Tyre question - slippery slope has begun

TW · 2004-05-18T11:05:05+00:00

Hi All,I have a very stock 2001 TJ 4.0L with automatic transmission and 3.07 diffgearing with Dana 44 rear. The bug has finally bitten me and I am at astage where I need to change the tyres. Currently I am running 225/70R16BF Goodrich All-Terrain T/A KOs on factory aluminium Icon 16x7inch rims.After doing the last run on the track, it seems that I need groundclearance, and fast. I have spent about a week researching what availablein the local market and what everybody else in the club is running and thechoice has come down to tyres.1) Goodyear Wrangler MT/Rs - they are only available in two 16 sizes 235/85(32 inch equivalent) and 255/70 (30 inch equivalent). I have read a lot ofgood reviews about them in magazines, but nobody is running them in NZ.They are expensive and hard to find. One of the dealers said, if you blowa tyre it would be a week or two for a replacement to arrive. I do likethe look of it and the reviews in mags have been wonderful.2) BF Goodrich Mud-Terrain T/A KM - they are available in various sizes andeverybody is running them here. They are also relatively cheaper to buyand more commonly available. I am interested in three sizes 235/85 (32inch), 265/75 (32 inch) and 255/85 (33 inch). I don't think I can go widerthan 265s on 7 inch rims. Also I don't really want to change the rims atthis stage.The questions I have:1) Any personal opinions on how the two tyres would perform in mud, wettracks and wet rocks (it rains a lot in NZ).2) Two guys in our club are running 32/10.5 R15 BF Goodrich Mud-Terrain onstock TJ suspensions and without sway bars and have no rubbing at all atany stage. I was thinking, can I perhaps then go with narrower 33s(255/85R16) for now and upgrade the suspension in 3/4 months (which I can'tdo rightnow due to the need for spreading the budget a bit). I am new tothis sport, so don't do it every weekend. I can be careful during theperiod while my suspension is stock.3) How much of a power loss would it be due to 3.07...

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Bob 22 years ago

Crazy New Zealanders! ;-)

Yeah, my knowledge of what is or isn't sold is strictly limited to the U.S. market. If I'd known you were in a foreign market I would've just kept my mouth shut about that.

Hey I learned something new!

At least you are able to get that 44 without the "upgrade". Kinda nice, really. It's almost silly getting the 3.73 ratio with it here in the U.S. for anyone who wants the 44 just because it's better but just plans to build it with 33s or 35s. They're gonna have to regear whether it's a 3.07 or 3.73 axle ratio. If they offered the 44 with the crappier 3.07 ratio but for a few hundred cheaper, I'd jump all over it (IF were I in the market for a brand new TJ).

Good luck with your tire upgrade man. You're gonna love it when you DO regear...it's like a whole new jeep (I just recently went from 3.55:1 diff gears with 33s to 4.56:1 diff gears.)

/Bob

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Steve 22 years ago

... and dumb easy to install.

Steve

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CRWLR 22 years ago

The coil spacers I have heard about around here are 2", I think.

I think the stock gearing will work better with the 32s than the 33s. The coil spacers should work better with the smaller tires as well. If you bought the smaller tires today, then used the next two years or so to upgrade the suspension and gearing, then you will be ready for 33s. I think the best option today is for 32s.

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TW 22 years ago

Well, my brain says 32s, but heart says 33s. I think I'll use my brain and stick with 32s. Thanks for your advice. I am off to the shop tomorrow to see how soon can they be installed.

TW

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TW 22 years ago

Its another Jeep thing!!! We don't get the 2.5L model at all. Another Jeep thing. I am now leaning more towards 32s. Off to the shop tomorrow.

Thanks TW

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TW 22 years ago

It will get easier the second time around... :-)

TW

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TW 22 years ago

Went to the shop and after comparing tyre sizes by putting them next to each other and in the wheel wells. My brain kicked in and took everybody's advice, I ordered 265/75R16s. These work out to be marginally taller than

32x10.50R15 inch floatation size tyres. I went for the BFG Mud-Terrains AT KMs as we mostly have crushed volcanic rock used on highways as gravel, which would have severely limited Goodyear Wrangler MT/Rs lifespan on the highways. I am getting them fitted next Saturday as the shop was out of stock and I can't go to the shop during the week. I have a club run on next Sunday, so should be perfect timing for testing them.

Now I need to find the speedo gear, I'll try the local market tomorrow.

Thanks all for all your advice and valuable input. TW

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Mike Romain 22 years ago

I would recommend you check your speedo with a GPS before you change gears.

When I went up to 235's on my Cherokee, my speedo ended up right on. Same for my CJ7. Somehow when I went to 33's my speedo went dead on.

Mike

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

TW wrote:

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TW 22 years ago

Mike, thanks for the suggestion. I'll check it before committing to new speedo gear. I was also thinking about taking the current gear out to see how many teeth it has. Knowing my luck, I will have to change it because going from 225/70R16 to 265/75R16 is a significant change in circumference of the tyre......

The other question now is, will the tyre fit the spare tyre carrier and the third light, oh well I'll have to wait and see.

Thanks TW

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Mike Romain 22 years ago

I saw a 3rd light done in the center of the oversized spare. Just a round button light. Looked good.

Mike

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TW 22 years ago

Hi All,

I had the tyre changed yesterday, with white lettering mounted on the inside. Measurements are:

BEFORE change (225/70R16 - BFG ATs) Bumper lower edge (Front) - Left 470mm / Right 465mm Bumper lower edge (Rear) - Left 405mm / Right 415mm Fender flare lower edge (Front) - Left 805mm / Right 800mm Fender flare lower edge (Rear) - Left 825mm / Right 815mm Differential lowest point (Front) - 210mm Differential lowest point (Rear) - 200mm

AFTER change (265/75R16 - BFG Muds) Bumper lower edge (Front) - Left 515mm / Right 510mm Bumper lower edge (Rear) - Left 450mm / Right 460mm Fender flare lower edge (Front) - Left 850mm / Right 845mm Fender flare lower edge (Rear) - Left 870mm / Right 860mm Differential lowest point (Front) - 255mm Differential lowest point (Rear) - 245mm

Looks like I have gained 45mm in ground clearance all around. It also seems like my right front is consistently sitting lower, probably because of our steering being on the right side as well? I know the right rear bumper is slightly off balance because it is slightly bent upwards.

I drove around city yesterday and today did a 250kms round trip on the highway in high wind (60+ kphs) and heavy rain. The tyres are not noisy at all (yet) and the feel is not too bad. I do have to actively drive it now more than before, but its a small price to pay for Muds. There is very slight thump when doing

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Tyre question - slippery slope has begun

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