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What would it take to run 37 inch tires?


Jainee

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Oct 19, 2019
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Virginia
Hello,

I have 1998 Jeep TJ manual and I have been trying to restore it slowly as I could.

It’s currently running Mickey Thompson 33” tires with Dick Derek 15” wheels.

I’m looking into upgrading to 37” tires and read numerous posts online about it’s a serious upgrade vs what could go wrong. I’m not an off-road person and this would be my daily driver.

Could you please help me understand what would it take to use 37” tires or otherwise don’t do it? What would be the amount I am looking at with support say Dana 30 and Dana 35 beef up package?


These are the things already done on her. The ride is little bumpy and don’t know if that’s the way it should be. Any help will be highly appreciated.

R/C 3.25" LIFT KIT EXHAUST MANIFOLD
NEW RADIATOR
NEW WATER PUMP
5.13 GEAR PACKAGE
D35 AXLE SEALS
D30 AXLE SEALS
H/S STEERING SHOCK TIE ROD @PITMAN ARM 43 TOOTH SPEEDO GEAR

Again I have read so many threads with variety of advice. It’s confusing for me personally because I don’t know much about mechanical parts.

if someone could please list what I must do and what could wait - that’s perfect pitch.
I understand I could stick to 33” or take 35” but I want to see why shouldn’t I go for 37 and what takes to go to 37.

thanks
 

Brian83

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Oklahoma City, OK
If you search this forum you will find plenty of info why not to run 37s on a TJ. But the main facts are that the axles can't handle it no matter what you do and the wheel base is to short with out a stretch.
 

Chris

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I’m not an off-road person and this would be my daily driver.
Stop right there.

Let me preface this by saying I am not trying to come across as a dick, nor am I trying to come across as aggressive, so please don't take it that way.

37s have no place on a daily driver, period. In addition, 37s have no place on a TJ unless you plan on stretching the wheelbase.

35s are widely considered to be the max tire size for the TJs short wheelbase, before you need to start stretching things.

What will you need to run 37s on your TJ?
  • A bigger brake kit such as a Vanco big brake kit that @mrblaine sells.
  • Upgraded alloy axle shafts
  • A V8 swap, a supercharger, or some other way of obtaining a good 100+ extra horsepower (unless you want life to suck, the 4.0 with 5.13 gears isn't going to be fun to drive with 37s as a daily driver)
  • A 5" lift and highline fenders
  • etc
Since you don't plan on off-roading, I guess you can skip aftermarket axles, etc.

However, life is going to suck with 37s on 5.13s for a daily driver. If you're just doing it to look cool, what's so wrong with 33s? I mean "to each their own", but that would be just miserable to daily drive if you ask me.

I can think of 100 reasons not to run 37s on a daily driver TJ. I can't think of one reason however that you would run them on a daily driver.

Again, not trying to be a dick, but if you saw how much I was rolling my eyes here, you might laugh ;)
 

JMT

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New axles front and rear
6” of lift or 3” lift plus highline
Stretched wheelbase
Deep gears
BBK
All the other typical stuff


My guess is the axles alone will cost $12k. In all $20k.

Edit: I also think you are insane thinking 37’s as a non-off-road person and daily driving it.
 
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Chris

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Hey @toximus, tell us what it takes to run 37s ;)

If you really wanted to run 37s on a daily driver, the JL is a much better platform for that. You can first 37s on them stock with no lift at all. Should you do it? No. However, you certainly can, and very easily too.
 
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JMT

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Even going to 35’s you’ll need to Super your D35.

I personally can’t see a daily driver over 33’s. There are many here who think 35’s is max for a daily driver.
 

qslim

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The 33"s I run on my TJ with a 4" lift are enough to keep me from using it as a daily driver. To each their own, but if I had to drive this thing every day as my primary transportation I would lower it and put smaller tires on it.
 
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J

Jainee

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Virginia
Thank you!

this is easy and very clear now :)

to be frank I got confused because of different opinions and I do see YouTube video saying they are running it. Some did call - it depends on your driving skills.

20K $ for running 37 - it doesn’t look worth it and I don’t think I would do V8 and other stuff.

I was not doing it for others but I do like bigger tires :) it was just for my own satisfaction and she is not for display. :)

Do you guys think 35’s can fit without any addition?
 

bluescapegoat

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I am one of those weirdos running 37s and daily driving. And (eek) my axle shafts are still stock.

4" savvy lift with 1.25" body lift and aftermarket (non-highlined) fenders just slightly kiss the tires at full bump, not enough to scuff the powdercoat. You have to hammer the pinch welds in the rear wheel well and you're left with less than an inch of placement front to back of the rear axle to clear both the tub in the front and gas tank in the rear. But you don't need 6" of lift and high lined fenders unless the travel you get from a Savvy 4" lift isn't enough for you.

I've also got the D44s, which are still not up to the task if I'm ever planning on moderately hard wheeling. They're geared 5.13 but with the 6 speed's steeper ratio it was enough to make it driveable. Now I've recently supercharged it and it's actually a pretty decent daily and quite quick, although horribly inefficient. I do wheel it, but like I said, not too hard. Generally If I can't idle it in low, I just don't do it.

