Just upgraded to 37" tires!

[Timmy]

Woo hoo! Just upgraded to 37" tires. Found a set of almost new Toyo's at a good price that I just couldn't pass up on Craigslist.

My previous were Micky T Baja ATZ's. I also run DuraTrac studded in the winter. I must say, these 37" tires are smoother and quieter on the road than the Baja ATZ's, which is incredibly surprising to me given that they have much wider spaced lugs on them. The upgrade came sooner than I was expecting as I was planning on getting other things upgraded in preparation first, but I figured it would be drivable enough as it was. My only issue right now is that I am getting a touch of front bumper rub when I crank the wheel hard and hit a bump. I'm actually finding it rubbing in three different spots. I was planning on upgrading to an AEV bumper, so that just moved up on the list (it was my next upgrade anyway.) They are also rubbing slightly on the air deflector under the bumper, which I'll lose with the AEV bumper, so I don't really care. There is slight rub on the front inside fender down at the bottom by where the step is located, but it just needs a little more securing to get it tighter to the body and it should be good to go. I know if I get flexing this that the fender itself will rub, so down the road I'll probably switch out to flat fenders.

On the power side of things. I'm still running the 3.73 axle ratio (it's a manual trans.) It's not horrible, and in fact the change was less dramatic than I was expecting from the 35" tires. It is still 100% drivable in every day traffic. I'm just holding in a lower gear a little longer, so really, it's only 1st gear and 6th gear that are the biggest issues. I think I'm going to follow Ross's lead on this one and only upgrade to 4.56 gears. I think 4.10 gears would have been more than fine for the 35" tires, so 4.56 should be great for the 37". That being said, I'm looking forward to hearing from FerrariFast on this as I know he just got his Jeep with the same tire setup, but went with 4.88 gears (granted he got a supercharger as well!)

Looks wise... Well... When I bought the Jeep with the 35x12.50R20 tires on it and 4" lift, I always felt it looked a high-school-ish, like the Jeep was trying to jump off the tires. Now, it looks proper. Today my point was proven perfectly. I picked my daughter up from school and her boyfriend told her "the tires look too big on your dad's Jeep." And... point for dad. Only a high school student would make such an outlandish comment, and this is the same kid that thinks an AWD Subaru could go anywhere my Jeep could go.

As we all know, pics hardly do justice, but here you go...

Before with 35" Micky T Baja ATZ's on 20" XD Bully wheels
1524

After with 37" Toyo Open Country M/T's on 20" XD Bully wheels
1525

Ps. If someone could send me a link to what type of gear I need to purchase, I'd be grateful. I've looked on northridge4x4 (they are in Seattle, just 4 hours from me so shipping is quick) but there are so many different gear options I'm not sure what all I would need for a 4.56 gear change.

[ljvsnyder]

Looks good, you should challenge the boyfriend with an off road adventure and he can drive the Subaru. Make sue you take plenty of recovery gear, you will be towing him a lot. From the looks of the 37's you may need to upgrade those fenders and chop the bumper.

[2k13jk]

If your going to stay with 37s for a long time i recommend 4.88 gears

[Pznivy]

If your going to stay with 37s for a long time i recommend 4.88 gears

I say the opposite. Autos need gears worse than manual trans. Think about what you are spending on the gear change, and think about a power mod. A supercharger would make a huge difference.

I say pay for everything else and drive for a while with the 37s and see how you feel.

I drove 37s with 4.10 for a long time. Then i thought 4.88 was too much when I changed. But we do a lot of highway driving in the northeast.

[FLIPmeOVER]

Nice upgrade. I love the toyos. The aev bumper will be heavy. Are you keeping stock flares?

PieFace (ross) will be here sooner or later that guy is the gear guru.

When you do get gears...Get Yukons. No matter what you may have read.....LOL

[JeepLab]

Ahhhhhh Gear talk!..... Seems like yesturday I was in the same spot, and got it wrong.

