Topic: Time for tires...30 or 31's?

[OldSkull75]

How much of a Power loss will I take if I go from 30-31"s? My past jeeps have all been 4.0's and tire size wasnt an issue.Im going with BFG AT's...
thanks!

[chrisfranklin]

I'd say 31s and MTs.  On the off chance you go on trail runs with any 4x4 clubs, most of those clubs will want you on 31s minimum.  31s still drive ok with the 4banger, 5th gear is usable on flat highways, you'll just need to gear down on hills. I have 31MTs and its fine.

[OldSkull75]

I was leaning torwards 31's, But Ive heard alot of horror stories about the loss of power on hills and highways with the 4banger. Im keeping it mostly stock. I'd like to at least be able to keep up with the flow of traffic...LOL
thanks again

[Jeffy]

31 AT's will be around 30.5" or so.

Personally, I'd go with 31 MT's and live with the slight power drop.  Has for horror stories, they're a bunch of whiners.  31's and stock gears is downright peppy coming from stock gears and 33's or larger.   

[chrisfranklin]

I was leaning torwards 31's, But Ive heard alot of horror stories about the loss of power on hills and highways with the 4banger. Im keeping it mostly stock. I'd like to at least be able to keep up with the flow of traffic...LOL
thanks again

If its stock, then yeah the 31s might slow you down a little bit more than with a slightly modified engine.  I remember trying to wind my Jeep out in stock form and it would run out of air at higher rpms even with the stock 27-28" AT tires

For a while, though, I've have a borla exhaust, intake, PD ignition and 62mm TB and these items probably don't hurt to have with 31MTs.   But, even so, I'd still say I'm lucky if my Jeep is making an extra 10hp/10lbft with those parts.  Still looking for somebody to make a chip for the YJ 2.5 5spd.
 

[Jesse-James]

most of those clubs will want you on 31s minimum.

This a false statement. Every club I've been affiliated with or been around welcomes vehicles of any level, including stock.

That said, go for the 31's.

[chrisfranklin]

This a false statement. Every club I've been affiliated with or been around welcomes vehicles of any level, including stock.

That said, go for the 31's.

Any clubs in areas worth driving its 31s.  Keep in mind I said "most" not all.

False statement? Dude, why don't you go put another CJ grill on your YJ? Talk about false

[radark1]

I don't think you will even feel a difference. My recommendation is to just go to 33's and gear down when needed. Any mid to rough terrain....you will need 33's anyway. The answer really lies in what you plan on doing with the Jeep. You won't get a speeding ticket with 33's.

[ddrongowski]

I am running 31's and have no problems. Just make sure to get the right speedo gear, unless you don't care about your speed.

[radark1]

Good point! I didn't have that problem when I went to 4.88 gears with my 33" tires...the gears balanced out the tires with the speed....so my speedo works perfect....as verified with my GPS.

[Jesse-James]

Any clubs in areas worth driving its 31s.  Keep in mind I said "most" not all

I'm glad we have all your experience to rely on here, Chris. Now BTT

31's are about the limit you want to go without regearing.

[OldSkull75]

Its a Daily Driver,Im keeping this one mostly stock.I'll do some light off roading,Camp jeep with my kid, and fun in the snow. .I wasnt sure what power loss to expect going up to 31"s. Im more concerned about bieng able to cruise along at 70 mph and stay with the flow of traffic on hills. This is my 5th wrangler. My first was a 4cyl but never went bigger than 30"s. My last 3 were 6cyls so I didnt have to worry about tire size much. Is there a noticable loss of power between 30s and 31s?
thanks again for the replies!

[Jeffy]

I am running 31's and have no problems. Just make sure to get the right speedo gear, unless you don't care about your speed.

That's not the only consideration.  If the engine is MPFI then you'll need the signal to be correct for the PCM.

[stan98tj]

Its a Daily Driver,Im keeping this one mostly stock.I'll do some light off roading,Camp jeep with my kid, and fun in the snow. .I wasnt sure what power loss to expect going up to 31"s. Im more concerned about bieng able to cruise along at 70 mph and stay with the flow of traffic on hills. This is my 5th wrangler. My first was a 4cyl but never went bigger than 30"s. My last 3 were 6cyls so I didnt have to worry about tire size much. Is there a noticable loss of power between 30s and 31s?
thanks again for the replies!

31 MTs are your best all around tire if ya dont want to go bigger. they will fit just fine under the stock conditions, depending on how aggressive the tread is, they may rub when the wheel is put hard over right/left. this can be corrected via spacers (pretty cheap) or a different wheel. You won't feel a power loss that will make you wish you hadnt switched. THey are excellent for light to medium trail levels. I run a Pepboy brand tire-(31 MTs) Dakota Destiny. apparently they arent too expensive (cant give ya an estimate cause they were sold with my jeep) but ive heard they arent too expensive. They have a great tread pattern, look great, do pretty well in the mud, great in the snow, cant complain about the ride on pavement, be it wet, dry or snowy. I ran a snowy/muddy trail with my buddy the other day. he has a 6cyl wrangler with 31s BFGs all terrain tread. he bogged down twice in the mud and snow due to the lack of grip...i went through without a hitch....and i got to yank him out twice :)

[oldjeep]

31's are about the limit you want to go without regearing.

Meh - 35's and stock gearing works, you just never use high gear

That's not the only consideration.  If the engine is MPFI then you'll need the signal to be correct for the PCM.

The PCM doesn't care.  I'm still running the original speedo gear with my 35's