38's are the Goldilocks of tires (owner review)

[JeepCode4]

I just mounted up a set of 38/13.5r17 Falken Wildpeak RT01 on my AEV Borah beadlocks and am very happy with the new tires so far. I had a JK on a few different lifts and tires and now two JT's with multiple sets of tires and lift heights. On the JT's I've run 285/75r17 KO2s, 35/11.5r17 Toyo ATIII, 37/12.5r17 KM3s, 37/12.5r17 KO2s, and now the 38" Falken RTs.

The Falken RT mounted on the truck comes in at 37.1 inches. My notoriously small 37 KO2s measured at 35.7 inches. It's a noticeable difference and one I think will make a difference on the trail. Additionally, my perspective on width has changed the more I hit the rocks. At 11.5" wide I was rubbing my wheels on every rock I tried going around. Even a 12.5 mounted on a beadlock would rub the hell out of the ring. The extra width is going to come in handy while crawling over obstacles.

I've always been a fan of AT tires since I spend most of my time on the road, but after a but of research I'm giving these RT's a try. I'll report back after I spend a Minnesota winter on them. So far the road manners are great, slightly louder than the KO2s (which were very quiet).

The other thing I kept hearing when considering jumping to a 38 was to just go 40's. This is a no go for me for a few reasons.
1. I'm already regeared to 4.56 and that will work for 38s but not 40s. If I could do it again I'd choose 4.88 or maybe 5.13 but I can get by at 4.56. I think 40s would force a regear.

2. When I decided on 38s I knew I would want to beef up my brakes (powerstop rotors and pads) and axles shafts (RVC up front, dana chromoly rear). This is a considerable expesne at $3k but I would be looking at 6X the cost for new axles if I went 40s.

3. I'd need a taller lift to fit 40s. At 38" I can keep my current lift (AEV 2.5") and retain a ride I really like. I did gut the fender liners and still need to check clearance at full lock/full stuff but I had quite a bit of room when I was running the 37s with the full fender liner. 40s and a 4.5" lift would mean I would no longer fit in my garage, another demerit.

Overall, it's just my opinion, but 38's are the Goldilocks of tires for these trucks. Not too small, but not too big.

Here are the quick specs on my JT for those curious:
2021 JTR AEV JT370 (4.56 gear package) auto transmission
AEV 2.5 lift
Metalcloak CAs (all 8)
Currylink steering (tie rod/draglink)
Teraflex rear upper control arm extended travel kit
Rancho adj trackbar
38/13.5r17 Falken Wildpeak RT01 on Borah Beadlock wheels (+25mm offset)

Jeep looks great man. Funny i have a similar sign in my garage.

I just got the R/T01's also and LOVE them. Slightly more noise on the roadway than the AT3W's but they ride nicer on the highway and are better offroad.

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[Wolf Island Diver]

I just mounted up a set of 38/13.5r17 Falken Wildpeak RT01 on my AEV Borah beadlocks and am very happy with the new tires so far. I had a JK on a few different lifts and tires and now two JT's with multiple sets of tires and lift heights. On the JT's I've run 285/75r17 KO2s, 35/11.5r17 Toyo ATIII, 37/12.5r17 KM3s, 37/12.5r17 KO2s, and now the 38" Falken RTs.

The Falken RT mounted on the truck comes in at 37.1 inches. My notoriously small 37 KO2s measured at 35.7 inches. It's a noticeable difference and one I think will make a difference on the trail. Additionally, my perspective on width has changed the more I hit the rocks. At 11.5" wide I was rubbing my wheels on every rock I tried going around. Even a 12.5 mounted on a beadlock would rub the hell out of the ring. The extra width is going to come in handy while crawling over obstacles.

I've always been a fan of AT tires since I spend most of my time on the road, but after a but of research I'm giving these RT's a try. I'll report back after I spend a Minnesota winter on them. So far the road manners are great, slightly louder than the KO2s (which were very quiet).