Now, take into account, that BB had a supercharger. So my experience is with a very light tire, (km2) Light wheel (Weld Racing at the time, PMtruck Wheels now)

So if your truck is a slug now with the toyos, and whatever wheels you have, You may want to consider 4.88. If its "livable" with 3.73, then I say go to 4.56.

What you are giving up with the 4.88 is the highway criusing gear. BB was SLOOOOOOOOW with 4.88s. I swore I ruined her. with 4.56s now, she is still not the rocket she was with 4.10 on the highway. But she is more responsive across the RPM band.

Gears are a leap. You want to be certain you get it right the first time. The expense for doing it twice is horrendus.

[Snarf77]

I think the 4.88 v 4.56 is a matter of how much you intend to take her off road. My jeep is for weekends, bad weather, and whenever I feel like it. The only time I'm above 70 with her any more is on the way to drive her off road in PA. That being ssaid, I'm perfectly comfortable with my 4.88s at 70mph. I don't feel the RPMs are too high and crusing is a breeze. The low-end crawling benefits of 4.88s with the MT are great. Very low crawl ratio.

If I had the turbo before the gears...I may have gone 4.56, its hard to say. I'm with ross that if you DD your vehicle and spend a lot of time on the highway at 75mph then 4.56 may be the better choice. Gears are a leap...you really just have to read enough about them to make a decision you are comfortable with. Either way, I think the only mistake would be to spend the money on something like 4.10s. You'd be happy 4.56 or 4.88.

[Timmy]

Looks good, you should challenge the boyfriend with an off road adventure and he can drive the Subaru. Make sue you take plenty of recovery gear, you will be towing him a lot. From the looks of the 37's you may need to upgrade those fenders and chop the bumper.

Oh believe me, if he actually OWNED a vehicle, I would. Really nice kid, but honestly, he was riding with us and made a comment that Subaru's were made in German. I told him "I hate to burst your bubble, but Subaru's aren't German. You know what a Rice Burner is right?" Well, you can imagine the rest of the story.

Yep, fenders and bumpers on the list. I've actually been prepping for 37" tires for a while, and I was going to do fender and bumpers before the 37" tires, but the opportunity came up so I jumped on it. I can't really go banging around off-road right now because I know I'll rub on the fender. When I back up and turn sharp, the bumper rubs. So... I'm going to get the new bumper here pretty quick to at least take care of that.

Fortunately I already have the Teraflex rear tire carrier, so at least I don't have to upgrade that, but I do need to go get a new 37" Toyo mounted on my spare as it is still holding my 35" Baja's. Why in the world people only buy and sell 4 tires at a time on craigslist is beyond me. A complete set to me is 5 tires. Oh well, saved enough money by buying on CL to save on the cost of a new spare ;-)

[Timmy]

So if your truck is a slug now with the toyos, and whatever wheels you have, You may want to consider 4.88. If its "livable" with 3.73, then I say go to 4.56.

Yep, what you just said is exactly the way I feel. It is livable with 3.73 right now. If I absolutely had to, I could drive her with 3.73 until the day I got rid of her and enjoy it a ton. I really think 4.56 is going to be the right gearing for me.

So... Can you guys give me an idea, exactly what do I need to purchase? Are we talking two of these for $238 a piece or is it something more? I have a local shop just 20 seconds from my house that could probably do the install for me.
1527

[Timmy]

I think the 4.88 v 4.56 is a matter of how much you intend to take her off road. My jeep is for weekends, bad weather, and whenever I feel like it. The only time I'm above 70 with her any more is on the way to drive her off road in PA. That being ssaid, I'm perfectly comfortable with my 4.88s at 70mph. I don't feel the RPMs are too high and crusing is a breeze. The low-end crawling benefits of 4.88s with the MT are great. Very low crawl ratio.

