4.10 gears and 35's ????

[Ilikeparts]

http://www.ringpinion.com/Calc_RPM.aspx

check this out. i used to work for these guys and most of the time you get a pretty damn accurate result with these calculators.

remember like kastein said, if your goal is a DD rig that gets highway miles, shoot for a little bit deeper than stock RPM range. That way you will be as close as possible to factory-optimized (fuel economy-optimized) rpm range plus the extra power you need to compensate for the weight of tires and others mods.


different rigs with the same motor/tranny/R&P ratio will get different MPG b/c MPG is a function of a ton of different factors (engine health, wind resistance, weight, etc. etc. etc.)

but when you're choosing a R&P for for a highway driven vehicle the only function you can really control is RPM range

RPM range on most vehicles is tuned for max fuel econ from the factory, so the rpm range on stock config makes a good base line you can use for picking out where you want your RPMs to be.

 

[ausi02]

I dont know how ppl only go 65 mph.... Im at 4.56 and 35s and a ax-15 and when im on the highway (5th gear) I wish that there was 4.27 cause im close to 3000 rpms at 80 and I would like to at least go 85-90. Whoever wants 5.13s on 35s clearly hasn't had to run I-25 and I -70 to get up to the slopes. 65 will get you run over in the right hand lane on I-25, I guess we are just speeders here lol.

 

[XJfire75]

I run 4:10s and 35s. I don't mind it at all. I get 16 MPG. I run on average 50 MPH to and from work on highways with inclines and hills and I rarely have to get out of OD. I drive my Jeep like a Jeep. It wheels fine for me and yeah I wouldn't mind the extra push that lower gears or smaller tires would give me but when you're just cruising to and from work and occasionally into town I dot have a problem with it.

That being said I am gonna drop to a 296/75(34x11.5) on my next set of tires just because they'll fit better and prolly get a little better MPGs being ATs.

I got a smokin deal on gears for the front and a great deal on a set-up rear axle so I couldn't complain.

 

[trail rate this]

Hell, I'll trade ya axles. I've got 4.10 gears.

 

[ExTankerGuy]

I ran 4.56s with 35s and HATED IT! I now have 5.38s and 36s and LOVE IT! If I want to go over 70, I'll drive my Tahoe or my wife's G6!

 

[Jeff in VA]

4.56's on 35's in my MJ with AX15.....just about perfect for me. I was running 33's on 4.56's with it when it was a 2.5, and it was just too much for the little 4 banger to handle, so I swapped in a 4.0. Then I had too much engine, and stepped to 35's.

my .02...

Jeff

 

[Darky]

I dont know how ppl only go 65 mph.... Im at 4.56 and 35s and a ax-15 and when im on the highway (5th gear) I wish that there was 4.27 cause im close to 3000 rpms at 80 and I would like to at least go 85-90. Whoever wants 5.13s on 35s clearly hasn't had to run I-25 and I -70 to get up to the slopes. 65 will get you run over in the right hand lane on I-25, I guess we are just speeders here lol.

I don't know how people do 80-90 in a lifted brick! If you want to be fast on the highway, try something else, like a vehicle that's designed to be stable at those speeds. I never understand how people can be driving big lifted rigs (XJs, Superduties, whatever) and try to drive like they're in a lowered Civic. I keep my XJ to around 65, maybe 70. It's stable there and I should be able to react without rolling in an emergency.

 

[89xj]

I don't know how people do 80-90 in a lifted brick! If you want to be fast on the highway, try something else, like a vehicle that's designed to be stable at those speeds. I never understand how people can be driving big lifted rigs (XJs, Superduties, whatever) and try to drive like they're in a lowered Civic. I keep my XJ to around 65, maybe 70. It's stable there and I should be able to react without rolling in an emergency.

x2 on the speed. my racing days are over. i dont think it has to do with the traffic speed on how fast someone else drives, but the age of the driver when it comes to speed.

i run 4.10 r&p, 31's, with a 5sp in my 89 and find it to be a good combination for power and mileage(15mpg city/20mpg hwy). its a little deeper then stock, but i would rather be too deep then too tall when it comes to gearing. on the highway, i have no real need to downshift from 5th gear. stock gearing on 31's w/5speed was nothing but constant shifting.

 

[WaXJ_Skier]

I decided the minute I lifted my rig, that speeding was pointless. Ive run

worn 32s(31s) with 3.07 and 4.10
33s with 3.55, 4.10, and 4.88
35s with 4.88

the best milage Ive ever had was with the 33s and 4.88 I was able to average between 21 and 22mpg going up and over a mountain pass by keeping my speed about 55. An XJs stock gearing sucks, I think they should have all been geared 3.73 from the factory.

 

[MoparManiac]

I don't know how people do 80-90 in a lifted brick! If you want to be fast on the highway, try something else, like a vehicle that's designed to be stable at those speeds. I never understand how people can be driving big lifted rigs (XJs, Superduties, whatever) and try to drive like they're in a lowered Civic. I keep my XJ to around 65, maybe 70. It's stable there and I should be able to react without rolling in an emergency.

It's relative to one's definition of "stable". BTW, a lowered civic is probably a bad comparison as most of those out there ride like CRAP :roflmao: but I understand your analogy.

I find I cruise to the trail anywhere between 70-80 mph. Is it stable? To me yes. Do I run a front sway bar? Nope.

Go ahead, call me unsafe, call me whatever you want. I also consider myself a halfway decent driver and look far enough ahead of me to avoid most situations that would typically put others in an accident.

