BFG 30" or 31" on tj?

Question

I'm finally getting some BFG A/T KO tires for my 98 tj this weekend. I have 3.73 stock gears and, I'm stuck on deciding which size to get. I prefer the look and clearance of the the 31's of course but, I'm thinking the bigger tire will make the engine work a little harder, making the already dismal MPG worse. Is this correct? I currently have the GSA 30 inch tires and fifth gear is just tolerable.

Also, I don't need huge ground clearance, but I do want good snow traction. With the weight of the jeep in consideration would the wider 31 x 10.5" size be better or worse than the 30 x 9.5"?

Thanks Jeff

Jerry Bransford · Accepted Answer

Skinny tires give better traction on snow-covered streets than fatter tiresdo, no doubt. :)Jerry--Jerry BransfordTo email, remove 'me' from my email addressKC6TAY, PP-ASELSee the Geezer Jeep at

twaldron · Answer

31s!!  :)stephjeff wrote:

Mike Romain · Answer

I went from the BFG 31x10.5 that measured close to 10.5" on the tread to BFG 33x9.5's that measure 7.5" on the tread and the improvement in winter handling was extreme.

With the 10.5's 40 - 45 mph was about tops on the highway in 4x4 and

4-6" of snow down. It would get on top and lose grab on the road any faster.

With the 9.5's I can easily follow along with transport trucks at 50- 60

+/- mph in 4x4 and have no control issues at all.

Off road on sand pit wall winter climbs, the guys with 10.5's and front and rear lockers can almost keep up to me with my open diffs.... ;-)

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

stephjeff wrote:

L.W.(ßill) · Answer

Thirty twos on stock springs works prefect: Well, that's

Pete Weber · Answer

I just upgraded my 2000 TJ's Goodyear GSAs with BFG 31" All-Terrains. I'll be up in Tahoe this weekend, so I'll find out how the tires do on the Jeep in snow. You will get a noticeably lower MPG when driving around the city as you'll bog your engine a tad and that sucks up gas. On the Freeway, you probably won't notice the change in MPG. A skinnier tires will do better in the snow. There is only an inch difference. I should have stayed with the

30s when I got new tires, but I like the 31s.

Pete

Tirya · Answer

I went from the GSA 30s to BFG AT 31s and absolutely love them. No appreciable change in engine effort or mileage - I average between 17 and 19 MPG mixed city/highway. I have a 4.0 engine, though, so if you've got a

4-cyl, it might make a difference.

Clearance isn't a problem - if you're disconnected and at full articulation, you may get a slight rub. You may have to adjust your bump stops with a washer or two, though.

Tirya '99 TJ Sahara

stephjeff · Answer

I hear ya! I'd love the 31's too. And once I go 31's, there's no looking back. The smaller ones will never be as cool- lol! It's the ratchet effect. I think for my practical purposes the 30's will be alright. This is for my 98 Wrangler which I bought new and I'm just now gettin' around to putting on the BFG's I've wanted since I got it!! This jeep is mostly driven in city and it's only got 27K miles on it!!!

The guy at NTB was pretty much against the 31's for me. He said it would not fit, and I'd need a lift! I told him about the steering stop adjustment with 31's and he said that they don't do that, and I was better off with 30's for MPG as well as for the snow.

Thanks for the help. This is always the best place to come for jeep help.

Jerry B. is king of the jeep info! You rock bro'.

BFG 30" or 31" on tj?

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