If I had the turbo before the gears...I may have gone 4.56, its hard to say. I'm with ross that if you DD your vehicle and spend a lot of time on the highway at 75mph then 4.56 may be the better choice. Gears are a leap...you really just have to read enough about them to make a decision you are comfortable with. Either way, I think the only mistake would be to spend the money on something like 4.10s. You'd be happy 4.56 or 4.88.

Well dang, now you have me questioning if I should go to 4.88. Since I don't have a Rubicon, I will say the low-gear range on the Jeep has never felt low enough to me. When I had my 35" tires and I would go off road with the kids to some places, I just never felt like I was able to crawl as slow as I really wanted to (it wasn't horrible, I just liked a bit more crawl-ability to it.)

It is a DD for me (though I have my other vehicle as needed, it's only a DD because it's fun to drive.) I really don't drive 75 Mph very often. I just ran to the airport yesterday, and shoot, the highway speeds are only 60-65mph. I'd pretty well have to drive to Idaho to get to 75mph speed limits. I do that on occasion, but not a ton.

Here's my percentage driving (if it helps anyone to help me pick the right gearing.)
40% - 0mph-40mph
40% - 40mph-60mph
10% - 60mph-80mph (my sedan makes up any other highway driving as needed if it is for business, etc.)
10% - Off-Road (hopefully this number will increase as I learn the area a bit more.)

I do plan on putting a supercharger in, but unfortunately other things keep getting in the way of finances for this. I'd love to say it will go in this year, but every time I say that, it seems to just always be out of my grasp slightly.

[Yoinkers]

You sir, are in a pickle. This is the hardest decision you will ever make with your rig. And getting it wrong is a nightmare. Ive seen guys that knew what they were doing and still hate their trucks after new gears. Others love them.

If you only got 4 tires on craigslist, I say, just run 4.

You will not change a 37" tire on the side of the road. Go with that streamline tail with no tire.

[Timmy]

You sir, are in a pickle. This is the hardest decision you will ever make with your rig. And getting it wrong is a nightmare. Ive seen guys that knew what they were doing and still hate their trucks after new gears. Others love them.

If you only got 4 tires on craigslist, I say, just run 4.

You will not change a 37" tire on the side of the road. Go with that streamline tail with no tire.

Haha, thanks for the supporting thoughts ;-) I think the 4.56 is the least "daring" of the two given that my current gearing is drivable. As for a spare tire... Well, I'll always run one. There is no way I will ever be stranded somewhere with my kids because I popped and wasn't prepared, it's just not an option.

[Timmy]

I just finished my Teraflex rear tire carrier install. I had installed the door bracket a while back to support the extra load of the 35" tire, but I hadn't installed the actual tire mount yet because I wanted to wait until I had the 37" tires first so I could get the adjustments right on it. One of the reasons I went with the Teraflex HD system is because it they did a great job with keeping the tire as close to the rear door as possible, and since it's mounted on the door, it operates just like factory solution to open up the rear door. Other solutions I found had the tire mounted pretty far from the back tail gate, which only made the Jeep that much longer, and many required a two step process to open up your tail gate.

In all, I'm thrilled with the solution. I had to take off one of my 37" tires from the hub so I could test fit everything since my spare is still the 35" tire. I didn't want to take it in to get the 37" tire yet until I had the Teraflex mount in place. Here's some pics to show just how close the tire is to the tailgate. They actually have you push the mount as far in as possible to get the tire to literally touch the bracket for added support.