I don't change lanes frequently (typically I'm in one lane the entire trip), I don't take my eyes off the road (maybe once or twice if my GPS falls over), and I slow down to ~60 mph when there are lots of other cars around.

I'm ~80 miles away from the closest trail.

 

[Darky]

It's relative to one's definition of "stable". BTW, a lowered civic is probably a bad comparison as most of those out there ride like CRAP :roflmao: but I understand your analogy.

I find I cruise to the trail anywhere between 70-80 mph. Is it stable? To me yes. Do I run a front sway bar? Nope.

Go ahead, call me unsafe, call me whatever you want. I also consider myself a halfway decent driver and look far enough ahead of me to avoid most situations that would typically put others in an accident.

I don't change lanes frequently (typically I'm in one lane the entire trip), I don't take my eyes off the road (maybe once or twice if my GPS falls over), and I slow down to ~60 mph when there are lots of other cars around.

I'm ~80 miles away from the closest trail.

It's a 40 mile drive to anything other than a grocery store from here. 80 miles or so to Johnson Valley (the nearest official off-road area) also. I also have no sway bars and consider myself a decent driver. But it's the others on the road I don't trust. Between them and wildlife, I prefer to be at a speed that allows more reaction time and safer handling.

I run 33s with 4.88s. My wife's 03 Caravan with the 3.3 is faster than me. But, I have enough power to handle most of the hills around here. The steeper ones drop me out of OD, but I have no real complaints. At some point I'll do a stroker and all will be good.

 

[89xj]

I don't take my eyes off the road (maybe once or twice if my GPS falls over),

I'm ~80 miles away from the closest trail.

i hope your exaggerating. that might be the most dangerous thing you could do while driving. fixating on a point or even an area(just the road in front of you) will put the brain asleep.

 

[Cody90XJ]

I don't know how people do 80-90 in a lifted brick! If you want to be fast on the highway, try something else, like a vehicle that's designed to be stable at those speeds. I never understand how people can be driving big lifted rigs (XJs, Superduties, whatever) and try to drive like they're in a lowered Civic. I keep my XJ to around 65, maybe 70. It's stable there and I should be able to react without rolling in an emergency.

I set the cruise controll on 80 during the last trips that I took. Felt fine to me. Certainly didn't feel as stable as my prepped 280zx turbo that I've been working on for years but, it still felt fine.

 

[jeepcomj]

i hope your exaggerating. that might be the most dangerous thing you could do while driving. fixating on a point or even an area(just the road in front of you) will put the brain asleep.

actually, distracting yourself is the most dangerous thing you could do while driving.


Why do you think that the Germans do not have cup holders or mp3 plugins in their cars? simple fact...they don't allow it because it's a distraction to drivers




anyways, I keep my eyes on the road as well. My cruise speed is around 60-65mph and around 2100rpm. I don't like doing 80 in it if I don't have to, but that has everything to do with 6.5" and short arms and NOTHING to do with 35's and 4.10's

 

[ausi02]

Im pretty sure driving in a straight line doesn't require that much "stability", I mean its not autocross. If you are doing a lot of lane changes and you weave a lot then I agree, it would not be a safe situation. I used to live 2.5 hours out from skiing so going fast was a must to beat people to the bottle necks on I-70, but the majority of the trip was a straight road.

 

[Cody90XJ]

Im pretty sure driving in a straight line doesn't require that much "stability", I mean its not autocross. If you are doing a lot of lane changes and you weave a lot then I agree, it would not be a safe situation. I used to live 2.5 hours out from skiing so going fast was a must to beat people to the bottle necks on I-70, but the majority of the trip was a straight road.

I agree straight road, curvy road and traffic is a totally different story.

As for 35's and 4.10's. I would think that would be hard to drive on a regular basis. I went to 4.88's and it's so much better than the stock gearing. Anything lower would be hard to put up with if you ask me.

 

[jeepcomj]

I agree straight road, curvy road and traffic is a totally different story.

As for 35's and 4.10's. I would think that would be hard to drive on a regular basis. I went to 4.88's and it's so much better than the stock gearing. Anything lower would be hard to put up with if you ask me.

did you mean numerically lower or higher?


4.10's and 35's really isn't that bad for d/d. That said, the full size axle swap will involve 4.88's because I do think that 4.10's is not deep enough for what I do.

 

[Cody90XJ]

I ment numerically lower. Sorry for the cunfusion.:laugh:

 

[MoparManiac]

It's a 40 mile drive to anything other than a grocery store from here. 80 miles or so to Johnson Valley (the nearest official off-road area) also. I also have no sway bars and consider myself a decent driver. But it's the others on the road I don't trust. Between them and wildlife, I prefer to be at a speed that allows more reaction time and safer handling.

I run 33s with 4.88s. My wife's 03 Caravan with the 3.3 is faster than me. But, I have enough power to handle most of the hills around here. The steeper ones drop me out of OD, but I have no real complaints. At some point I'll do a stroker and all will be good.

I agree, I don't trust other people. There's no way for me to handle every situation at any speed, but I leave plenty of space in front of me to be able to react to situations at highway speeds.

With 33s and 4.88s, the fastest I ever cruised at was 75.

i hope your exaggerating. that might be the most dangerous thing you could do while driving. fixating on a point or even an area(just the road in front of you) will put the brain asleep.

If you're staring at one spot in the road, you suck at driving.

 

[Frank Z]

A question for the OP:
Any chance your engine is running cold (under 195). If so you're stuck in open loop mode and burning alot more gas than you would in closed loop.