37's ?

JKGUY

New member
So I've had my first Jeep for a month now and I'm ready to start doing some mods. What is the deal with 37" and up tires? Is it true that with 37"s it adds mote stress on everything and make it more likely to break? I would really like to run 37" tires. Any feedback would be a great.
 
So I've had my first Jeep for a month now and I'm ready to start doing some mods. What is the deal with 37" and up tires? Is it true that with 37"s it adds mote stress on everything and make it more likely to break? I would really like to run 37" tires. Any feedback would be a great.

37" tires will add stress to parts of your Jeep. 37's add greater ground clearance between ground and differentials. With 37's you would definitely need to re-gear your axles and lift your Jeep some. My advice would be to get out and wheel your Jeep some, and start your build based on your needs for your type of wheeling. Make it your own.


2010 JKU Sport
1977 CJ5

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Thank for the info. I have been a little bit at a time. Regearing. What gears should I change to?
 
So I've had my first Jeep for a month now and I'm ready to start doing some mods. What is the deal with 37" and up tires? Is it true that with 37"s it adds mote stress on everything and make it more likely to break? I would really like to run 37" tires. Any feedback would be a great.

Yes, it's absolutely true if you wheel your jeep hard enough. To do it right, you would want to make some upgrades and I'm not talking about sleeving your front axle.
 
Yes, it's absolutely true if you wheel your jeep hard enough. To do it right, you would want to make some upgrades and I'm not talking about sleeving your front axle.

I'm also prepping to run 37's. So far I've put on sleeve and gussets, front driveshaft, and I'm having gears installed as we speak. What else do you recommend?
 
I'm also prepping to run 37's. So far I've put on sleeve and gussets, front driveshaft, and I'm having gears installed as we speak. What else do you recommend?

...........

edit: you should be good with your 44. maybe upgrade to chromos and start your PR44 fund :D

andrew -
 
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i haven't been wheeling hard for long time like few members here but just built one to do just that.
Have both 37" and 40" tires to run my jeep.. ets just say D44 locked, sleeved couldnt handle 40" tires for 500km.. Cracked the diff and was bleeding gear oil..
i think the 37 and 40 weight about the same so it might happen to you if you are very unlucky like my self.

now ineed to throw away that $2000 + dollars i put into D44 and upgrade to D60.
 
I'm also prepping to run 37's. So far I've put on sleeve and gussets, front driveshaft, and I'm having gears installed as we speak. What else do you recommend?

You are more likely to break an axle shaft any day of the week than you are to break an axle housing. Assuming you have a Rubicon, chromoly shafts with full circle clips is what I would gotten over sleeves. If you have a 2-door, you will want to get a new rear 1350 shaft sooner than later as the amount of lift needed to clear your 37's will be significant enough that your factory shaft will fail sooner than later. If you have automatic or a 2012-up, you will want to get a front shaft too. While 5.38's will give you a nice ratio for 37's, the pinion on a Dana 44 will be really really small and will be a weak point. I would not recommend anything bigger than a 5.13 here.
 
You are more likely to break an axle shaft any day of the week than you are to break an axle housing. Assuming you have a Rubicon, chromoly shafts with full circle clips is what I would gotten over sleeves. If you have a 2-door, you will want to get a new rear 1350 shaft sooner than later as the amount of lift needed to clear your 37's will be significant enough that your factory shaft will fail sooner than later. If you have automatic or a 2012-up, you will want to get a front shaft too. While 5.38's will give you a nice ratio for 37's, the pinion on a Dana 44 will be really really small and will be a weak point. I would not recommend anything bigger than a 5.13 here.

You just answered all my questions as well thank you, Any specific company you would recommend for the shafts?


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You just answered all my questions as well thank you, Any specific company you would recommend for the shafts?


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I have run a lot of shafts and prefer JE Reel if only because they come with made in the USA Neapco u-joints. Coast makes nice shafts too and use Spicer joints. If you're running 37's or bigger, you definitely want to run a 1350. With a set of 35's, a 1310 will be fine.
 
I have run a lot of shafts and prefer JE Reel if only because they come with made in the USA Neapco u-joints. Coast makes nice shafts too and use Spicer joints. If you're running 37's or bigger, you definitely want to run a 1350. With a set of 35's, a 1310 will be fine.

Thanks for quick response!!!


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You are more likely to break an axle shaft any day of the week than you are to break an axle housing. Assuming you have a Rubicon, chromoly shafts with full circle clips is what I would gotten over sleeves. If you have a 2-door, you will want to get a new rear 1350 shaft sooner than later as the amount of lift needed to clear your 37's will be significant enough that your factory shaft will fail sooner than later. If you have automatic or a 2012-up, you will want to get a front shaft too. While 5.38's will give you a nice ratio for 37's, the pinion on a Dana 44 will be really really small and will be a weak point. I would not recommend anything bigger than a 5.13 here.

Dang, the shop is installing the 5.38's as we speak. Looks like I may have to rethink the 37's and stick with 35's. Thanks everyone for all the good info:beer:
 
I would call the shop an tell them hold up. I'm not sure I've heard anyone run that high of gear and if they recommended, than that is not good advice and contrary to chart.

If your stuck, than next move us your call. Neither will be optimal.
 
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