[Don't mind the crazy straps hanging from the rafters. I did that to hold up the tire so I could take it on and off to make adjustments without having to lift it up each time.]
1530
1531
1532
1533
1534

[Timmy]

Let's see, other news. So I decided I'm going to order the MetalCloak control arms to get rid of my suspension squeeks. I was going to go to the $200 AV/Stock control arm route, but after I watched was videos on the MetalCloak solution, I just decided to go big and do it right the first time (well, second time, to get rid of these nasty Pro Comp piece of junk control arms.) I'm thinking of also putting in their dual rate springs, as they sound pretty nice and I can see that my 4" lift is just a little shy with the new 37" tires from a clearance perspective. I'm hoping the fully adjustable MetalCloak control arms though will help me with that so maybe I won't need the springs. I think I need to bring my rear axle back slightly so that my tire won't hit the pinch seem if it compresses up into the body. Right now, it looks like it will rub if I have any up travel, though I do believe the axle moves backwards during up travel so maybe not?

Also on deck is the new bumper. OEM bumper is rubbing slightly on hard turns. I may turn my OEM bumper into a stubby for a short while until I get a new bumper.

Should be a fun year of upgrades!

[ljvsnyder]

Looking good timmy, keep us posted on the tire carrier, i know there have been issues with it in the past.

[Timmy]

Looking good timmy, keep us posted on the tire carrier, i know there have been issues with it in the past.

Do tell. I haven't heard of any issues, so I'd like to know what to keep an eye out for.

[ljvsnyder]

The welds crack and brake.

[WhiteRavenRR]

I think that had to do with the older design on the carrier part itself. It has been redesigned. I just installed the same carrier a couple weeks ago. My issue is that my tire can't sit up against the hinge like it specifies due to my JCR rear bumper. It doesn't have the notch for the tire to sit in like the OEM or other bumpers. I even pressed the studs into the 37" tire location even though I am running 35s, for now, so the tire sits at the highest location.

[Timmy]

I think that had to do with the older design on the carrier part itself. It has been redesigned. I just installed the same carrier a couple weeks ago. My issue is that my tire can't sit up against the hinge like it specifies due to my JCR rear bumper. It doesn't have the notch for the tire to sit in like the OEM or other bumpers. I even pressed the studs into the 37" tire location even though I am running 35s, for now, so the tire sits at the highest location.

Ahh yes, I think you are right. I had been researching this today since ljvsnyder brought it to our attention. It does appear that early on Teraflex had an issue and has redesigned the bracket and weld a bit, of which I believe I have the new design. That being said, I'm going to keep a close on eye it. It's pretty easy to check whenever I'm putting groceries in the back ;-)

Bummer that you can't get your tire up close. I could have actually installed mine in the 35" slots and the tire would have literally rested on the back bumper perfectly. It went back and forth about which being better, resting on the bumper, or being pushed all the way to brackets in the 37" holes. I opted for the latter because I was worried that possibly the rear door would not latch correctly if the bracket drooped at all and thus had the tire hit sooner on the bumper.

Either way, thanks guys for the input!

BTW... Metalcloak control arms are on order! Can't wait to get rid of these stupid squeeks. Now I have to decide when I'm going to pull the trigger on the bumper because the slight rubbing is getting annoying. Right now, I'm a rolling sound machine when I come into the parking lots between the squeeks and the tire rub. I'm sure people are looking at me like "idiot, doesn't know how to put a Jeep together." They're probably right ;-)

[ljvsnyder]

Good to know it has been corrected.

[Timmy]

Ahhh, the pain!!!! MetalCloak arms are 2 weeks out! I swear, I'm not sure I can possibly grease these dumb Pro Comp bushings enough to last for two weeks. This is gonna kill me!

[JeepLab]

The welds crack and brake.

Crap i need to check mine. Otherwise I love the teraflex carrier. I think its reall the only option leaving the ability to really customize the rear bumper. The other carrier i like, is AEV. Not their bumper tho, just the carrier, and cut it into whatever bumper you choose. PURELY because of their fuel carry option. I love that.

[gbaumann]

It is a DD for me (though I have my other vehicle as needed, it's only a DD because it's fun to drive.) I really don't drive 75 Mph very often. I just ran to the airport yesterday, and shoot, the highway speeds are only 60-65mph. I'd pretty well have to drive to Idaho to get to 75mph speed limits. I do that on occasion, but not a ton.

