Bigger Tires/Lifting

[Green Goblin]

Here's the deal...

Wanting to upsize to a 30" or 31" tire.

My ride is a stock '04 TJ 2.4L

Questions follow...

Will I need a lift to keep reasonable flex/clearance?

Will I need to beef up the braking system to keep a safe/responsive braking capability?

Am I forgetting anything???

TIA

[AaronC]

you can fit 31's on a stock set up.. it will restrict your flex though, and may bottom out under serious conditions.. brakes should be fine the way they are.. if i were you, i would go with a small lift.. unless you plan on going bigger in the future.. www.rubiconexpress.com (http://www.rubiconexpress.com) has a budget lift that will give you more than enough clearence for 31's, and still have room to spare.. if you go bigger than the budget lift, lets say to a 3.5", you should look into SYE kits, and CV driveshafts to reduce vibrations.. but, thats only if you want to go that big..

[MotorSeven]

The 31's are gonna rub on the inside when you crank the steering wheel all the way over. Plan on moving the steering stops out buy adding some(1/2 inch worth) washers. Your turning radius will be slightly gigger, but you won't notice it at all. This rub occures whether you lift or not with stock wheels.....

[we3jeepers]

Originally posted by MotorSeven:
The 31's are gonna rub on the inside when you crank the steering wheel all the way over. Plan on moving the steering stops out buy adding some(1/2 inch worth) washers. Your turning radius will be slightly gigger, but you won't notice it at all. This rub occures whether you lift or not with stock wheels..... 1/2" wow
i only added 1 washer on each side

http://www.iaxs.net/~leif/LPsJeepTJ/imagesdigitalphotos/SteeringStopWashers700x500.JPG

here is a write up on it (http://www.iaxs.net/~leif/LPsJeepTJ/TiresSpeedoRims/)

[Green Goblin]

Thanks for all of the input.

The tech write-up was especially insightful.

Any more insight will also be appreciated.

Next question...has anyone had any experience with, or known someone who runs, Mastercraft tires (specificly the Courser MT)link (http://mastercrafttires.com/us/en/ProductDetails.asp?ProdType=LtTruck&id=183&title=Light+Truck+Tires)

['03 X Colby]

My buddy runs 32's on his 97 TJ. He doesn't have room for much flex at all, but his tires don't rub. If yours do then you might think about getting different rims with the right backspacing. I run 30's and it's just fine. My dad has a rubi with the normal tires which are about 31's. And my other buddy runs 31's and has plenty of flex and doesn't rub either. None of us have lifts either. So you'd be fine with 30's or 31's with flex, but 32's don't give hardly any flex.

[Green Goblin]

well, I ended up buying a set of 31x10.5/15's

Compromised between what I want, and what is practical, as I have a 45 minute dd in the Goblin. Bought the Bridgestone Dueler APT III.

Just a bit of rub at full cut of the wheel, and looks like good clearance otherwise.

First impressions, ride is just a bit rougher, tread is quiet at speed, no steering or stability problems.

Now I need to get the speedo adjusted for the bigger tires.

I will try the washer trick this weekend.

[00TJ4L]

I turn 31s on my TJ and the speedometer difference is hardly noticable... it isnt anything that will get you a speeding ticket.

[Green Goblin]

Latest update...
Not sure about the speedometer, but the odometer is off by 1/10 of a mile...The Odometer rolls to the next mile exactly 1/10 before I cross the mile marker.

Taking that into consideration, my gas mileage came in at 20 MPG...I was getting 19 MPG earlier this year (march).

Not sure if it is just that the engine is finally broke in(about 22k miles now), cooling temps, or the tires...or a combo of all three.

[Knuckelhead]

Originally posted by Green Goblin:
the odometer is off by 1/10 of a mile...The Odometer rolls to the next mile exactly 1/10 before I cross the mile marker.Wouldn't that mean that you would be going 5 mph slower than indicated at 50 mph?
And your mileage (mpg) would be less because the distance traveled would be less than indicated...

[RoCKSToRM]

i got 31's on my stock yj...i have full turning radius...just get wheels with good backspacing...i had to trim my fender flares down though.

[Green Goblin]

Knucklehead,

I may have reversed when the "O" rolls, in my last post, will have to check again tomorrow, to see if it is before or after I cross the mile marker.

If it is as I posted, then you are absolutely right.

But, I know that it is off by exactly 1/10 of a mile.

I think(that is likely my biggest mistake)that, by default, bigger tires should indicate,on the odometer, less miles traveled, than actually covered, because the larger diameter tire takes fewer revolutions to cover the same distance....right?

:D :D

[Knuckelhead]

Yep. ;)

[Green Goblin]

Double checked, and I did reverse the info

[Knuckelhead]

So now you milage (mpg) is?

[Green Goblin]

The MPG is as I figured before...20 MPG...I just described it wrong when I posted previously.

The way I figured it was...

Miles listed on odometer plus 10% / gallons added at fill-up.

Will check again on next fill-up.

[Knuckelhead]

You must be driving with a fairly light foot eh?

[Green Goblin]

Usually go with the flow of traffic...between 60-70 MPH.

When I bought the Jeep, it had 10,600 Miles on it, I am now just over 22,000, so I am wondering if the increased MPG may be more related to engine break-in, than any other factor.

My pre-tire upgrade mileage was based on a check made just after purchase.

Also, my daily drive is nearly all Interstate.

[Knuckelhead]

With a 4" lift, 35" tires (456's) and an automatic I'm betting around 15 mpg in town...