Looking on going to 37's from 315's. (1 Viewer)

Joined
Aug 15, 2014
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Los Angeles, CA
I know its been discussed before just looking for a little more insight. 315s are almost shot and its time for tires. Up until now I've gotten by with stock gears. Financially I can't cover new tires, gears and lockers so leaning to tires and rims first. I have a non-locked 80. I have a spartan auto locker in the rear but would like to go harrop front and rear once I regear to 488s. Any insight or suggestions is very appreciated. TIA
 
Joined
May 26, 2005
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Phoenix
I was very happy when I went to 37's from 35's, and also very happy when I went to 5.29's several years later. You don't have to do them at the same time. You don't even have to do gears at all, many people are happy with 37's on stock gears. 37's are an improvement (if you take the truck off road, anyway) with or without gears.
 

jfz80

Cruisin’
Joined
Jun 5, 2005
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Madison NC
:meh: Ran 37s for many years on stock gears but with FI. Mostly flat around here 500-1000 and adventure trips 500-5000 at most. But dropped back down to 35s and haven’t missed much. A good driver locked can Usually keep up, just not as easy of a ride. Braking with 37s in my mind was the shortcoming.
 
Joined
Aug 14, 2019
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Los Angeles, CA
OP, I'm in LA as well and have 10% UD gears in my transfer case and with 315s it still feels insufficiently geared to me. Offroad it's fine (have the crawler gear so low range is good) but whenever I hit the highway passes getting into the mountains I reconsider regearing the axles. No way I'd run 37s without diff gears, but I also like to mostly keep up with traffic...if you're OK being in the right lane with blinkers on I guess it might be ok? I'm also at sea level and tend to camp/wheel at 6K-10K feet, so there's a lot of uphill getting out of town.

I did stock gears on 315s for exactly one trip to Big Bear and reprioritized the transfer case gears...maybe I'm sensitive to it.
 
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Feb 9, 2013
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OP, I'm in LA as well and have 10% UD gears in my transfer case and with 315s it still feels insufficiently geared to me. Offroad it's fine (have the crawler gear so low range is good) but whenever I hit the highway passes getting into the mountains I reconsider regearing the axles. No way I'd run 37s without diff gears, but I also like to mostly keep up with traffic...if you're OK being in the right lane with blinkers on I guess it might be ok? I'm also at sea level and tend to camp/wheel at 6K-10K feet, so there's a lot of uphill getting out of town.

I did stock gears on 315s for exactly one trip to Big Bear and reprioritized the transfer case gears...maybe I'm sensitive to it.

That’s kind of where I’m at with it. Stock would probably be ok if just wheeling or around town. I wouldn’t like climbing 10k+ passes with stock gears. I cruise fairly easy 55-60 climbing with 5.29.
 
Joined
Aug 15, 2014
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Los Angeles, CA
Thanks for in input and insight. My 80 is the second vehicle that only gets used when hitting the dirt to explore or camp with the family. I normally cruise down the freeway around 65-70 at around 2200 rpm but I didn't think going to 37s would hurt that much. From a stop to get going again is where I figured most of the issues would be. I suppose for slow speed dirt venturing the transfer case low gear upgrade would really help. Also looking to swap out OME 3.5 heavies for some dobinson variable rate 3inch coils. So may have the OME coils for sale soon.
 
Joined
Jul 30, 2015
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So Cal
If I were to do it all over again from 35's to 37's and re-gear. I would have re-gear first then put on 37's. It was very noticeable to me when driving on the highway or even going up a little hill on stock gear vs 5.29 now.
 
Joined
Feb 27, 2018
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Los Santos
Totally agree on re-gear first, but then might as well kill 2 birds 1 stone and do the lockers and gears together since you need to open up the diffs anyways.

Another data point from my experience is 35s and 4.88s is good, but not ideal. 37s and 4.88s has been excellent (back to stock ratios).
 
Joined
Apr 19, 2017
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Colorado Springs
I run 37s with stock gears a 7k ft and I like it a lot. I plan to do the 3:1 for crawling but that is all I plan on doing. Being able to cruise to Moab or Mexico going 80mph is sweet. And 2nd gear at 4000rpm is 67mph for me so perfect for the big passes on I70
 
Joined
Oct 6, 2014
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Colorado
Gears, lockers or tires. I would do gears first.

I ran 39" tires on 5.29's and it was fine. 37's and 5.29 with a turbo and I can do burnouts.
Now only off-roading I would do a locker over 37's. You will go more places locked than you would with 37's or gears.
 

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