If your truck is a DD in any respect then lean toward the lower ratios. I have 4:10's and a supercharger (soon to be hemi). I drive mostly on the road and mostly at irresponsible speeds (this post will be in evidence at my trial). I love my setup. Most guys focused on being off road want/need something taller. I thought hard about 4:56s and would think that they will serve you well in most situations. At some point when I wake up from my drunken binge spending and am ready for my next "bender" I plan on upgrading to Dynatrac axles. At that time I'll probably go with 4:56s. Every time I do the math 4:88s and taller gears result in too high RPMs for my comfort everywhere but in the dirt (unless you've got 40" tires). Just my thoughts.

BTW - nice looking truck.

[Timmy]

The other carrier i like, is AEV.... PURELY because of their fuel carry option. I love that.

You mean like this fuel carrier option for the Teraflex? (grin)
Link to forum posting (http://www.jk-forum.com/forums/jk-show-tell-33/teraflex-rear-tire-carrier-who-else-has-one-you-running-after-mkt-bumper-too-288558/page5/)
1536

Or maybe this one?
Link to forum posting (http://www.jk-forum.com/forums/jk-show-tell-33/expedition-modded-jeeps-lets-see-em-181613/page344/)
1537

[Timmy]

At that time I'll probably go with 4:56s. Every time I do the math 4:88s and taller gears result in too high RPMs for my comfort everywhere but in the dirt (unless you've got 40" tires). Just my thoughts.

BTW - nice looking truck.

Thanks for the comments. I think you're right, 4.56's sound the best for now. Since I have manual, I can always downshift easily enough, but if you are in 6th gear on the highway and it has too high of RPM, well, there's nothing you can do about that. I'd rather 6th gear be a hair too short on the highway then too tall.

Thanks for the compliment. I get comments about it all the time when in town but really the only thing different about it than a standard Sahara is the lift and tires. That will change this year though as I get a new bumper, hood, front lights and 50" light bar and who knows, maybe some type of decal on it as well (like a big picture of South Park's Timmy on the hood, that would be funny, and the "Timm-ey" sound as the horn, ba haha.)

[JeepLab]

You mean like this fuel carrier option for the Teraflex? (grin)
Link to forum posting (http://www.jk-forum.com/forums/jk-show-tell-33/teraflex-rear-tire-carrier-who-else-has-one-you-running-after-mkt-bumper-too-288558/page5/)
1536

Or maybe this one?
Link to forum posting (http://www.jk-forum.com/forums/jk-show-tell-33/expedition-modded-jeeps-lets-see-em-181613/page344/)
1537

Thats cool! Is there a pic with the tire in place?

[2k13jk]

I just regeared from 3.21s on 35s with a manual to 4.10s and it is a perfect combo for my 2 door 2013 jk with a ripp super charger

[Timmy]

Thats cool! Is there a pic with the tire in place?

Just did some snooping around on google images and found the following
http://i73.photobucket.com/albums/i230/NemesisGTP/984FBFA0-DE40-43F5-99EA-2CC98821A69D-20115-00001DB862B28FB1_zpsf7c0281e.jpg

http://i73.photobucket.com/albums/i230/NemesisGTP/5E5584AC-81F5-440C-8FDA-0467652DD75B-19423-00001C0708625A1D_zpse14e0c81.jpg

http://i59.photobucket.com/albums/g310/tattooedtank/Mobile%20Uploads/CB4EBB65-0869-4841-8B6D-DD55D491BE47_zps9uktyj9o.jpg

http://i59.photobucket.com/albums/g310/tattooedtank/Mobile%20Uploads/1049E902-F61D-442B-8C77-A55BCBDE9B47_zpsiu7ddxi8.jpg

http://i59.photobucket.com/albums/g310/tattooedtank/Mobile%20Uploads/181255BD-E76A-4888-BF44-5B8CE0BF8CB2_zpsgvmqt2je.jpg

http://www.jk-forum.com/forums/attachment.php?attachmentid=446330&d=1365825188

[ljvsnyder]

That alone would make me want the terraflex setup.

