The 5.29 Mega Thread!!

@SSM, I'm in the same situation too lol (285/75/17 tires). But for me, because I tow a boat almost every weekend, my gutt is telling me to go with the 5.29s.

 

To be honest for me it really comes down to my 6th gear rpms at 75mph. For the MT 5.29 with 35’s (315/75r16) is too high for my liking.
2736 rpms (529)
2523 rpms (488)
2224rpms (433)

 

Decisions, decisions! I am actually leaning toward the 4.88 since I go on a lot of longer trips and do quite a bit of highway driving. If my plan were to go to 35's eventually I would go with 5.29 but I'm on 285/70/17 and planning 285/75/17 or 295/70/17.

 

Yea, that's what my concern is too (high RPMs at highway speeds). I rarely go over 70mph so not sure if that would still be an issue for me.

 

as far as RPM go I've seen different figures used than ones you've posted. So confusing ;/ But like someone said here, not enough data to support a definite con/pro. One thing I remember even from my 2nd gen was that it was running lower RPMs with a larger size tires but because it was such a heavy pig it kept downshifting at any slightest hills and also putting strain on transmission constantly. In the end MPG still sucked basically even with lower RPM range. Several shops told me to re gear to 5.56 or 4.88 and RPM would jump up BUT MPG would be better because motor is not working as hard, it's just spinning ... not sure how true this myth is lol I guess it's too late for me, I'm half way in for 5.29s by about now with Nitro gears

 

Give your feedback once it's all done!

 

whats the general impressions ? any change in MPG? whats sort of set up are you running ?

 

100% will for sure! I'm picking it up this Saturday.

 

So the MT in my opinion gets a little screwed on the top end when it comes to gears. The MT gets a better first gear but then it sucks after that.

The ATs are what really benefit from the lower gearing. If you daily your truck or use it for general use then the 4.88s are probably better on the MT. If you tow all the time or offroad a lot then 5.29s are probably the better way to go.

Really just comes down what you mainly use the truck for

 

I was wondering if what
jhipwundah
mentioned earlier is for MT and not AT as far as the calculations for RPM go. "2736 rpms (529)" does seem high for going 75 especially with 35" tires.

 

That rpm is for MT, the AT would be around 2209. Basically the 5th gear on the AT is the same ratio as the 6th gear on the MT

 

Ok beautiful ! I was hoping to hear that... though Im going to be on 33s for a while but still at least it's not redlining lol

 

http://www.grimmjeeper.com/gears.html

Here is the calc that I use in case anyone wants to run their own numbers.
.71 6th gear for manual transmission (MT)
.58 6th gear for automatic transmission (AT)

Also notice if you put in tire size in metric is shows you actual height in inches. 285/75r16 (32.8”)
315/75r16 (34.6”)
That being said actual height of a 35x12.5 varies between manufacturers and is usually around 34.5” anyways.

 

General impressions: Really happy with them. Much more power at lower speeds, and it doesn't feel like a challenge to get up to highway speeds anymore. I am running steel armor front and rear, winch, RTT, gear, etc. On 255s currently until next week when the 315s/LT kit go on. It's been a huge delay with the shop and my life so I have been waiting to get that all in. I will update you all when the new gear goes on!

 

Nice will be very curious to hear how you like the LT going from mid travel icons. I'm taking delivery of the truck and it has brand new set of BP51s with upgraded ome HD leaf and camburg uca... But I've been wondering about those LT set ups it's just so much $$$ cab chop, fender shop etc if you're planing to run 35s

 

For sure, I'll put the updates on my thread so I'm not cluttering up too much TW haha.

I agree, its a ton of money. I have a shop close by that has been working with me on it all which helps, but yeah, there's a lot of custom work with MT/LT kits that there isn't with other lift options. It's not really as bolt on as I'd like, but that's part of the fun!

 

Dang, I was sold on going 5.29's with my LT setup on 35's. I even ordered them. But now that this speed governing issue is coming to light i'm a little concerned. Even Matt has mentioned in the OVTUNE thread that this is an issue he's heard of from multiple people running 5.29s. If governed at 85mph that means the speed will be limited at 75mph. Not an absolute deal breaker but would suck just to know I wouldn't be able to go past 75mph if I needed to.

 

It's not though.

I have driven my truck [stock gears + 33s] over 85 -- 89 confirmed by radar. I have driven 5.29s + 33s over 75. I will confirm the 5.29s + 35s with radar when it get installed next week.

 

OMG, WOW... What a beautiful truck, do you have a side picture?

 

Awesome! Hopefully you'll report back with some good news.