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Topic Review (Newest First)
06-10-2014 01:30 PM
AeroSynch I can still do stupid stuff with 35s and 3.21s so yea, there is no immediate need to regear. Will I in the future? Probably, but it's very driveable at the moment.

06-10-2014 10:26 AM
JE01
Quote:
Originally Posted by Cdwright View Post
How do you like the wildpeaks? How big is your lift?
They are awesome, had a nail go into one of them...weeks later, they are still not flat. Get better mileage than the m/t I had. I currently run a 2.5" RC springs and shocks lift.
06-09-2014 10:08 PM
Cdwright
Quote:
Originally Posted by JE01 View Post
2 dr, 2012 pentastar, 3.21 gears, 2.5" lift, front and rear metal bumpers with wired winch, Falken's 315/70r17 Wildpeak A/Ts, and FlashCal. I get 16 mpg on city and 18 on highway. It doesn't seem to bother me even when I use my trailer, but I do plan to upgrade my FlashCal to Flashpak.
How do you like the wildpeaks? How big is your lift?
05-14-2014 11:36 PM
JE01 2 dr, 2012 pentastar, 3.21 gears, 2.5" lift, front and rear metal bumpers with wired winch, Falken's 315/70r17 Wildpeak A/Ts, and FlashCal. I get 16 mpg on city and 18 on highway. It doesn't seem to bother me even when I use my trailer, but I do plan to upgrade my FlashCal to Flashpak.
08-25-2013 10:39 AM
OrangegasmJKU
Quote:
Originally Posted by sebbekk View Post
Those with a manual tranny, watch your clutch! With 35" tires and 3.21 gears the clutch will wear and fail prematurely. Changing the gears when adding a supercharger is a good idea. Watch out for the Magnuson supercharger. It should become available for the 3.6L in 2014.
You are very correct, clutch wear is definitly increased, especially starting off on any type of grade, doesn't matter if it's a paved street downtown or climbing out of a ditch on some trail. That's why I suggested running hilly offroad terrain in 4Lo in 2nd or 3rd. It's a good speed to move along at and it's also alot easier on your clutch and you still have ample torque to get you over obsticles. 35s and 3.21 are very capable, just be smart about how your drive, it's all in the operators hands.
08-25-2013 03:48 AM
sebbekk Those with a manual tranny, watch your clutch! With 35" tires and 3.21 gears the clutch will wear and fail prematurely. Changing the gears when adding a supercharger is a good idea. Watch out for the Magnuson supercharger. It should become available for the 3.6L in 2014.
08-24-2013 09:38 PM
OrangegasmJKU I know this is an old thread but I just want to say that the 3.6 is definitly capable of running 35"s with 3.21s. I just recently installed 315/75R16 GY Duratracs on my 12' 6spd and today I made a 600km highway trip over the semi hilly terrain of northern ontario! I averaged 11.2L/100km (21mpg) and the majority of the run I used 6th, yes I said it, 6th gear, even over upward slopes! It is possible. Keep it between 65-75mph and your safe, gear down to 5th when approaching bigger hills and 4th when over taking and you'll be fine. I found cruising at around 65 in 6th was around 1500rpm which is good for MPGs. I did all my distance and speed calculations using GPStracker. As for offroading, don't climb big rocks and on tricky trails, use 4Lo and bomb along in 2nd or 3rd. Just takes time to get used too but they are actually pretty decent IMHO. That said, 4.56s will be in my distant future and possibly RIPP supercharger When I recieve my diablosport tuner this week, I'll post any MPG or power change results, sry of the long post! Keep the 35s and 3.21 results coming for the 3.6, there's lots of people out looking for honest opinions from people who actually have them just like when I was searching 2 weeks ago. Keep on crawling!!!
06-12-2013 05:20 AM
OffRoadCam09 I have 35x12.50's with 1.5" lift, goin to 2.5" with 3.21's its still got plenty of power. Takes some time to get up to 25 mph but after that it rolls no problem. Also get 18 mpg with this setup
06-12-2013 04:22 AM
BLK2012
Quote:
Originally Posted by sebbekk View Post


Here are the charts by the way - make sure you look at the right one according to the engine you run (3.8L vs. 3.6L) and the tranny you have.
Does that chart have a manual 3.6 with 29's using 3.21's in yellow?