[KaiserBill]

I've got to say the Subaru Rally WRX Impreza from the mid-1990's was pretty unstoppable in FIA Rally course. Obviously, the Rally car isn't designed for crawling over obstacles like a lifted Jeep is but then again you probably would be doing a 120-130mph on an unprepared surface like the Impreza can.

https://www.youtube.com/watch?v=eTrBxVtQbe8

However, the best of both worlds-- Current 7 time Champs of the Dakar the KAMAZ...

https://www.youtube.com/watch?v=8FcEuuakWPg

It can do a 130mph in the open and crawl over rocks too...


I do have to ask one question like the kid if you are doing mostly highway driving why get the 37's? If it is just for the looks okay. You'll need to get a pinion puller for the pinion gear. As for gears get the best ones you can afford. Make sure they have a lot of contact between the teeth when they mesh. That way you will distribute the torque across the complete surface of the tooth. That is important cheap gears tend to have less contact area and can easily damage the teeth under high torque loads.

Here is the truth about gearing a truck-- you really need more than just a change in differential gears. You really need to change the gearbox gears as well. But no one does that-- unless you are a rally racer. Because you need to change the torque rise between each ratio to really get the best performance for your vehicle. The charts for tires and differentials only give you an approximation of the normal performance of your vehicle with the stock stuff. Since I don't care about top speed too much-- I always go for mechanical advantage. I would pop- 10:1 differential gears into the truck if I thought it would give me the Earth moving performance I wanted in 3 feet of snow or mud. But that is me.

[UselessPickles]

You really need to change the gearbox gears as well. But no one does that

No one does that because it's not actually needed. Transmission gear spread impacts how you make use of the engine's power as you accelerate and shift through the gears. Changing tire size has no impact on this relationship at all. If the transmission is already matched well enough to the engine's torque/power curve and the general intended usage of the vehicle, and it's not a racing transmission with reconfigurable gear ratios, then any benefit of optimizing the transmission setup to your personal preferences is not going to be anywhere near worth the cost/effort for anyone without very deep pockets.

Then again, if you have a configurable racing transmission, you probably already have pretty deep pockets, and also a vehicle for which there exist after market racing transmissions.

[KaiserBill]

Of course changing the tire size has an impact on the transmission's ratios. This is the reason why when you put a 4.88:1 on the differential and you keep your stock gear set in the gearbox you end up with a 300-500rpm increase for cruising at 75-80mph. If you want to get back to say cruising at 2200rpm for that speed instead of 2700rpm, you need to have more gears in your gearbox i.e. a second overdrive. So another progressive step in the system to get back to stock configuration.

You are correct it is expensive to have a customizable gearbox; but it is hardly not worth it.

[UselessPickles]

You are correct it is expensive to have a customizable gearbox; but it is hardly not worth it.

Clearly. That's why so many people are customizing their gearboxes on the Wrangler :)

[KaiserBill]

Clearly. That's why so many people are customizing their gearboxes on the Wrangler :)

Some times it is just a matter of swapping out a gearbox for another. Sometimes you need to put doublers on the system to get the effective ratios you want without changing the gearbox. Hence the reason Atlas makes doublers for transfercases because it is easier to swap out a transfercase or add a doubler to the existing one you want. However, you could also achieve the same effect by altering the gears in the transmission or swapping one for the other.

My point is merely changing the differentials is not exactly a perfect way to get back to stock configuration. Something will be lost in the setup usually cruising speed at a specific rpm will increase. Unless you do something radically different with your transmission. Like say find a guy that will make you a custom 7spd gearbox or a custom set of gears for your existing box. So, you get a gear set in the differentials that are within a 1-200rpm of your stock configuration you're doing pretty good.