The other thing I kept hearing when considering jumping to a 38 was to just go 40's. This is a no go for me for a few reasons.
1. I'm already regeared to 4.56 and that will work for 38s but not 40s. If I could do it again I'd choose 4.88 or maybe 5.13 but I can get by at 4.56. I think 40s would force a regear.

2. When I decided on 38s I knew I would want to beef up my brakes (powerstop rotors and pads) and axles shafts (RVC up front, dana chromoly rear). This is a considerable expesne at $3k but I would be looking at 6X the cost for new axles if I went 40s.

3. I'd need a taller lift to fit 40s. At 38" I can keep my current lift (AEV 2.5") and retain a ride I really like. I did gut the fender liners and still need to check clearance at full lock/full stuff but I had quite a bit of room when I was running the 37s with the full fender liner. 40s and a 4.5" lift would mean I would no longer fit in my garage, another demerit.

Overall, it's just my opinion, but 38's are the Goldilocks of tires for these trucks. Not too small, but not too big.

Here are the quick specs on my JT for those curious:
2021 JTR AEV JT370 (4.56 gear package) auto transmission
AEV 2.5 lift
Metalcloak CAs (all 8)
Currylink steering (tie rod/draglink)
Teraflex rear upper control arm extended travel kit
Rancho adj trackbar
38/13.5r17 Falken Wildpeak RT01 on Borah Beadlock wheels (+25mm offset)

What about the spare?

 

[RodRecket]

What about the spare?

Part of the AEV package relocates the spare to a flat mount in the bed. I utilize that. If I need the full bed in town I just dump the spare. I also don't have to worry about dragging the spare over obstacles that way.

 

[RodRecket]

Jeep looks great man. Funny i have a similar sign in my garage.

I just got the R/T01's also and LOVE them. Slightly more noise on the roadway than the AT3W's but they ride nicer on the highway and are better offroad.

Good to hear. So far I like them a lot. Interested to see how they do in the winter.

 

[JeepCode4]

Good to hear. So far I like them a lot. Interested to see how they do in the winter.

Yea same here, but I think they’ll be very good, nice thick tread knuckles

 

[Wolf Island Diver]

Part of the AEV package relocates the spare to a flat mount in the bed. I utilize that. If I need the full bed in town I just dump the spare. I also don't have to worry about dragging the spare over obstacles that way.

Gotcha. I didn’t see the AEV wheel mount. That’s a cool item. Unfortunately I can’t run that with all my crap on/in the bed so I’m maxed out at 37s. My logic is that if I go bigger, I’m probably going 40s and then doing a PCOR conversion or maybe a tire carrier bumper. It would be nice to run 38s. I agree it’s a sweet spot.

I asked about the spare because one thing I found recently on my Borah wheels is that the recessed valve paradoxically makes breaking the valve stem more likely. Its concerned me for a while but it finally happened. It’s when inflating tires with a lock-on chuck. This is especially true if you use metallic (vs rubber/brass) valve stems which become brittle very quickly. I very easily snapped one and watched the tire go flat in the driveway. Thankfully I had a full size spare that’s part of my 5 tire rotation and wasn’t stranded. I then had to detention the beadlock, crack the bead, replace the stem on the TPMS and retention the ring on the one I broke. Good times. I’m now going to do the valve stem swap out on the other 4 wheels. Fancy valve stems are a bad idea.

FYI, PowerTank has a new chuck that works better and is less likely to get jammed on the valve stem.

 

[GeneralMaximus]

Thats a nice looking truck. I was going to comment that I don’t think it would fit through that little garage door behind it. But then I noticed the bigger garage door in front!

 

[Wolf Island Diver]

I upgraded the AEV springs to the 3 inch heavy load (blue) springs. They’re more like 3.5 - 4” springs. With a full overlanding loadout, the truck still has a rake. It drives fine with these springs, even unladen, but I’d prefer a little more damping from the shocks. You may very well be able to fit 40s with those springs and aggressive trimming.

