Is it possible to have a true dual purpose Jeep?

dewon wiero

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Hi guys,

I recently picked up a jeep TJ project that someone else gave up on, so I am new to the jeep world. I had a TJ for a very short time in 2002 but soon after was laid off and had to sell for something older and cheaper and not a jeep. I have been reading a lot on this forum but a lot of information is over my head, especially when it comes to suspension, geometry, etc. I know a lot of people give up some on road performance, in one way or another, to gain off road performance. As I start planning my build I am wondering if it is really possible to have the off road performance and not give up quite as much on road when I don't need to go off road?

As much as I would like to think differently, this jeep will spend 99% of the time on road, with the occasional trip off road, that will hopefully get more and more challenging as I gain experience.

If I build the Jeep to off road on 35 inch tires, would there be any harm in running 33 inch tires the 99% of the time it is on road, other than the cost of an extra set of wheels and tires? I read the best way to start a build is to chose the tire size you want first, then build around it. So I know the tire size basically affects everything else. A 33x10.5 can use a much lighter rim with less backspacing than a 35x12.5, but would I lose anything or cause any problems by swapping to smaller tires for less rolling resistance, less affect on acceleration and braking, MPGs, wear and tear, etc, without changing anything else?
 
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I'd think if you end up with 5.38's on 33's you might struggle on the highways with your RPM's band being so high, but it'd be fine with the 35's. apart from that, your braking/acceleration/mpg would be better on 33's, and you could likely get some nature of AT that would help more on the hwy instead of the heavy offroad tires in a 35
 
What kind of trails would the 1% include? Any mud or rock crawling?

I would like to get to the point where I am confident enough to try rock crawling and some of the more difficult trails in Colorado as well as Utah &AZ as I travel there frequently to visit family. I want to be able to explore more in Colorado than just I-70 and I-25. But definitely easier stuff to start and learn what I am doing. I don't want to have to rebuild it later because I didn't do it right the first time.
 
I'd think if you end up with 5.38's on 33's you might struggle on the highways with your RPM's band being so high, but it'd be fine with the 35's. apart from that, your braking/acceleration/mpg would be better on 33's, and you could likely get some nature of AT that would help more on the hwy instead of the heavy offroad tires in a 35

Are 5.38s necessary for 35? I was thinking 4.88 from what I read. I didn't do any favors by not filling out my profile. It is a 6 cyl with a 5 speed.

I definitely need to be able to drive at highway speeds, both flat and in the mountains.
 
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LOL, that is really funny (not being sarcastic). I spent a few years in Central FL and the terrain here in Colorado is a little different than sugar sand and muddin'

Ohh i lol too every single time i go out, there seems to be a correlating trend between tire size and drivers intelligence level, the bigger they get the dumber their offroading becomes.

Another thing is
I read the best way to start a build is to chose the tire size you want first, then build around it
Its more like you figure out your challenges 1st, and then build around it by selecting tires and what it takes to run them. Florida or Colorado has little to do with things, considering your 1% expectation, and by the looks of it you are already for what ever reason have your mind set on specific build while still in planning phase for that mystical 1% that you are expecting to face.

You asked a question, a gave you an answer - Jeep on 31"s. Once you start increasing lift and tire size, you are compromising a great deal of stability, which is opposite of your goals. Now, if you would like to deviate from stability, ie a Jeep that is at least semi controllable when some clown cuts you off while you doing 50 mph, there are offroad capable builds on 33s and 35s that people can share with you.
 
Are 5.38s necessary for 35? I was thinking 4.88 from what I read. I didn't do any favors by not filling out my profile. It is a 6 cyl with a 5 speed.

I definitely need to be able to drive at highway speeds, both flat and in the mountains.

I have a 2002 with 4.0 and 5 speed manual. 35” KO2’s & 4.5” suspension lift. I went with 4.88’s. It’s serving me well on the road and trail (conquered the Rubicon no problem). Expect to be downshifting to 4th when climbing in the mountains, but I don’t see an issue. Gearing isn’t ideal crawling, but I think the proper way to address that is the transfer case which is high on my list...
 
Are 5.38s necessary for 35? I was thinking 4.88 from what I read. I didn't do any favors by not filling out my profile. It is a 6 cyl with a 5 speed.

