Do I need to re-gear?

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WallyWest

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Recently bought a 2003 Sport. It has 30 inch tires on it. I stupidly thought that the Sport meant it had a higher than standard axle ratio. After killing the engine a few times trying to launch uphill I wondered about that.

So I looked up the build sheet and nope, it has 3.07 axles. Reading some of the guides on this forum I see that the 2003 5 speed manual, 6 cylinder with 30 inch tires shows a recommended axle ratio of 4.10. Great.

I assume if I wanted to do any off-road stuff, or lift it and put even bigger tires on it, that I'd definitely need to re-gear. But how big a deal is it with the way it is now?
 
You are stalling it because manuals are harder to drive off road. If you had an auto, that wouldn't happen. As far as regearing, be honest with yourself as to what you want to do with the Jeep as far as tire size is concerned, then either regear to that now, or get the tires first and live with the suck, then regear.

I lived with the suck of 33's and 3.07's far too long, but I recently regeared to 4.10 and love it. I'm running the 32RH 3 spd auto.
 
WallyWest said:
Recently bought a 2003 Sport. It has 30 inch tires on it. I stupidly thought that the Sport meant it had a higher than standard axle ratio. After killing the engine a few times trying to launch uphill I wondered about that.

So I looked up the build sheet and nope, it has 3.07 axles. Reading some of the guides on this forum I see that the 2003 5 speed manual, 6 cylinder with 30 inch tires shows a recommended axle ratio of 4.10. Great.

I assume if I wanted to do any off-road stuff, or lift it and put even bigger tires on it, that I'd definitely need to re-gear. But how big a deal is it with the way it is now?
Click to expand...

The previous owner of mine put on 31" tires and I ran with that for a while in my 1997 with 3.07s and a 5 speed. Wasn't horrible to do, just learned how it drive it to make it work
 
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WallyWest said:
Recently bought a 2003 Sport. It has 30 inch tires on it. I stupidly thought that the Sport meant it had a higher than standard axle ratio. After killing the engine a few times trying to launch uphill I wondered about that.

So I looked up the build sheet and nope, it has 3.07 axles. Reading some of the guides on this forum I see that the 2003 5 speed manual, 6 cylinder with 30 inch tires shows a recommended axle ratio of 4.10. Great.

I assume if I wanted to do any off-road stuff, or lift it and put even bigger tires on it, that I'd definitely need to re-gear. But how big a deal is it with the way it is now?
Click to expand...
30" tires came stock on a few of the TJ models, and I believe the manual versions of those typically came with 3.73 gear ratios, I could be wrong. The Rubicon came with what amounts to be a 30.5" tire and 4.10 gear ratio which is great for off road but a little less fuel mileage friendly that the 3.73 ratio. If you plan on lifting and going with bigger tires I would have to agree with @89grand and switch to the gear ratio appropriate for the future. If not 4.10 or 3.73 will work fine I would lead towards the 4.10 for off roading and the 3.73 for daily
 
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89grand said:
Well then you might need more practice driving a manual, because the gear ratio wouldn't cause it to stall.
Click to expand...

The base gear ratio on larger than stock tires will be harder to launch, because the effective gear ratio engine to pavement has changed.

I've driven manuals my whole life, this one just took a bit more throttle than I felt it should.

Driving home I was sitting at 1500 rpm at 50 mph in fifth gear. Plugged the numbers into one of those gearing calculators and that was closer to a 3.55 axle than a 3.07. So yeah, not sure. Of course my speedo might not be right if it wasn't adjusted for the tires. Going to jack it up this weekend and count driveshaft rotations to find out for sure.
 
I'm not saying 3.07 is a good ratio, because it isn't unless you had 25" tires, I'm just saying it won't cause the Jeep to stall.
 
Probably need to re-gear, but just learn to drive
 
WallyWest said:
Recently bought a 2003 Sport. It has 30 inch tires on it. I stupidly thought that the Sport meant it had a higher than standard axle ratio. After killing the engine a few times trying to launch uphill I wondered about that.

So I looked up the build sheet and nope, it has 3.07 axles. Reading some of the guides on this forum I see that the 2003 5 speed manual, 6 cylinder with 30 inch tires shows a recommended axle ratio of 4.10. Great.

I assume if I wanted to do any off-road stuff, or lift it and put even bigger tires on it, that I'd definitely need to re-gear. But how big a deal is it with the way it is now?
Click to expand...
Hey if you cannot launch 30s with 3.07s.... you need some driving lessons.

Altho I'd not recommend 3.07s with 33s, I drove that combination thru a 5 speed for 10 years, altho I never used 5th on the highway, launching was not an issue. Depending on what you do... for me I loved it on forestry roads. 4LO it drove like a Mustang. It would cruise a 60mph in 4LO. I'd go up to the Idaho Peak Forestry Lookout in 2nd, 4HI and come down in 3rd, 4LO.

Gearing is all about how you use it. I now have a Rubi, 33s with 4.10s and I still wish I had 3.73s... or taller.
 
WallyWest said:
I've driven manuals my whole life, this one just took a bit more throttle than I felt it should.
Click to expand...

Don't take what anyone is saying as a dig on your driving, but more like advice. These rigs aren't as light as they seem and they'll take a bit to get moving with 3.07s regardless of what size tire you have. Also, dont rule out any stupid issues choking the engine down and robbing it of power down low, like plugs, dirty throttle body, etc.
 
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