What impact can I expect tire weight to have on my stock TJ?

[pefrey]

My reading here and other places has not really cleared up my understanding of the impact my mods will have on my TJ.

I bought my Jeep new in 98 and have about 247K miles on it. It is a manual, 6 cylinder with the 30" tires and Gambler rims. I like the look of 33's but am concerned about the weight of the tire. Stock were about 40lbs/tire, while BF Goodrich K02's 33x10.5x15 come in at 51. I could just go with 31's which come in at 44 lbs, but don't want to be disappointed with the look as it won't be much different than stock.

What impact can I expect tire weight to have on my stock TJ? I don't want to have to regear and I don't want to kill my mileage.

 

[TheBoogieman]

No lift=No 33s. Stick with 31s.

 

[Tob]

Diameter increase has a worse effect than weight increase. Your differential gearing, which is at most 3.73, is not enough for 33s.

 

[macleanflood]

Good read...

Thread 'A Beginners Guide to Lifting Your Jeep Wrangler TJ'

Jan 10, 2016

One of the questions I see so commonly asked in the Jeep Wrangler TJ community relates to people who are new to the Wrangler TJ and have questions about what kind of lift they need, what the best lift is, what tires they can run with each lift, etc.

I'm going to try and sum it all up in one thread so that any of the new owners have a resource to help guide them in their path to building their Wrangler the way they want it.

First and foremost, in order to determine what kind of lift you want, you need to ask yourself a few questions:



First start by answering these questions:...

• Chris
• Replies: 390
• Forum: TJ Resources

• 

-Mac

 

[pefrey]

Thank you. A lot of my driving involves highway hence my desire to maintain mpg. I'd also like to stay out of the rabbit hole (I know how futile that sounds) of pursuing a look.

I suppose my dilema is the following, does this seem accurate?

31's = tires + suspension = $2,000 - 2,500
33's = $2,000 - 2,500 + driveline adjustments ($$) + regearing ($$$$) + noticeably diminished mpg ($)

I will be doing all the work myself, except of course the mounting and balancing of tires.

 

[Artsifrtsi]

There is a big jump in the price of a 33 vs a 31 as well. Drivability; I will be regearing relatively soon (running 3.07 currently), I put in a 2 inch spring lift with a 1.25 inch body lift and 33x12.5x15 tires; I do ok on commuting, and can use 6th on most areas that you're usually in high gear for and shift about the same points that a stock auto will on hills, offroad I am in 4lo, and don't see a huge impact. I get 16 MPG of mixed driving.

If you are wanting 33's, you will need a lift, as flexing on a curb will get you into the flares. 31's will fit stock, but in really flexed out you may rub.

 

[06lj]

31's are a good size for a TJ. 33's require a lot of work and money if you want to do it right. I ran 31's on a stock TJ and took it all over the mountains of Colorado. I did have some slight rubbing but it wasn't to bad. You can keep things very simple by sticking with the smaller tire. To improve the looks, chose and aggressive looking tread pattern. Duratracs or BFG KO2's are nice looking tires that have good drivability. If you have some issues with rubbing you could always toss in some small spring spacers or install a body lift.

 

[Artsifrtsi]

Duratracs or BFG KO2's are nice looking tires that have good drivability.

The Falken Wildpeak AT3 I put on are very quiet, better than the BFG's I had on, and still a load C tire so very nice and supple. The new AT4 is what I'm putting on my JT, and they are a 60k mile warrantied tire... the AT3 is 50k mile...

 

[deserteagle56]

You WILL lose fuel mileage with heavier tires. That 4.0 is a great engine in the rough stuff but it struggles at highway speeds unless you gear the axles a lot lower. Without a gearing change taller tires will make the engine work harder and use more fuel.

 

[pefrey]

Doing it right is a priority. Everything is pointing me to the 31's, then the only mod I will have to do is the speedo gear. I am still going to redo the suspension as it is stock right now and probably worn out. I do know that the ball joints on my front track bar have popped out so at the minimum I will be doing the JKS disconnects. Now time to look at 0-2" lifts.

On a side note, since my 98 Jeep TJ Sport came stock from the factory with the 30" tires, does that mean my Jeep also came with some sort of a lift as compared to a stock Jeep with 215 or 225 series tires which are about 28" in diameter?

