Wrecked

I'm wondering if my jeep would still be capable as a daily driver if I was to put some 33x10.5 BFG A/Ts on it. I know everybody says 33's are the limit on stock gears but most people run 33x12.5 and there is a lot of weight difference between the two. So, I would think the 10.5s would be fine but I figured I would ask around first.

jdf2010

you should be fine running 33's with stock gears, you will have a little bit of a power loss and gas will go down but thats about it

zfranklin92

i run 33x12.5. I definatly want to re gear, but its really not that bad at all right now. 33x10.5 probably would be too bad. It also depends on what tire you get as well. Roll resistence will make a big difference as well.

ergolarry

The issue with running 33's that is of concern for use in a stock geared daily driver (not talking about rock crawling) vehicle is acceleration. The 235/70/15 stock tires have a 15.5% smaller diameter, meaning that when compared to 33/10.5/15's, the smaller tires have a significant mechanical advantage accelerating. If you can live with accelerating 15% slower, then you can enjoy the benefit of your rpm's also being 15% lower at speed; potential fuel savings, less engine noise, etc. Obviously your speedometer will also be off, reading significantly slower than you're travelling at all speeds.

Mike H.

The loss of mechanical advantage will make for poor gas milage, not better. The increased diameter and weight will make the engine work harder.

Can it be done? Sure.
Personally, I would gear first, then add larger tires.

96_xj

i run 33x10.5 TSL's and the only issue i have to run the high way in 4th alot of the time, 5th for flat land cruising at 70 only, any slight hill i have to down shift. And my engine has more than your average power... As far as around town i have not noticed any difference.

Rmart30

X2...... 33's on mine with 3.55's when i bought it. almost impossible to run it in overdrive and keep the trans at a good temp.

troy fritz

Rpms lower ,yes,mpg better ,no.Your motor will work harder and gas will go quicker.

C.J.

I know this might be a stupid question but what is the best way for calculating fuel mileage after switching to 33s since the speedometer is now off roughly 5 mph. If I go off the mileage on my trip meter I am getting roughly 15.5mpg but in reality it is actually better right?

I am figuring since the speedometer is off I am actually traveling more distance than my trip meter is indicating. How can I calculate in the difference?

offroadnut36

Yes in reality its actually better than 15.5 mpg. The speedo is a ratio, the faster you go the more off it will be. When you're going 55mph you're probably going 60 mph so 5mpg like you said. But when you are going 75 mph you're probably going closer to 85-90 mph.

96_xj

i still have the stock speedo and i check mine with a GPS. here is the general speeds:

25-28/29
45-50
55-61
60-65/66
65-74
70-80
75-86
80-92
85-97

**all confirmed with a GPS that i use always.

gas mileage using the gallon to miles is about 13.2 highway, 10-15.6 city depends how heavy your foot is. I can be gentle and get 15's or drive normal and get 13's and drive like a maniac and get 10's.

C.J.

Do these jeeps use a speedometer gear or something that could be changed to account for the tires?

96_xj

^^yes they do but as far as i know, they do not make one with few enough teeth to be accurate with stock gearing and larger tires.

here is it looks like

offroadnut36

Bah you beat me. x2 though. Not sure about if they make a gear with few enough teeth though.

C.J.

Ok well it is only a matter of time until I re gear to 4.56s is that more or less equivalent to stock?