Perfect tire size at 81 mph

Flo-France

Flo-France

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Hi every body,

It’s my first publication, my english is not perfect. I write you from france. Actually i’ve got a jeep tj 4.0, 2006, 42RLE, gear 4.56 with 35 tires.(With stock airbox with sport filter, sport header, and throttle body). I would like to drive around the europe, so i would like to have the best gearing to do higway to be on best place (500-800 miles) . And when i will arrive in some off road place, i can play with the Jeep(i’ve got 4 lift, front sway bar currie, rock jock controls arms, sye and ARB differential with 30 and 44 dana, and front/rear rockjock panhard and rock jock steering ). In europe we don’t have official honor trail. You can’t drive during fews days in the middle of nothing. So i have read all posts. I understand for 4.56 gear and 42 rle the best way is 31 or 32 tires. My question is : in europe the highway max speed is 81 mph(not 70-75 like you). So to save gas, is it better to keep 33 tires ? The jeep will be good on classic road (not higway) ? I’ve got 10x15 soft 8 wheels, facility for me is to put 33 tires, but 32 is normally better. My second problems is : 32 tires is in 11.5 wide, so it’s not perfect for a 10 wheels ? Thanks for all your advises
 
Ideally you just regear your axles to 5.13.

Yes, 10" wide wheels are too wide for a 32x11.5 tire.floatation sizes measured in inches are always smaller than advertised.

You want smaller tires? Or just better gearing and handling on the road?
 
I would like to keep the 4.56 gear because it’s difficult to find someone to change gear here. We dont have real 4x4 with axle. So it’s more Easy for me to change tire size and wheel size. So if. The good way is 32 i prefer change wheel with 15x8. But it is very bad with 33 tires? It is not better to save some rpm on highway at 81 .I don’t understand why is more bad. Is the car lost power ?
 
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I understand . 81 mph it’s the basic limit in europe. Most a car go faster. When you are at 81 you are in reality the slower car in the highway, and people have basic car. I complitly ok with you, our jeep tj is not for speed. We can have lot’s of troubles. It’s for that i change a lot of parts. I have possibility to drive slow on highway but under 71 it’s very dangerous. I try to have the best possibility.
 
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tnjeepguy said:
I will say again, driving high speed (70+) in a TJ jeep is asking for trouble. Slow down, they are not a sports car.
Click to expand...

Truth! I cringe when I see guys on here bragging how they can "comfortably cruise at 85 with one finger on the wheel". That's great if you're TJ handles well (for a TJ), but it doesn't make it a Porsche.
 
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So considering my usual particularity, is it okay(not perfect) to use 33s ? Or the best way is to go to 31-32 tires ?
 
tnjeepguy said:
I will say again, driving high speed (70+) in a TJ jeep is asking for trouble. Slow down, they are not a sports car.
Click to expand...

I personally would be afraid of doing sustained 70+ in a tj. Both due to a possible failures as well as handling. You can have the tj maintained well (as you see it) but in a 20 some year old jeep? Things can fail without warning. God forbid if all of sudden there's a DW.
 
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Unless you're not maintaining your jeep properly, I don't understand the fear of going 70+. I've done it every day since I bought this Jeep. If I couldn't do that, it wouldn't have made sense to buy it. Yeah, I can see if you're heavily modified for mostly trail use or, again, not keeping up with maintenance and running all 20+ year old parts. But otherwise, it's no bigger risk than any other vehicle, old or new--Especially the new crap the dealerships are selling these days.
 
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Flo-France said:
I would like to keep the 4.56 gear because it’s difficult to find someone to change gear here. We dont have real 4x4 with axle. So it’s more Easy for me to change tire size and wheel size. So if. The good way is 32 i prefer change wheel with 15x8. But it is very bad with 33 tires? It is not better to save some rpm on highway at 81 .I don’t understand why is more bad. Is the car lost power ?
Click to expand...