If so that chart means little as that's garbage...
01-22-2013 06:09 PM
bearman95 I have a 12 JKU auto with 2.5 lift and 35 tires. It has a 3:73 gearing and it pulls very easily, on and off road.
01-22-2013 06:02 PM
sebbekk

Here are the charts by the way - make sure you look at the right one according to the engine you run (3.8L vs. 3.6L) and the tranny you have.
01-21-2013 03:46 PM
Xcrossbow Have a 2013 Unlimited automatic with 3" lift, 35's on 18"XD's and a stock 3.21 gear. It is bearable as I have other vehicles to satisfy my torque fix.

Are there any proven negative mechanical effects over the long term with running a set-up like this?
12-07-2012 12:42 AM
JeepHerz They are not as bad as you might think. Just depends on what you are doing. Plenty of fun still to be had- it is still a Jeep.
Even though I'll be re-gearing.
12-06-2012 11:58 PM
BeyondYourFrontDoor I run a 6 speed JKU 09 Rubi with 4.10's... 2.5" lift and 35" Duratracs - what you are asking about. I find 4.10 to be a bit tall for my liking... defiantly requires a lot more use of low range for in the dirt... It's workable... not enjoyable. I can't imagine 3.21's being fun off road...
12-06-2012 10:39 PM
JeepHerz
Quote:
Originally Posted by kjeeper10 View Post
ALL tires run smaller mounted.

My 35's KM2'smeasure 33.5-33.75 new
Stock 30.50 40K

I run 28 front 26 rear.
Hmmmm....I might have to try that. Never thought to lower the rear more.
Lol. Please keep that clean.
12-06-2012 10:32 PM
kjeeper10
Quote:
Originally Posted by en480c4

Not really. KM2s notoriously run small. As noted, they measure less than 35" on the rim as a spare with no load.

AEV tuned their suspension running KM2s at 28 psi on their rims, so it seemed like a good place to start. I've been very happy with the ride and the tires have worn evenly.

Here's a shot from a few weeks ago when I put the hard top back on:
ALL tires run smaller mounted.

My 35's KM2'smeasure 33.5-33.75 new
Stock 30.50 40K
Default superchips settings are 1.1/4 less

I run 28 front 26 rear.
12-06-2012 08:56 PM
JeepHerz
Quote:
Originally Posted by en480c4 View Post
Not really. KM2s notoriously run small. As noted, they measure less than 35" on the rim as a spare with no load.

AEV tuned their suspension running KM2s at 28 psi on their rims, so it seemed like a good place to start. I've been very happy with the ride and the tires have worn evenly.

Here's a shot from a few weeks ago when I put the hard top back on:
Nice! Also running 28 PSI.
X2. Though it is not just KM2s. I went back and forth a ton (3.21 freak out) and I was surprised how many "35s" are not 35s. Check tire width too- the KM2s also run narrower. But they are 15 lbs. less per tire than the Toyo's I had originally bought. (And still pine over....)
Just for sh**s and giggles 'cuz its not a Prius- but if I get 15 MPG (auto) I am giddy. But Elvira is really packing on the lbs.
12-06-2012 12:31 PM
en480c4
Quote:
Originally Posted by cverstij View Post
At 28psi, to make a 35" tire measure 33.5", do you have a bulge at the bottom of your tire?
Not really. KM2s notoriously run small. As noted, they measure less than 35" on the rim as a spare with no load.

AEV tuned their suspension running KM2s at 28 psi on their rims, so it seemed like a good place to start. I've been very happy with the ride and the tires have worn evenly.

Here's a shot from a few weeks ago when I put the hard top back on:

12-06-2012 10:36 AM
cverstij
Quote:
Originally Posted by en480c4 View Post
From earlier in the thread...
At 28psi, to make a 35" tire measure 33.5", do you have a bulge at the bottom of your tire?
12-06-2012 10:25 AM
en480c4
Quote:
Originally Posted by cverstij View Post
What is your engine, gearing, transmission type, and tire size?
From earlier in the thread...

Quote:
Originally Posted by en480c4 View Post
I've been running 3.21s and 35" KM2s on my '12 6-speed since May, which has been about 7,000 miles.

My 35s measured 33.5" from top to pavement @ 28 psi on the Jeep (and well over 34" on the spare).
12-06-2012 07:14 AM
cverstij
Quote:
Originally Posted by en480c4 View Post
I stopped calculating my mileage this summer because it wasn't changing, but I tend to get just shy of 16 on the highway (65 and above) and around town (stop & go, below 40), and close to 17 on two-lane roads where I'm going between 45 and 60.

