after you get the 32's so you can fully appreciate the change, like me. :lol:

Hood whats up and yes after you get the lift and tires...also if you ar going to grt lockers then would be the time so you only have to take everything apart once...

InCommando · **Posted:** Thu Feb 07, 2008 12:43 am

http://www.4lo.com/4LoCalc.htm

Assuming you are starting at 29" ( shorter than even a 235/70) and going to a 32" (235/85/16 or 265/75/16), this recommends going to 4.10's (4.11's.) As there are no ratios in between for the D30a, those are the available options. Any change from a 225/75/16 would have less impact as is nearly 30" tall anyway. The difference between a 225/75 & and a 245/75 are almost negligible. You may be feeling extra weight from the tires/wheels and wind resistance from a lift as opposed to gear change due to tire height.

Would a six-speed be easier to live with after a lift, even starting with a 3.55, due to the ratio's in the tranny?

You know, from the basic stock tire to the largest (by consensus) "usable" tire you will only net 1.5" of ground clearence increase, and maybe only 1"? And depending on brand of tire & the variances among the same size, you may not even see that.

With the D30a and current lifts, is the extra 1/2" of height that a 32" tire gives over the (usually) lighter 245/75 (31"), worth it for the vast majority of us?

tommudd · **Posted:** Thu Feb 07, 2008 1:01 am

InCommado, simply stated ...not really in most circumstances, going from the 235-70X16 (29.1inches tall) to a 265-75X16 (31.7 inches tall) gives you an extra 1.3 inches of ground clearance. So good driving can get you over most things with either tire IMO. I think it would be really hard to have two identical KJs one with each size tire going over the same trail be that much noticeable overall. Sure you can argue that its an extra inch but ....let the skids drag you through :wink:

I agree I have been places where it may of helped some but for the extra work needed, not sure its feasible for 75/80% of us. I do admit it does look good with 265 70s or 75s and I will have 4.10s but its only to offset the extra weight. A six speed would help get one rolling easier but on top end you will lose the power needed to keep running at the speed you want to be at.

tjkj2002 · **Posted:** Thu Feb 07, 2008 1:12 am

tommudd wrote:

InCommado, simply stated ...not really in most circumstances, going from the 235-70X16 (29.1inches tall) to a 265-75X16 (31.7 inches tall) gives you an extra 1.3 inches of ground clearance. So good driving can get you over most things with either tire IMO. I think it would be really hard to have two identical KJs one with each size tire going over the same trail be that much noticeable overall. Sure you can argue that its an extra inch but ....let the skids drag you through :wink:

I agree I have been places where it may of helped some but for the extra work needed, not sure its feasible for 75/80% of us. I do admit it does look good with 265 70s or 75s and I will have 4.10s but its only to offset the extra weight. A six speed would help get one rolling easier but on top end you will lose the power needed to keep running at the speed you want to be at.

I clear obsticals that USAFCOP hits on,I'm running 265/75R16's and he runs 245/75R16's,it makes a huge difference offroad on those rocks.Those rocks have a nasty habit of holding you up when trying to "scrap" over them on your skids.

dieselenthusiast · **Posted:** Thu Feb 07, 2008 1:25 am

tjkj2002 wrote:

tommudd wrote:

InCommado, simply stated ...not really in most circumstances, going from the 235-70X16 (29.1inches tall) to a 265-75X16 (31.7 inches tall) gives you an extra 1.3 inches of ground clearance. So good driving can get you over most things with either tire IMO. I think it would be really hard to have two identical KJs one with each size tire going over the same trail be that much noticeable overall. Sure you can argue that its an extra inch but ....let the skids drag you through :wink:

I agree I have been places where it may of helped some but for the extra work needed, not sure its feasible for 75/80% of us. I do admit it does look good with 265 70s or 75s and I will have 4.10s but its only to offset the extra weight. A six speed would help get one rolling easier but on top end you will lose the power needed to keep running at the speed you want to be at.

I clear obsticals that USAFCOP hits on,I'm running 265/75R16's and he runs 245/75R16's,it makes a huge difference offroad on those rocks.Those rocks have a nasty habit of holding you up when trying to "scrap" over them on your skids.

I can verify those findings. I’ve been on two LOST ROCKIES runs in which Troy and Ted’s KJ traveled the same route. In multiple cases, Troy had little to no trouble whereas Ted’s KJ would either seriously scrape or get hung up. I agree, most of us do not need to count every inch, but when it comes to off-roading, every inch counts and sometimes is the difference between a successful approach or a failed attempt.

tommudd · **Posted:** Thu Feb 07, 2008 1:44 am

I agree on both statements above but again what most do, they dont really need the extra, IMO but yes I have been hung up on rocks before and where an inch would of made a difference, have also went the whole route up to running 40s and with all the gear changes etc that went with it just so I could go wherever I wanted to go.
But with the KJ and what most do Im still not sure its worth the extra, in gears/ gas/ tires/ wear and tear, etc... granted like I said I will have 4.10s and somewhat bigger tires but....still

InCommando · **Posted:** Thu Feb 07, 2008 1:08 pm

The difference between your average 245/75 and 265/75 is 1" overall, or .5" net. By running through different specs on the tires, sometimes the difference is only about .25", depending on the tire brands chosen.