For the transmission you have 31" tires are fine with 4.56 gears. 33" tires will be better than your 35" tires for fuel consumption .

The bottom line is that anything smaller than 35" tires will be better with the 42rle and 4.56 gears
 
Okay i understand. I check my jeep every week, and i choose best parts (i replace all the old parts). But It’s not a problem for me to drive slower and don’t drive more 70, i prefer security to problems, i don’t buy a jeep to go quick, just enjoy the moment. My question is : 33s on my actually wheel(15x10) will be okay (not perfect) ? Or is it better to stay and not save money and buy new wheels(15x8) + tires 31-32 ?
 
Rickyd said:
For the transmission you have 31" tires are fine with 4.56 gears. 33" tires will be better than your 35" tires for fuel consumption .

The bottom line is that anything smaller than 35" tires will be better with the 42rle and 4.56 gears
Click to expand...

Thanks a lot
 
Flo-France said:
Hi every body,

It’s my first publication, my english is not perfect. I write you from france. Actually i’ve got a jeep tj 4.0, 2006, 42RLE, gear 4.56 with 35 tires.(With stock airbox with sport filter, sport header, and throttle body). I would like to drive around the europe, so i would like to have the best gearing to do higway to be on best place (500-800 miles) . And when i will arrive in some off road place, i can play with the Jeep(i’ve got 4 lift, front sway bar currie, rock jock controls arms, sye and ARB differential with 30 and 44 dana, and front/rear rockjock panhard and rock jock steering ). In europe we don’t have official honor trail. You can’t drive during fews days in the middle of nothing. So i have read all posts. I understand for 4.56 gear and 42 rle the best way is 31 or 32 tires. My question is : in europe the highway max speed is 81 mph(not 70-75 like you). So to save gas, is it better to keep 33 tires ? The jeep will be good on classic road (not higway) ? I’ve got 10x15 soft 8 wheels, facility for me is to put 33 tires, but 32 is normally better. My second problems is : 32 tires is in 11.5 wide, so it’s not perfect for a 10 wheels ? Thanks for all your advises
Click to expand...

In your situation I think the balanced answer is a 33” tire. You’ve got 4” lift and 32’s will look way too small. 33’s will look just right. Your gas mileage really is not going to change much. You’re going to be in the 12-14mpg range (I don’t know what that is in kmpg). This way you can also get a 12.5” wide tire. The gearing won’t be the best, but you also have to mitigate possible driveline vibrations with deeper gearing. So, stay with 4.56, 33” tire, and enjoy your trip! 75mph should be no problem in a Jeep. 🍻
 
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GregBelleville said:
I cringe when I see guys on here bragging how they can "comfortably cruise at 85 with one finger on the wheel".
Click to expand...

So do I. Two fingers minimum on the wheel for safety. 🤫 I drove my old Jeep on 35s to the Florida Keys (16 hours one way) and I only slowed down to 85 when I saw cops. :cool:
 
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JMT said:
In your situation I think the balanced answer is a 33” tire. You’ve got 4” lift and 32’s will look way too small. 33’s will look just right. Your gas mileage really is not going to change much. You’re going to be in the 12-14mpg range (I don’t know what that is in kmpg). This way you can also get a 12.5” wide tire. The gearing won’t be the best, but you also have to mitigate possible driveline vibrations with deeper gearing. So, stay with 4.56, 33” tire, and enjoy your trip! 75mph should be no problem in a Jeep. 🍻
Click to expand...

Thanks . For this answer personalized. I think that to. I can switch with new wheel and tire 31, but after Its better to change the lift to 2.5/3. So its a lot of change.
 
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I don't have a 42RLE; rather, an NSG370 with stock Rubicon gears (4.10/4.11) and 33" tires. I've driven this road several times, keeping up with traffic, in the summer heat, no less:

1714348537152.png


I didn't feel any more unsafe than any other vehicle I've driven on it. My LJ has low miles, though (about 55k now).
 
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