Anyone with 37”+ tires doing long road trips?

[The 1]

I’m looking into lifts and tires. I’d like to go 38” tires, but I’m planning some out of state trips soon. I live in Houston so out of state means high mileage trips. Does anyone here do high mileage trips on tires 37 inches or bigger? Just looking for experiences. Thanks

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[FLUndertaker]

As long as you do the recommended regearing when adding the tires I don’t see why a trip of any length would be a problem.

 

[Renegade]

I’ve done a few 400 mile trips in mine. With 4.10 gearing and the automatic, it will cruise comfortably at 75, and a little less so for periods at 80+. This is on generally flat interstate.

 

[Jeeperjamie]

I agree with @Renegade if you got 4.10 gears and a 8spd then anything 37 or 38 shouldn't present a issue. The 8spd does great IMO and I'm on 35's right now and haven't noticed really much of a difference in power loss or mpgs. I'm getting around 19mpgs for most part city/hwy combined. I'm shopping for 37's right now but if I see a set of 38's that's a good deal I would probably get them and still not regear.

 

[Aberk]

I’ve done a few 400 mile trips in mine. With 4.10 gearing and the automatic, it will cruise comfortably at 75, and a little less so for periods at 80+. This is on generally flat interstate.

Same. I have found that 75 is much better with fuel than 80, but I can maintain 80 no issues.

 

[Jeeperjamie]

Same. I have found that 75 is much better with fuel than 80, but I can maintain 80 no issues.

Yeah even on 35's it seems like the sweet spot is between 72-78mph anything above 80 you start losing MPGs unless it's super flat. For the most part who needs to go 80 in JT anyways, it's a truck. In NC the most the speed limit gets is 75 and I could be wrong on that and it may be just 70.

 

[Hootbro]

I agree with @Renegade if you got 4.10 gears and a 8spd then anything 37 or 38 shouldn't present a issue. The 8spd does great IMO and I'm on 35's right now and haven't noticed really much of a difference in power loss or mpgs. I'm getting around 19mpgs for most part city/hwy combined. I'm shopping for 37's right now but if I see a set of 38's that's a good deal I would probably get them and still not regear.

Did you re-flash for the 35's? How is highway shifting and does it hunt and peck between 7th and 8th gear on the highway?

I am debating on 35's myself but do not want to re-gear to keep a normal highway driving use.

 

[LordEnzo]

Doing a trip from Central FL to N GA right now. RC 3.5 spacer lift and 37 MT. 3.6 auto. There is a small power drop, but nothing the motor and tranny can't handle. No need to regear unless you're high altitude (1500'+ I think). Going up hill it'll drop a gear or 2, but doesn't struggle. Don't expect to see 8th gear tho and try to keep it at/under 75. Mpg average about 14. I'm expecting 12-13 after GA.

 

[Jeeperjamie]

Did you re-flash for the 35's? How is highway shifting and does it hunt and peck between 7th and 8th gear on the highway?

I am debating on 35's myself but do not want to re-gear to keep a normal highway driving use.

Yes I recalibrated using JScan and no it does not search for 7th or 8th. Stays in 8th most of the time unless I hit a decent incline, hardly ever drops below 7th. Heres a 4 minute stretch on I-85

 

[Andrew05LJR]

Uh, I just regeared to 488s and Ill tell you this... Before, I thought 373s were fine with 37s, boy was I wrong. I thought it drove great before the regear and now its MUCH MUCH MUCH better. I also had a JLUR on 37s with the 410s, you should still regear. Period.

 

[Jeeperjamie]

Uh, I just regeared to 488s and Ill tell you this... Before, I thought 373s were fine with 37s, boy was I wrong. I thought it drove great before the regear and now its MUCH MUCH MUCH better. I also had a JLUR on 37s with the 410s, you should still regear. Period.

I agree if you got 3.73 gears you shouldn't even run 35's without a regear, but the 4.10s do great with 35's and my buddies running 37's without much difference in performance as my JT. I'm guessing a JLUR is engineered a little different than the JT

 

[CivilJeep]

I’m looking into lifts and tires. I’d like to go 38” tires, but I’m planning some out of state trips soon. I live in Houston so out of state means high mileage trips. Does anyone here do high mileage trips on tires 37 inches or bigger? Just looking for experiences. Thanks

This is a great tool to see what different tire combinations will have on your effective gear ratio;

Gear Ratio Calculator (tiresize.com)

It obviously doesn't give you seat of the pants feel, but it will at least put some real numbers to what you might want to do.

 

[CivilJeep]

I agree with @Renegade if you got 4.10 gears and a 8spd then anything 37 or 38 shouldn't present a issue.

I agree if you got 3.73 gears you shouldn't even run 35's without a regear

This is where a gear ratio calculator is helpful. The effective ratio for 4.10's with 37" tires is 3.49, and 3.40 for 38" (assuming you start with a Max Tow and stock wheels). My Overland with 3.73 and 35" tires would have an effective ratio of 3.42, which is almost identical.

 

[Jeeperjamie]

This is where a gear ratio calculator is helpful. The effective ratio for 4.10's with 37" tires is 3.49, and 3.40 for 38" (assuming you start with a Max Tow and stock wheels). My Overland with 3.73 and 35" tires would have an effective ratio of 3.42, which is almost identical.

I agree somewhat with the charts except they can't really measure real world experience. I get the science behind them but different tires that weigh different but are the same size are going to perform differently on any jeep. Also they all don't measure the same some taller some not. The chart is a good start and can give you a idea but real world driving on a particular tire and how the Jeep or whatever the tire is on is the best way to find out. That's why I try to find every scenario a tires been through before buying a particular tire, also one of the reasons I've been running BFG's.

 

[CivilJeep]

I agree somewhat with the charts except they can't really measure real world experience. I get the science behind them but different tires that weigh different but are the same size are going to perform differently on any jeep. Also they all don't measure the same some taller some not. The chart is a good start and can give you a idea but real world driving on a particular tire and how the Jeep or whatever the tire is on is the best way to find out. That's why I try to find every scenario a tires been through before buying a particular tire, also one of the reasons I've been running BFG's.

Agree. I don't think wheel weight is given nearly enough thought by most people. I read your post yesterday about the Kanati tires and was impressed with your insistence on factoring tire weight into your choice. The rotational mass is a significant factor in how it will feel when you're driving.

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