 

[RodRecket]

Gotcha. I didn’t see the AEV wheel mount. That’s a cool item. Unfortunately I can’t run that with all my crap on/in the bed so I’m maxed out at 37s. My logic is that if I go bigger, I’m probably going 40s and then doing a PCOR conversion or maybe a tire carrier bumper. It would be nice to run 38s. I agree it’s a sweet spot.

I asked about the spare because one thing I found recently on my Borah wheels is that the recessed valve paradoxically makes breaking the valve stem more likely. Its concerned me for a while but it finally happened. It’s when inflating tires with a lock-on chuck. This is especially true if you use metallic (vs rubber/brass) valve stems which become brittle very quickly. I very easily snapped one and watched the tire go flat in the driveway. Thankfully I had a full size spare that’s part of my 5 tire rotation and wasn’t stranded. I then had to detention the beadlock, crack the bead, replace the stem on the TPMS and retention the ring on the one I broke. Good times. I’m now going to do the valve stem swap out on the other 4 wheels. Fancy valve stems are a bad idea.

FYI, PowerTank has a new chuck that works better and is less likely to get jammed on the valve stem.

That sounds like a pain in the ass. I've unfortunately experienced something similar with balance beads wedging themselves into the valve core and deflating the tire... never again. I could see how a rigid valve stem and quick connect could be an issue. Luckily I have the rubber valve stems because I have struggled with the getting the moreflate connections off.

I've found I really enjoy basecamping and being able to leave camp behind to go explore or hit the trails. I've also gotten more and more into rock crawling which has inspired a lot of these mods.

 

[RodRecket]

I upgraded the AEV springs to the 3 inch heavy load (blue) springs. They’re more like 3.5 - 4” springs. With a full overlanding loadout, the truck still has a rake. It drives fine with these springs, even unladen, but I’d prefer a little more damping from the shocks. You may very well be able to fit 40s with those springs and aggressive trimming.

I was looking into those springs but I don't usually carry more than the spare when on the street and then add 150lbs when going on the trail. I really like the ride now and was afraid they'd be too stiff. We'll see how much rubbing I have when it gets really twisted up.

 

[MrT]

38 Ridge Grapplers

 

[Dickster]

38s are a good fit. 4.5lift and no rub just need a shorty bumper. If you rock crawl axle shafts and possibly trusses if you get crazy.

 

[RodRecket]

38s are a good fit. 4.5lift and no rub just need a shorty bumper. If you rock crawl axle shafts and possibly trusses if you get crazy.

Axle shafts are the next upgrade for me

 

[Dickster]

Axle shafts are the next upgrade for me

Nice what are you going with? I went with RCV single front, and Revolution chromoly rear. I am getting 5.38 gears installed next week so perfect time to upgrade shafts.

 

[RodRecket]

Nice what are you going with? I went with RCV single front, and Revolution chromoly rear. I am getting 5.38 gears installed next week so perfect time to upgrade shafts.

I keep going back and forth on which front shafts to go with.

I was sold on RCV until I read about the boot grease. Having the front knuckle a greasy mess is dissuading me. I'm also unsure the frequency of greasing them. I normally rotate tires on each oil change and that's when I'd grease, unsure if that would be frequent enough. Also, they are damn expensive. Smooth turning 4wd turning and their strength is appealing though.

The other option I was looking at is Dana Spicer. Their front shafts are stronger and use 1410 u joints. They are also nearly $600 less than RCV. No real downside their other than retaining the "crow hop" in 4wd. I plan on retaining FAD and have read (on the JL forum) their shafts don't have the correct bushing size for the fad inner shaft. Not sure if that's still an issue.

I'm still planning on running Dana Spicer rear chromoly shafts either way. I'm leaning towards Dana Spicer front and rear. More affordable, stronger than stock, and (unsure how much it matters) all one companies products working together.

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