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My honest opinion on 35s w/ 3.21 gearing

23K views 162 replies 45 participants last post by  SRM 
#1 ·
#3 ·
The question is where do you live? Bring it out to where the big hills are and I think you will find it is not so good.
 
#6 ·
I'm in Northeast Ohio, with 3.21 gears and 315 KO2S. With the lighter 35 it's livable. I've been told my jeep has to be a dog (compared to a proper geared one.. probably) also, but with little effort from a stop, it will climb a hill and pull away effortlessly from traffic.
What I do notice is long winding revs to get rpms up to get to shift points, and once in a while will get stuck in 4th on the highway. There's some searching and sticking going on that will be eliminated. I'm getting regeared next Monday.
I'm expecting quicker shift points and grab when coming from stops. The 3.6 does a great job, but it will do better gear properly.
I was surprised at first how much power there still was, and I was expecting horrible performance, but after driving this setup for about 3 months I can see the need for improvement.
 
#7 ·
Thanks for the useful input. Looking at 34" range on 3.21 and all the points of view help.
 
#8 ·
I found that even 32's on 3.21 felt sluggish compared to 4.10's. I was willing to go 500 miles away to find 3.73 since I can't get 4.10 on a Sahara...

35's on 3.21 feel horrible to me. So that's my "honest truth".

However, I acknowledge that others may not agree with me. :beerdrinking:
 
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#11 ·
Nope, bit I did trade up to the jeep from a Lexus RX 450h Hybrid...and rented a tesla last weekend....so im familiar.

I dont translate the obvious mechanical advantage of higher gears to being better (especially when more shifting/less mpg). 3.21 is plenty peppy with a 2 door. I travel on a a 20% grade hill no problem on stock sport S 32s.

Sent from my SAMSUNG-SM-G890A using Tapatalk
 
#12 ·
Since my Jeep is my only vehicle at the moment:


Had 3:21's with stock 32's. For my use, it was livable, but wanted more off the line pep.

4:10's much better! Heck, I should have gone with 4:56's, but *again* that is just me.

My background is performance vehicles. Someday I'll have both a Jeep and a muscle car. :)
 
#13 ·
MY father in law owns a built 2006 Rubicon Unlimited with 35s. His is a manual and it's honestly not a huge difference than his rig with 4.10s. I know he has the older 4,0l and maybe that is why.
When I was reading forums on this topic initially people would literally make it sounds like it would be nearly impossible to drive, but that is far far from the truth.
I can still get from 0-60 without a problem and I am sure I can tow plenty.
 
#16 ·
I have a 2016 Sahara Unlimited Automatic and just got the Mopar 2" lift with Nitto Ridge Grappler 35x12.50x17 tires and new wheels with 4.5 inch back spacing. I was not happy with the 3.21 gears. I don't think it is a question of power so much. For me the Jeep just felt really heavy! It felt like I had to push the gas pedal harder to get going. Maybe it also has something to do with my tires, those 35 Ridge Grapplers are heavy! My gas milage really suffered around town as well with the 3.21 gears. Since putting in the 4.56 gears I am much happier. I wouldn't describe it as having more power, to me the jeep seems to drive and shift much more effortlessly with the 4.56 gears. I am very happy with the new gears. I am not saying the jeep was impossible to drive with the 3.21s but for me it is a much better experience with the 4.56s.
 
#17 ·
I have driven 3.21 and definitely found it sluggish on 32 inch tires. It actually was designed to be the gearing for the standard Sport 29 inch tires. I have driven 3.73 on 32 inch tires, and it was "ok". And I have driven 4.10 on 32 inch tires - this was by far the best combination.

Also, running too tall of a gear increases wear and tear on the transmission, and gives you a ton more wheel spin, which is not a good thing.
 
#19 ·
To be fair... you mention after market exhaust and intake, and reprogram... which also is the subject of many 'to tell the truth' videos about how great/sucky they are...

IMHO, I don't even like 33's over 4.10... no fun. But that's me. It is way more telling on the trails... My old Rubi with 35's over 4.10 could not run my favourite trails without going into 4lo... which was painful. 4:1 low range makes for very harsh shifts...

'Pretty sure it will work' is not a scientific term... you use that phrase 10 times. 'You're not going to have any problems'... hmmm... well, some people will, some people won't.

Don't tow that Corolla... you will be at least 1500 lbs over if you are using a trailer. That weight (ever 3500) requires a brake controller, which I don't imagine your Jeep has.

If you crash, a collision analyst like me will make note of that and your insurance will walk away from you.
 
#21 ·
Sorry but with 3.21 gears you are limited to 2000lbs. Now that you have put 35's on there it will be a bear pulling even that. I've got a manual, 4.10's and while it works it is much harder on the engine and drive train than the stock tires where. Overdrive is useless on the Seattle freeways even when traffic is moving well. I pretty much need to be around 70 if I don't want to shift every time I see a little hill. This won't be a problem next month when I install my 4.88's.

You can almost live with anything but why would you.
 