I've done d30/d35 before. I'd stay 33s, or save up and get some dynatracks or rockjock axles and go big.

I guess that was a lot of words to say I've done what probably shouldn't be done, but it's not nearly as terrible as everybody makes it out to be. And even with still mostly stock axles and a short arm lift, I'm over $30k in parts. It adds up.
 
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billiebob

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I’m not an off-road person and this would be my daily driver
first you'll need a much bigger gas tank, fuel budget
you want to build something with zero practical reasoning for what ?

but if you want 37s for the street and you have 5.13s.... bolt on and go.
 

JMT

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Thank you!

this is easy and very clear now :)

to be frank I got confused because of different opinions and I do see YouTube video saying they are running it. Some did call - it depends on your driving skills.

20K $ for running 37 - it doesn’t look worth it and I don’t think I would do V8 and other stuff.

I was not doing it for others but I do like bigger tires :) it was just for my own satisfaction and she is not for display. :)

Do you guys think 35’s can fit without any addition?
Again, no. Biggest tire on stock suspension is 31x10.5r15, and evening then a minority rub and have to adjust steering stops
 
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JMT

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Hello,

I have 1998 Jeep TJ manual and I have been trying to restore it slowly as I could.

It’s currently running Mickey Thompson 33” tires with Dick Derek 15” wheels.

I’m looking into upgrading to 37” tires and read numerous posts online about it’s a serious upgrade vs what could go wrong. I’m not an off-road person and this would be my daily driver.

Could you please help me understand what would it take to use 37” tires or otherwise don’t do it? What would be the amount I am looking at with support say Dana 30 and Dana 35 beef up package?


These are the things already done on her. The ride is little bumpy and don’t know if that’s the way it should be. Any help will be highly appreciated.

R/C 3.25" LIFT KIT EXHAUST MANIFOLD
NEW RADIATOR
NEW WATER PUMP
5.13 GEAR PACKAGE
D35 AXLE SEALS
D30 AXLE SEALS
H/S STEERING SHOCK TIE ROD @PITMAN ARM 43 TOOTH SPEEDO GEAR

Again I have read so many threads with variety of advice. It’s confusing for me personally because I don’t know much about mechanical parts.

if someone could please list what I must do and what could wait - that’s perfect pitch.
I understand I could stick to 33” or take 35” but I want to see why shouldn’t I go for 37 and what takes to go to 37.

thanks
Read this

 
OP
J

Jainee

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Joined
Oct 19, 2019
Messages
23
Location
Virginia
@bluescapegoat thank you! This is what I wanted to hear. There are enough information available saying don’t do it but your advice is very reasonable. Do you mind sharing pics and also share what all you didn’t like?

@JMT thank you for sharing the link and your advice. it’s very good info given by @Chris and I wish if I had seen it earlier. A very nice write up.

@billiebob there is no practical reason why I want to do it. I got very sincere advice and I understand it needs a lot of work and not efficient or practical. I very well understand the difference between “want” and “need” and the expertise here is the reality check.

I think I will upgrade first to Rancho shocks as it’s a bumpy ride may because of RC kit shocks .

I will read more about 35’s and plan it out eventually and take it slow.

thanks a lot for valuable advice. :)
 
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Chris

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35s would certainly be a better choice. 37s really don't have any place on a TJ (or even an LJ) without a considerable amount of work.
 
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J

Jainee

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Location
Virginia
Thank you @Chris . I appreciate it.

I see that it will still require some work to run 35’s?

what else would you recommend to get done? I’m trying to search if there is a ordered list of things which a beginner can use to upgrade in sequence. Or a list of must-have.
 

Chris

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Messages
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Thank you @Chris . I appreciate it.

I see that it will still require some work to run 35’s?

what else would you recommend to get done? I’m trying to search if there is a ordered list of things which a beginner can use to upgrade in sequence. Or a list of must-have.
Even if you never plan to take it off-road, you're still going to want 5" of lift, most likely in the form of a 4" suspension lift and a 1" body lift. At that height you'll need a SYE and a CV driveshaft, as well as adjustable control arms.

The other very important thing will be the big brake kit I mentioned. 35s on stock brakes (even with upgraded brake pads) is going to be scary should you ever need to really hit your brakes. You'll want a Super 15 or Super 16 Vanco big brake kit.

The first thing I would start with is the lift and SYE / CV driveshaft, then the brakes, and finally the tires. You can upgrade the axle shafts last. Technically you can probably drive it just fine with the stock axle shafts since you'll never be off-roading it, but if you ever really get on it, there's a chance you could still break the axle shafts with 35s, so at some point it will be ideal to upgrade to some nice alloy axle shafts (i.e. Revolution).

Gearing could be done very last.
 

JMT

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THANK YOU! This is very nice way to make a newbie understand.
BTW, congratulations on your new Jeep! Get ready to Just Empty Every Pocket so you can Just Explore Every Place.

These are super fun rigs, the funnest I’ve ever had. I had never ventured into working on my own vehicle before. Now I won’t let anyone touch my vehicles except me. I enjoy working on it as much as driving it.

I never planned to wheel, but now I can’t get enough of it.

I hope you have a great journey.