 

[pefrey]

Does a gearing change affect mileage very much? It sounds like not doing a gear change will have a more negative impact than the gear change.

 

[Artsifrtsi]

You WILL lose fuel mileage with heavier tires. That 4.0 is a great engine in the rough stuff but it struggles at highway speeds unless you gear the axles a lot lower. Without a gearing change taller tires will make the engine work harder and use more fuel.

On the TJ I went from 18 to 16 going from the stock 215's to a 33. On my JT going from the stock 255/75/18's to a 35/12.5/17 I went from 19 to 15. Neither is regeared, JT it's not needed, TJ it could use more gear. The drop in mileage is a combination of the heavier tire, and more resistance via aero and contact. YMMV...

 

[Sensei]

The Falken Wildpeak AT3 I put on are very quiet, better than the BFG's I had on, and still a load C tire so very nice and supple. The new AT4 is what I'm putting on my JT, and they are a 60k mile warrantied tire... the AT3 is 50k mile...

I love the wildpeak, running a set of 35x11.5x17 load C on my tj having gone up from 33s and the ride is night and day. The biggest variable between the two however was the load range for the tire. The 33s were a set of Toyo Open Country AT IIs, which are still a high quality tire, but they were load E. After having driven a load E tire for 5-8 years, I would not recommend anything BESIDES a load C tire if you care about on road comfort for your tj. Price is very fair to for such a large and aggressive tire imo. Think I paid around 300$ each.

 

[LostintheForest]

The Falken Wildpeak AT3 I put on are very quiet, better than the BFG's I had on, and still a load C tire so very nice and supple. The new AT4 is what I'm putting on my JT, and they are a 60k mile warrantied tire... the AT3 is 50k mile...

I also run these on my stock wrangler @ 31x10.5/15 on American racing gamblers, they are stamped 8x15”. No rubs, good ride and quiet on the road.

 

[nitrofalcon]

I've got Falken Wildpeak AT3 on my 03 as well. Smooth ride and quiet.

 

[LostintheForest]

Here is how they look on the Jeep. I chose to have the aggressive lettering out, but the symmetrical tread lets you choose the more subtle lettering if you’d like.

 

[DuckNut]

Doing it right is a priority. Everything is pointing me to the 31's, then the only mod I will have to do is the speedo gear. I am still going to redo the suspension as it is stock right now and probably worn out. I do know that the ball joints on my front track bar have popped out so at the minimum I will be doing the JKS disconnects. Now time to look at 0-2" lifts.

On a side note, since my 98 Jeep TJ Sport came stock from the factory with the 30" tires, does that mean my Jeep also came with some sort of a lift as compared to a stock Jeep with 215 or 225 series tires which are about 28" in diameter?

Tires...31 and 33 are popular tire sizes. Not only for jeep but all trucks. Tire manufacturers have learned this and charge accordingly.

If you want to save some money, look at the standard size equivalent. 285/75/16 is the same as 33. Sometimes the standard sizing is also available in different plys and load ratings. If you mainly drive pavement, that is the route I would go.

 

[Artsifrtsi]

Tires...31 and 33 are popular tire sizes. Not only for jeep but all trucks. Tire manufacturers have learned this and charge accordingly.

If you want to save some money, look at the standard size equivalent. 285/75/16 is the same as 33. Sometimes the standard sizing is also available in different plys and load ratings. If you mainly drive pavement, that is the route I would go.

And to further that a bit, sometimes the metric equitant is available in a different load range.

 

[B1Toad]

On a side note, since my 98 Jeep TJ Sport came stock from the factory with the 30" tires, does that mean my Jeep also came with some sort of a lift as compared to a stock Jeep with 215 or 225 series tires which are about 28" in diameter?

My 2000 shows 30" tires as being a factory option and I have no lift. It had 31's when I bought it with no issues, I switched to the ravine wheels and 30" tires and I like it so much better, it handles better, gets better MPG and has more power. Looks Ok to me too, I never understood doing big tires and lifts on a vehicle just to look good. IMO if you don't need it don't do it.

 

[DuckNut]

And to further that a bit, sometimes the metric equitant is available in a different load range.

Yes, thank you. I started typing that and got derailed and didn't type it.

Edit...after going back and reading it, I did type it.