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#23 ·
I've towed my boat over the pass last summer, had a passenger in my jeep and rest of it packed with camping stuff, the boat gas tank was full and the boat it self had bunch of shit in it as well. The jeep motor may have worked just a bit harder with 33s on it than my Chevy Silverado 1500 5.3l V8 doing the same job in the previous year. Thats just my experience
 
#28 ·
Lol, ok let me get it clear, I am not praising it but simply saying that it is not all that bad and I can still tow with it. I was extremely impressed with how it drove with the 35s. From everything I have read I expected a lot worse, everyone makes it out to be the end of the world when it's far from it. Maybe I just don't know what I am missing :)
 
#30 ·
Don't you find it boring that they can't even accept that you find it acceptable.

I find this argument the same as getting married. I have friends that have been dating since they were 16 years old, got married at 22, and have been extremely happily married for 30 years. I have people questioning the fact of their happiness. Their excuse is how can they know. They have only dated 1 person their entire life. Whereas dating 10, 20, or 100 is somehow significantly more. However, those critical people aren't dating tall people, short people, fat people, people with different religions, people with different values, people with different cultures, so again, how would they know that they are happy or not. They keep dating similar types of people which is nearly the same as dating just 1 person.

The reality is that we should praise people for finding happiness. Just because someone else's happiness doesn't agree with yours, it doesn't mean they aren't happy.

We don't need to drive a Jeep with a 4.10 or 4.56 to understand happiness. We can just as easily ask, how can you be happy with that measly 3.6, you should go drive a Jeep with a HEMI swap, then you will realize your jeep is horrific and pathetically under powered. That excuse of go drive something faster, and you will know what you are missing is meaningless. There will always be faster and better vehicles than the one I currently own and drive.

I guess I should also have an affair, just so I know what I am missing.

I just find it amazing when we can't even let people be happy. Is it because those who criticize can never be satisfied?
 
#33 ·
If I wasn't able to regear to 4.56 from 3.21... I would still put the 315 KO2S I have on. I could easily live with it here in Ohio, but we're driving to Colorado in May and we moving out west. I just want to regear but I don't have to. That said, previous post said it perfect. This post was to point out that it is a livable setup.. depending on you
 
#34 ·
None of you have done a proper side by side with the same setups to have a "whats better" opinion.

Wheel weight and tire weight will make a huge difference when comparing 3.21 to 4.10. Just the potential 100+lb rotating mass between one set of tires/wheels to another is reason alone to notice a difference in acceleration. Let alone stopping power. So many guys adding rotating weight, but so few talk about the other side - stopping power.

Form over function is a common theme in most young guys builds.

Just an old man saying that yes, I was young too.

FWIW - 32" KO2's on stock 75th anniversary wheels with 3.21 and I am more than happy with my performance.
 
#35 ·
None of you have done a proper side by side with the same setups to have a "whats better" opinion.



Wheel weight and tire weight will make a huge difference when comparing 3.21 to 4.10. Just the potential 100+lb rotating mass between one set of tires/wheels to another is reason alone to notice a difference in acceleration. Let alone stopping power. So many guys adding rotating weight, but so few talk about the other side - stopping power.



Form over function is a common theme in most young guys builds.



Just an old man saying that yes, I was young too.



FWIW - 32" KO2's on stock 75th anniversary wheels with 3.21 and I am more than happy with my performance.


I will be upgrading brakes soon, just like you said to counter the weight gain. I'm still running stock bumpers and no winch.. yet. I also drive slower, don't tailgate, and stop sooner. It helps a little.
 
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#41 ·
I'm willing to bet at least 80% of the non-Rubicon JK's you see driving around town on 35's have 3.21's. It works, but so does taking a rowboat to Hawaii. Doesn't mean it's the best way.

When shopping for our Jeep 3.73's were absolutely necessary, it probably cut nearly 90% of our choices down. Don't regret it for a second.
 
#42 ·
The reason I chimed in is because I had the 3.21s with the 35s for a couple of weeks and then I got the 4.56 gears. With the tires I put on, the 3.21s were not good at all for me. I actually felt I had made a big mistake getting the lift and tires. Luckily the 4.56 gears made a big improvement and I am now happy. I think people who research a lift with 35s should know that they may not be okay with 3.21 gears. It can get expensive very quickly trying to get the Jeep to perform the way you want it to. That is why I feel I need to let people know my experience. The next things I am looking at are upgrading my brakes, definitely feel I need to with the Nitto RG 35s. Also, looking into wider fender flares. The 12.50 inch wide tires spray a lot of rain, slush and mud all over the jeep. Also, not all 35s are the same, some are taller and heavier. This can greatly impact how the 3.21 gears perform. The Nitto RGs are really heavy! Great tires but heavy.
 
#44 ·
For about a month I was running 35s on 3.73s and the auto would dip down to about 1000rpm at times. Even putting a ProCal on it did not help. Got some good gas mileage, but def loss of umph. Doing 65, barely could get enough going to pass. around here with the hills, I don't think 3.23s would ever get into OD.
 
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