Could it be that different lifts are moving the body higher and enabling morse clearence from one to the other, as opposed to the .5" tire height making the difference? I guess what was actually getting hung up would be the determining factor there.

I am sure there are people hitting it hard enough that the extra .5" will matter. There are surely places where that can matter, even if it seems small. It is just that, to me, I'd make dang sure I needed that .5" before I stressed the front end anymore than I had to. I am just kinda geared that way. I kept the tires on my Chero at 33" for the sake of the axles, and it has D44's F/R.

Of course, if you are running the 265's to be a better poser and will never tax your KJ anyway, the point is moot. I just agree with Tom that for the majority of those lifting their KJ's, the current lifts with the tried-and-true 245/75 combo is the way to go, even if it won't get you the best bragging rights in a sig line.

KJ04 · **Posted:** Thu Feb 07, 2008 3:21 pm

I've mostly been an advocate of the the 265/75/16 , as I'm now on my 3 rd. set of them. However, considering the current gas prices and averaging 10.5 mpg winter and 12.5 mpg warm weather, I'm thinking a decrease of about 1.3" in diameter to a 30.6" 245/75/16 would have at least added some mpg and a little more power back to the beast, not to mention a little better braking and increased pad life.

dieselenthusiast · **Posted:** Thu Feb 07, 2008 8:42 pm

tommudd wrote:

I agree on both statements above but again what most do, they dont really need the extra, IMO but yes I have been hung up on rocks before and where an inch would of made a difference, have also went the whole route up to running 40s and with all the gear changes etc that went with it just so I could go wherever I wanted to go.
But with the KJ and what most do Im still not sure its worth the extra, in gears/ gas/ tires/ wear and tear, etc... granted like I said I will have 4.10s and somewhat bigger tires but....still

Oh, TOM! You’re posting on a 4X4 thread with a bunch of serious KJ off-roaders. Is there anything that we do on this forum that makes sense to you? :shock:

Do you actually think any of us are smart enough to doubt the worth for the extra, in gears/ gas/ tires/ wear and tear, etc? :shock:

We are Jeep people, nothing we do makes sense! :lol:

Look at your list of modifications, you are the pack leader causing us younger people to follow in your “experienced” footsteps. :twisted:

Let’s face it, if you go an inch bigger, then I will go an inch bigger. :oops:

It’s people like you that make me want 4:10’s! :twisted:

As a matter of fact, the next time that I get in trouble with the wife over jeep funding, I will tell her to call “YOU” (the pack leader) if she has any questions! Then you can explain to her that an extra inch doesn’t matter! :shock:

tjkj2002 · **Posted:** Thu Feb 07, 2008 8:46 pm

dieselenthusiast wrote:

tommudd wrote:

I agree on both statements above but again what most do, they dont really need the extra, IMO but yes I have been hung up on rocks before and where an inch would of made a difference, have also went the whole route up to running 40s and with all the gear changes etc that went with it just so I could go wherever I wanted to go.
But with the KJ and what most do Im still not sure its worth the extra, in gears/ gas/ tires/ wear and tear, etc... granted like I said I will have 4.10s and somewhat bigger tires but....still

Oh, TOM! You’re posting on a 4X4 thread with a bunch of serious KJ off-roaders. Is there anything that we do on this forum that makes sense to you? :shock:

Do you actually think any of us are smart enough to doubt the worth for the extra, in gears/ gas/ tires/ wear and tear, etc? :shock:

We are Jeep people, nothing we do makes sense! :lol:

Look at your list of modifications, you are the pack leader causing us younger people to follow in your “experienced” footsteps. :twisted:

Let’s face it, if you go an inch bigger, then I will go an inch bigger. :oops:

It’s people like you that make me want 4:10’s! :twisted:

As a matter of fact, the next time that I get in trouble with the wife over jeep funding, I will tell her to call “YOU” (the pack leader) if she has any questions! Then you can explain to her that an extra inch doesn’t matter! :shock:

Guess it is true about women,that extra inch is important :-)r

tommudd · **Posted:** Thu Feb 07, 2008 9:04 pm

Troy , I was going to make the "inch" remark last night but held back...glad you said it!

All others I am so glad that I can make some think more, some dislike me, others just sitting back thinking "Hes too darn old to know anything anyways!" :lol:

Now with all that said IF I did not drive mine 35,000 miles a year it would higher, wider, wilder and much better/ different....some day....maybe soon who knows. The heck with gas mileage :wink:

When to switch from 3.73's to 4.10's?

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