I definitely need to be able to drive at highway speeds, both flat and in the mountains.

You want 513 for 35s.

One very important thing I can tell you is that if you build your Jeep to perform well on the highway, it will take very good care of you off road.
 
You want 513 for 35s.

One very important thing I can tell you is that if you build your Jeep to perform well on the highway, it will take very good care of you off road.

Good point. Mine has come a long way. Keeping up with the Jones' at freeway speeds is fine now. Replaced/upgraded a lot of parts.
 
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Hi guys,

I recently picked up a jeep TJ project that someone else gave up on, so I am new to the jeep world. I had a TJ for a very short time in 2002 but soon after was laid off and had to sell for something older and cheaper and not a jeep. I have been reading a lot on this forum but a lot of information is over my head, especially when it comes to suspension, geometry, etc. I know a lot of people give up some on road performance, in one way or another, to gain off road performance. As I start planning my build I am wondering if it is really possible to have the off road performance and not give up quite as much on road when I don't need to go off road?

As much as I would like to think differently, this jeep will spend 99% of the time on road, with the occasional trip off road, that will hopefully get more and more challenging as I gain experience.

If I build the Jeep to off road on 35 inch tires, would there be any harm in running 33 inch tires the 99% of the time it is on road, other than the cost of an extra set of wheels and tires? I read the best way to start a build is to chose the tire size you want first, then build around it. So I know the tire size basically affects everything else. A 33x10.5 can use a much lighter rim with less backspacing than a 35x12.5, but would I lose anything or cause any problems by swapping to smaller tires for less rolling resistance, less affect on acceleration and braking, MPGs, wear and tear, etc, without changing anything else?

The biggest difference you'll experience swapping back and forth from 33's to 35's on the road is gearing. You really do want to re-gear for your final tire size, and in CO with steep and long passes you will want deeper. 513 is good for 35's 488 for 33's.

With a 99:1 on vs off-road rig I'd just build for 33's and call it a day. They are much easier to get up into. You can go a ton of places. In many cases it makes the obstacles more challenging and keeps them fun. If you can't handle rubbing and scraping then build for 35's. Also, if you really get into wheelin in CO you'll probably want 35's. That's a decision you have to make.

As mentioned, how it performs on road depends on how well you put it together. You can definitely make it perform well on road with 33's or 35's. Off-road performance follows naturally.
 
Another thing I can say from a lot of experience is that you are better off building for your final tire size, run that tire size, and deal with it.

The one inch difference in height between 33s and 35s is not worth the hassle of switching back and forth. But having two sets of tires for street and off road or for summer and winter is a different matter.
 
With a 99:1 on vs off-road rig I'd just build for 33's and call it a day.

I'll second this from @JMT. After running my 2003 on 31's for about a year and a half, I recently upgraded to 33's and what a difference! I have a lot more fun off road with the 33's. Granted, with the big change from the stock (~28") tire size, the gearing needed to be upgraded as well. I just got it back from the shop with 5.13 gears and it drives like a dream! Took it from the shop to the trails and between the new gears and new front and rear lockers I had the best time I've ever had off-roading.

In summary - going from near stock w/31's and 3.73 gears to 33's with 5.13 gears made a huge difference. It behaves well on-road and off.
 
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I would like to get to the point where I am confident enough to try rock crawling and some of the more difficult trails in Colorado as well as Utah &AZ as I travel there frequently to visit family. I want to be able to explore more in Colorado than just I-70 and I-25. But definitely easier stuff to start and learn what I am doing. I don't want to have to rebuild it later because I didn't do it right the first time.

Welcome to the forum. If that's your 1% and timeline, here's what I'd do:
  1. Drive it on those easier trails and learn how to choose good lines over obstacles. There are effective mods you can make that cost very little (e.g. airing down, disconnecting your front swaybar).
  2. Once you've gained some confidence and experience, try some more challenging trails. Ask yourself:
    1. Does it lose traction? Are you hitting obstacles? Use that information to inform your build's parameters.
 
All I can say is if you want good handling on and off road, do not skimp on suspension parts. Mine rides almost like stock on a 4" Currie Lift :cool:,
now my buddies TJ on a Skyjacker :rolleyes: not so much. It hard to get great handling and ride performance on a little budget.
 
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