Help me decide 4.88 or 5.13 for my use

[gearhead22]

I’m on 5.38’s and 37’s. I recently drove 900 miles back from Moab and had my cruise set at 84 mph pretty much the entire drive back. I was at 2850 rpm and stayed out of the 2nd stage of the oil pump when cruising in 8th, which was most of the drive through the flats of Nebraska. You’ll be just fine on 5.13’s staying out of high lift cam.

Everything I’ve read says it engages around 2700. I’m wondering how you were at 2850 and it wasn’t engaged

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[pcrawfordpt]

Sounds like you have talked yourself into 4:88. Many of us have suggested 5:13 or even 5:38 with sound logic behind our suggestions. You have your reasons for leaning that way, so just go for it. It won't be terrible no matter what. Worst case, you change your mind and/or don't like the 4:88 and you pay another $5K and go to 5:13. As far as thinking you will go to 38's....why? You're not into off roading that much, so there's no clearance benefit, (only 1/2" anyway) and the 38's won't fit in the spare tire carrier. You'll likely stick with 37's, especially if you go 4:88.

 

[Minty JL]

Like tire choice.....if you think you want more ...buy once, cry once. Nothing worse than spending time & money and not happy with the end product

 

[gearhead22]

Like tire choice.....if you think you want more ...buy once, cry once. Nothing worse than spending time & money and not happy with the end product

I agree. I can just see situations where I could be unhappy with 4.88’s and 5.13’s. Just a matter of which one would make me happier overall. And that I can’t seem to figure out.

 

[gearhead22]

Sounds like you have talked yourself into 4:88. Many of us have suggested 5:13 or even 5:38 with sound logic behind our suggestions. You have your reasons for leaning that way, so just go for it. It won't be terrible no matter what. Worst case, you change your mind and/or don't like the 4:88 and you pay another $5K and go to 5:13. As far as thinking you will go to 38's....why? You're not into off roading that much, so there's no clearance benefit, (only 1/2" anyway) and the 38's won't fit in the spare tire carrier. You'll likely stick with 37's, especially if you go 4:88.

I’m torn between 4.88 and 5.13. I can see situations where I could be unhappy with either as well as happy. The reason I would go 38’s is because why not. I have the ability to and some 38’s are even cheaper than 37’s. Albeit there isn’t as many choices in 38’s compared to 37’s. But I’m content with what options are available. I do wish some other tires were made in 38’s. But unfortunately there aren’t. 5.38’s are extremely overkill for anyone under a 40, and not even in the ballpark for someone with my use case.

 

[1550jrit]

Everything I’ve read says it engages around 2700. I’m wondering how you were at 2850 and it wasn’t engaged

I’m fairly certain it does not engage until 3000 rpm. I can get to just a smidge under, like 2950 rpm and 85 mph before my oil pressure spikes and you get into high cam and 2nd stage of the oil pump. You’ll be totally fine with 5.13’s.

 

[1550jrit]

5.38’s are extremely overkill for anyone under a 40, and not even in the ballpark for someone with my use case.

In full disclosure, I only went with 5.38’s because I re-geared post faux-demic when 5.13’s were back ordered for months. I found one supplier who had a single set of Dana Spicer 5.38’s and just rolled with it. 5.38’s are only 4.5% deeper than 5.13’s and I can honestly say I enjoy the way the truck drives on and off road. My Mojave has the 2.72:1 transfer case and 5.38’s pair well, I really enjoy wheeling with them. Overall I’m happy with them, though I’m sure I would have been happy with 5.13’s or even 4.88’s. I’ve got 35k miles on my 5.38’s and they’ve held up well. ( Just sharing the experience, not trying to convince anyone on 5.38’s)

 

[gearhead22]

In full disclosure, I only went with 5.38’s because I re-geared post faux-demic when 5.13’s were back ordered for months. I found one supplier who had a single set of Dana Spicer 5.38’s and just rolled with it. 5.38’s are only 4.5% deeper than 5.13’s and I can honestly say I enjoy the way the truck drives on and off road. My Mojave has the 2.72:1 transfer case and 5.38’s pairs well, I really enjoy wheeling with them. Overall I’m happy with them, though I’m sure I would have been happy with 5.13’s or even 4.88’s. I’ve got 35k miles on my 5.38’s and they’ve held up well. ( Just sharing the experience, not trying to convince anyone on 5.38’s)

Luckily I have the rubicon with the 4:1 so I think I can get away with a lower (numerically) gear

 

[NewGladdyOWNR]

I regeared to 4.88’s a few weeks ago. I’m on 37” KO2’s with a 2” lift. My RPM’s at 70mph+ are around 2100-2200 which was my stock rpm’s with no modifications. So far I’m loving this combination and it has PLENTY of power. If I had a true 37” I may have gone to 5.13’s, but right now I’m hitting 8th at 45mph which seems overgeared for 36” tires.

 

[gearhead22]

I regeared to 4.88’s a few weeks ago. I’m on 37” KO2’s with a 2” lift. My RPM’s at 70mph+ are around 2100-2200 which was my stock rpm’s with no modifications. So far I’m loving this combination and it has PLENTY of power. If I had a true 37” I may have gone to 5.13’s, but right now I’m hitting 8th at 45mph which seems overgeared for 36” tires.

My JTR sees 8th at just under 50 as is with my 37 bfg’s

 

[Minty JL]

I agree. I can just see situations where I could be unhappy with 4.88’s and 5.13’s. Just a matter of which one would make me happier overall. And that I can’t seem to figure out.

Trust me brother, same battle I have in my head. I travel up and down the east coast so the 4.10s have been decent, 4.88s would be ideal .......5.13s great, but not the best for my highways needs......but fun as fuck around town

 

[gearhead22]

Trust me brother, same battle I have in my head. I travel up and down the east coast so the 4.10s have been decent, 4.88s would be ideal .......5.13s great, but not the best for my highways needs......but fun as fuck around town

That’s where my concern is. My daily driving is just through town so no worries there. But it does get on the highway often and It will see multi hour roadtrips that are solely highway driving so I don’t want it to suck. But it will also see some towing, albeit minor, still towing. Offroad is the one thing it doesn’t see much of but I would like to change that at some point. Just trying to find more people and events locally.

 

[NewGladdyOWNR]

My JTR sees 8th at just under 50 as is with my 37 bfg’s

I doubt it happens regularly with 4.10’s. You have plenty of good info in this thread. Good luck to ya!

 

[pcrawfordpt]

I agree. I can just see situations where I could be unhappy with 4.88’s and 5.13’s. Just a matter of which one would make me happier overall. And that I can’t seem to figure out.

What would make you unhappy with 5:13's?
Pros: You'll have more torque off the line. Will crawl better when off roading. Would support the 38's you think might go to eventually. Can tow better with less stress on the system. Will pull mountain grades with ease. Always better to be geared lowered (5:13) as it's easier on the engine and trans.
Cons: Lower top speed overall, but that's a moot point with these bricks. Slightly worse fuel economy, again a moot point with 37's+, it's always gonna suck.
Do your own "Ben Franklin" and pull the trigger...

 

[gearhead22]

I doubt it happens regularly with 4.10’s. You have plenty of good info in this thread. Good luck to ya!

Happens frequently if I’m cruising at those speeds. If I’m accelerating to get to 70 then no of course not. If I had 5.13’s the only difference would be that I’m in 8th gear. The rpm would be the same as my 7th gear with 4.10’s. It would be no more or less efficient. At that time. The only difference would be with 4.10’s if the load is low enough I can move into 8th and hit a lower rpm and use less fuel. 4.88’s would split the gap

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