That was with everything adjusted with the Procal, and using GasCubby on my iPhone to track and calculate my milage.
What is your engine, gearing, transmission type, and tire size?
12-06-2012 06:53 AM
en480c4 I stopped calculating my mileage this summer because it wasn't changing, but I tend to get just shy of 16 on the highway (65 and above) and around town (stop & go, below 40), and close to 17 on two-lane roads where I'm going between 45 and 60.

That was with everything adjusted with the Procal, and using GasCubby on my iPhone to track and calculate my milage.
12-05-2012 05:24 PM
Lucy Brown
Quote:
Originally Posted by cverstij View Post
So, with 35s, 3.21 gearing, in a 2012 manual, what is the true mileage per gallon? Mine is showing 14 around town, but i know that isn't right. And how far off is my speedometer?
I have 35's with a 3.25 lift, 4.10's, auto and the procal. It's brand new. 2 weeks old with 400 miles on it and my avg around town is 13.9
12-05-2012 04:33 PM
cverstij So, with 35s, 3.21 gearing, in a 2012 manual, what is the true mileage per gallon? Mine is showing 14 around town, but i know that isn't right. And how far off is my speedometer?
10-25-2012 12:22 PM
en480c4 Even before the tires, 6th was only used on relatively flat terrain. 75 was between 2,000 & 2,100 RPMs, which was enough to maintain speed, but I certainly couldn't accellerate or hold on any kind of grade.
10-25-2012 11:30 AM
JeepHerz
Quote:
Originally Posted by watson View Post
Thanks for the answer. When you say you lose sixth gear. Do you mean that you can't get even RPMs to use it?
See the threads posted above. 1500 RPMs is kinda useless- no torque. Your Pentastar becomes the Pant-astar. This is what I would call the "3.21 lug" effect.
10-25-2012 02:45 AM
Beachmonster FWIW, I just installed 35" tires on my jeep. 3.6l 6mt 3.21 gearing, bone stock.

Tires measure 33.75" true diameter at 23 psi.

At 65, I get just above 1500rpm in sixth gear, and around 2000 in 5th.

The biggest difference i felt is with the braking. The car feels noticeably heavier.
On acceleration, I just have to add more gas

I was considering a regear before the winter, but put it off till next spring now that I know that it's completely drivable with the 3.21's, even on the highway.

All you gots to do is shift.

Car still feels like a dragster next to my dd (corolla)
10-24-2012 11:10 PM
RRTRI My wife drives a 3.21 sitting on 35's everyday. I was all set to regear for her but she has talked me out of it. It's already been mentioned but the big difference between mine (3.73) and hers (3.21) is getting it rolling (once it is rolling there is little difference 2-5) and it might as well be a 5 speed as 6th is not really used unless rolling downhill for an extended period. I am able to use 6th in many situations in mine (w 3.73)

We've added a ton of weight to hers (bumpers, rails, hardtop, etc) with the 3.21 so it is about as bad as it can be and it is still everyday drivable in her opinion. I don't drive it often but when I do I don't find it super hateful. As long as your aren't drag racing it will get you down the road (both paved and otherwise).

Having said that I have found that even with the 3.73 gearing in mine I've had trouble getting it going in thick stuff off road in 4H at times. When I encounter that I just drop it to 4L to get myself unstuck and then back to 4H. I've not driven hers in that exact senerio but I'm sure it is that much more an issue.
10-24-2012 09:30 PM
watson
Quote:
Originally Posted by JeepHerz

Technically there is a difference- why there are two gearing charts by Jeep. I can't seem to find the right one; if someone has a link.....
From a "driving perspective"- in manuals you basically lose 6th gear and first is harder to launch as mentioned. (Seems to be the general consensus; there are those that are ok). With the automatic it tends to downshift at too low an RPM or "lug"- but the tranny still does the work. Put it in drive and go. I have an auto and find it annoying enough to re-gear. (4.10s coming for me). But imagine losing an entire gear and having to give it extra gas just to get out of first. Makes the performance change in the manual much more pronounced.
Thanks for the answer. When you say you lose sixth gear. Do you mean that you can't get even RPMs to use it?
10-23-2012 08:58 PM
chim-chim7 You need more than just gears if you want to run 35's for any extended mileage.
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